Free Communications, Oral Presentations: Ankle Instability

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-7.

Biomechanical Analysis Of Stiffness And Laxity Of The Ankle: Diagnosing Lateral Ligament Injuries

JE Kovaleski ¹, JM Hollis ¹, RJ Heitman ¹, LR Gurchiek ¹, AW Pearsall ¹

Abstract

To examine the effects of lateral ankle ligament injury the nonlinear load-displacement characteristics of the joint must be considered. The purpose of this study was to evaluate the use of end-range stiffness and laxity following simulated ankle injury to the anterior talofibular (ATFL) and calcaneofibular (CFL) ligaments. Using 6 fresh-frozen cadaver ankle specimens (mean age = 64 years), direct comparisons between sectioned and intact ankles were made by computing laxity and stiffness for the sectioned conditions to the values for the intact joint. Laxity was defined as anterior displacement at the 75 and 125 N force-loads. Stiffness was defined as force per displacement (N/mm) and was calculated by dividing 50 N by the anterior displacement between the 75 N and 125 N force levels. Using an instrumented ankle arthrometer that quantifies load-displacement [J Athl Train, 37(4), 2002] the ankles were loaded in anterior drawer at the neutral flexion angle. One-Way Repeated Measures ANOVA's were used to evaluate stiffness and laxity between the sectioned and intact ankles. No (F_2,10 = .037, P = .964) significant main effect for stiffness was observed: [intact: (19.13 ±?5.3 N/mm); ATFL: (18.30 ± 10.2 N/mm); ATFL + CFL (19.26 ± 5.2 N/mm]. Main effects for laxity were significant at the 75 = 11.19, P N (F_2,10 = .003) and 125 N (F_2,10 = 10.01, P = .004) force-loads. Post-hoc comparisons showed significant differences (P < .05) between the intact and sectioned ankles [75 N: intact (4.86 ± .2.3 mm), ATFL (7.15 ± 2.8 mm), ATFL + CFL (8.58 ± 2.5); 125 N: intact (7.67 ± .2.8 mm), ATFL (10.47 ± 3.4 mm), ATFL + CFL (11.33 ± 2.2)]. Our results are based on completely sectioned ligament preparations of cadaver ankles in which dynamic muscle control could not contribute to stability. These findings indicate that end-range stiffness as measured does not appear to be useful for the diagnosis of lateral ankle sprains following ankle ligament disruption. The absence of change in stiffness between the intact and ligament deficit ankles shows that other structures (joint capsule, bone geometry, intact soft tissues) surrounding the ankle-subtalar joint complex function to maintain stiffness in the absence of the ATFL and CFL. We conclude that during anterior drawer testing for the ligament deficient ankle, load-displacement (laxity) produces a more sensitive determination of pathological ligament injury and provides a more precise means for measuring it.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-7.

Assessment Of Fibular Position In Those With Self-Reported Chronic Ankle Instability

TJ Hubbard ¹, J Hertel ¹, LC Olmsted ¹

Abstract

Recent evidence has suggested that either anterior or posterior displacement of the fibula on the tibia may contribute to chronic ankle instability. With anterior displacement of the fibula the anterior talofibular ligament is placed in a loosened position, possibly resulting in increased joint laxity. With posterior displacement, the ankle mortise is opened, potentially predisposing the ankle to injury. Different methods of assessment of fibular position do not allow us to make comparisons between studies. The purpose of this study was to observe the position of the distal fibula in relation to the distal tibia in subjects with self-reported, chronic ankle instability (CAI). Ten subjects with unilateral CAI (age=19.7 ± .82 yr., mass=73.4 ± 35.4 kg, ht=166.1 ± 5.6 cm) and 10 healthy controls (age=20.4 ± 1.3 yr., mass=71.9 ± 13.6 kg, ht=164.1 ± 8.7 cm) consented to participate in this study. All subjects had to satisfy an established set of criteria used to determine their instability status prior to participating. Subjects were positioned side lying with the ankle in dorsiflexion. A fluoroscope recorded images of both the right and left ankles. The distance from the anterior margin of the tibia to the anterior margin of the fibula was recorded in millimeters. A 2 × 2 mixed model ANOVA was run with the between factor being group (CAI, control) and the within factor with repeated measures being side (involved, uninvolved). There was not a significant group by side interaction (F = 1.547, p = .230). There was a significant main effect for side (F = 18.514, p < .001). The injured ankle (18.03 ± 5.9mm) of the CAI group had a fibula that was positioned more posterior then the uninvolved ankle (12.8 ± 5.1mm). However, there was also a significant difference within the ankles of the control group (16.91 ± 4.2mm vs. 14.02 ± 3.0mm). There was no significant difference between the CAI and control group (F = .001, p = .977). This is one of the first studies to use radiographs to observe the position of the distal fibula in relation to the tibia. Our mean fibular position is similar to previously reported data using MRI to measure fibular position. There seems to be a trend towards posterior displacement of the fibula on the tibia in a group with unilateral CAI. We currently do not know if repetitive bouts of ankle instability caused the posterior displacement or if the displacement was a predisposing factor to injury. Further research is needed to elucidate the contribution of fibular position to chronic ankle instability.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-7–S-8.

Arthrogenic Muscle Inhibition Is Present In Patients Exhibiting Functional Ankle Instability

ED McVey ¹, RM Palmieri ¹, CL Docherty ¹, SM Zinder ¹, CD Ingersoll ¹

Abstract

Functional ankle instability (FAI) or a subjective report of “giving way” at the ankle may be prevalent in as many as 40% of patients following an acute sprain of the lateral ligament complex. Damage to mechanoreceptors within the lateral ankle ligaments following injury has been hypothesized to interrupt neurological feedback mechanisms resulting in FAI. Altered afferent output from joint mechanoreceptors following injury or effusion is known to result in weakness of surrounding joint musculature, a phenomenon referred to as arthrogenic muscle inhibition (AMI). AMI may be the underlying cause of FAI promoting a cyclic inhibition of the ankle joint musculature that cannot be overcome with traditional rehabilitation protocols. Establishing the involvement of AMI in FAI is critical to understanding the underlying mechanisms promoting chronic ankle instability. Therefore, the purpose of this investigation was to determine if AMI is present in the ankle joint musculature of patients exhibiting unilateral FAI. Twenty-nine subjects, 15 with unilateral FAI and 14 healthy control subjects, consented to participate. Bilateral soleus, peroneal, and tibialis anterior H-reflex and M-wave recruitment curves were obtained for all subjects. Maximum H-reflex (Hmax) and maximum M-wave (Mmax) values were extracted from the recruitment curve and used to calculate the H:M ratios that were used for data analysis. Separate 1 × 2 ANOVAs were ran for the FAI and control groups to evaluate differences between limb on the H:M ratios. Bonferroni multiple comparison procedures were used to make all post hoc comparisons (P < 0.05). The soleus and peroneal H:M ratios for subjects in the FAI group were smaller in the injured limb when compared with the uninjured limb (P < 0.05). No limb difference was detected for the tibialis anterior H:M ratio for subjects in the FAI group (P = 0.904) No side-to-side differences were detected for the H:M ratios in patients without a previous history of ankle injury (P > 0.05). Depressed H-reflex amplitudes in the injured limb suggest that AMI is present in the dynamic ankle stabilizers of patients exhibiting FAI. Establishing and utilizing therapeutic techniques to reverse AMI may have the potential to reduce the incidence of FAI.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-8.

Functional Performance Deficits Are Present In Participants With Ankle Instability

CL Docherty ¹, BL Arnold ¹, BM Gansneder ¹, SR Hurwitz ¹, JH Gieck ¹

Abstract

Functional performance tests are a dynamic measure used to assess the extent of injury and return to play criteria. To date, conflicting results have been reported on the sensitivity of these tests to detect pathological defects. The purpose of this study was to investigate the relationship between performance on functional tasks and ankle instability. Sixty participants (43 females, 17 males, 22.4±4.9 yrs, 169.9±9.7 cm, 72.6±16.3 kg) were recruited to participate in the study. Five items were used to determine the presence of ankle instability in each participant. They included a “feeling” of instability on a flat surface, uneven surface, during sport activity, climbing stairs, and descending stairs. A point was added for each “yes” response to provide a continuous variable of ankle instability. Four unilateral hopping tests were used in this study: figure 8 hop, up-down hop, side hop, and single hop. For the first three tests the total time was recorded with a handheld stopwatch to the nearest 0.01-second; for the single hop for distance test the distance was recorded to the nearest 0.01 meter. Correlations were computed with ankle instability and each of the four functional performance tests. No relationship was revealed between ankle instability and single hop for distance or up-down hop, with values of r equal to −.008 and .245 respectively. A significant relationship was found between ankle instability and the side hop (r = .380; df = 59; P ≤ .01) and figure 8 hop (r = .323; df = 59; P ≤ .01) measures. The primary finding was that participants with ankle instability performed worse on the side hop and figure 8 hop than the uninjured participants. Both of theses tests force the participant to move laterally placing stress on the structures on the outside of the leg, and the figure 8 test concurrently provides a rotational stress to the lower leg. Conversely, the single hop and up-down hop are done in the frontal plane with little accessory movement. This likely explains the non-significant findings for these tests. These findings suggest that a functional test that places appropriate stress on the ankle would reveal performance deficits in participants with ankle instability.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-8.

Comparing Stabilization Times In Individuals Presenting Functional Ankle Instability And Mechanical Instability

SE Ross ¹, KM Guskiewicz ¹

Abstract

While the presence of functional ankle instability (FAI) without mechanical instability has been frequently reported, researchers also have reported mechanical instability in individuals with FAI. In addition, evidence of research studies have indicated that individuals with FAI take longer to stabilize than individuals with stable ankles after single leg landing. However, it is not clear whether individuals presenting FAI with mechanical instability have different stabilization times than individuals presenting FAI alone. Theoretically, mechanical instability could contribute to longer stabilization times. Therefore, this study compared stabilization times between groups presenting stable ankles (N=8), FAI (N=8), and FAI with mechanical instability (N=8). Mechanical instability was assessed with the anterior drawer and talar tilt tests. Subjects completed seven jump-landings, which required them to jump at 50% of their maximum jump height, and land atop a force plate on a single leg. After landing, subjects stabilized and remained motionless. Anterior/posterior (A/P) and medial/lateral (M/L) stabilization times were calculated from the ground reaction force. Lower values of stabilization times indicated greater stability. Two separate one-way ANOVAs were used for analyses. A significant between group main effect was found for A/P stabilization time (F_(2,21)=6.10, p=0.008). Tukey post hoc analyses revealed longer A/P stabilization time in the FAI group with mechanical instability (2.40 ± 0.97 sec.) compared to A/P stabilization times of the FAI (1.53 ± 0.37 sec.) and the stable ankle (1.38 ± 0.33 sec.) groups. However, there was no significant between group main effect for M/L stabilization time (F_(2,21)=1.68, p=0.21). We speculate that the shear force created between the foot and leg allowed excessive sagittal plane movement of the subtalar joint in subjects presenting mechanical instability. Medial/lateral stabilization time differences between groups may not be evident because subjects jumped anteriorly, and probably produced greater sagittal plane shear forces than frontal plane shear forces. We contend that the frontal plane shear forces produced from the landing were not large enough to create excessive subtalar joint movement. Future work should explore the relationship between the direction of the jump-landing and stabilization times in subjects presenting mechanical instability.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-8–S-9.

Time-To-Boundary Measures Of Postural Control And Chronic Ankle Instability

LC Olmsted ¹, J Hertel ¹

Abstract

Postural control deficits have been shown to be associated with ankle instability, however traditional force plate-derived measures of postural control such as mean center of pressure (COP) velocity may not be sensitive enough to detect these deficits. An alternative approach to measuring postural control is calculation of time-to-boundary (TTB) of COP excursions. Our purpose was to examine postural control in single leg stance using traditional and TTB measures. Fifteen physically active females (19.7±1.3 yrs, 166.6±6.6 cm, 70.0±15.5 kg) with unilateral chronic ankle instability (CAI) and 9 healthy female controls (22.7±2.6 yrs, 163.7±6.7 cm, 61.58±7.9 kg) participated. Each subject performed three 10-second trials of eyes open quiet standing on a force plate on both their right and left legs. A 2×2 group by side ANOVA was performed on each dependent variable. The “traditional” postural control measures were calculated separately for the frontal and sagittal planes. These included: mean COP velocity, standard deviation of COP, range of COP, and percent of available range utilized. The TTB measures were calculated separately for the frontal, sagittal, and resultant planes. These included: absolute minimum TTB, mean of the minimum TTB samples, and standard deviation of the minimum TTB samples. There were no group by side interactions for any of the measures. For the traditional measures, there was a significant group main effect for mean COP velocity in the sagittal plane. The CAI group (2.09±.17 cm/s) had significantly higher velocity than the control group (1.5±.22 cm/s). For the TTB measures, there were significant group main effects for all 9 variables. The CAI group had significantly lower scores for all TTB measures compared to the control group. Only one of the 8 traditional postural control measures revealed significant differences between the CAI and control groups, while all 9 of the TTB measures showed significant differences. For the absolute minimum and mean of the minimum samples, the CAI group had lower TTB values indicating greater postural instability. For the standard deviation of TTB measures, the CAI group demonstrated less variability than the control group. Our findings indicate that CAI subjects demonstrated bilateral postural control deficits as assessed by TTB measures in relation to the control group. This indicates a change in centrally mediated postural control strategies associated with CAI. Our findings are consistent with postural control deficits in bilateral stance identified in the elderly and in Parkinson's patients. The TTB measures appear to be more sensitive to detecting postural control deficits related to CAI compared to more traditional measures.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-9.

Is There A Temporal Relationship Between Lateral Ankle Sprain And Deficits In Postural Control?

TA Evans ¹, J Hertel ¹, RA Braham ¹, WJ Sebastianelli ¹

Abstract

As a component of functional ankle instability, postural control deficits have been reported following lateral ankle sprain. The length of these deficits, however, remains uncertain. Our purpose was to compare measures of postural control in subjects with no history of lateral ankle sprains to those with a previous sprain within and outside of the past 12 months. We assessed the postural control of 460 collegiate athletes (234 men, 226 women) from 23 sports. Three 15-second trials of unilateral stance with eyes open and three with eyes closed were performed on the left and right legs while subjects stood on a force plate. Center of pressure excursion velocity (COPV) was the dependent measure. Each left and right ankle was assigned to one of the following sprain history classifications: no history of sprain (healthy), history sprain within the past 12 months (inside 12), history of sprain outside the past 12 months (outside 12). Eyes open and eyes closed COPV measures, for the left and right ankles, were analyzed with independent t-tests for the following comparisons: left healthy (n = 287) vs left inside 12 (n = 58), left healthy vs. left outside 12 (n = 85); right healthy (n = 237 ) vs. right inside 12 (n = 74), right healthy vs. right outside 12 (n = 107). Effect size (ES) was calculated for all significant findings. Those with ankle sprain within past 12 months had impaired COPV compared to those without ankle history for: 1) eyes open left (p=.016), 2) eyes closed left (p=.05), and 3) eyes open right (p=.04), but not for eyes closed right (p=.36). Small effect sizes of 0.27, 0.33, and 0.27 were found for the three significant findings respectively. Those with ankle sprain greater than 12 months ago did not have postural score scores significantly different than those without a history of sprain in any of the 4 comparisons (p > .05). Although we found significant differences between three of the four comparisons of healthy ankles and those with a history of sprain within the past 12 months, the small effect sizes raise doubt as to the clinical meaningfulness of these differences. COPV may not be best way to assess for PC differences in those with more subtle PC impairments.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-9.

A Comparison Of Ankle Muscle Reaction Times Following Sudden Ankle Inversion During Walking And Standing

TA McLoda ¹, JT Hopkins ¹, SM McCaw ¹

Abstract

Dynamic ankle muscle response characteristics following sudden ankle inversion have traditionally been tested in a static, standing position. However, this model does not take into consideration activity and loading characteristics associated with normal gait. The purpose of this study was to compare muscle reaction times of sudden ankle inversion during standing and walking. Surface EMG was collected from the peroneus longus (PL), peroneus brevis (PB), and tibialis anterior (TA) of the dominant leg from 25 subjects (14 male, 11 female, age 20±1 yr, ht 174.0±10.2 cm, mass 74.3±12.9 kg) for each condition (walking and standing). For the walking condition, subjects walked the length of a 6.1 m runway 30 times. A trap door mechanism was released at heel contact of six randomly selected trials for each leg. Subjects walked to the beat of a metronome (90 bpm), and wore goggles that blocked the lower field of vision. For the standing condition, subjects stood on a platform. The trap mechanism was released six times for each leg in a random order. A magnetic switch marked the release of the trap door mechanism during both conditions. Custom software, verified by visual inspection identified the onset of muscle activity. Normalized peak and RMS EMG was calculated for the 100 msec following onset of muscle activation. Onset of muscle activity was defined as the point when muscle activity exceeded two standard deviations of the activity prior to release. Hotelling's T² was used to identify significant differences between groups for each dependent variable. The time to complete the permitted inversion range of motion (28°) was greater in the walking group (114.9±15.0 ms) than in the standing group (65.6±17.8 ms, P<0.05), whereas reaction time was less in all muscles in the walking group (PL 56.9±8.4 ms, PB 60.1±10.6 ms, TA 65.0±14.9 ms, P<0.05) compared to the standing group (PL 74.3±8.5 ms, PB 73.5±8.2 ms, TA 73.3±8.3 ms, P<0.05). A slower muscle loading time coupled with a faster muscle reaction time during the perturbed walking model provides evidence that a dynamic response to ankle injury mechanisms is faster than previously demonstrated using a standing model. A walking model may be a more functional approach for evaluating dynamic response characteristics of ankle musculature following sudden ankle inversion.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-10.

The Effects Of Ankle Taping And Spatting On The Reaction Times Of The Supporting Musculature Of The Ankle After Sudden Inversion

JI McKenzie ¹, BL Van Lunen ¹, M Walker ¹, C Joyce ¹, JA Onate ¹

Abstract

Ankle taping is a common practice in the athletic training room, but there is minimal evidence to support its effectiveness in enhancing muscle activation. The purpose of this study was to examine the effects of ankle taping on muscle activation following sudden inversion in functionally unstable and healthy ankles before and after exercise. Eight (5 males and 3 females) (age = 22 ± 3.0 yrs, ht = 173.08 ± 9.55 cm, mass = 69.60 ± 13.84 kg) recreational athletes with a unilateral functionally unstable ankle volunteered to participate. A functionally unstable ankle was defined as an individual having sustained an inversion ankle sprain that required the person to miss at least one day of normal physical activity and in the past six months the same ankle also needed to have had a feeling of “giving way”. Surface EMG electrodes were placed on the peroneals and anterior tibialis muscles of both extremities. Each subject received four treatment conditions; ankle taping, ankle taping with spatting, spatting, and no tape in a randomly assigned, counterbalanced order. A custom-made platform was constructed that allowed the foot to be randomly dropped into 32 degrees of inversion. Subjects reported for testing on four different occasions and performed three random drops for each ankle after receiving the indicated taping. Following initial testing, participants performed an exercise protocol consisting of treadmill jogging and box jumps while landing in various foot positions, then completed the post-exercise testing session. The independent variables were taping condition, muscle tested, ankle stability, and time of test. Two separate repeated measures ANOVA's (p<.05) were used to analyze onset of muscle activity (onset time) and time to peak muscle activity (peak time). A main effect was found for muscle; the anterior tibialis reached peak muscular contraction significantly faster than the peroneals. A significant interaction was found between tape and time; the anterior tibialis onset time after exercise was significantly faster than pre exercise. A significant interaction was found between tape, muscle, and time. Ankle taping with spatting significantly decreased onset time of the peroneal musculature as compared to spatting alone. Our results support the findings of previous investigators that have reported that ankle taping with spatting will reduce the time to onset of the peroneals after sudden inversion. Future research should evaluate an inversion platform which includes a plantarflexion component and testing participants that are spatted on a regular basis. Supported by a grant from the NATA Research & Education Foundation Osternig Master's Grant Program.

Special Interest Group #1: Ankle

Wednesday, June 16, 2004, 10:15am–11:15am, Room 336; Discussants: Mitchell L. Cordova, PhD, ATC, and Rod A. Harter, PhD, ATC/R

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-11.

Development Of Standards And Criteria For The Selection, Training, And Evaluation Of Athletic Training Approved Clinical Instructors

TG Weidner ¹, JM Henning ¹

Abstract

An increasing need has been identified within the profession of athletic training to provide training and development for clinical instructors. The purpose of this study was to develop research-based and peer-reviewed standards and criteria to be used as a foundation in the selection, training, and evaluation of Approved Clinical Instructors (ACIs). In conjunction with the purpose of this study, we addressed the following research questions: Is each proposed standard clear, necessary and appropriate for the selection, training, and evaluation of ACIs?, and; Are the proposed criteria for the ACI standards useful, clear, specific, and consistent with the standards? Standards are defined as a degree or level of requirement, excellence or attainment. Criteria are defined as items on which a judgment or decision can be based for the attainment of a standard. A previously developed set of 7 physical therapy clinical instructor standards/criteria, and 2 additional standards/criteria developed through a literature review, were systematically adapted, judged and revised using the Delphi technique. Sixteen athletic training education experts currently employed as program directors for an entry-level CAAHEP-accredited athletic training education program who had a doctoral degree; had a minimum of 5 years of experience as a clinical instructor, and; who had familiarity/experience with clinical instruction in various athletic training clinical education settings. Panelists' critiques and ratings were used to make sequential revisions in a series of three Delphi rounds. Standards were rated using a 5-point Likert scale as to whether they were clear, necessary, and appropriate. Criteria for each standard were rated using a 5-point Likert scale as to whether they were useful, helpful, clear, specific, and consistent. Consensus to retain an item was defined as a minimum mean score of 4.0 with a standard deviation of ≤ 1.0. A final set of 7 standards and 50 associated criteria to measure these standards were developed. The accepted standards include legal and ethical behavior, communication skills, interpersonal relationships, instructional skills, supervisory and administrative skills, evaluation of performance, and clinical skills and knowledge. These 7 standards and associated criteria should be used as guidelines rather than as minimal requirements. They could be helpful in not only selecting, training, and evaluating an ACI but also in developing an understanding of the requirements of clinical education in general. Further research should include validating these standards/criteria among athletic training ACIs representing various clinical settings. Supported by a grant from the NATA Research & Education Foundation.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-11.

A Nationwide Study Of Undergraduate Athletic Training Students' And Educators' Individual Moral Philosophies And Ethical Decision-Making

SV Caswell ¹, TG Gould ¹, RG Deivert ¹

Abstract

Educational program reforms have increased the curricular breadth and have improved the quality of students' educational experiences by moving toward a competency-based model of education. Ethics comprise only a small portion of the athletic training curriculum with 23 of the 542 educational competencies focusing on ethics. Therefore, the problem of this study was to investigate how an individual's ethical ideology may affect their ethical decision-making abilities as a practitioner. We chose the Ethics Position Questionnaire (EPQ) and Dilemmas in Athletic Training Questionnaire (DAT-Q) to assess respondents' ethical ideologies and ethical decision-making. The EPQ assesses two dimensions of subjects' ethical ideology: idealism and relativism. Idealism refers to the extent that individuals consider how the consequences of their actions affect the health of others. Relativism refers to the extent that individuals reject universal moral principles. The DAT-Q assessed subjects' ethical decision-making. Respondents (N = 598) included 373 females (62.4%) and 225 males (37.6%), ranging in age 18 to 63 years (M = 23.5, SD = 6.3). Principle components factor analysis with varimax rotation revealed both the EPQ and DAT-Q to possess reasonable construct validity. Internal consistency via Cronbach's alpha coefficients for the EPQ's idealism and relativism subscales and the DAT-Q scale were .79, .72 and .82 respectively. Respondents reported higher idealism (M = 37.56, SD = 4.91) than relativism scores (M = 31.70, SD = 4.80). The mean DAT-Q score for all respondents was (M = 80.76, SD = 7.88). The research design incorporated three separate 2(gender) × 3(education level) factorial ANOVAs utilizing idealism, relativism and DAT-Q scores as dependent measures. The main effect for gender illustrated that males reported significantly higher relativism scores (F_{1, 592} = 9.18, P<.05, η² = .015) than females. The main effect for education level revealed significant differences between students' and instructors' idealism (F_{2, 592} = 3.99, P<.05, η² = .013), relativism (F_{2, 592}= 15.53, P<.001, η² = .050), and DAT-Q scores (F₂, 592 = 8.06, P<.001, η² = .027). Post-hoc analysis using Tukey's HSD indicated instructors possessed lower idealism scores (P < .05), relativism scores (P < .05), and higher DAT-Q scores (P < .05) than students. These results do not support changes in athletic training educational practices to address gender specific needs. This was the first study of its kind in athletic training. Findings should serve as a baseline for future research examining students' and instructors' ethical ideologies and ethical decision-making levels.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-11–S-12.

Behavioral Analysis In The Athletic Training Clinical Learning Environment

SA Denhup Jr ¹, MA Sandrey ¹, A Hawkins ¹, VG Stilger ¹

Abstract

Taking inventory of clinical interactions and coding behaviors within the clinical learning environment has been identified, but correlating observed with perceived clinical behaviors by the athletic training student and clinical instructor has not. The purpose of this study is to correlate the frequency and duration of observed behaviors with perceived behaviors in the athletic training clinical learning environment and analyze clinical instruction behavior frequency and duration trends over a period of six observation sessions. Two female ATCs (26 years ± 0.41) with ACI credentials, and three male and four female athletic training students (20.29 years ± 0.95) from an NCAA Division-III CAAHEP approved athletic training education program participated in this study. This study utilized two designs; a correlation design of observed versus perceived behavior of approved clinical instructors (ACI) and athletic training student (ATS) behaviors and a single subject descriptive quantitative design using ACI clinical behaviors over time. The independent variable was time and the dependent variable was the frequency and duration of eight selected behaviors (Behavioral Feedback, Skill Feedback Corrective, Skill Feedback Evaluative, Skill Feedback Descriptive, Screening / evaluative technique: Questioning, Screening / evaluative technique: Clarify, Screening / evaluative technique: Documentation and Screening/evaluative technique: Manipulation). This study employed the use of the Clinical Instruction Analysis Tool-Athletic Training II (CIAT-AT II) placed into Behavioral Evaluation Strategy and Taxonomy (BEST) software (Educational Consulting, Inc). In addition to the CIAT-AT II, a clinical instruction questionnaire was administered to document perceived frequency and duration of eight selected behaviors. Subjects were evaluated six time periods during a competitive season. A Pearson bivariate correlation and linear trend analysis using R² values and a predicted trend line were used. Skill Feedback: Evaluative (r = .814, P = .049) and Skill Feedback: Descriptive (r = .723, P = .105) were considered strong in this study for ACIs even though they lacked clinical significance. Screening and Evaluative Technique: manipulation (r = .669, = .017) and Screening and Evaluative Technique: Documentation (r = .886, P = .000) were considered strong in this study for ATS. None of the R² values were higher than .39 for frequency statistics with skill feedback: descriptive having the highest R² for both ACIs. The result of this study suggests that the individuals within the clinical learning environment are unaware of the behaviors they exhibit. Additionally, due to a low R² value, a lower degree of relationship between the independent variable of time and the dependent variables of the behaviors exist.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-12.

Athletic Training Students' Perceptions Of Their Clinical Field Experience: A Qualitative Examination

DC Berry ¹, MG Miller ¹, LM Berry ¹

Abstract

Athletic training clinical field experiences are designed to allow students access to “hands-on” learning experiences with a variety of athletes/patients. In order for these experiences to be worthwhile, athletic training education programs need to offer quality clinical experiences where students are provided with adequate time to engage in active learning with quality clinical instructors. Therefore, the purpose of this study was to gather qualitative data regarding students' perceptions of their clinical field experiences while enrolled in CAAHEP accredited athletic training education programs. Completed as part of a larger study examining students' utilization of clinical field experience time, program directors at 131 CAAHEP accredited ATEP were sent “Utilizing Time and Active Learning Survey” packages. One hundred and eight three subjects (M=67, F=116), out of 193 (95%) subjects representing 25 institutions and eight of the ten NATA districts completed the 4 open-ended questions. The subjects' mean age was 22 (± 3.15) with subjects completing their clinical field experiences in the following settings; college/university (n=149), high school (n=32), and clinical/industrial/corporate (n=2). The data were analyzed using the phenomenological approach in an attempt to understand the meaning, events, and interactions of students while engaged in their clinical field experiences. The four questions were separated, read, and re-read until a sense of possible coding categories were identified. Evolving from the coding categories were specific themes that provided a portrait of the students' perceptions of their clinical field experiences. When asked if and why the time spent during their clinical field experience was a worthwhile educational experience, the emerging themes included: the creation of positive (hands-on) learning experiences, positive professionalism, and clinical setting diversification. When asked how could time be utilized to improve or provide a better learning environment, numerous themes emerged such as the need for feedback from clinical instructors/supervisors (interaction and communication), altering clinical affiliations, changing training room schedules, and staffing issues were factors influencing the learning environment. Students found experiential (hands-on) learning, clinical setting diversification, autonomy, and clinical instructor's/supervisor's interaction to be the most beneficial components of their clinical field experiences. The results from this study suggest that improving the quality of clinical field experiences is going to require athletic training educators to critically analyze their clinical settings and clinical instructors/supervisors to determine if quality clinical education of athletic training student is occurring. Additionally, athletic training educators need to listen to the needs of their students in order to improve the quality and level of clinical field experience engagements.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-12.

Exploring The Subjective Warrants Of Potential Athletic Training Recruits

J Mensch ¹, M Rodger ¹, M Mitchell ¹

Abstract

Becoming a Certified Athletic Trainer (ATC) is a career choice. What attracts individuals to athletic training and not other health related professions matters—especially when acknowledging the need to attract competent candidates to the 243 CAAHEP-accredited programs (nearly double the number of programs that existed just one year ago). One key concept in this recruitment process involves a subjective warrant or perceptions of the skills and abilities necessary for ATC preparation and practice. Correcting flawed subjective warrants is a key function of professional preparation programs, once candidates have chosen to become ATCs. Prior to entry into professional preparation programs, however, these same flawed subjective warrants may attract some and repel others. Clearly, a richer understanding of this construct has implications for understanding and influencing who pursues an ATC career. The purpose of this initial descriptive study was to explore the subjective warrants of college students with varying levels of interest in athletic training (N=26; 13 attracted = A; 13 not attracted = NA). A qualitative research design was used, involving semi-structured interviews that had been piloted and revised for clarity. This approach allowed trained ATC interviewers to probe beyond the formally written questions for clarity in participant responses when necessary. Data analysis was completed in two parts by three ATCs (all with graduate degrees) coding data independently: (1) content analysis and comparison of interview data across participants (A and NA); and (2) contrast of interview data to the 1999 Role Delineation Study. Trustworthiness was established by data analyst triangulation (Patton, 1990) where 100% agreement was negotiated among the three independent coders. Results indicated three shared perspectives on role responsibilities between groups: First, the notion of being responsible for care and prevention of injuries (11 A; 11: NA); second, the idea of being a first responder (8 A; 9 NA); and third, the belief that ATCs are “ankle tapers” (10 A; 6 NA). The belief that ATCs need to be good communicators was mentioned by 12 of 13 attracted students and only 2 of the 13 not attracted students. In a comparison to the Role Delineation Study, 5 of the 6 domains, 16 of 37 (43.2%) tasks, and only 28 of the 331 (8.5%) specific knowledge and skills were accounted for in participant responses. It is unlikely that prospective recruits with less than a 10 % understanding of the ATC job can make informed decisions about whether or not this is a good career match for them. A more comprehensive strategy for announcing the requirements of this career is needed if desirable candidates are to be attracted and undesirable candidates are to be discouraged from pursuing an ATC career.

Special Interest Group #2: Clinical Education

Wednesday, June 16, 2004, 2:00pm–3:00pm, Room 336; Discussants: Catherine Stemmans, PhD, ATC, and Linda Platt Meyer, EdD, ATC

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-13.

Estrogen And Progesterone Concentrations Across The Menstrual Cycle Are Not Significantly Related To Motoneuron Activity Or ACL Laxity

MA Hoffman ¹, RA Harter ¹, BT Hayes ¹, EM Wojtys ¹, P Murtaugh ¹

Abstract

Despite extensive efforts to identify the mechanism or combination of mechanisms responsible for the high incidence of female non-contact ACL injuries, the exact etiology remains unknown. The purpose of this study was to determine if changes in estrogen concentrations over the course of the menstrual cycle were related to alpha motoneuron activity and ACL laxity. Twenty-eight female subjects (mean age= 22.4 ± 3.4 yrs) who reported regular menstrual cycles between 28 and 30 days in length with no more than 3 days of variation over the past 3 cycles participated in the study. Female volunteers were excluded if they reported the use of hormone-based birth control within the past year. Fifteen male subjects (mean age = 22.3 ± 3.7 yrs) served as the control group. Saliva samples, Hoffmann reflex measurements, and ACL laxity values were obtained each testing day. Female subjects were tested every other day, starting on the second day of their cycle; male subjects were tested every fourth day over 28 days. Hormone levels (ESTROGEN and PROGESTERONE) were measured using a 2 ml saliva sample collected via passive drool, then centrifuged and frozen at −70° C for later analysis. The ratio of the Maximum H reflex to Maximum M wave (Hmax/Mmax ratio) in the soleus muscle served as the H-reflex outcome measure. We applied 133.5 N force using a KT-2000 arthrometer with Compu-KT software to quantify anterior tibial displacement (LAXITY). Correlations of the outcome variables were calculated for each subject by pairing measurements made on the same day. One-sample t-tests were used separately for male and female data of each variable to evaluate whether the mean correlation differed from zero (a = 0.05). In addition, two-sample t-tests were used to test the difference of the male and female correlations for each variable. The following mean correlations and p values were obtained: LAXITY vs. ESTROGEN [males: r= −0.11, p=0.13, females: r=0.04, p=0.62, test of the difference of the correlations p=0.13]; LAXITY vs. PROGESTERONE [males: r= −0.17, p=0.26, females: r=0.10, p=0.14, test of the difference of the correlations p=0.11]; Hmax/Mmax RATIO vs. ESTROGEN [males: r= −0.03, p=0.89, females: r=-0.01, p=0.86, test of the difference of the correlations p=0.93]; Hmax/Mmax RATIO vs. PROGESTERONE [males: r= −0.23, p=0.02*, females: r=-0.09, p=0.14, test of the difference of the correlations p=0.17]; Hmax/Mmax RATIO vs. LAXITY [males: r= −0.31, p=0.01*, females r=-0.04, p=0.46, test of the difference of the correlations p<=0.01*]. These results indicate no association between female hormone levels and motoneuron activity or knee laxity during the menstrual cycle. It is interesting to note significant correlations between motoneuron activity and both progesterone and laxity in the male subjects. In addition, not only was the correlation between Hmax/Mmax ratio and laxity significant it was significantly different from the female group's correlation. Supported by a grant from the NATA Research & Education Foundation.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-12–S-13.

Minimum Serum Hormone Levels At Menses Predict The Magnitude Of Change In Knee Joint Laxity Across The Menstrual Cycle

DH Perrin ¹, SE Kirk ¹, TC Sander ¹, SJ Shultz ¹

Abstract

Previous work has shown that changes in sex hormone concentrations across the female menstrual cycle influence knee joint laxity. However, consistent with the variability in menstrual cycle characteristics between females, the magnitude of change in knee joint laxity across the cycle is also quite variable. The data for this study from a larger project on gender, hormones, and knee laxity, determined whether absolute levels or the relative change in hormone concentrations across the menstrual cycle predict the magnitude of change in knee joint laxity. Twenty-two normal menstruating females (23.0±3.5 yrs, 163.4±5.6cm, 65.0±11.6 kg, 24.3±3.5 BMI) were tested daily across one complete menstrual cycle for serum levels of estradiol (E = pg/mL), progesterone (P = ng/mL), and testosterone (T = ng/mL), and knee joint laxity (mm displacement at 134N) measured with a standard knee arthrometer. Five days representing menses, the initial estrogen rise near ovulation, and the early and late luteal phases (total of 20 days) were analyzed. Separate stepwise linear regression analyses for 1) minimum, 2) maximum and 3) relative change (maximum − minimum) in hormone levels from menses to peak levels were performed to determine if they predict the magnitude of change in knee laxity. Knee laxity changed on average 2.9+1.1mm across the menstrual cycle (range 1.36–4.77mm). Minimum levels of estradiol (39.9±11.8pg/mL; range 23.3–57.5) and progesterone (.61±.27ng/mL; range .30–1.10) during the first five days of menses accounted for 48.9% of the variance in the magnitude of change in knee laxity across the cycle (adjusted R² Progesterone =.358, P=.002; adjusted R² Change Estradiol =.149, P=.023). Lower minimum estradiol concentrations (r =-.423) coupled with higher minimum progesterone levels (r=.623) were related to greater increases in knee laxity across the cycle. Neither maximum hormone levels (E = 203.3±49.2pg/mL; P =12.3±4.3 ng/mL; T = 65.0±17.6ng/mL) (adjusted R² Estradiol =12.4%; P=.06) nor the relative change in hormone concentrations (E = 164.9±50.5pg/mL; P =11.8±4.4 ng/mL; T = 46.9±16.7ng/mL)(adjusted R² Estradiol =4.4%; P=.176) were significant predictors of the change in knee laxity. These findings suggest that the absolute minimum concentration, rather than the magnitude of increase in serum hormone levels across the menstrual cycle, may in part dictate the sensitivity of the knee joint's response to changing hormone levels. Supported by NIH Grants RO3 AR47178, MO1 RR00847 and U54 HD28934

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-14.

The Influence of Gender on Knee Kinematics, Kinetics and Muscle Activation Patterns During Side-step Cutting

CM Powers ¹, SM Sigward ¹, S Ota ¹, K Pelley ¹

Abstract

In response to the high incidence of ACL injury in female athletes, previous studies have attempted to define “at risk” movement patterns by evaluating gender differences in performance. While differences in knee kinematics and muscle activation patterns during cutting activities have been found, more comprehensive evaluations that include knee joint moments are important for the identification of potentially injurious patterns in female athletes and to better define the mechanism of ACL injury. The purpose of this study was to evaluate gender differences in knee joint kinematics, kinetics and muscle activation during a side-step cutting maneuver to determine if females perform this maneuver in a manner that is suggestive of increased risk of ACL injury. Thirty healthy college level soccer players (15 male, 15 female) with no history of ACL injury participated. Each performed a side-step cutting maneuver at 6–7.0 m/s by planting their right foot and changing direction to the left at a 35–60 degree angle. Anthropometric data, 3-D knee kinematics (VICON Motion System, 120 Hz), and ground reaction forces (AMTI force plate, 2400 Hz) were used to calculate moments at the knee (inverse dynamics). Muscle activity of the quadriceps, medial and lateral hamstrings was recorded with surface electrodes (2400 Hz). Four trials were collected for each subject. EMG data were normalized to the EMG obtained during a maximal voluntary isometric contraction. Average angles, normalized EMG, and peak moments were identified during 2 phases of deceleration (early and late). To determine if these variables differed between groups or phases, 2 × 2 ANOVA's were performed. No significant gender differences were found for knee angles or transverse plane moments. However, when compared to males, females demonstrated a greater knee adductor moment (0.43 ± 0.5 vs. 0.006 ± 0.3 Nm/kg, p< 0.01) and a smaller knee flexor moment during early deceleration (1.4 ± 0.8 vs. 2.1 ± 0.8 Nm/kg, p=0.05). In addition, females had greater average quadriceps EMG than males during late deceleration (183 % MVIC vs. 141 % MVIC, p=0.05). These results indicate that females perform side-step cutting differently than males. In general, females experienced greater frontal plane moments and less sagittal plane moments during early deceleration. These differences are suggestive of an “at risk” pattern in that frontal plane support is afforded primarily by passive structures (including the ACL) and increased quadriceps activity and smaller flexor moments may suggest less sagittal plane protection (i.e. increased tendency towards anterior tibial translation). Supported by a grant from the NATA Research & Education Foundation.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-14–S-15.

Gender Differences In Drop Jumps From Unknown Heights: An EMG And Kinematic Analysis

KA Swanik ¹, CB Swanik ¹, KC Huxel ¹, KL Hamstra ¹, RT Tierney ¹, HJ Hillstrom ¹

Abstract

Many studies have identified biomechanical gender differences that may predispose females to non-contact injuries. However, the research models currently used include relatively low joint loads, slow movement speeds or conventional athletic maneuvers. These conditions do not adequately simulate non-contact injuries and the events surrounding sudden, unanticipated functional joint loading. The purpose of this study was to compare female and male dynamic restraint mechanisms during drop jumps from unknown heights. The independent variables were gender, knowledge of the drop jump height (full vision, vision impaired but knowledge of drop height, and vision impaired without knowledge of drop height) and 2 drop heights (50 cm control height, 35 cm early landing height). Forty healthy subjects (20 male, 20 female) participated in the study (age: male = 22.25 ± 2.40 yrs; female = 21.65 ± 2.06 yrs, height: male = 179.90 ± 8.83 cm; female = 166.50 ± 5.56 cm, mass: male = 80.27 ± 11.40 kg; female = 61.32 ± 9.11 kg). A total of thirty-six randomized drop jumps were performed by each subject (6 drop jumps/condition and height). Surface EMG (Noraxon USA Inc.) measured quadriceps and hamstring muscle activity to determine preparatory and reactive strategies. Kinematic variables at the hip, knee, and ankle were measured using the PEAK Motion Analysis System. Descriptive and comparative statistics were used to analyze the data. Multiple ANOVA tests 2 (gender) × 3 (knowledge) × 2 (height) with repeated measures revealed several significant (p<.05) kinematic differences. At the hip and knee, females used less ROM, had smaller max flexion angles, and achieved max flexion angles in less time (p<.05) when compared to males. Females also landed with the hips significantly (p<.05) more extended. No significant kinematic differences were observed at the ankle and no significant gender differences were observed in preparatory or reactive EMG values. These results affirm differences in the overall movement strategies of males, suggesting that females generally employ a stiffer landing strategy without evidence of increased thigh muscle activity. Moreover, females do not anticipate or react differently when confronted with a sequence of events simulating non-contact injuries. Expanded biomechanical testing using premature, functional joint loads may help identify aberrations in hip muscles activation strategies or frontal plane kinematics that compromises dynamic restraint and knee joint stability. Supported by a grant from the NATA Research & Education Foundation.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-15.

Neuromechanical Factors For Injury During Tasks Implicated In Noncontact ACL Injuries

TC Sell ¹, CM Ferris ¹, JP Abt ¹, Y Tsai ¹, JB Myers ¹, FH Fu ¹, SM Lephart ¹

Abstract

Observational analyses of noncontact ACL injuries have implicated jumping and landing tasks that have a change in direction with a deceleration component as a possible mechanism of injury. Biomechanical research has focused primarily on cutting tasks and straight landing tasks during controlled and planned laboratory tests. The purpose of this study was to examine jumping and landing tasks that incorporate both directional change and deceleration components like the mechanisms implicated in noncontact ACL injuries. This examination also included tasks with a reactive component that was designed to better simulate game conditions. Thirty-five healthy, high school basketball players (18 males [age: 16.4±1.5 yrs], 17 females [age 15.9±1.1 yrs]) underwent a neuromechanical analysis of the right knee during two-legged stop-jump tasks in three different directions (left, vertical, and right) under two different conditions (planned and reactive). A computer generated visual cue was provided for jump direction following the initiation of the reactive jumps. Ground reaction forces, joint kinematics, joint kinetics, and EMG activity of the quadriceps and hamstrings were assessed during the task. All data were analyzed with three-way ANOVA for jump direction, condition (planed vs. reactive), and sex. Significant differences were observed (p<0.05) among the jump directions such that jumping away from the right knee resulted in increased anterior tibia shear force, flexion moment, valgus moment, vertical ground reaction forces, deceleration forces, and a decreased flexion angle at initial contact. During the reactive jumps, subjects demonstrated significantly (p<0.05) greater anterior tibia shear force at takeoff, greater flexion moment, greater deceleration forces, and less knee flexion at initial contact. Females demonstrated significantly greater anterior tibia shear force, less knee flexion, less deceleration forces, greater hamstrings activity, and co-contraction of the quadriceps and hamstrings compared to males (p<0.05). Both jump direction and type of task (planned vs. reactive) significantly influenced the neuromechanical characteristics of the knee during the jumps indicating that future research should target reactive athletic tasks that include a change in direction. There was also a difference between sexes in dynamic knee stabilization strategies as evidenced by the greater anterior tibia shear force. This may possibly indicate that females are at a greater risk for noncontact ACL injuries during jumping and landing tasks that include a deceleration component and a change in direction.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-15.

Fatigue and Sex Differences During Lower Extremity Kinematics of a Single-Leg Stop-Jump Task

A Habu ¹, TC Sell ¹, JB Myers ¹, JP Abt ¹, SM Lephart ¹

Abstract

Many factors have been investigated for their role in noncontact anterior cruciate ligament (ACL) injuries. Very little attention has been focused on how fatigue may affect lower extremity kinematics, and consequently noncontact ACL injuries. The purpose of this study was to examine the kinematic characteristics of hip and knee joint during a single-leg stop-jump task before and after exercise-to-fatigue, and to examine if fatigue affected each sex equally. Thirty healthy, physically active subjects (15 males, 15 females, Male = 22.67±1.63 years, 180.27±7.69 cm, 79.93±10.51 kg; Female = 22.13±1.73 years, 169.07±6.55 cm, 60.72±7.39 kg) participated in this study. Knee and hip joint kinematics were calculated utilizing three-dimensional video analysis interfaced with one force plate. Each subject performed five single-leg stop-jumps before and after exercise-to-fatigue. The stop-jump consisted of a single-leg standing broad jump onto a force plate followed immediately by a maximal vertical jump. All subjects underwent a fatigue protocol using the modified Astrand protocol in conjunction with a standard Rating of Perceiving Exertion (RPE). Each subject performed a three minute warm-up on a treadmill (2 mph, 0 % grade). As soon as the warm-up was completed, the speed was increased to 5–8 mph for three minutes (0 % grade) according to the subjects' normal running pace. After 3-minutes at 0 % grade running, the grade was increased 2.5% every 2-minutes throughout the session until the termination of the fatigue protocol. Fatigue was assessed using RPE along with the subject's heart rate every minute until the termination of the fatigue protocol. All data were analyzed using two factor (test × sex) repeated measures ANOVAs (p<0.05). Both males and females revealed significantly decreased maximal knee valgus (p=0.038) and decreased knee flexion at the initial contact (p=0.009). The maximal vertical jump height decreased significantly in males, but increased in females (p=0.025). No significant differences were identified in hip joint angles between sessions or between sexes. The results suggest that both males and females might not be able to utilize the same strategies for dynamic knee stability while fatigued that they do when not fatigued. The decrease in knee flexion at initial contact may be the result of the inability to efficiently stabilize the knee secondary to muscular fatigue. Our results did not reveal any sex differences in this specific task which may indicate that fatigue affects both sexes equally. Supported by a grant from the NATA Resarch & Education Foundation Osternig Master's Grant Program.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-15–S-16.

Neuromuscular Landing Performance Subsequent To Ipsilateral Semitendinosus And Gracilis Autograft Anterior Cruciate Ligament Reconstruction

GL Vairo ¹, JB Myers ¹, TC Sell ¹, FH Fu ¹, CD Harner ¹, SM Lephart ¹

Abstract

The hamstrings are a vital component of the dynamic restraint mechanism present at the knee joint. However, previous research suggests that potential deficits to this mechanism may result from harvest of the ipsilateral semitendinosus and gracilis autograft (ISTGA) for anterior cruciate ligament reconstruction (ACLR). The purpose of this study was to investigate the effects of ISTGA ACLR on neuromuscular and biomechanical performance during a vertical drop landing (VDL). It was hypothesized donor site morbidity subsequent to ISTGA ACLR would result in neuromuscular and biomechanical deficits during a functional task such as landing. Fourteen physically active subjects (age = 22.5 ± 4.1 yrs, height = 1.67 ± .08m, mass = 68.4 ± 14kg) who underwent ISTGA ACLR (21.4 ± 10.7 months prior) were matched by sex, age, height and mass to fourteen control subjects (age = 22.8 ± 3.5 yrs, height = 1.67 ± .08m, mass = 65.4 ± 13.3kg). Testing consisted of three-dimensional motion analysis and surface electromyography assessments of subjects performing single-leg 30cm VDLs. Additionally, isokinetic knee joint flexion strength (60°/s) and endurance (240°/s) measurements were completed. Multiple dependent t-tests were calculated to determine within group (involved/uninvolved) and independent t-tests were performed to analyze between group (experimental/control) differences of dependent variables p<.05. The experimental group demonstrated no significant differences in hip or summated extensor moments bilaterally or when compared to the control group. However, ISTGA ACLR subjects demonstrated significantly decreased peak vertical ground reaction forces landing on the involved lower extremity in comparison to both the uninvolved (p=0.024) and matched control (p =0.0001) lower extremities. The experimental group also elicited significantly greater reactive ISEMG activation of the vastus medialis (p=0.013), vastus lateralis (p=0.008) and medial hamstrings (p=0.024) musculature compared to the control group. Furthermore ISTGA ACLR subjects produced significantly less preparatory (p =0.005) and reactive (p=0.010) ISEMG activation of the medial gastrocnemius musculature in the involved compared to uninvolved lower extremity. No statistically significant differences were present for knee joint flexion strength and endurance within the experimental group or between groups. The results of the current research study suggest that harvest of the ISTGA for purposes of ACLR does not appear to result in significant neuromuscular, kinetic, or strength and endurance deficiencies due to donor site morbidity. However, it is clearly evident that experimental subjects exhibit specific neuromuscular and kinetic adaptations suggested to stabilize the knee previously subjected to ACL trauma and safeguard the reconstructed joint. Supported by a grant from the NATA Research & Education Foundation Osternig Master's Grant Program.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-16.

Sex Differences In Neuromuscular Responses To Knee Extension Perturbations As Evidenced By Reflex Timing, Amplitude, And Knee Extension Moments

AS Kulas ¹, TC Windley ¹, RJ Schmitz ¹, DH Perrin ¹, SJ Shultz ¹

Abstract

The anterior cruciate ligament (ACL) contributes to joint stabilization through feedback mechanisms when excessive loads or joint motions are perceived. Although sex differences in neuromuscular and biomechanical function have frequently been observed, differences in sensory feedback mechanisms triggering these behaviors are uncertain. This study assessed sex differences in reflex behavior using a custom device (patent pending) that initiates knee extension reflexes under anterior-tibial loading conditions. Ten males (24.5±3.4yrs,176.4±5.5cm, 86.2±14.0kg) and 10 females (22.8±4.7yrs, 158.9±5.0cm, 62.3±19.6kg) were positioned side-lying in a modified ligament-testing device with a reflex hammer attached via a steel mounted frame. Knee extensor reflexes were produced while anterior-directed loads (20N, 50N, 100N; counterbalanced) were applied to the posterior tibia between pre and post baseline conditions. Data acquisition was triggered via a load cell imbedded on the reflex hammer. Surface EMG recorded mean quadriceps (Q) and hamstring (H) reflex time (R_Time=ms) and amplitude (R_Amp=%MVIC) from 5 trials at each condition. A load cell on the anterior tibia positioned .23m distal to the joint line was used to acquire knee extension force (N) and calculate peak extension moments (KE_Mom=Nm/kg). Separate RM ANOVAs for R_Time, R_Amp, and KE_Mom compared females and males across 5 load conditions. R_Time was faster in females (18ms) than males (24ms) across all load conditions (P=.001). A sex by muscle interaction for R_Amp(P =.014) indicated that females had significantly greater R_Amp in Q (280vs100%MVIC) and H (83vs. 34% MVIC) compared to males, but the difference between Q and H was greater within females (delta QH=196 ± 117%MVIC) than within males (delta QH=71±72%MVIC). These reflex behaviors resulted in sex differences in KE_Mom by load (P=.033). While females had greater KE_Mom across all loads compared to males, females were affected by joint load (P=.001) whereas males (P=.746) were not. This load effect within females revealed greater moments at the 50N load (.18±.06Nm/kg) compared to the post-test baseline (.14±.05Nm/kg). These results suggest that in response to an external stimulus, reflex sensitivity was substantially greater in females compared to males, with females showing greater activation of the quadriceps relative to the hamstrings. These sex differences were subsequently supported by larger knee extension moments in females, which attenuated across loading conditions. These results suggest the need for further research evaluating sex differences in accommodation strategies in response external stimuli under joint loading conditions. Supported by a faculty grant from the University of North Carolina at Greensboro.

Special Interest Group #3: ACL

Thursday, June 17, 2004, 4:00pm–5:00pm, Room 336; Discussants: Darin Padua, PhD, ATC, and Sandra Shultz, PhD, ATC

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-17.

Computerized Neuropsychological Assessment Of Collegiate Athletes: Establishing Normative Data

CN Brown ¹, KM Guskiewicz ¹, J Bleiberg ¹

Abstract

Computerized neuropsychological testing provides an accurate and time-efficient method for testing athletes with sport-related concussion. The Automated Neuropsychological Assessment Metrics (ANAM) provides a battery of tests that includes simple reaction time (SRT), math processing (MTH), Sternberg Memory Search (ST6), matching to sample pairs (MSP), procedural reaction time (PRT), code digit substitution (CDS), and a sleep score (SLP). Little normative data exists for such tests, particularly for a college-aged population. The purpose of this study was to establish baseline normative data for non-symptomatic collegiate athletes. Subjects included 327 Division I freshmen athletes from the following sports: women's soccer, lacrosse, field hockey, and basketball, men's football, soccer, lacrosse, wrestling, and men's and women's cheerleading and men's and women's track. Athletes were baseline tested prior to their competitive seasons and self-reported their concussion history, SAT scores, and the presence of any diagnosed learning or attention deficit disorders. Through-put scores (number of correct responses per minute) were used as the dependent variable for each test with higher scores reflecting increased accuracy and speed of responses. Three independent samples t-tests were performed to identify differences in scores by gender, learning disorder, and if the sport was in or out of season. Four one-way ANOVAs were performed on the data, evaluating each test by sport, SAT scores, number of previous concussions, and years played. T-tests revealed out of season sports scored significantly higher than in season sports on all tests (P<.05) except ST6 and PRO. There were also significant differences between genders for SRT1 and SRT2, ST6, and MSP (P<.05). Athletes with learning disorders scored significantly lower only on the MTH subtest (P<.05). The ANOVAs revealed the highest SAT group scored higher on all tests except SRT1 and PRO (P<.05). No differences were found between groups based on number of previous concussions or years participated (P>.05). Differences were found between individual sports on all tests except SLP (P<.05). Neuropsychological testing appears to be affected by systemic fatigue from intense pre-season training. Baseline testing should be conducted during this pre-season period to obtain a score reflective of the fatigued “in-season” state. If baselines are not available, clinicians may need to consider the athlete's gender, sport, and potential learning or attention deficit disorder prior to making comparisons.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-17.

Recovery Patterns Of Symptomatology, Postural Stability And Neuropsychological Testing During The First Three Days After Concussion

AJ Notebaert ¹, KM Guskiewicz ¹

Abstract

Postural stability and neuropsychological testing are valuable clinical tools for evaluating athletes with concussion. Recently, however, researchers have questioned the efficacy of such testing while the athlete is still symptomatic. Traditionally, testing has been conducted beginning at 24 hours post-injury, regardless of the athlete's symptomatology. Commonly debated questions are: Why is testing necessary if the athlete is still symptomatic, and how do symptoms impact the neuropsychological and postural stability scores? Therefore, the purpose of this study was to compare the recovery patterns for symptomatology, neuropsychological testing, and postural stability testing over the first three days post-injury. Subjects included 36 high school and collegiate athletes sustaining a concussion during the 2001 or 2002 athletic seasons. We analyzed pre-season baseline scores, and days 1, 2, and 3 post-injury scores on a graded symptom checklist (GSC), Standardized Assessment of Concussion (SAC), Automated Neuropsychological Assessment Metrics (ANAM), and Balance Error Scoring System (BESS). Repeated measures analyses of variance performed on GSC scores revealed higher mean scores at days 1 (19.3±16.2) and 2 (10.9±11.9) post-injury compared to baseline (5.7±7.2) (F_3,73=13.8, P<.001). Recovery curves for simple reaction time test followed those of the GSC, revealing significant differences at day 1 (221.7±52.7), 2 (225.6±52.0), and 3 (217.5±68.0) post-injury compared to baseline (255.8±34.1) (F_3,58=6.82, P=.001). None of the other neuropsychological or postural stability measures followed a similar recovery pattern. Additionally, Pearson bivariate correlation analyses revealed no correlations higher than r=.38 on respective days between any of the measures, including GSC scores. These results suggest that simple reaction time is initially affected by concussion and recovers slowly across the initial 3 days post-injury. The ANAM matching to sample subtest, SAC, and BESS each demonstrated an initial decline at day 1 post-injury, however, was not statistically significant (P>.05). The other ANAM subtests (Sternberg memory search, math processing, and continuous performance) did not reveal significant deficits relative to baseline at day 1, 2, or 3 post-injury. Our results suggest that post-injury neuropsychological and postural stability testing might best be conducted after the athlete is asymptomatic. Additionally, including simple reaction time as part of the assessment battery may be important for identifying shared motor/cognitive deficits. Finally, our findings underscore the importance of considering all possible factors related to concussion, as increased symptomatology is not necessarily associated with neuropsychological or postural stability deficits.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-17–S-18.

An Investigation Of Collegiate Athletes' Knowledge Of Concussions

SC Livingston ¹, CD Ingersoll ¹

Abstract

Recognizing and properly assessing concussions among athletes is critical for appropriate management and safe return-to-play decision making. Mild traumatic brain injuries (MTBI) are often difficult for the athletic trainer to recognize; the symptoms are often numerous and variable in both type and severity. Due to a general lack of knowledge or a misunderstanding about concussions, an athlete may fail to report their symptoms. The purpose of our study was to assess collegiate athletes' general knowledge about concussions and to determine if there are differences in this knowledge when comparisons are made by gender, sport, the number of years participating, and prior concussion history. A descriptive study using a written questionnaire based on subjects' self-report was conducted at the University of Virginia. The survey instrument was developed to address mechanisms of concussive injury, definition of a concussion, immediate and long term effects, and return-to-play (RTP) decisions. Face validity was established for this instrument using a subset of intercollegiate athletes. Subject demographics (age, gender, sport played, year in college, and years playing sport) along with a self-reported history of concussion(s) were also gathered. One-hundred and seventy-two collegiate athletes (112 male, 60 female, ages 18 to 23), were surveyed. There were 71 self-reported concussions among the participants (41.3%). The highest incidence of self-reported concussion was reported among football players (25). The majority of respondents (48.2%) correctly recognized a concussion as a “mild traumatic brain injury resulting from an injury to the head,” but almost 23% associated this definition with a loss of consciousness (LOC). Over 86% of the respondents recognized typical mechanisms of injury (MOI), although almost 60% reported the MOI producing a concussion always results in LOC. 55.4% reported LOC as a short-term symptom. Almost 67% recognized the potential long term effects of concussion, but over 12% responded “don't know” to this question. In response to RTP decision making, 17.5% felt that the RTP decision was the athlete's own choice. The results of our study identify a general lack of knowledge among collegiate athletes about concussions, specifically post-concussion symptomatology. Many athletes inaccurately believe that a concussion is associated with being “knocked out” (LOC) and a disturbing number felt that RTP decisions are athlete-driven (i.e. determined by when the athlete feels ready to return). Athletic trainers must be proactive in the education of our athletes about concussions. Such efforts will not only assist ATC's in identifying the athlete who has sustained a concussion, but will also improve accuracy of reporting sports-related concussions.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-18.

Balance Performance With A Cognitive Task: A Dual-Task Paradigm

SP Broglio ¹, PD Tomporowski ¹, MS Ferrara ¹

Abstract

Competitive athletes interpret sensory information to perform simultaneously complex motor movements and cognitive decisions. Current concussion evaluation batteries separate the cognitive evaluation from the motor/balance evaluation. While each aspect of the battery assesses different cerebral functions, some researchers propose combining the two tasks will provide a more sensitive method of concussion assessment. Our laboratory previously reported a dual-tasking paradigm of serial 7's and balance beam walking as a potential addition to a concussion assessment protocol. The purpose of this project was to evaluate the dual-task methodology in healthy subjects using computer based measures of cognition and postural control. Twenty male (n=10) and female (n=10) college students (age:22.30 ± 2.06, height:175.26 ±10.13cm, mass:72.20 ± 17.29kg) volunteered to participate in this study. Each participant was evaluated in two sessions separated by 24 to 72 hours. Subjects were oriented to the testing methodology during session one and data were collected during session two. Cognition was evaluated with a Switch-Task (ST) computer program in which the subject identified either the number or letter from a number-letter pair within a four quadrant box. Reaction time was recorded for each response. A modified Neurocom Sensory Organization Test assessed postural control during conditions that permitted the use of vision. During the second session, single task tests were counterbalanced and were followed with the dual-task. During the dual-task procedure, each participant was asked to maintain balance while performing the ST as rapidly and accurately as possible. Data were evaluated using multiple, repeated measures t-tests for significant differences between single-task and dual-task conditions. Statistical analyses revealed significantly improved balance for three of the four conditions (p<.05) and decreased reaction time (p<.05) in three of the four quadrants during the dual-task condition. A four (balance condition) × four (number-letter position response time) within subject, repeated measures analysis of variance (ANOVA) evaluated the relationship between balance conditions and response time. Mean response times increased as the balance condition became progressively more demanding (p<.01). Post hoc-analysis indicated that response times were significantly faster when the support surface and walls were fixed compared to sway referencing (p<.05). Previous studies using young adults as participants also report improvements in both balance and cognitive processing with dual-task paradigm. However, findings are reversed in older individuals. Improvements in balance and cognition seen here may have resulted from learning effects as participants were repeatedly exposed to the tasks.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-18–S-19.

Understanding The Relationship Between Heading A Soccer Ball And Neuropsychological Performance In Girls Interscholastic Soccer

TW Kaminski ¹, MJ Higgins ¹

Abstract

Participation in girl's interscholastic soccer has increased dramatically over the last 5 years, due in part to the success of the women's US National program. Heading a soccer ball is one aspect of the game that has become a target in the popular press as being dangerous and detrimental to brain function. The purpose of this study was to determine if a relationship exists between soccer heading and neuropsychological performance before and after a competitive soccer season in a group of female high school players. A total of 100 interscholastic soccer players (age = 16.1±1.2 years; ht. = 164.5±6.5 cm; mass = 59.4±9.3 kg) with an average of 5+ years of playing experience, were tested before and immediately after one competitive soccer season. The Automated Neuropsychological Assessment Metrics (ANAM) computer program was used to assess neuropsychological performance. Throughput scores for Matching to Sample (MTS) and Sternberg Memory (STN) were analyzed. Throughput scores combine accuracy and speed, therefore the higher the score, the better. Headers were tabulated during each sanctioned match using a simple tally system. The Pearson Product Moment Correlation Coefficient was employed to analyze the relationship between the number of headers per game and total headers, and pre/post-season scores on these two measures of neuropsychological performance. The average number of total headers for the season was 20.2, while the average headers/game was 1.0. There were no significant correlations between total headers (pre MTS r = .06, post MTS r = .14, pre STN r = −.04, post STN r = −.03) or headers/game (pre MTS r = .03, post MTS r = .13, pre STN r = −.04, post STN r =.01) and the two neuropsychological tests. The STN and MTS sequences of the ANAM are designed to test working and visual memory respectively. The results of this study indicate that there is no relationship between total headers and headers/game and these measures of brain function. The implications of these findings point to the fact that heading a soccer ball, if performed properly by skilled players, is not related to any deficits in memory function as measured in this study. Interestingly, it appears that over the course of an entire season, interscholastic female soccer players on average do very little heading of the soccer ball in sanctioned matches. Additional research is needed to get a better understanding of the relationship between neuropsychological performance and soccer heading over the long-term. (This study was funded in part by a grant from the Mid-America Athletic Trainers' Association)

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-19.

The Effect Of Wet And Dry Ball Conditions On Linear Head Accelerations During Soccer Heading

V Liberi ¹, JG Richards ¹, TL Claiborne ¹

Abstract

The main objective of this investigation was to determine the effect of wet and dry ball conditions on resultant head accelerations during soccer heading. Sixteen varsity collegiate male soccer players volunteered for this investigation (mean age = 19.5). For each condition, the soccer ball was delivered via a mechanical leg from a distance of 18.5 meters, at a velocity of 15.5 m/s, and a trajectory of 32 degrees. The subjects then headed the soccer ball back in the same direction from which the ball was delivered. For the wet ball condition, the ball was submerged in water for five minutes prior to testing, and all balls were standardized for air pressure prior to testing. Each subject performed three trials for the wet and dry ball conditions. Resultant accelerations from the 'Y' (anterior/posterior) and 'Z' (vertical) directions were evaluated using a triaxial quartz beam accelerometer, positioned over the base of the skull at the inion, and held in place with an adjustable nylon strap. The results of a one way ANOVA with repeated measures analysis demonstrated significantly greater head accelerations between wet (205.19 ± 30.27m/s/s) and dry (220.27 ± 25.24 m/s/s) ball conditions. Descriptively, mean impact force across conditions was 1200 ± 186.2 N, and mean impact duration between the soccer ball and the head was 10.5 ± .5ms. The affects of cumulative head trauma is not well understood. However, there is anecdotal evidence that soccer heading over time may contribute to chronic symptoms consistent with cumulative head trauma. The results of the current investigation showed significantly smaller head accelerations during wet ball conditions. Due to more recent waterproof technology, soccer balls no longer absorb water. Therefore, the decrease in head accelerations during the wet ball condition can most probably be attributed to decreased surface friction, allowing the ball to glance off the head. These results have practical importance in that cumulative trauma due to repetitive soccer heading may be altered as a result of the environmental conditions in which the sport is played.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-19.

No Changes To Collegiate Soccer Players Balance After A Specialized Heading Practice

BC Mangus ¹, HW Wallmann ¹, M Ledford ¹

Abstract

A common skill used in soccer is the heading of the ball for a variety of purposes. Some researchers have indicated that heading may be dangerous, leading to long term neurological changes in the athlete. Others have demonstrated that heading a ball is safe without producing any long term effects on the athlete. What have not been demonstrated are the immediate changes to balance from heading a soccer ball. The purpose of this study was to determine if any immediate changes in balance were discernable in college soccer players after a specially designed heading session. The heading session was designed to be similar to that used by a collegiate soccer player during a practice or match. Skilled collegiate soccer players (8 male and 2 female; age 21.4 ± 1 yr; height 1.74 m ± 0.1 m; mass 72.27 ± 9.4 kg) were administered a baseline sensory organization test (SOT) (PRE) using the Smart Balance Master system (NeuroCom), followed by heading 20 balls kicked consecutively by a teammate from the touchline to a point near the goal. This was followed by a post-test (POST) using the same testing technique. The subjects reported to the testing laboratory, were PRE tested, walked approximately 500 meters to the soccer field, performed the heading task and walked back to the testing site for the POST test. The number of headings was based on an average number of heading occurrences in a game from the available literature. All balls were from the same manufacturer and inflated to the recommended PSI. Subjects were tested on six different balance conditions in the SOT, three trials for each condition. The mean score for each condition is called the equilibrium score. Paired t-tests were used to compare balance ability PRE and POST for each condition. Calculation of the six conditions together resulted in a composite equilibrium score. There was no difference in balance as observed PRE vs. POST (85.30% & 86.20% respectively) from the composite equilibrium score. Additionally, no significant differences were noted PRE vs. POST in the mean equilibrium scores for the six different conditions on the SOT. It is concluded that an acute session of heading soccer balls may not result in balance changes in collegiate soccer players.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-19–S-20.

Sex Differences In Post-Concussion Symptoms And Neuropsychological Recovery Of Collegiate Athletes

T Covassin ¹, C Swanik ¹, M Sachs ¹, Z Kendrick ¹, P Schatz ¹, E Zillmer ¹, C McKeever ¹

Abstract

It is known that sex differences exist in the incidence of concussions among collegiate athletes. Moreover, brain structure and function is different between sexes, but no research exists comparing post-concussion function and symptoms between sexes. Therefore, the purpose of this study was to determine if sex differences exist in neuropsychological functioning, post-concussion symptoms and recovery rates of collegiate athletes. A prospective cohort design was used to compare baseline and post-concussion neuropsychological test scores and symptoms. All athletes were administered the Immediate Post Concussion Assessment Cognitive Testing (ImPACT) neuropsychological test battery prior to the start of their season. When an athlete sustained a concussion he or she completed the ImPACT test which included post-concussion symptoms during the following three test periods: up to 2 days, 2 to 5 days, and 6 to 10 days. Division I intercollegiate athletes (N = 1093) at five Northeastern Universities were administered the ImPACT test battery during the 2002–2003 academic year. Eighty athletes sustained a concussion during the study period with 33 athletes (12 males and 21 females) completing the entire test protocol. The ImPACT battery, the American Academy of Neurology definition and grading scale were used by physicians and certified athletic trainers to assess athletes who suffered a concussion. Results revealed that concussed athletes performed significantly better on pre-test than all three post-test times for memory verbal neuropsychological test scores (F_3,32 = 7.72, P = .001) and had significantly decreased reaction time scores across the three post-tests (F_3,32 = 3.19, P = .038). No significant differences were observed in the recovery rates for males and females, however, males reported significantly higher symptoms of sadness (F_1,32 = 4.43, P = .043) and vomiting (F_1,32 = 7.30, P = .01) when compared to female athletes. Collegiate athletes reaction time and memory verbal scores (ability to remember words such as fork, ball, water) had the greatest decrements as a result of a concussion and should warrant special attention when evaluating a concussed athlete. These male and female athletes exhibit different post-concussion symptoms, possibly due to the specific pathophysiology or severity of concussions. In conclusion, this suggests that sex specific evaluation tools and grading scales need to be considered. Supported by a grant from the NATA Research & Education Foundation sponsored by Proctor & Gamble.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-20.

Gender Differences In Dynamic Stabilization During Head Acceleration

RT Tierney ¹, MR Sitler ¹, CB Swanik ¹, KA Swanik ¹, M Higgins ¹, JS Torg ¹

Abstract

Recent epidemiological research revealed that gender differences exist in concussion incidence but no study has investigated why females are at greater risk. Our purpose was to determine if gender differences existed in head-neck segment kinematic and neuromuscular control variables responses to an external force application. Forty male (N = 20, age = 26.3 +4.3 years, height = 177.1 ±6.1 cm, mass = 84.5 ±11.8 kg) and female (N = 20, age = 24.2 ±4.1 years, height = 165.3 ±5.3 cm, mass = 59.0 ±5.1 kg) physically active volunteers participated in the study. The independent variable was gender. The dependent variables were selected kinematic and EMG variables, head-neck segment stiffness, and head-neck segment flexor and extensor isometric strength. Using a pulley system, a standardized external load (50 N) was applied to the participants head-neck segments while they were seated. Statistical analyses consisted of multiple multivariate and univariate analyses of variance with appropriate follow-up tests (alpha < .05). The results revealed that gender differences existed in head-neck segment dynamic stabilization during head acceleration. Females exhibited significantly greater head-neck segment peak angular acceleration (70%) and displacement (46%) than males despite using a greater percentage of their maximum head-neck segment muscle activity (83% peak activity and 111% muscle activity area). The head-neck segment acceleration differences may be because females exhibited significantly less isometric strength (49%), neck girth (30%), and head mass (43%), resulting in lower levels of head-neck segment stiffness (34%) than males. These biomechanical and neuromuscular gender differences in dynamic restraint may predispose females to excessive head-neck segment acceleration and increased risk of concussion. These findings support the need for resistance training with females to enhance their head-neck segment dynamic stabilizers and reduce the risk of concussions.

Special Interest Group #5: Concussion

Friday, June 18, 2004, 10:15am–11:15am, Room 336; Discussants: Kevin Guskiewicz, PhD, ATC, and Tamara Valovich McLeod, PhD, ATC

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-21.

Public's Perception Of Job Responsibilities Of An Athletic Trainer Vs. Athletic Therapist As A Healthcare Professional

T Botto ¹, D Fuller ¹

Abstract

In recent years the nomenclature of Athletic Trainer (ATC) has been challenged by many. Some have suggested a name change to Athletic Therapist (Ather), a profession that presently does not exist within the U.S. The purpose of this study was to identify how the general public perceived the roles and responsibilities of an athletic healthcare professional. A 30-question descriptive survey was developed based on the NATABOC's Role Delineation Study. Twelve athletic training professionals from various settings and educational backgrounds were used to determine interrater reliability, content and construct validity of the survey instrument. Frequencies and percentages were calculated on SPSS 11.0. Surveys were administered during pre-game activities at 3 Division I football games in the northeastern U.S. Study consisted of 258 participants (133 males, 125 females). The average age was 38.6 years, 153 received a Bachelor Degree or higher, 71 participants knew an Ather in the U.S., and 103 knew an ATC in the U.S. Participants were asked questions pertaining to various roles, responsibilities and qualifications of an athletic trainer as defined by the Role Delineation study. For each of the questions, the participants were provided the following four options: (a) Athletic Trainer, (b) Athletic Therapist, (c) Both Athletic Trainer and Athletic Therapist, and (d) Neither Athletic Trainer nor Athletic Therapist. Participants were given no information on ATC's or Ather's. Data that supported ATC's were: Develops strength, power and endurance programs (ATC 52%, Ather 5%, Both 35%), Applies bracing, taping and strapping (ATC 42%, Ather 22%, Both 31%), Provides emergency care (ATC 44.2%, Ather 14.3%, Both 27.1%), and Develops cardiovascular programs (ATC 37.6%, Ather 12.8%, Both 38.8%). Data that supported Ather's were: Evaluates orthopedic injuries (ATC 16%, Ather 40%, 30%), Counsels individuals through injury and refers (ATC 12%, Ather 38%, Both 39%), Applies therapeutic modalities (ATC 21%, Ather 41%, Both 30%), Works under the direction of a physician (ATC 12%, Ather 42%, Both 33%), Applies joint mobilizations (ATC 17%, Ather 36%, Both 35%), Educates patients on the role of therapeutic drugs (ATC 5%, Ather 27%, Both 21%), Applies therapeutic massage (ATC 15%, Ather 42%, Both 37%), Obtained a 4-year college degree (ATC 9%, Ather 19%, Both 63%), and is recognized as a healthcare professional by the AMA (ATC 10%, Ather 28%, Both 38%). In conclusion, this data demonstrates the public's misperception of the role and responsibilities of an athletic trainer among athletic healthcare professionals.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-21.

California High School Administrators' Awareness Of Athletic Trainers' Roles And Responsibilities

A Felling ¹, L Kahanov ¹, S Lilienthal ¹, S Schlicher ¹

Abstract

Research regarding the public's knowledge of athletic training roles and duties is minimal. The few studies that have been conducted report misinterpretations and inconsistencies with regard to the roles and responsibilities of athletic trainers. Thus the objective of this study was to determine the knowledge possessed by administrative personnel in California high schools regarding the roles and responsibilities of the athletic trainer. This descriptive study was modeled after Hoppel et al.(2001), however demographic questions were modified to change the vernacular from parent to administrative personnel. The survey, which included 24 Likert scale questions was mailed to California high schools, with one survey for the principal and one for the athletic director. A total of 596 administrators from 300 California high schools were surveyed, of which, 219 (36.9%) were returned. Cross-tabulations were performed to assess associations between principals and athletic directors. Approximately half of the schools that responded (57.3%, N=213) currently employed an athletic trainer. Most respondents were knowledgeable about the roles and responsibilities of athletic trainers; however, there was a discrepancy between perceptions of athletic directors compared to principals for 10 of the 15 athletic training questions. More athletic directors strongly agreed with statements describing athletic trainers' capabilities and roles. Principals had a greater tendency to moderately agree or feel neutral about athletic trainers' roles and education. Some large differences existed between the responses of schools that currently employed an athletic trainer when compared to schools that did not. Schools with athletic trainers agreed stronger with statements regarding athletic trainers' roles and responsibilities. For example, the majority of responses from schools with athletic trainers (72.6%, n=117 and 54.0% n=87) strongly agreed with the statement that athletic trainers conduct injury rehabilitation, and organization and administration of athletic health care, compared to 54.0% (n=87) and 37.2% (n=86) respectively. The data implies that California high school administrators have a favorable opinion regarding the roles and responsibilities of athletic trainers. However, the majority of administrators strongly agree that athletic training is a misunderstood profession. This supports the findings of previous research that established athletic training as a misunderstood field. A lack of knowledge concerning athletic training and other medical options, particularly from the principle, may make the acquisition of proper medical staff difficult. Findings from this study indicate that schools may benefit from including athletic directors in the hiring process of athletic trainers since some of the principals' perceptions of athletic training were inaccurate.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-21–S-22.

The Perceptions Of Superintendents, Principals, And Athletic Directors Concerning The Need For, Willingness To Hire, And Important Factors In Hiring Certified Athletic Trainers In Utah High Schools

JL Knerr ¹, DA Kaiser ¹, JW Myrer ¹, GW Fellingham ¹

Abstract

The purpose of this investigation was to assess the perception of Utah high school administrators regarding the need for, and the willingness to hire certified athletic trainers. A secondary objective was to determine what factors these administrators would consider before hiring an ATC. This study was descriptive research, which used survey instruments to collect data. Modifying the survey used by Ray in Michigan in 1987, three survey instruments were developed by the investigators. The instruments were evaluated for content and face validity by a panel of experts in the areas of athletic training and high school administration. The research polled the entire subject population of district superintendents (39), high school principals (115), and high school athletic directors (124) in the state of Utah. The overall response rate for the surveys was 57%. The return rate for the superintendents was 77%, for principals was 53%, and for athletic directors was 55%. Percentages or response frequencies were tabulated for each question and the data analyzed with descriptive statistics. Athletic directors reported the most need ATC's in the high schools (90%), while superintendents saw the least need (37%). Budgetary constraints were identified as the single most important factor for not hiring an ATC. Possessing a secondary or vocational teaching certificate was identified as the factor that would most enhance the employment potential for the athletic trainer. The results of this investigation indicate that high school administrators need more information regarding the role of ATC's in injury prevention and treatment, as well as the reduction of legal liability. Superintendents, because of their major role in hiring, should be a primary focus.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-22.

Competing Perspectives During Organizational Socialization On The Role Performance Of Athletic Trainers In High School Settings

C Crews ¹, J Mensch ¹, M Mitchell ¹

Abstract

Certified athletic trainers (ATCs) are hypothesized to proceed through three socialization phases en route to becoming professionals and each phase warrants scrutiny to better understand and improve professional practice. Anticipatory socialization occurs as recruits explore what it takes to become a professional. During professional socialization, usually in a college program, recruits gain requisite skills and dispositions. Next is a transition to a job where ATCs are organizationally socialized into a specific workplace. In this last phase, there is often a competition among personal perspectives, professional program perspectives, and perspectives of colleagues (e.g., coaches), that shape the actual practice of ATCs. The purpose of this exploratory study was to identify and contrast the perspectives of high school basketball coaches and ATCs toward the athletic training role. A qualitative research design was used, involving semi-structured interviews that had been piloted and revised for clarity. This approach allowed the trained interviewer (an ATC with 5 years experience at the high school level) to probe beyond the formally written questions for clarity in participant responses when necessary. Participants were coaches (9 males and 1 female) of varsity basketball teams (5 boy's teams and 5 girl's teams) from 5 high schools (student enrollment range: 915 to 2,059), and the five ATCs (4 males; 1 female) assigned to these teams. Interviews (30 minutes to 1 hour) focused on the athletic training services provided during various phases of the season. Data were transcribed, coded, and analyzed inductively using a constant comparative method (Glasser & Strauss, 1967). Trustworthiness was established by data analyst triangulation (Patton, 1990), where three ATCs (all with graduate degrees) independently analyzed the interview data and probed for researcher bias and clarified interpretations. Data analyst triangulation resulted in a 100% agreement of the results. Three significant themes emerged: 1) none of the coaches had knowledge of the experience or qualifications of their athletic trainer—they worked with whomever was assigned; 2) coaches expressed a general sense of wanting athletic trainers to be available without being able to articulate specific duties, in contrast to much more specific descriptions by athletic trainers; and 3) coaches and athletic trainers overwhelmingly identified positive communication as a critical component in having a good coach-athletic trainer relationship. Paradoxically, while good communication is valued by all participants, poor communication appears to limit athletic trainer contributions to player performance beyond simply being “available.” ATCs must educate coaches regarding how to ensure they are getting qualified athletic training support and to get the most out of their ATC toward improving athlete performance.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-23.

There Is More To Electrothermometer Reliability Than Manufacturers' Claims: Differences Between Machines, Thermocouples, And Temperature

KL Knight ¹, LS Jutte ¹, BC Long ¹

Abstract

Scientists using electrothermometers to record temperature in thermal modality studies have accepted manufactures claims of instrument reliability (usually ±0.1°C). We were unaware of any independent study of the reliability of these electrothermometers. Our purpose, therefore, was to determine the reliability of 3 electrothermometers from 2 manufacturers at various temperatures. Six thermocouples [2 (IT-18; implantable), 2 (IT-21, implantable), 2 (PT-6, surface)], all manufactured by Physitemp (Clinton, NJ) were attached to each of 3 electro-thermometers; a Dataloger MMS 3000-T6V4 and 2 Isotheremexes. One Isotheremex was manufactured to measure temperatures from −50°C to 50°C, the other to measure temperatures from −20°C to 80°C. The 18 thermocouple tips were immersed in water baths at 35°C, 25°C, 18.4°C, 15°C and 5°C for 4 minutes each. Water bath temperatures were monitored using a research-grade mercury thermometer graduated by 0.1°C. Measurements were taken every 10 seconds for 4 minutes at each temperature. The absolute differences between the electrothermometers and the mercury thermometer were computed. ANOVA followed by Tukey-Kramer post-hoc testing was used to evaluate for significant differences between the mercury thermometer and each thermocouple. There were differences between machines, thermocouple types, and temperatures. The two Isothermex units were more stable than the Datalogger (p<.05), the IT-18 and PT-6 were more stable than the IT-21 (p<.05), and the higher temperatures were more stable than lower temperatures. For example, at 25°C using PT-6 thermocouples, the deviation from the mercury thermometer was 0.052 ± 0.050°C, 0.072 ± 0.036°C, and 0.794 ± 0.023°C for the 3 instruments. At 5°C using IT-21, the deviations were 0.169 ± 0.066°C, 0.146 ± 0.049°C, and 0.956 ±?0.159°C. Also, the isothermex units under-reported water bath temperatures; the Datalogger over reported them. Scientists using this technology should test and report the specific reliability of the instrument and thermocouples they use in an experiment, at the temperatures they studied. Results from such studies must be interpreted in light of the specific reliability of the equipment used. And readers must use caution when comparing research reports using different equipment and thermocouples, especially if the reliability has not been reported.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-23.

Cold Modalities Placed On Thermocouple Leads Influence Temperature Measures

LS Jutte ¹, BC Long ¹, KL Knight ¹

Abstract

Thermocouples interfaced with electrothermometers are used to measure temperature in therapeutic modality studies. Temperature is determined by the voltage gradient at the thermocouple tip; therefore, a modality such as a hot or cold pack, which alters the temperature of the metal thermocouple wire, may influence the reported temperature. Physitemp Instruments, Inc. (Clifton, NJ) reports the reliability of their Type-T thermocouple wire as ±0.1°C. Our purpose was to determine if an ice bag applied to the thermocouple lead affects temperature measurement. Ten thermocouples [5 implantable (IT-21) and 5 surface (PT-6)] were attached to a Columbus Instruments Isothermex. The sensing thermocouple tips were immersed in a room temperature water bath (18.3°C). Water bath temperature and ice bag-thermocouple interface temperature were both monitored using mercury thermometers graded by 0.1°C and 0.5°C respectfully. Temperatures were monitored before (5 min), during (10 min), and after (5 min) cold application. Measurements were taken every 20 seconds. Means and standard deviations were computed for the absolute differences between thermocouple and water bath mercury thermometer temperatures. An ANOVA for repeated measures followed by a Tukey-Kramer post-hoc test were used for statistical analysis. As a group, the PT-6's measures were not influenced by placing ice on the leads (before = 0.12±0.04°C, during = 0.13±0.04°C, after = 0.11±0.04°C). The IT-21 measures were influenced by the ice application (before = 0.15±0.03°C, during = 0.20±0.13°C, after = 0.32±0.16°C). The differences found in the IT-21's were statically different (Tukey-Kramer, p<0.05) and beyond what the manufacture reports as the reliability of the Type-T wire (±0.1). When evaluating the individual thermocouples we identified one PT-6 that was beyond the manufactures reported reliability, but was not statistically different across time or from the other PT-6 thermocouples. When the lead temperature was influenced by ice bag application, Physiotemp's model PT-6 thermocouple was found to be within the manufactures reported reliability while the IT-21 model was not within the manufactures reliability. Therefore, if IT-21 thermocouples are used and cold modalities are applied to the leads, the reported reliability needs to be adjusted to ±0.5. We suggest that all thermocouples, regardless of model are assessed for their reliability prior to each study, especially when thermal modalities are applied to the leads. The influence of heat modalities on thermocouples is yet to be determined.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-23–S-24.

Placement Technique And Exercise Affects Triceps Surae Thermocouple Position As Measured By Magnetic Resonance Imaging

BA Piatt ¹, JB Brucker ¹, ML Cordova ¹, TJ Demchak ¹

Abstract

This study sought to investigate the following: 1) thermocouple position between 2 commonly used insertion techniques before and after exercise, 2) whether or not the thermocouple reached the desired theoretical depth, and 3) to validate superficial tissue thickness as measured by skinfold caliper to MRI assessment. Both calves of 3 active male volunteers (age= 20.7±0.6 yrs, mass=82.1±10.1 kg, ht=183.3±12.6 cm) served as subjects. A 2 × 2 fully repeated measures design guided this study, where insertion technique (traditional and catheter-assisted) and time (pre and post exercise) were the independent variables. The dependent variables evaluated were three-dimensional positions (X, Y, Z) of the thermocouple relative to the insertion point, and superficial tissue thickness (mm) as measured by MRI and skinfold caliper measurements. Thermocouples were inserted superior and inferior the greatest girth of each calf according to 2 methods to a theoretical depth (3 cm plus ° the caliper superficial tissue measure). The traditional routine employed a sterile hypodermic needle to implant the thermocouple, after which the needle was retracted. The catheter-assisted technique used a previously inserted intravenous catheter to guide placement of the thermocouple. Subjects remained prone until after the pre-exercise MRI scans were completed. Following the initial scans, subjects performed calf raises through a full range of motion until exhaustion. After exercise, a second set of MRI scans were taken. Initial MRI scans revealed that the caliper and MRI superficial tissue thickness measurements did not correlate (r_xy = 0.56, P =0.25). Additionally, it was revealed that the actual thermocouple depth obtained for the traditional technique (24.3±7.9 mm) did not differ compared to the catheter-assisted technique (32.5±3.0 mm; P=0.11). When values for both techniques were pooled, actual depth obtained was 4.70 mm short of the theoretical depth (P = 0.04). After exercise, the thermocouple backed out 8.7±6.2 mm regardless of insertion technique (P=0.004). In the medial/lateral plane, position was only affected by the insertion technique used (P =0.024); whereas, position in the superior/inferior plane remained unaffected by exercise (P = 0.46) and insertion technique (P = 0.37). In conclusion, it appears that the current technique used for estimating superficial tissue thickness using a skinfold caliper to establish insertion depth is inaccurate when compared to MRI. Moreover, the catheter-assisted technique is more likely to reach the desired tissue depth with less variation as compared to the traditional technique. Lastly, implementation of exercise following thermocouple implantation alters the position of the thermocouple.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-24.

Intramuscular Tissue Temperature After A 10-Minute 1 Mhz Ultrasound Treatment Tested With Thermocouples And Thermistors

JL Leonard ¹, J Tom ¹, CD Ingersoll ¹

Abstract

Scientists performing therapeutic ultrasound studies commonly use the thermistor and thermocouple to measure intramuscular temperature. The temperatures taken with the thermistor seem to be higher than those taken with the thermocouple. No one has directly compared these two temperature devices. The purpose of this study was to determine if temperature measurements differed between the thermocouple and thermistor, when inserted into the same treatment site, following a standard ultrasound treatment. This study was a 1 × 2 repeated measures design. The independent variable was the temperature-measuring instrument (thermocouple and thermistor). The dependent variable was the mean temperature difference and their heating trends over time. This study was performed in the Sports Medicine/Athletic Training Laboratory at the University of Virginia. Sixteen healthy volunteers (6 males, 10 females 23.56 ± 2.25 years, 170.97 ± 6.67 cm, 73.43 ± 17.82 kg) completed the study. A 1 MHz, 1.5 W/cm², continuous ultrasound treatment was delivered with a thermocouple and thermistor injected into the treatment site. This study was stopped early due to unexpected adverse events. During the first 7 minutes of ultrasound, the estimated mean difference between the thermistor and the thermocouple reading was 0.53°C [95% CI (−0.03 to 1.08), P=0.063]. When including the 2-minute baseline temperatures to the 7-minute treatment (9 minutes), the estimated mean difference was 0.48°C [95% CI (−0.01 to 0.97), P=0.054]. No significant time trend, with respect to the difference between the two instruments was observed for 7 minutes [slope = 0.054[degrees Celsius/min], 95% (−0.035 to 0.143, P=0.218] or for 9 minutes [slope = 0.070 [degrees Celsius/min], 95% (−0.026 to 0.166), P=0.141]. Therefore, the thermistor tended to be about a half-a-degree higher than the thermocouple.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-24–S-25.

Cutaneous Vesiculations On Anterior Shin In 3 Research Subjects After A 1 Mhz, 1.5 W/Cm², Continuous Ultrasound Treatment

JA Tom ¹, JL Leonard ¹, CD Ingersoll ¹

Abstract

While conducting a research experiment examining the temperature differences provided by two intramuscular temperature devices, 16 healthy volunteers (6 males, 10 females 23.56 ± 2.25 years, 170.97 ± 6.67 cm, 73.43 ± 17.82 kg) participated in the study. Three female participants (26.33 ± 3.79 years, 169.34 ± 3.89 cm, 63.39 ± 3.81 kg) developed cutaneous vesiculations on their anterior shin following a 1 MHz, 1.5 W/cm² continuous ultrasound treatment (Chattanooga Intellect Combination Unit). Each of the volunteers had a thermistor and a thermocouple inserted 5 cm into the gastrocnemius muscle. The instruments were inserted parallel to each other with 3 cm separating the two. The ultrasound treatment was delivered on the posterior aspect of the calf perpendicular to the insertion of the temperature measuring instruments in an outlined area two times the effective radiating area. The treatment time for one subject was 4.5 minutes, one subject was 4 minutes, and another subject was 10'. The intended treatment time for the study was a maximum of 10 minutes. The two subjects with the shorter treatment times felt an intense burning sensation in their shin therefore treatment was discontinued. The third subject reported warmth in her shin but did not feel the treatment needed to be terminated. The subject was encouraged to be honest about her sensations and to avoid attempting to “tough out” the treatment if it was uncomfortable. The subject reassured us that it was just a warm sensation and that it was completely tolerable. Two subjects had redness on their shin immediately following the ultrasound treatment. This research study was terminated after the third adverse event was reported. The first event was reported on day 6 of data collection. Five subjects were collected following this adverse event without any complications. The second two reports were the last two subjects to participate, as the study was terminated after their reports. Within 24 hours after their ultrasound treatment, two subjects reported one small (∼1 cm diameter) blister on the anterior aspect of the shin, while the third subject reported ∼10–12 very small blisters (∼1 mm diameter). All vesiculations were located on the anterior shin directly across from the posterior location where the ultrasound had been delivered on the gastrocnemius. Subjects had no altered physical function. The study physicians saw each of the subjects following their reports. Because these were unexpected events, thought was given to any possible cause besides the ultrasound that may have caused this reaction. The ultrasound unit's calibration was verified to be correctly calibrated following termination of the study. Subjects were questioned about their sun exposure, applications of lotions to the skin, table cleaning solvents, or any sources of friction that would have caused such a blister. None of these questions led to a probable diagnosis. Therefore, the vesiculations were believed to be caused by the interaction between the ultrasound treatment and temperature instruments. No laboratory tests were done. Subjects were instructed to keep their blisters clean and to avoid popping the blisters. After follow-up, all subjects' skin has healed appropriately with no further complications. It is rare for standard therapeutic ultrasound parameters to cause a burn to individuals. Additionally, it is unique for the burn to be located on the anterior aspect of the shin when the ultrasound was delivered to the posterior aspect. Because this was a research situation, we feel it is important to report these events to other researchers so they are aware of such possible complications. To our knowledge, there have not been any other similar adverse events published in the ultrasound literature.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-25.

Site Of Ultrasound Application Over The Hamstrings During Stretching Does Not Enhance Knee Extension Range Of Motion

TS Tashiro ¹, TC Sander ¹, SM Zinder ¹, KM Cross ¹, CD Ingersoll ¹

Abstract

Previous literature indicates that heating soft tissues results in a time limited “stretching window” where greater range of motion (ROM) can be achieved during stretching sessions. The objective of this study was to determine whether the specific site of application of ultrasound (US) over the hamstrings enhances the affect of a combined US and static stretch treatment designed to increase knee extension ROM. Thirty-four (20 males, 14 females) participants (24.9 ± 4.02 years, 174.5 ± 31.33 cm, 76.4 ± 3.57 kg) received three treatments using counterbalanced assignment. The first treatment (Control) consisted of lying in a supine position for seven minutes. The second treatment (USS) consisted of a seven minute, 1MHz continuous US application over the mid-belly of the hamstrings in conjunction with static stretch. The third treatment (MUSS) consisted of a seven minute, 1MHz continuous US application over the area of the hamstrings where the subject felt the greatest perceived tightness in conjunction with pre-treatment static stretch. Before and after each treatment, each participant's knee was passively extended using a KinCom Isokinetic Dynamometer (Chatanooga Group Inc., Hixson, TN) until a force of 111.25 N was achieved. Knee extension ROM was measured with an electrogoniometer (Penny and Giles, Gwent, UK). A 1 × 3 repeated measures analysis of variance was used to identify differences between treatment groups (Control, USS and MUSS), determined by change in passive knee extension ROM. Individual differences between the three groups were determined using Sidak post hoc analysis. Differences were found between treatment groups (P < .001). When specifically comparing the control to the treatment groups, USS ROM was 6.1% greater (P < .002) and MUSS was 6.2% greater (P < .001) than the control. No differences were found between the USS and MUSS groups (P = 1.00). In a healthy population, application of US over the area greatest perceived tightness during stretching does not appear to enhance knee extension ROM when compared to application of the same treatment over the mid-belly of the muscle. However, further research should investigate whether site of US application affects ROM increases with stretching in patient populations.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-25.

The Regression Equation Of The Omnisound 3000P Is Valid: Ultrasound Treatments Should Be Temperature Dependent Not Time Dependent

AM Wells ¹, DO Draper ¹, WJ Vincent ¹

Abstract

When thermal effects of an ultrasound treatment are desired it is essential that the correct parameters are followed. Two of these are time and intensity. We have noticed improvements in publications and practice with respect to increased treatment times, however, there is still a lot of guesswork taking place. For example, when the patient alerts us to the fact that the soundhead feels too warm, we should respond by turning down the intensity. But how many of us counter that action by increasing the length of the treatment? The Omnisound 3000P was recently developed as a portable ultrasound unit with a microchip that automatically adjusts treatment time according to the intensity used during the treatment. The purpose of this study was to determine if the Omnisound 3000P was valid at raising muscle temperature 4°C during a 3MHz ultrasound treatment when the intensity was frequently altered. Eight subjects gave informed consent and participated in the study. Independent variable was treatment and dependent variable was temperature increase at 1 cm and 2.5 cm. Two 23 gauge thermistors were inserted into the subjects medial gastrocnemius at 1cm and 2.5cms depth. The isothermex recorded temperatures to the nearest 0.1°C every 30 seconds. Treatment area was 2 ERA delivered in a circular fashion using a template as a guide interfaced with ultrasound gel. The Delta T temperature mode keypad labeled 4°C was depressed and the treatment commenced. The following intensity progression was followed: 1W/cm² for 2 mins; 1.4W/cm² for 2 mins; 1.2W/cm² until the timer shut-off (1.5 mins.). A Z-test was used to determine if there was a difference in actual changes in temperature and a standard of 4 degrees set by the ultrasound machine. There was no significant difference between the measured temperature increase and the desired standard increase of 4° C above baseline by 3 ° mins at the 1 cm depth and by 4 ° mins at the 2.5 cm depth (p<.001). The average temperature increase between the two depths was 4.4°C. The Omnisound 3000P is valid at raising muscle temperature 4°C or higher during a 3MHz ultrasound treatment when the intensity is frequently altered. The Omnisound 3000P ultrasound unit ensures that thermal goals are achieved while adjustments in intensity provide for greater patient comfort.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-25–S-26.

A Comparison Of Temperature Increases In Human Muscle During 3 MHz Continuous And Pulsed Ultrasound With Equivalent Temporal Average Intensities

JA Gallo ¹, DO Draper ¹, GW Fellingham ¹, LT Brody ¹

Abstract

Many clinicians mistakenly think that pulsed ultrasound applications are non-thermal. The purpose of our study was to compare changes in intramuscular temperature of pulsed ultrasound against continuous ultrasound with an equivalent spatial average temporal average (SATA) intensity. A repeated measures cross-over design was used. Independent variable was the type of ultrasound (pulsed or continuous) and the dependent variable was peak intramuscular temperature. Subjects were 16 volunteers (mean ± SD = 21.3 ± 2.5 years of age) free of left lower extremity injury who gave informed consent. Each subject was treated with pulsed ultrasound (3 MHz, 1.0 W/cm², 50% duty cycle, for 10 minutes) and continuous ultrasound (3 MHz, .5 W/cm², for 10 minutes) during a single testing session. Temperature was recorded every 30 seconds for 10 minutes using a 26-gauge needle microprobe inserted at a depth of 2 cm in the left medial gastrocnemius muscle. The microprobe was interfaced with an isothermex digital thermal system. Tissue temperature returned to baseline and stabilized between treatments and treatment order was randomized. Data were analyzed using a linear mixed model. Treatment with continuous ultrasound produced a peak temperature increase of 2.8° ± 0.8°C above baseline. Treatment with pulsed ultrasound produced a temperature increase of 2.8° ±?.7°C above baseline. Statistical analysis revealed no significant differences in either the extent or rate of temperature increases between the two modes of ultrasound application. Pulsed ultrasound (3 MHz, 1.0 W/cm², 50% duty cycle, for 10 minutes) produces similar intramuscular temperature increases as continuous ultrasound (3 MHz, .5 W/cm², for 10 minutes) at 2cm deep in the human gastrocnemius. Spatial average temporal average (SATA) intensity is an important consideration when selecting pulsed ultrasound parameters intended to deliver “non-thermal” effects. During 3 MHz ultrasound treatment, if moderate intensities are pulsed, temperature increases approaching 3°C might be reached that theoretically lead to increased blood flow. This could be detrimental during the acute stage of healing.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-26.

Ultrasound Beam Profiling: Comparative Analysis Of 4 New Ultrasound Heads At Both 1 And 3.3 Mhz Shows Variability Within A Manufacturer

LD Johns ¹, SJ Straub ¹, EG LeDet ¹

Abstract

Recent research has demonstrated a need to better understand critical components of ultrasound in order to establish trustworthy guidelines to improve clinical efficacy. While current clinical guidelines have been based upon research that utilized a single ultrasound head per data set, more recent reports have demonstrated significant differences in the abilities of various therapeutic ultrasound machines/heads to heat human tissue. These differences were found in spite of controlling for frequency, overall intensity, time of exposure and depth of heating. Therefore, there may be sound head variability factors that have not been defined. The purpose of this study was to develop new methods aimed at measuring variability within the ultrasound field. Four 5cm ultrasound heads (BNR 3.5-2.9, ERA of 4.5–5.7 at 3.3 MHz) were purchased from a single manufacturer. Prior to beam analysis, all heads were tested/calibrated to acceptable clinical standards. Lateral beam profiles were obtained for both 1 and 3.3 MHz, with an intensity of 1.2W/cm² utilizing a Schlieren analysis. Schlieren analysis has previously been validated and is reliable. Lateral beam profiles were analyzed at 1cm increments over a distance of 7cm from the transducer surface. The descriptive analysis of the beam included means, standard deviations and coefficient of variance of beam widths at 20, 40, 60 and 80% of the beam's relative intensity across 7cm of the beam. At 1MHz the highest 20% of the beam's intensity was contained within 0.56cm ± 0.15 (coefficient of variance, CV=27.0%), the highest 40% was contained within 0.9cm ± 0.24 (CV=26.9%), the highest 60% was contained within 1.29cm + 0.25 (CV=19.1%) and the highest 80% was contained within 1.83cm + 0.27(CV= 15.0%). At a frequency of 3.3 MHz, the highest 20% of the beam's intensity was contained within 0.92cm ± 0.34 (CV=37.4%), the highest 40% was contained within 1.55cm ± 0.18 (CV=11.3%), the highest 60% was contained within 1.86cm ± 0.16(CV=8.7%) and the highest 80% was contained within 2.23cm ± 0.1(CV=4.4%). Beam widths generated at 3.3 MHz were significantly (p = .001) wider than beam widths generated at 1 MHz. Since beam width is frequency dependent, clinicians should consider the frequency when determining an effective treatment area. Secondly, the beam width variability is significantly (p < .001) different across the beams' relative intensities with the beam width at 20% showing the greatest variability. This variability in intensity within the ultrasound field suggests that non-uniform heating rates may exist even with low BNR's.

Special Interest Group #6: Modalities

Saturday, June 19, 2004, 10:15am–11:15am, Room 336; Discussants: Craig R. Denegar, PhD, PT, ATC, and David O. Draper, EdD, ATC

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-27.

The Influence Of An ACL Injury Training Program On Knee Mechanics During A Side-Step Cutting Maneuver

CM Powers ¹, SM Sigward ¹, S Ota ¹, K Pelley ¹

Abstract

Although several injury prevention programs have been found to reduce the incidence of ACL injuries in female athletes, little is known about the mechanism underlying their success. The purpose of this study was to quantify the influence of an ACL injury prevention program in altering knee mechanics during sidestep cutting. Thirty-nine female soccer players between the ages of 14 and 18, with no history of ACL injury participated. Over the course of a season, 20 subjects participated in an ACL injury prevention program as part of their normal soccer practice (experimental group) while 19 subjects participated in their normal soccer practice and did not receive the intervention program (control group). Biomechanical testing was performed before and after their season. Subjects performed a side-step cutting maneuver at 6–7.0 m/s by planting with their right foot and changing direction to the left at a 35–60 degree angle. Anthropometric data, 3-D knee kinematics (VICON Motion System, 120 Hz), and ground reaction forces (AMTI force plate, 2400 Hz) were used to calculate knee moments (inverse dynamics). Muscle activity of the quadriceps, medial and lateral hamstring was recorded with surface electrodes (2400 Hz). Four trials were collected for each subject. EMG data were normalized to the EMG obtained during a maximal voluntary isometric contraction. Average angles, normalized EMG, and peak moments were identified during 2 phases of deceleration (early and late). A repeated measures ANOVA (group × phase) was performed to compare pre and post measures between groups. No differences were observed in average knee kinematics or EMG in either group. However, following the season, subjects in the control group demonstrated increased peak knee abductor and external rotator moments (1.2 ± 0.4 vs. 1.6 ± 0.5 Nm/kg, p= 0.02; 0.41 ± 0.1 vs. 0.48 ± 0.2 Nm/kg, p=0.03, respectively). In addition, the experimental group demonstrated increased knee flexor moments (1.2 ± 0.9 Nm/kg vs. 0.57 ± 0.09 p= 0.05) during early deceleration. These data suggest that participation in an ACL injury prevention program can have a positive effect in young female athletes. In particular, participation resulted in an increase in the knee flexor moment (ACL protective) and was successful in preventing the increase of more detrimental transverse and frontal plane knee moments. These results indicate that the mechanism underlying the success of these programs may not only be in establishing protective patterns at the knee but also by preventing the emergence of injurious movement strategies.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-27.

The Influence Of Experience On Kinematic, Kinetic And Muscle Activation Patterns During Side-Step Cutting In Young Female Athletes

SM Sigward ¹, S Ota ¹, K Pelley ¹, CM Powers ¹

Abstract

Experience level has been proposed as a risk factor with regards to non-contact ACL injuries. Although it is generally believed that novice athletes are at greater risk, there is little research to support this premise. In particular it is not known if novice athletes perform athletic tasks differently than those with more experience. The purpose of this study was to evaluate the influence of experience on knee joint kinematics, kinetics and muscle activation patterns during a sidestep cut. Fifteen novice (< 5 years experience) and 15 experienced (> 8 years of experience) high school female athletes with no history of ACL injury participated. Each performed a side-step cutting maneuver at 6-7.0 m/s by planting their right foot and changing direction to the left at a 35–60 degree angle. Anthropometric data, 3-D knee kinematics (VICON Motion System, 120 Hz), and ground reaction forces (AMTI force plate, 2400 Hz) were used to calculate moments at the knee (inverse dynamics). Muscle activity of the quadriceps, medial and lateral hamstrings was recorded with surface electrodes (2400 Hz). Four trials were collected for each subject. EMG data were normalized to the EMG obtained during a maximal voluntary isometric contraction. A co-contraction ratio (CCR) was calculated using average normalized EMG (hamstrings/quadriceps). Average angles, normalized EMG, CCR, and peak moments were identified during 2 phases of deceleration (early and late). To determine if these variables differed between groups or phases, 2 × 2 ANOVA's were performed. No significant differences were found in knee kinematics. During early deceleration, novice athletes demonstrated significantly smaller flexor, adductor, and internal rotator moments at the knee than the experienced athletes (0.11 ± 1.3 vs. 1.2 ± 0.6 Nm/kg, p< .01; 0.39 ± 0.6 vs. 0.9 ± 0.7, p=0.03; 0.08 ± 0.1 vs. 0.18 ± 0.1 Nm/kg, p= .01, respectively). No group differences were found for average EMG, however, the novice athletes had a significantly greater CCR (0.44 ± 0.2 vs. 0.34 ± 0.1, p=0.04). Contrary to previous thinking, novice athletes do not appear to be at greater risk to ACL injury than more experienced athletes. The finding of smaller knee moments and greater muscle co-contraction in the novice group suggests that these athletes may adopt a protective strategy in response to a relatively unfamiliar task. In addition, these results suggest that increased moments at the knee emerge with experience indicating that more skilled athletes may be at greater risk for ACL injury.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-27–S-28.

The Influence Of An ACL Injury Prevention Training Program On Lower Extremity Mechanics During A Landing Task

CD Pollard ¹, SM Sigward ¹, S Ota ¹, K Pelley ¹, CM Powers ¹

Abstract

Females experience 3–8 times the number of anterior cruciate ligament injuries (ACL) as their male counterparts. Several studies have implemented specific prevention training programs and have demonstrated an associated decrease in the incidence of ACL injury. However, the biomechanical changes resulting from such training programs are unknown. The purpose of this investigation was to examine the effects of an ACL injury prevention training program on lower extremity kinematics, kinetics and muscle activation patterns during a landing task. Subjects consisted of 34 healthy female high school soccer players who participated in two testing sessions. For the experimental group (N=18), the testing sessions occurred prior to and following a soccer season which included an ACL injury prevention training program. Testing sessions for the control group (N=16) occurred prior to and following a comparable time period. During each session three-dimensional kinematics (six camera Vicon motion analysis system, 120 Hz), ground reaction forces (2400 Hz) and surface electromyographic (EMG) signals (2400 Hz) from five selected lower extremity muscles were collected while each subject performed a drop landing task from a height of 46 cm (3 trials). Lower extremity joint moments were calculated using inverse dynamics equations. Peak hip and knee joint angles and moments were measured during the initial deceleration phase of landing. In addition, EMG data were averaged over the same phase. Separate ANOVA's with repeated measures were used to compare peak kinematics, kinetics and muscular control strategies of the experimental group pre-and post-training with those of the control group pre- and post-training. Post prevention program evaluation revealed decreased peak hip internal rotation angles (p=0.01), increased peak hip abduction angles (p=0.02) and increased hip flexion moments (p=0.04) in the experimental group whereas no coincident differences were evident in the control group. There were no differences in knee mechanics except for increased knee internal rotation moments (p=0.01) in the experimental group which were comparatively small in magnitude. In addition, there were no differences in muscle activation patterns in either group. Previous investigators have suggested that excessive hip internal rotation and adduction may predispose female athletes to ACL injuries. Therefore, the measured reduction in these motions following participation in the training program may contribute to the observed decrease in ACL injuries in this population. Although knee kinematics or kinetics were minimally influenced by this training program, such changes may become evident during a more challenging lower extremity task (i.e. cutting).

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-28.

The Effects Of A Plyometric Training Program On Neuromuscular Characteristics Of Female Athletes

AA DiPasquale ¹, KKW Tsang ¹, J Powell ¹, C Womack ¹

Abstract

Plyometric training programs have been implemented in recent anterior cruciate ligament (ACL) injury prevention programs. Plyometric exercises are designed to aide in the improvement of muscle strength and neuromuscular control. Our purpose was to examine the effects of a plyometric training program on lower leg strength and postural control in female athletes. Twenty-five (age = 20.3 ± 1.9 yrs, height = 167.6 ± 6.9 cm, mass = 59.8 ±?9.3 kg) physically active females were divided into control and experimental groups. The experimental group performed a plyometric training program for 6 weeks, 3 days per week. All subjects attended 4 testing sessions, prior to the start of the training program and after weeks 2, 4, and 6. An AMTI Accusway force plate (AMTI Inc., Watertown, MA) was used to measure postural control variables. Subjects performed three 30-second trials of single leg balance on their dominant leg. Center of pressure excursion velocity in the frontal and sagittal planes (VAvg), total length of path pressure (PLength), and the area of the 95 % confidence ellipse formed by the center of pressure excursion (Area95) were measured. Hamstring and quadriceps strength (dominant leg) were assessed using a Biodex System 3 (Biodex Inc., Shirley, NY) isokinetic dynamometer. Two trials of 10 repetitions were performed for knee flexion and extension at speeds of 60° per second and 120° per second. Peak torque (PeakTq), average peak torque (AvPkTq), and average power (AvgPower) generated by the muscle groups were measured. The repeated measures analysis of variance revealed significant interactions between time and group for flexion peak torque (P = .030) and average power (P = .020) at 120°?per second. Post hoc analysis further revealed peak torques at 120° per second were higher in the plyometric group than the control group at testing session 4 and average power was higher in the plyometric group than the control group at testing sessions 2, 3, and 4. Data analysis also revealed increased peak torque and average power from testing session 1 to session 4 in the plyometric group. Our results indicate that the plyometric training program improved hamstring strength, improved hamstring:quadriceps ratio and was able to improve concentric strength with eccentric actions. Additional research is warranted to better understand the effects of plyometric training on neuromuscular control and the affective use of plyometrics in preventing ACL injuries.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-28–S-29.

Effects Of Agility Training On Thigh Muscle Activation And Knee Joint Kinematics During A Side-Step Pivot Maneuver In Female Basketball Players

DR Wilderman ¹, DA Padua ¹, SE Ross ¹

Abstract

Biomechanical factors, including muscle activation and joint kinematics, are believed to be important factors that may influence ACL injury risk. It is believed that biomechanical factors may be altered through physical training. However, there is limited research investigating the influence of physical training on biomechanical factors. Therefore, the purpose of this study was to examine the effects of a 6-week agility-training program on knee flexion kinematics and muscle activation amplitude of the quadriceps and hamstrings during a side-step pivot maneuver. Thirty healthy female intramural basketball players were randomly assigned to a training group (n=15; age= 21.0±3.6 yr.; ht= 171.4±5.6 cm; wt= 67.5±7.7 kg) or a control group (n=15; age= 21.0±1.8 yr.; ht=171.0±3.6 cm; wt= 65.1±7.1 kg). During testing, subjects were required to perform a side-step pivot on their dominant leg while running at a controlled speed. The side-step pivot involved subjects performing a 45° pivot in the direction opposite their pivot leg. The following knee kinematic variables were assessed using an electromagnetic tracking system: knee flexion at initial contact, maximum knee flexion during stance, and knee flexion displacement during stance. Surface EMG was used to record mean amplitude of the lateral hamstring (LH), medial hamstrings (MH), vastus medialis (VM), and rectus femoris (RF) during the preparatory response (50 msec before initial ground contact) and loading response (50 msec following initial ground contact) phases. Subjects were tested on two occasions: pre-training and post-training. Between the pre-training and post-training sessions the training group participated in three agility training sessions each week over a 6-week period. Control group subjects maintained their normal physical activity levels and did not participate in the agility-training program. Statistical analysis was performed using separate mixed-model repeated measures ANOVA. The results of this study revealed a significant test-by-phase–by-group interaction for MH mean amplitude (p=0.003). Tukey's post hoc analysis indicated that the training group had significantly greater MH mean amplitude during the loading response phase at post-training when compared to pre-training. Knee kinematics and mean amplitudes of the VM, RF, and LH were not significantly influenced in the training group. Increased MH muscle activity following agility training may help improve knee joint stability and protect the ACL from injury. The relationship between agility training and ACL injury rates requires further study. Supported by a grant from the NATA Research & Education Foundation Osternig Master's Grant Program.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-29.

Hamstring To Quadriceps Strength Ratios: An Analysis And Strength Training Study

HJ Lee ¹, WR Holcomb ¹, MD Rubley ¹, JA Mercer ¹, A Morcos ¹

Abstract

A contributing factor to ACL sprains and hamstring strains is a poor hamstring to quadriceps (H:Q) strength ratio. The purpose of this study was to examine the H:Q strength ratios of female soccer athletes, and to test the effects of a six week strength training program on this ratio. Twelve NCAA Division I female soccer athletes (age = 20 ± 0.8 yr, height = 168 ± 8.6 cm, weight = 61 ± 7.7 kg) were required to complete two practice test sessions, a pre test, six weeks of strength training, and a post-test. The independent variables were test, leg dominance, and angular velocity. The dependant variables were the conventional (concentric:concentric) and functional (eccentric:concentric) H:Q strength ratios. Isokinetic testing was performed with gravity correction on a Kin-Com 125E Plus dynamometer. Eight repetitions of knee flexion and extension (10–90° ROM) at each angular velocity were performed in the following order: concentric 240, 180, 60°/s and eccentric 60, 180, 240°/s with 90 seconds rest between sets. The highest peak torque from each set was used to calculate the H:Q strength ratios. Strength training with an emphasis on hamstring development was conducted 4 times weekly for 6 weeks. Each day 1–3 of the following hamstring specific exercises were added to pre-season workouts: hamstring curls, hip hyperextensions, straight leg dead lifts, good mornings, fitball leg curls, and resisted sled walking. Following the training period subjects were post-tested in a manner identical to the pretest. Conventional and functional H:Q strength ratios were analyzed separately with 2 (test) × 2 (leg dominance) × 3 (angular velocity) ANOVAs with repeated measures. Significance was set at 0.05 apriori. The functional ratio was 12% higher following training (p=0.049), while the conventional ratio did not significantly change (p=0.116). Both conventional and functional ratios showed significant differences in dominance with the non-dominant limb greater than the dominant limb (p= 0.002 and p = 0.013, respectively), and in angular velocities with 240>180>60°/s (p<0.001) for each ratio. These findings suggest that six weeks of hamstring specific strength training can significantly increase the functional H:Q strength ratio. Although the ideal functional H:Q strength ratio is not known, the assumption is that a higher ratio will provide a lower risk of ACL sprains and hamstring strains.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-29.

Prefabricated Foot Orthotics Decrease Internal Tibial Rotation During Hopping In Females

PA Houglum ¹, CR Carcia ¹

Abstract

Excessive internal tibial rotation during deceleration activities increases anterior cruciate ligament strain and injury risk. Foot orthotics have been utilized to decrease internal tibial rotation during walking and running. The effect of foot orthotics on tibial rotation during deceleration tasks however is unknown. Therefore, the primary purpose of our study was to compare tibial rotation during two deceleration tasks with and without a foot orthotic. As females exhibit greater internal tibial rotation during deceleration tasks compared to males, a secondary purpose was to determine if males and females responded differently between test conditions. Using a repeated measures[RM] counterbalanced design, a convenience sample of 20 participants (age=22.1±0.7yrs; height=171.1±8.6cm; mass=68.3±10.1kg) completed three trials of a hopping and landing task with and without a prefabricated foot orthotic. The prefabricated foot orthotic (Interpod®; St Kilda, AU) was semi-rigid and included a 6° rear-foot varus post. Participants performed a single-leg hop at a distance equal to 45% of their height onto the center of a force plate. They also performed a single-leg landing from a box (height=25cm) onto the center of a force plate. An electromagnetic tracking system measured three-dimensional lower extremity kinematics while the force plate identified ground contact. Tibial excursion was defined as the difference between peak rotation and initial contact joint angles. A mean of the three trials for both activities and conditions was used for data analysis. Hop and land data were analyzed with separate RM ANOVA with one within factor at two levels (foot orthotic; no foot orthotic) and one between factor (sex). There were no differences in tibial rotation with or without a foot orthotic for either the hop (P =0.33) or landing activity (P =0.13). When sex was considered, a hop by sex interaction was noted (P =0.028) indicating males and females responded differently between test conditions. Tukey's post hoc analysis revealed that while male tibial excursion did not differ between test conditions, female internal tibial excursion decreased from 4.5±3.7° without the foot orthotic to 3.2±3.9°?with the foot orthotic. A land by sex interaction however was not apparent (P=0.87). When male (n=7) and female (n=13) groups were compared it was observed that females internally rotated 5.3±7.5° and 6.1±7.58° more than males for both the hopping (P=0.006) and landing (P =0.01) tasks, respectively. The results suggest that females internally rotate more than males during both hopping and landing and that a prefabricated foot orthotic device is capable of decreasing internal tibial rotation in females during hopping. Additional study investigating the effect of a foot orthotic device on lower extremity kinematics in females is warranted.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-29–S-30.

Prediction Of Tibial Rotation During Landing And Hopping In Females

CR Carcia ¹, PA Houglum ¹

Abstract

Increased internal tibial rotation during dynamic activity has been suggested as a non-contact ACL injury risk factor. Females display greater internal tibial rotation excursion than males when performing deceleration activities. The factors responsible for the observed lower extremity kinematic pattern in females are unknown. Therefore, the purpose of our study was to develop a model of anatomical variables capable of predicting tibial rotation during single leg deceleration activities in females. After quantifying several anatomical variables (navicular drop [ND] = 6.9 ± 2.8mm, BMI = 22.8 ± 2.9, hip anteversion [AV] = 1.9 ± 4.25°, hip external rotation strength = 0.12 ± 0.04), 13 recreationally active female participants (age=22.3 ± 0.7yrs; height=165.7 ± 4.4cm; mass=62.6 ± 7.3kg) completed three trials of two separate deceleration tasks in a counterbalanced fashion. Participants performed a single leg landing from a box (height = 25cm) onto the center of a force plate. They also performed a single leg hop at a distance equal to 45% of their height onto the center of a force plate. An electromagnetic tracking system measured three-dimensional lower extremity kinematics while the force plate identified ground contact. Tibial excursion was defined as the difference between peak rotation and initial contact joint angles. A mean of the three trials for both activities was used for data analysis. For both the land and hopping activities, the tibia internally rotated 3.03 ± 4.11° and 4.54 ±?3.75°, respectively. Using the aforementioned independent variables to predict tibial rotation excursion, a significant multiple linear regression model was calculated for the landing activity (P = 0.04; R² = 0.57; Adjusted R² = 0.43; SEE = 3.12°) while a trend was noted for the hopping task (P = 0.09; R² = 0.49; Adjusted R² = 0.32; SEE = 3.09°). For landing, the regression equation that predicted tibial rotation excursion using beta weights = 22.009 ± (1.09)(ND) − (1.083)(BMI) − (0.771)(AV). The significance levels of the independent variables included in the regression equation were 0.007, 0.028 and 0.063 for ND, BMI and AV, respectively. Hip external rotation strength did not significantly contribute to the variability in either task. The results of this study suggest that dynamic tibial rotation during landing in females can be predicted by the combination of several simple descriptive and anatomical measures. Future study is necessary to develop a linear combination that more accurately predicts tibial rotation during hopping and to validate the identified landing prediction model.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-30.

Gender Differences In Internal And External Tibial Rotation Strength At Three Knee Flexion Angles

KM Keller ¹, I Cucina ¹, J Bernier ¹

Abstract

Women in sports participation has increased dramatically over recent years. With this increase, there has been an increase in interest regarding anterior cruciate ligament (ACL) injury. The hamstrings function together with the ACL to provide anterior stability. When the hamstrings contract they decrease forward displacement and rotation of the tibia . The purpose of this study was to determine if there was a gender difference in internal and external tibial rotation strength at three knee flexion angles. A total of 15 female and 15 male voluntarily participated in this study. The mean age was 22.3, mean height was 67.76 inches, and mean weight was 159.3 pounds. The Biodex isokinetic dynamometer was used to measure peak torque to body weight ratio (PTBWR) at 30°/s. Peak torque was determined at knee flexion angles of 20°, 45°, and 90°. Subjects performed three maximum repetitions of internal and external tibial rotation at prescribed angles of 20°, 45°, and 90°. A 2 × 2 × 3 mixed factorial analysis of variance (ANOVA) was used to determine if differences existed in PTBWR across the degrees of knee flexion. Tukey's Honestly Significant Difference post hoc analysis was used for determination of interactions. A significant gender by angle by direction interaction (df, 12 F=4.211, p = .020) was found. Internal tibial rotators of males were stronger than their external tibial rotators at 20° and 45°. Females internal tibial rotators were weaker than their external tibial rotators in all three cases. Further research is recommended to compare internal to external tibial rotation strength ratios to hamstring/quadriceps ratios and to determine if there is a biomechanical relationship between function, EMG, and internal to external tibial rotation strength ratio.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-30–S-31.

Navicular Drop Predicts Transverse Plane Knee Moments In A Single-Leg Weight-Bearing Perturbation

TC Windley ¹, AS Kulas ¹, SJ Shultz ¹, DH Perrin ¹, RJ Schmitz ¹

Abstract

Knee rotation moments have been reported to cause ACL strain. While lower extremity alignment (LEA) has been proposed as an ACL injury risk factor, little research has examined the influence of LEA on knee rotation moments during functional tasks. Hence, our purpose was to examine the effect of select LEA on knee rotation moments during a single-leg weight-bearing perturbation. Twenty subjects (10M,10FM; 24.9±4.1yrs, 171.5±7.7cm, 73.6±17.2kg) were measured for navicular drop (ND), tibial torsion (TT), and hip anteversion (HA). ND was the change in navicular height from standing subtalar neutral to relaxed stance. TT was the angle between the femoral condyles and the malleoli in the transverse plane. HA was the angle between vertical and the line of the shank with a 90° flexed knee when the greater trochanter was most prominent to palpation in prone. Intratester reliability for ND (ICC=.98,SEM=.5mm), TT (ICC=.78,SEM=2.1°), and HA (ICC= .97,SEM=1.1°) was confirmed. An electromagnetic tracking system and a non-conducting force plate monitored kinematics and kinetics while a lower extremity perturbation device produced an internal (IRP) or external (ERP) rotation perturbation of the femur on the weight-bearing tibia at 30° of knee flexion. ND, external TT, HA, and internal rotation moments of the tibia on the femur were expressed as positive. Stepwise linear regressions predicted knee rotation moments (peak, and initial to peak) from ND, TT, and HA for ERP and IRP. Means±sd for ND, TT, and HA were 7.5±3.5mm, 16.6±3.4°, and 12.7±6.5°. Means±sd for mass normalized knee rotation moments for IRP were (peak=.08±.09N*m/kg), and (Ä=.04±.05N*m/kg) and for ERP were (peak=.11±.20N*m/kg), and (Ä=.13±.24N*m/kg). ND predicted 32.8% of the variance (adjusted R²,P=.005) in the change in knee internal rotation moment during IRP and 20.8% of the variance (adjusted R²,P=.025) in the peak internal rotation moment during ERP. TT and HA did not significantly contribute to the prediction of knee rotation moments. Research suggests that increased pronation or ND is associated with a concommitant increase in internal tibial rotation. These results support that research and suggest that during IRP persons with greater ND may experience higher knee internal rotation moments than persons with less ND. During ERP persons with less ND may little to no pronation as a function of the task, however persons with high ND may excessively pronate to provide stability causing greater peak internal rotation moments. The effect of ND and static alignments on lower extremity kinetics should be further examined during dynamic activities.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-31.

Landing Kinematics Of Collegiate Women's Basketball Athletes Correlate With Isokinetic Peak Torque Values

PA McGinn ¹, CG Mattacola ¹, RL Shapiro ¹, TR Malone ¹, DL Johnson ¹

Abstract

The purpose of this study was to observe the relationships between knee joint kinematics during landing and isokinetic strength variables. Fourteen collegiate female, right leg dominant, basketball athletes volunteered for participation (age, 19.0 ± 1.07 years; height, 174.12 ± 5.82 cm; mass, 66.72 ± 6.18 kg), and reported no history of lower extremity surgery or occurrence of a lower extremity injury within 3 months prior to testing. Each athlete performed four repetitions of two single-limb landing tasks (hop and step) on each leg. Six Falcon high-speed video cameras recorded kinematic data (120 FPS) in conjunction with Expert Vision Analysis (EvaRT) software (Motion Analysis, Santa Rosa, CA). Isokinetic peak torque for the hamstrings (concentric) and quadriceps (concentric and eccentric) were measured using the Biodex Isokinetic Dynamometer (Biodex Medical Systems, Shirley, NY). Bilateral isokinetic strength evaluations were performed at an angular velocity of 180°/second for both concentric and eccentric tests. We calculated peak torque relative to body mass (Newton·meters/kilogram) as the maximum torque over five repetitions for the concentric test and three repetitions for the eccentric test. Kinematic data used in reduction began 50 msec prior to impact and extended through the landing phase; ending 350 msec after impact. Post processing of kinematic data was performed using KinTrack software (Motion Analysis, Santa Rosa, CA). All kinematic and strength data were statistically analyzed using SPSS®; alpha level p < .05 (a priori). No bilateral differences existed when comparing 1) traditional hamstring/quadriceps (H/Q) strength ratios, 2) concentric/eccentric H/Q strength ratios, 3) hamstring peak torque, and 4) eccentric quadriceps peak torque values. However, concentric quadriceps peak torque values were significantly larger for the left limb compared to the right limb (p = .002). Pearson correlations indicated moderately high negative correlations between 1) right concentric hamstring peak torque (RCHPT) and right knee rotation displacement (r = −.673, p =.012) during the hop task and 2) RCHPT and right knee rotation displacement (r = −.646, p =.017) during the step task. These results indicate that as hamstring peak torque increases, the magnitude of knee internal rotation decreases. Our findings support that concentric hamstring strength, may influence knee joint rotation kinematics in female basketball athletes when performing single limb landing tasks. Further investigation is needed to evaluate the relationship between leg dominance and kinematic and strength variables.

PERMALINK

Free Communications, Oral Presentations: Ankle Instability

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JE Kovaleski

JM Hollis

RJ Heitman

LR Gurchiek

AW Pearsall

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Abstract

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J Hertel

LC Olmsted

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Abstract

Arthrogenic Muscle Inhibition Is Present In Patients Exhibiting Functional Ankle Instability

ED McVey

RM Palmieri

CL Docherty

SM Zinder

CD Ingersoll

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Abstract

Functional Performance Deficits Are Present In Participants With Ankle Instability

CL Docherty

BL Arnold

BM Gansneder

SR Hurwitz

JH Gieck

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Abstract

Comparing Stabilization Times In Individuals Presenting Functional Ankle Instability And Mechanical Instability

SE Ross

KM Guskiewicz

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Abstract

Time-To-Boundary Measures Of Postural Control And Chronic Ankle Instability

LC Olmsted

J Hertel

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Abstract

Is There A Temporal Relationship Between Lateral Ankle Sprain And Deficits In Postural Control?

TA Evans

J Hertel

RA Braham

WJ Sebastianelli

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Abstract

A Comparison Of Ankle Muscle Reaction Times Following Sudden Ankle Inversion During Walking And Standing

TA McLoda

JT Hopkins

SM McCaw

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Abstract

The Effects Of Ankle Taping And Spatting On The Reaction Times Of The Supporting Musculature Of The Ankle After Sudden Inversion

JI McKenzie

BL Van Lunen

M Walker

C Joyce

JA Onate

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Abstract

Development Of Standards And Criteria For The Selection, Training, And Evaluation Of Athletic Training Approved Clinical Instructors

TG Weidner

JM Henning

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Abstract

A Nationwide Study Of Undergraduate Athletic Training Students' And Educators' Individual Moral Philosophies And Ethical Decision-Making

SV Caswell

TG Gould

RG Deivert

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Abstract

Behavioral Analysis In The Athletic Training Clinical Learning Environment

SA Denhup Jr

MA Sandrey

A Hawkins

VG Stilger

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