Free Communications, Oral Presentations: Clinical Applications of Cryotherapy

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-32.

Effects Of Knee Joint Effusion And Cryotherapy On Lower Chain Function

Abstract

Arthrogenic muscle response (AMR) is an ongoing reflex inhibition or facilitation of joint musculature that plays a central role in maintaining neuromuscular deficits of the quadriceps following knee joint injury. While cryotherapy has been shown to disinhibit the quadriceps following joint injury using a resting measure (H-reflex) of motor recruitment, more data are needed to determine if joint cryotherapy will result in preservation of voluntary knee joint function following joint injury. The purpose of this study was to quantify muscle recruitment changes and knee joint function following joint effusion and subsequent joint cryotherapy. Subjects were 45 (26 male 19 female) volunteers (age 21±2 yrs, ht 174.8±10.2 cm, mass 78.1±15.4 kg) randomly assigned to 1 of 3 equal groups (normative, effusion/control, and effusion/cryotherapy). Baseline (pre) measures of joint torque and power from the lower chain and average and peak vastus medialis (VM), vastus lateralis (VL), medial hamstrings (MH), and gastrocnemius (G) normalized EMG were collected during the extension phase of a seated recumbent stepping motion with a resistance of 36% of 1 RM and a controlled speed of 1.5 Hz. Following baseline measures, 50 mL of sterile saline was injected into the knee joint capsule. Once the effusion was confirmed, all measurements were repeated immediately (post), at 30 min, and at 60 min. In the cryotherapy/effusion group a 1.5 L bag of crushed ice was wrapped to the anterior surface of the knee immediately following injection and removed prior to the 30 min measurement. Subjects in the effusion/control group were prepared with a similar bag filled with a non-cooling substance of the same weight and texture. Dependent variables were measured at the same time intervals for a normative group, which was not injected with saline. MANOVAs with repeated measures on time were used to detect differences between groups across measurement intervals for knee joint kinetic data and average and peak EMG data. An overall time × group effect was detected for knee kinetic variables (F_24,504=2.228, P=.001) and peak EMG measures (F_24,504=2.062, P=.002). Univariate tests revealed a decrease in peak torque (P=.005, Sidak's) and average power (P=.018, Sidak's) at 30 min intervals and peak power (P=.001, Sidak's) at 30 and 60 min post-injection for the effusion/control group relative to the effusion/cryotherapy group. A decrease in peak VL activity was also noted at post (P=.014, Sidak's), 30 min (P=.001, Sidak's), and 60 min (P=.047, Sidak's) intervals in the effusion/control group. These data suggest that joint cryotherapy helps restore normal joint kinetics following effusion. This could be due to re-established VL activation from disinhibition of the motoneuron pool. Supported by a grant from the NATA Research & Education Foundation.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-32.

Ankle Cryotherapy Facilitates Peroneus Longus Motoneuron Activity

BA Krause ¹

Abstract

It is well recognized that the peroneus longus is an important dynamic lateral stabilizer during ankle injury rehabilitation. A growing body of literature has supported the use of cryotherapy prior to activity and rehabilitation. These studies provided evidence that joint cooling enhances voluntary and resting motor function of the soleus muscle. The purpose of this study was to examine the affects of ankle cryotherapy on resting motor function and eversion torque in the peroneus longus muscle. A 2 × 3 doubly-repeated measures factorial design was used. Treatment order was assigned using a Latin Square. Eleven healthy, physically active volunteers (age=19.6±1.3yr; ht=174.7±4.8cm; mass=74.4±10.3kg) were tested for a normalized Hoffmann reflex (a ratio of the maximum H-reflex to the maximum motor response) and peak eversion torque. Peroneus longus H-reflexes and M-responses were elicited by percutaneous electrical stimulation of the sciatic nerve and recorded by surface electromyography. Isokinetic eversion torque (a mean of five trials) was collected at 60° per second. An ice bag was placed over the dorsum of the foot and ankle for 30 minutes as the subject remained semireclined. H-reflex and torque measurements were collected prior to, immediately following and at 30 minutes post cryotherapy. Surface temperatures were recorded near the EMG electrodes to assure a constant temperature at that site. Separate two-way repeated measures ANOVAs were used to detect main effect differences across time. Ankle joint cooling resulted in a facilitation of the peroneus longus normalized H-reflex (F_{2, 20} =12.76, P<0.0001) and an increase in the eversion torque (F_2,20 =8.97, P ≤ 0.001). Pairwise comparisons revealed that H-reflexes and eversion torques were greater immediately following and at 30 minutes post cryotherapy relative to baseline measurements (P<0.05) and controls (P<0.05). The peroneus longus motoneuron pool is facilitated following 30-minutes of crushed ice applied to the ankle and following a 30-minute postcooling period. These data support the use of cryotherapy prior to activity and ankle joint rehabilitation.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-32–S-33.

Effects Of Unilateral Ankle Ice Water Immersion On Normal Walking Gait

JB Brucker ¹, KL Knight ¹, MD Ricard ¹, JW Myrers ¹, SS Schulthies ¹, GB Schaalje ¹

Abstract

To determine the effect of a 20-min 1°C ankle immersion on treated and contralateral limb walking gait biomechanics, we designed a 2 × 2 × 13 factorial experiment with repeated measures on the last 2 factors. The independent variables were treatment order (immersed on day 1 or day 2), treatment (immersion & no immersion), and gait set (pre-immersion & 0.5, 4, 8, 12 min post-immersion). The 1^st 3 uncompromised gait trails out of the 5 in each set were used for analysis. The average post immersion time for the 3 gait trails chosen was computed from a running stopwatch. A 6-camera infrared system with 2 force platforms embedded in a 15m carpeted walkway was used to collect and calculate 46 gait measures for both limbs using the real-time gait parameter curves. Each leg was considered independent. Additionally, 13 gait pattern graphs (normalized to 100% stride cycle) were inspected for shape changes. A principal component analysis was performed to determine if any variables explained a large portion of the variability. Moreover, a plot of the 1^st versus 2^nd principal components of the gait variables was used to identify outliers. Gait variables were analyzed using a mixed model with cycle velocity as a covariate on the remaining variables with significance set a priori at 0.05 and not adjusted for multiplicity. Twenty male volunteers (23.60 ± 2.50yrs, 182.2 ± 0.06cm, 80.45 ± 10.72kg), free of injury and cold hypersensitivity, participated. Inspection of the movement pattern graphs indicated only the treated limb plantar/dorsiflexion angle and moment, and hip flexion/extension moment shapes were affected by the immersion, which means that 77% of the ipsilateral limb and 100% of the contralateral gait parameter curves were unchanged. Moreover, the majority of the gait variables (29/46 treated limb; 36/46 contralateral limb) were not affected by the immersion, and more than 50% of those that were affected returned to normal within 4.5 minutes. We conclude that immersing an ankle in a slush bath for 20 minutes does not increase risk of injury during whole body submaximal exercise following immersion.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-33.

Cryotherapy Treatment Does Not Impair Dynamic Stability In Healthy Females

SE Miniello ¹, ME Powers ¹, MD Tillman ¹, MB Horodyski ¹, EA Wikstrom ¹, GC Dover ¹

Abstract

The lateral ankle sprain is a common injury suffered by individuals who compete in cutting and jumping sports such as volleyball, soccer, and basketball. Although this injury is not gender specific, the increased participation of females since the inception of Title IX has resulted in a corresponding increase in the number of injuries suffered by females. Regardless of gender, clinicians frequently use cryotherapy when managing lower extremity injury. While cryotherapy affects nerve conduction and other components of neuromuscular control, it is unclear whether it would affect performance during a functional task (e.g. jump landing). It is quite possible that changes in tissue temperature would affect balance and dynamic stability. If cryotherapy impairs neuromuscular function, clinicians might need to change their decision with regards to returning to play immediately following treatment. Thus, the purpose of this study was to determine if lower leg cold immersion would alter dynamic stability during a functional task. Seventeen healthy female subjects (age=20.9±1.1 yr., ht.=165.5±4.8 cm, mass=65.9±13.9 kg) were assessed for time to stabilization (TTS) and preparatory and reactive muscle activity (EMG) during a jump-landing task immediately before and after receiving a cryotherapy treatment. Subjects were also reassessed following a 5-min recovery period after treatment. The dependent measures were assessed during a single leg landing from a jump height equivalent to 50% of each subject's maximum. Subjects stood 70-cm from the center of a force plate and jumped with both legs toward the center of the plate. Subjects were instructed to land on the preferred leg, stabilize as quickly as possible and balance for 20-sec. The cryotherapy treatment consisted of a slush bucket set at tibial tuberosity level and maintained between 13°C and 16°C for 20-min. One-way repeated measures ANOVA revealed that lower leg cold immersion therapy increased preparatory muscle activity of the tibialis anterior (F_2,16=10.65, p=.004] as the activity immediately following treatment was significantly greater than before treatment and after 5-min of recovery. ANOVA also revealed a significant decrease in the preparatory (F_2,16=10.93, p=.004) and reactive (F_2,16=8.26, p=.004) activity of the peroneus longus when comparing the immediate post-test to the pre-test. EMG activity of both muscles returned to normal following 5-min of recovery. TTS did not change following treatment. The results of this study suggest that lower leg cold immersion therapy does not impair dynamic stability during a functional lower extremity task. Thus, return to participation following cryotherapy treatment is not contraindicated.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-34.

Effects Of Cold And Warm Bath Immersions On Postural Stability

MD Rubley ¹, AR Gruenenfelder ¹, RD Tandy ¹, WR Holcomb ¹

Abstract

Cryokinetics is common practice for treatment of ankle sprains. One common functional activity during cryokinetics is single leg standing balance or stork standing, yet some argue that immersion immediately prior to exercise is contraindicated. Performance has been evaluated after cold treatments however, ice bath immersion effects on postural stability have not been actively researched. Therefore the purpose of this study was to determine if measures of center of pressure (postural sway) following ankle immersion differ during specific treatment conditions, and additionally if center of pressure changes over time. Eighteen healthy college students with previous experience with ice bath immersion (9 males, 9 females, age 25±5yrs, ht. 174.4±13.2cm, wt. 81.7±25.1kg) completed 3, 30-second single leg balance trials prior to, immediately post and 5 minutes post immersion for each of the immersion conditions. The conditions consisted of subjecting the right foot and ankle to a 20 minute 1°C ice bath, a 45°C warm water bath, and a control condition, which were performed on 3 separate days. Force data (200 Hz) were recorded for total distance traveled (m), mean medial/lateral distance (m) and mean anterior/posterior distance (m) while subjects performed right leg standing balance on a Kistler force plate. Dependent variables were compared between and among gender, treatments and time using repeated measures ANOVA with significance held at 0.05. No significant time or treatment condition effects for the total distance, mean medial/lateral distance and mean anterior/posterior distance were observed. However, the female participants had a greater total distance traveled (F_{1, 16} = 9.292, p = 0.008) than the males; 4.78±1.08m & 3.56±0.45m, but less (F_{1, 16} = 11.34, p = 0.004) mean medial/lateral distance; 0.031±0.005m & 0.036±0.005m, and less (F_{1, 16} = 9.265, p = 0.008) mean anterior/posterior distance; 0.033±0.005m & 0.036±0.005m under all treatment conditions and at each point in time. Female participants adjusted their center of pressure more frequently resulting in greater total distance traveled, but moved within a smaller square area than the males. This observation was constant over time and across conditions. Ice bath immersion does not cause a greater loss of balance as measured by total distance traveled, anterior/posterior sway and medial/lateral sway. The lack of significant differences across time or between conditions suggests postural sway is not compromised following ankle immersion, as used during cryokinetics.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-33–S-34.

Loss Of Mitochondrial Oxidative Function Following Blunt Injury In Skeletal Muscle

MA Merrick ¹

Abstract

Cryotherapy for acute injury management is largely based on the premise that it inhibits secondary injury although the data describing secondary injury and the timeline for its progression are sparse. The purpose of this study was to describe the early progression of secondary injury following blunt trauma as indicated by the loss of mitochondrial oxidative activity. A 2 × 21 (injury status × post-injury timepoint) factorial design was used. The dependent variable was flux through oxidative phosphorylation as indicated by cytochrome c oxidase activity. Following animal protocol approval, 168 male Sprague-Dawley rats (250 – 275g) were anesthetized and a uniform blunt contusion injury was caused to their right triceps surae using a drop weight method. The contralateral triceps surae served as an uninjured control. Both triceps surae were then excised at 15 minute intervals (n = 8 at each timepoint) starting immediately following injury and continuing to the 5-hour point, a total of 21 timepoints. Tissues were flash frozen in liquid N₂ and stored at −80°C until analysis. Whole muscle homogenates were analyzed for cytochrome c activity through a colorimic assay for the reduction of triphenyltetrazolium chloride (TTC). Data were analyzed using a 2 × 21 factorial ANOVA with Sidak corrected pairwise comparisons. An interaction effect was observed (P = 0. 041) as were main effects for both injury status (P <.0005) and post-injury timepoint (P = 0.038). From the period immediately following injury up through the 30-minute point, controls did not statistically differ from injured tissues and both displayed TTC reduction rates in the vicinity of 7.1 ± 0.94 μg·mg⁻¹·hr⁻¹. Beyond the 30-minute point, statistical differences between controls and injured tissues became evident. The decline in TTC reduction for the injured tissues was roughly linear from the 30-minute point until the final measured timepoint at 5 hours post-injury. At this point the controls had not changed but the injured tissues' TTC reduction had declined to 4.8 ± 1.04 μg·mg⁻¹·hr⁻¹. These data suggest that oxidative phosphorylation is disrupted by events that follow muscle trauma; that this disruption becomes statistically evident between 30 and 45 minutes post-injury; and that oxidative phosphorylation declines at a relatively linear rate for at least 5 hours following injury without leveling off in this timeframe. This suggests that secondary injury is a slowly developing problem of greater than 5 hours duration. This study was conducted in hopes of identifying a “window of opportunity” for intervention following trauma and such a window may exist somewhere within the first 30 minutes following injury. Supported by a grant from the NATA Research & Education Foundation.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-34.

Pelvis And Hip Neuromechanical Characteristics Predict Knee Biomechanics During A Stop-Jump Task

CM Ferris ¹, JP Abt ¹, TC Sell ¹, JB Myers ¹, SM Lephart ¹

Abstract

Previous observational research has described the position of the pelvis and hip relative to vulnerable knee positions during functional tasks. Limited quantitative data is available to define this relationship between the pelvis and hip and knee. The purpose of this study was to determine if pelvis and hip neuromechanical characteristics predict knee biomechanics during a functional task and to determine if sex differences exist between the pelvis and hip neuromechanical factors. Forty healthy high school basketball players (20 Females: age: 15.8 ± 1.2 years, height: 1.7 ± .1 m, mass: 64.3 ± 10.4 kg; 20 Males: age: 16.4 ± 1.5 years, height: 1.8 ± .1 m, mass: 71.4 ± 8.3 kg) underwent clinical and neuromechanical testing. Clinical measurements consisted of hip abductor and hip external rotator strength, and pelvic width to femur length ratio (PWFLR) assessments. Neuromechanical testing consisted of joint kinematics and kinetics using 3D motion analysis of the dominant limb during a vertical stop-jump (VSJ) task. The VSJ task consisted of a two-legged hop onto the force plates from a distance equivalent to 40% of the subjects' height, followed by a two-legged landing and an immediate vertical jump for maximal height. Standing pelvic tilt was assessed using motion analysis. EMG analysis of the dominant erector spinae, rectus abdominus, gluteus medius, adductor longus, rectus femoris, vastus lateralis, and medial hamstrings was performed. Stepwise regression analyses revealed that decreased hip abductor strength and increased PWFLR significantly predicted increased knee valgus moments. Additionally, increased anterior pelvic tilt, decreased hip rotation during the VSJ task, and hip external rotator strength significantly predicted decreased knee flexion angle and internal knee extensor moments. Independent t-test analyses determined that females had significantly less hip external rotator strength (p=.03), greater PWFLR (p=.02), and greater erector spinae (p=.01) and medial hamstring (p<.01) muscle activation levels 150 ms prior to initial contact than males. This study suggests that knee function may be influenced by hip and pelvis neuromechanical characteristics. Although EMG differences existed between sexes, both sexes performed the VSJ task comparatively. The greater muscle activity in females may be a compensatory strategy to account for the lack of hip external rotator strength. Clinicians should incorporate pelvis and hip assessments into clinical examinations and implement appropriate treatments, regardless of sex, to prevent knee injuries.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-34–S-35.

Eccentric Hip Strength And Kinematic Differences Between The Dominant And Non-Dominant Legs Of Men And Women During A Hopping Task

C Jacobs ¹, CG Mattacola ¹

Abstract

Women injure the anterior cruciate ligament (ACL) at a much higher rate than men. Many of these injuries have been suggested to occur when female athletes land from a jump. During this activity, the female knee is more likely to go into a position of increased valgus and rotation angles that stresses the ACL. Eccentric dynamic control by the hip abductors could decrease the magnitude of the valgus and rotation angles of the knee. The purpose of this study was to evaluate and compare eccentric hip abduction strength and kinematics of the lower extremities of men and women. Eighteen healthy volunteers participated in the study (10 female, age=22.1±2.3 years, ht=167.01±5.03 cm, mass=63.95±8.61 kg; 8 males, age=24.1±2.2 years, ht=179.55±3.11 cm, mass=76.22±9.23 kg). The dominant leg was determined to be the leg used to kick a ball. Peak angles in the sagittal, frontal, and transverse planes were determined for the hip, knee, and ankle during a functional hopping task. The hopping task consisted of a single leg hop over a 10 cm box from a distance of 45% of the subject's height. Subjects completed four trials and the average peak angles during landing were used for analysis. All subjects performed an isokinetic test for eccentric hip abduction (120°/s) to collect average peak torque measurements (normalized to body mass). The hopping task and strength test were performed bilaterally. Ten separate 2×2 mixed model ANOVAs (gender × leg) were performed on each joint angle and average peak torque. There were no significant main effects for gender for any of the joint angles or average peak torque. While not significant (p=0.078), women demonstrated larger peak knee valgus angles (13.22°) than men (9.16°). There was a significant main effect for leg dominance at all three joints. The non-dominant leg had higher peak hip internal rotation (p= 0.015), higher knee external rotation (p= 0.014), and lower peak ankle internal rotation angles (p= 0.006) than the dominant leg. There were no significant differences in average peak torque between the dominant and non-dominant hip, however, 7 of the 18 subjects (4 women, 3 men) had side-to-side differences greater than 15%. Joint angles did not differ between genders, however, asymmetry in both joint angle and strength exist in the lower extremities. Further investigations should address the clinical significance of increased rotational movements of the non-dominant lower extremity, as well as the effect of side-to-side eccentric hip abduction strength differentials.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-35.

Knee Flexion Angle Increases Valgus Knee Angle And Surface Gluteus Medius EMG Activity During A Single Leg Drop Jump

KA Russell ¹, RM Palmieri ¹, SM Zinder ¹, CD Ingersoll ¹

Abstract

Gender differences in landing mechanics and muscle activation have been identified as potential causative factors leading to the increased incidence of ACL injuries in female athletes. Research has focused upon the differences in knee flexion angle (KFA) between males and females during various landing tasks but has failed to consider differences in frontal plane motion. Valgus knee alignment has been suggested to place greater stress on the knee joint complex compared to a more neutral alignment. Gluteus medius (GM) activation may act to stabilize the leg and pelvis during landing, limiting valgus motion at the knee and potentially preventing ACL injury. Therefore, the main purpose of this investigation was to determine if valgus knee angle (VKA) and gluteus medius average root mean square (RMS) amplitude are affected by gender and knee flexion angle during a single leg drop jump. Twenty-eight subjects (14 males and 14 females; Males ht = 181.9± 6.3 cm, mass 84.1± 9.9 kg ; Females: ht = 163.3 ± 6.2 cm, mass = 62.6 ± 9.2 kg) performed 8 trials of a drop jump on their dominant limb from a fixed height of 60 cm. KFA and VKA were estimated by the VICON motion analysis system using an inverse dynamics model. VKA and GM average RMS amplitude were recorded at initial ground contact and maximum knee flexion angle. Separate 2 × 2 repeated measures ANOVAs were performed to determine if gender and KFA affect VKA and GM RMS amplitude. VKA was smaller at initial contact than at maximum KFA (P < 0.025). GM average RMS amplitude was greater at maximum knee flexion than at initial contact (P < 0.025). VKA and GM average RMS amplitude did not differ between genders at either initial contact or maximum knee flexion (P > 0.025). Valgus knee angle and GM muscle activation increase as knee flexion angle increases during a single leg drop jump.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-35.

Gender Differences In Gluteus Medius Muscle Activity Exist In Soccer Players Performing A Forward Jump

JM Hart ¹, JC Garrison ¹, DC Kerrigan ¹, JA Boxer ¹, CD Ingersoll ¹

Abstract

Non-contact ACL injuries are often associated with rapid decelerations, such as landing from a jump. An interaction among several factors leaves females more likely to experience non-contact ACL injuries than males. Landing from a forward jump is intended to simulate the rapid deceleration that an athlete may encounter in athletics. The neuromuscular strategy used by females compared to males while landing from a jump may help explain the differences in injury rates. The purpose of this study was to evaluate gender differences in lower extremity muscle EMG while landing from a forward jump. Eight male (19.1±1.4 yrs, 182.85±2.4 cm, 77.05±6.9 kg) and eight female (22±2.1 yrs, 168.6±6.8 cm, 61.8±3.2 kg) division-one varsity soccer athletes volunteered for participation in this study. Subjects performed 5 trials of a one-legged, 100 cm forward jump that involved a one-legged take-off and landing. Surface EMG was collected at the gluteus medius, vastus lateralis, medial gastrocnemius and lateral hamstring. All EMG trials were normalized to unilateral static stance. Data were interpreted by VICON workstation and analyzed with Acknowledge software. EMG signals from 200ms following initial heel contact from landing were used in data analysis. A fixed-effect MANOVA was used to compare mean values of EMG root mean square (RMS) signals at each muscle between genders. Gluteus medius EMG values were significantly higher in males (7.16±3.16) than females (2.62±.95) (F_1,16= 15.2, P=.002). There were no gender differences in any of the other muscles. Gender-specific neuromuscular strategies used to attenuate the forces of landing may involve more gluteus medius muscle activity in males than females.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-35–S-36.

Comparison Of Gluteal Muscle Activity And Hip Muscle Strength Between Individuals With Normal And Excessive Navicular Drop

NM Fava ¹, DA Padua ¹, WE Prentice ¹, MT Gross ¹, CJ Hirth ¹

Abstract

The purpose of this study was to compare subjects demonstrating normal and excessive navicular drop on gluteal muscle activation amplitude and strength of the gluteus maximus, gluteus medius, and hip external rotators. Thirty subjects were recruited for this study. Subjects were divided into two groups: 1) excessive pronators (EP) (n=15) and 2) normal pronators (NP) (n=15). EP group subjects demonstrated a navicular drop of 9 mm or greater. NP group subjects demonstrated a navicular drop of 5 mm or less. Force production of the gluteus medius, gluteus maximus and short external rotators of the hip were assessed using a hand-held dynamometer. Muscle activation amplitude of the gluteus maximus and gluteus medius were assessed as subjects ran on a treadmill. Muscle activation amplitude of the gluteus medius and maximus muscles were measured during the final 15% of the swing phase and the first 25% of the stance phase. All EMG data were normalized to the subject's maximal voluntary contraction (%MVC). Separate mixed model repeated measures ANOVA were performed for muscle activation amplitude of the gluteus maximus and gluteus medius muscles. These analyses involved “group” as the between-subjects factor (2 levels: NP and EP) and “activation phase” as the with-in subjects factor (2 levels: final 15% swing phase, first 25% stance phase). Independent t-tests were performed to compare strength of the gluteus maximus, gluteus medius and hip external rotators between groups. Statistical analyses revealed no significant main effect for group nor group by phase interaction for gluteus medius and gluteus maximus activation amplitude (P>.05). There was also no significant difference between NP and EP groups for gluteus medius, gluteus maximus, and hip external rotator force production (P>.05). It appears that hip muscle strength as well as gluteal muscle activation amplitude during treadmill running are not influenced by static measures of pronation (navicular drop). There was a trend for reduced gluteus maximus activation in the EP compared to the NP group. On average, the EP group demonstrated 50% less gluteus maximus activation than the NP. However, this difference was not significant due to poor statistical power. Thus, while not statistically significant, gluteus maximus activation should not be discounted as a potential factor influencing static measures of excessive pronation. Future research may consider investigating isokinetic measures of hip muscle strength as well as different functional tasks during which gluteal muscle activation is measured.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-36.

The Relationship Between Core Strength And Pelvic Position Of Female, Collegiate Volleyball And Soccer Athletes During Dynamic Activity

SE Wedekind ¹, BL Riemann ¹, AB Joyner ¹, SA Geisler ¹

Abstract

The core, consisting of the abdominals, paraspinals, hip flexors, hamstrings, and gluteal muscles, is believed to provide for optimal positioning of the trunk and pelvis, and therefore affect the segments comprising the lower extremities. Yet, despite the clinical popularity and strong theoretical support, little research has been published explaining if increased core strength translates to better pelvic stability during dynamic activities. The purpose of this study was to determine if a relationship exists between core strength and pelvic stability during single leg hopping and lateral step-downs. Thirty-four female Division I collegiate varsity soccer and volleyball players (mass=67.8±6.7, height=168.9±7.9, age=19.7±1.4) participated in the study. Core strength was quantified using a modified version of the thoracolumbar functional gym stabilization evaluation (TLFGS), and isokinetic (30°/second) and isometric hip abduction peak torque. Pelvic stability during the dynamic tasks was operationally defined as the quantity of pelvic rotation, obliquity, and tilt angular displacement as measured by an electromagnetic tracking system. The single leg hopping task was completed under both unconstrained and constrained (2Hz) frequencies, while the lateral step-downs were only conducted at a constrained pace (.5Hz). After considering the normality of all dependent variables, Pearson correlational analyses were conducted. Results revealed significant correlation coefficients between both the isokinetic (r =.418, p=.014) and isometric (r =.445, p=.008) peak torques and TLFGS. No significant (p<.05) relationships were revealed between the TLFGS and pelvic stability variables during the dynamic tasks. In other words, greater core strength did not transfer over to maintaining the pelvis in a relatively fixed position during the dynamic activities. An alternative interpretation of the data may be that the dependent variable used to quantify pelvic stability, angular displacement, may not accurately reflect pelvic stability. Additionally, little literature could be found describing valid and reliable measures of core strength. Thus, the methods used to measure core stability, TLFGS and hip abductor strength, although inter-related, may have not accurately assessed dynamic core stability. Future research is recommended to determine appropriate dependent variables that quantify pelvic stability during dynamic activities, as well as valid core strength tests.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-37.

Chronic Ankle Pain In A Collegiate Basketball Player

TW Harkins ¹, KM Ramsdell ¹

Abstract

An eighteen year-old female collegiate basketball player complained of chronic left ankle pain throughout the fall semester of her freshman year. The athlete reported a history of lateral ankle sprains as well as anterior and medial ankle discomfort. Arthroscopic debridement and drilling of a superficial osteochondral defect on the posterolateral aspect of the talus had been completed 9 months prior to her arrival at our institution. She had completed significant physical therapy over the summer and had been cleared for full athletic participation. Throughout the fall semester the athlete had persistent medial and lateral ankle pain. She completed an extensive rehabilitation program focused on decreasing ankle discomfort, improving ankle range of motion, ankle strengthening, and proprioception. The athlete was also fitted for both half and full-length orthotics, as she presented with significant pes planus and an externally rotated walking gait. Following completion of the rehabilitation program, the athlete gradually returned to athletic competition. She played significant time in two basketball games with minimal discomfort, but came out of her third game complaining of intense medial ankle pain. On physical examination, the athlete had significant point tenderness over posteromedial ankle joint, tibialis posterior tendon, and talar dome. No remarkable effusion or ecchymosis was noted, and she had full ankle range of motion, though weight bearing dorsiflexion gave her significant discomfort. Anterior drawer, talar tilt, and Kleiger's tests' were all negative. Differential diagnosis included an osteochondral defect, tibialis posterior tendinitis, os trigonum, and medial ankle sprain. X-ray evaluation with a left ankle series demonstrated no obvious talar or tibial bony abnormalities. An MRI revealed minimal changes over the anterior aspect of the talar dome, though no dramatic underlying bony changes were noted. Due to persistent ankle pain and the athlete's inability to complete activities of daily living without discomfort, a second surgical procedure was completed. Arthroscopic examination of the talus revealed a full thickness chondral defect (7 × 13 mm) with arthrofibrosis. The orthopaedic surgeon felt that the lesion could best be addressed through the osteoarticular transfer system (OATS procedure). Two osteochondral plugs approximately 6 mm in diameter were harvested from the edge of the lateral femoral condyle and inserted into the 6 mm beds that were created from medial to lateral in the talar defect. Insertion of these plugs provided excellent fit and contour of the talar dome. Post-operative rehabilitation included 2 weeks non-weight bearing, 3 weeks partial-weight bearing, early range of motion exercises, isometric strengthening, progressive resistive exercises for plantar and dorsiflexion, and bike once range of motionallowed. Control of ankle and knee joint effusion was also a post-operative focus, and was addressed through the use of cryotherapy, compression, and elevation. At the five week post-operative examination, the athlete was advised to progress to full-weight bearing, continue to improve lower extremity flexibility, and add four-way Theraband ankle strengthening. Upon completion of the rehabilitation protocol, the athlete had full ankle and knee joint range of motion, normal ankle joint strength, and decreased ankle joint discomfort. This case is unique in the fact that initial surgical intervention for an osteochondral defect was unsuccessful, though the athlete did experience a transient decrease in her symptoms. Also, a variety of conservative treatment options were exhausted prior to a second surgical procedure. It should be noted that an athlete with chronic ankle pain may have a significant osteochondral lesion, though an MRI may not demonstrate significant changes and a normal x-ray may be negative for any bony abnormalities. Another consideration related to the OATS procedure is the importance of the non-weight bearing period to eliminate stress to the repaired articular cartilage and allow for a successful outcome.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-37–S-38.

Risk Factors For Ankle Sprains In High School Athletes

TF Tyler ¹, MP McHugh ¹, DT Tetro ¹, MJ Mullaney ¹, SJ Nicholas ¹

Abstract

The purpose of this study was to determine if balance ability and hip muscle strength are risk factors for non-contact inversion ankle sprains. Previous studies have shown that single-limb ankle disk training reduces the incidence of ankle sprains. However, an association between balance ability in single-limb stance and risk of ankle sprain has not been established. Additionally, ankle pathology has been associated with hip weakness but it is not clear if weakness is a cause or a consequence of injury. One hundred sixty nine athletes (101 male, 68 female) from 6 teams within the same high school (football, men's basketball, men's soccer, women's gymnastics, women's basketball and women's soccer) were followed for two years. Balance in single limb stance on an instrumented tilt board and hip flexion, abduction and adduction strength (hand-held dynamometer) were assessed in preseason testing. Body mass, height, ligamentous laxity, previous ankle sprains and ankle tape/brace use were also documented. There were 20 non-contact inversion ankle sprains (10 GI, 6 GII, 4 GIII) resulting in 41 missed games and 154 missed practices (incidence=1.13 sprains/1000 athlete-exposures). Injury incidence was not different between sports (range 1.56 in women's basketball to 0.8 in women's soccer) and genders (male 1.12, female 1.15). The incidence of GII and GIII sprains was higher in athletes with a history of a previous ankle sprain (1.12 vs. 0.26, p=0.04). Balance and strength were significantly different between teams (p<0.001). Women's soccer players and gymnasts had the best balance while men's soccer and football players had the worst balance. Hip flexion, abduction and adduction torque per body mass was highest in the women's soccer team and lowest for the women's gymnastics team. Balance ability (p=0.72), hip strength (p=0.48) and hip strength imbalances (p=0.9) were not significant risk factors for ankle sprains, even when balance and strength values were corrected for differences between teams. Generalized ligamentous laxity and tape/brace use were also not significant risk factors (p>0.9). A higher body mass index (BMI) in male athletes was associated with increased risk: injury incidence was 0.78 for athletes with a normal BMI, 1.17 for overweight athletes and 3.24 for obese athletes (p=0.028). Obese athletes with a history of a previous ankle sprain had a much higher incidence of injury than normal weight athletes without a history of previous injury (5.3 vs. 0.53, p=0.008). Only BMI and a history of a previous ankle sprain were significant risk factors. Since all obese athletes were in the football team these findings should be verified in a larger sample of high school football players. Balance ability and hip strength were clearly not risk factors for non-contact ankle sprains. These data indicate that the previously demonstrated decreases in the incidence of ankle sprains with single-limb ankle disk training may not be due to an effect on balance ability. Additionally, the common finding of hip weakness in patients with ankle pathology is likely a consequence of the injury rather than a causative factor.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-38.

Risk Factors For Ankle Sprains In High School Football Players

MR Mirabella ¹, TF Tyler ¹, MP McHugh ¹, SJ Nicholas ¹

Abstract

The purpose of this study was to determine if body mass index and history of a previous ankle sprain were risk factors for non-contact lateral ankle sprains in high school football players. Based on our previous study it was hypothesized that a high body mass index (BMI) and a history of a previous ankle sprain increase the risk of a subsequent non-contact inversion ankle sprain. One hundred fifty eight athletes from four football teams were followed (two varsity and two junior varsity). Two teams were followed for 2 seasons and two teams were followed for one season. Prior to each season body mass, height, history previous ankle sprains and ankle tape/brace use were recorded. Missed practices and games due to ankle sprain were documented and exposures were recorded for each player. There were 24 ankle sprains of which 15 non-contact inversion sprains (11 GI, 3 GII, 1 GIII) resulting in 17 missed games and 125 missed practices (incidence 1.08 non-contact sprains/1000 athlete-exposures). Injury incidence was significantly higher in athletes with previous ankle injuries (2.60 vs. 0.39, p<0.001). Eleven of the 53 players (21%) with a previous sprain sustained a new sprain compared with only four of 105 players (4%) with no history of a previous sprain. BMI was also a significant risk factor (p=0.015): injury incidence was 0.46 for players with a normal BMI, 1.08 for overweight players and 2.33 for obese athletes. Six of 28 obese athletes (21%) sustained ankle sprains compared with six of 60 overweight players (10%) and 3 of 73 players (4%) with a normal BMI. The use of preventive taping or bracing did not reduce the incidence of sprains. Given the increased incidence of obesity in adolescents it is important to note that there was a positive relationship between BMI and risk of an ankle sprain in high school football players. If a player was overweight or obese and had a history of a previous ankle sprain they were 16 times more likely to sustain an ankle sprain than a player with a normal BMI. These athletes may benefit from a preseason, preventative ankle stability training program to reduce sprains.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-38.

The Effects Of Fatigue And Chronic Ankle Instability On Dynamic Postural Control

PA Gribble ¹, J Hertel ¹, CR Denegar ¹, WE Buckley ¹

Abstract

There has been extensive research investigating the residual effects of lateral ankle sprains and chronic ankle instability (CAI). There also appears to be a relationship between altered neuromuscular control and muscle fatigue. Deficits in static postural control related to CAI and fatigue have been investigated separately, but there is little evidence to link these factors to performance measures of dynamic postural control. The Star Excursion Balance Test (SEBT) is a measure of dynamic postural control that has been shown to be reliable and valid in assessing deficits in dynamic postural control related to lower extremity musculoskeletal injury; however further investigation of performance on the SEBT through kinematic analysis has been limited. The purpose of this study was to investigate the effects of fatigue and CAI on performance measures of the SEBT. Thirty subjects (15 males, 15 females) were tested. Subjects were divided into those with (22.5±2.4 yrs; 1.7±0.1m; 71.1±18.6 kg; 7 males, 7 females) and without (21.9±2.9 yrs; 1.7±0.1m; 71.8±12.8 kg; 8 males, 8 females) unilateral CAI. All subjects completed 5 testing sessions during which 3 reaching directions (Anterior, Medial, and Posterior) of the SEBT were performed by the same stance leg before and after a designated fatiguing condition. During each testing session, both legs were tested with a 30-minute rest between tests. The fatiguing conditions were as follows: isokinetic fatigue to sagittal plane movers of 1) ankle, 2) knee, and 3) hip; 4) a continuous lunging task; and 5) control (no fatigue). Isokinetic fatigue was defined when the subjects' peak torque dropped below 50% of MVIC for 3 consecutive trials. Lunge fatigue was determined when subjects' could no longer keep pace with a metronome for 3 consecutive lunge cycles. During each testing session, the reach distances normalized to leg length (%MAXD) and sagittal plane kinematics of the ankle, knee, and hip were recorded. The injured side of the CAI subjects displayed consistently worse dynamic postural control than the Controls as evidenced by smaller %MAXD values for the injured side (Anterior: 78± 1.6%; Medial: 88± 1.5%; Posterior: 89± 2.4%) compared to the contra-lateral side (Anterior: 82± 1.7%; Medial: 90± 1.8%; Posterior: 91%± 2.4%). The involved side of the CAI group used significantly less hip flexion (68.43°±4.75°) at maximum reach compared to the uninvolved side (73.492°±5.04°). Fatigue amplified the effects of CAI as the pre-post fatigue decreases were significantly larger for the CAI group for knee flexion at maximum reach in the Anterior (D = 3.61°) and Medial (D = 4.88°) directions. In all 3 reaching directions, the pre-post change in reach distance under the influence of fatigue was significantly predicted by the pre-post change in the sagittal plane position of the knee and/or hip. The results demonstrate that under the influence of fatigue and chronic ankle instability, the importance of proximal joint control was amplified as pre-post fatigue changes in sagittal plane motion significantly correlated with the reduction in maximum reaching distance. Supported by a grant from the NATA Research & Education Foundation sponsored by Proctor & Gamble.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-38–S-39.

Dynamic Balance Performance Of Soccer Players With And Without Previous Ankle Injuries

CD Davlin ¹

Abstract

The purpose of this study was to compare dynamic balance performance in NCAA Division I soccer players with and without a previous history of ankle injuries. 40 collegiate Division I soccer players (males; n = 15, age = 19.33 ± 1.0 yrs., height = 176.8 ± 5.7 cm, mass = 74.9 ± 5.1 kg, and females; n = 25, age = 19.2 ± 1.0 yrs., height = 167.2 ± 6.8 cm, mass = 62.7 ± 8.0 kg) participated in this study. Participants had no history of vestibular disorders or concussion in the last 5 years. Athletes were divided into two groups. Group 1 (n = 20) had experienced no lower extremity injuries in the past 5 years. The participants in Group 2 (n = 20) had sustained a grade 1 or 2 ankle sprain within the last 2 years, but had been asymptomatic for at least 6 months. Dynamic balance performance was measured on a stabilometer, which requires participants to continuously adjust his/her posture to maintain an unstable platform in the horizontal position for 30 seconds. Each participant performed 3 practice trials followed by 7 test trials. Participants were allowed to rest as much as they needed between trials. The stabilometer recorded the amount of time the participant held the platform within 5° of horizontal. Reliability (Cronbach alpha) for trials 1 to 7 was .94. The average of all seven test trials was used in the data analysis. An independent t-test showed no significant difference((t (38) = 0.07, p >.05) in dynamic balance performance between groups (group 1 = 18.9 ± 3.7, group 2 = 19.0 ± 4.1). The results of this experiment suggest that a history of ankle injury in NCAA Division I soccer athletes is not a significant factor in dynamic balance performance on a stabilometer.

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

Effect Of Foot Orthotics On Balance And The Muscle Activity Of Selected Leg Muscles During Bilateral Stance

CP Mulvihill ¹, CG Mattacola ¹, AJ Nitz ¹, TL Uhl ¹

Abstract

The purpose of this study was to investigate the effect of foot orthotics on balance and muscle activity of selected leg muscles during bilateral stance The research design for postural stability values consisted of a one between (group) and two within (time and orthotic intervention) mixed design analysis of variance (ANOVA). The independent variables were: Group (control vs. malaligned), Time (initial and four-week testing session), and Intervention (orthotic and non-orthotic). The dependent variable was balance assessed as an equilibrium score (expressed as a percentage score). The research design for EMG consisted of a one between (group), and three within (time, orthotic intervention, and muscle) repeated measures ANOVA. The independent variables were: Group (control vs. malaligned), Time (initial and four-week testing session), Condition (orthotic and non-orthotic), and Muscle (tibialis anterior, gastrocnemius, and fibularis longus). The dependent variables were RMS amplitude, and activation duration. Tibialis posterior activity was obtained by indwelling, fine-wire electrodes, therefore a separate one between (group) and two within (time and condition) ANOVA was run for the tibialis posterior. An alpha level of p <.05 was considered to be statistically significant for all ANOVA. A Holm-Bonferoni post hoc analysis was performed when appropriate. Nineteen subjects, twelve males and seven females(age= 22.94 + 3.35 years, wt= 77.28 + 17.28 kg, ht= 174.16 + 10.16 cm) were divided into two groups (control and malaligned), Inclusion criteria included navicular drop of 9mm or greater when moving from subtalar joint neutral position (STJN) to relaxed standing foot posture (RSFP), and rearfoot valgus of 5 degrees or greater. Subjects were fitted for orthotics in subtalar neutral position and impressions were sent to Foot Management Inc.(Pittsville, MD) for construction. Subjects were fitted for the semi-rigid orthotics, provided an adjustment period, and instructed to wear the orthotics 8–10 hr/day for 4 weeks. Subjects reported for testing on the NeuroCom SMART Balance Master (Neurocom Inc. Clackamas, OR) for two different occasions (Initial and 4 weeks after orthotic intervention). Three-20 sec, bilateral trials were completed for each test condition. Equilibrium scores increased from the initial test (88.63) to week four (90.5) following the orthotic intervention for the malaligned group in the eyes open static stance condition. Equilibrium scores were significantly higher for the control group (92.26) versus the malaligned group (89.34) for the eyes-closed sway referenced condition. The use of foot orthotics did not significantly affect the RMS amplitudes or muscle activation durations of the muscles tested. In conclusion, the use of foot orthotics may improve balance scores without affecting the way the muscles of the leg function.

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

Relationship Between Physical Activity And Balance In Physically Active And Sedentary Elders

VA Hamel ¹, RA Hess ¹, CM Biddington ¹, RH Kane ¹

Abstract

The main purpose of this study was to determine if there is a relationship between physical activity and dynamic functional balance in elders. A single-shot quasi-experimental design was performed. Thirty-seven elder subjects over the age of 65 years of age volunteered to participate from the surrounding California, Pennsylvania area. These subjects were asked to several question pertaining to their health such as current medication(s), past medical history and/or injuries, experiencing a fall, feeling unsteady, usage of orthodic or brace, and/or a walking aid. Subjects using a walking aid or have used a walking aid in the past 6 months was excluded from the study. Nineteen subjects were assessed by the activity index as being moderately/high active (subjects scoring between 25–125 points), with 18 elders assessed into the low/sedentary active group (subject scoring between 0–24 points). The Tinetti Assessment Tool assessed balance and gait and was scored out of a maximum 28 points, indicated the subject's overall dynamic functional balance. A score of 28-25 points indicated independence, a score of 24-19 indicated the subject has a risk for falls, and a score below 19 points denoted a high risk for falls. Posture scores were based on discriminating deviation (0 points) in posture from the norm (5 points). The activity index indicated subject's current physical activity level from a total of 125 possible points. The index is based on duration (out of 5 points), intensity (out of 5 points), and the frequency (out of 5 points) of exercise, and is scored by multiplying three sections together. Results from an Independent Sample T-test indicated that physically active elders had significantly better balance than sedentary elders (t(35) = −2.34, P = .025). A Pearson Product Moment Correlation was calculated for both of the following results, a significant moderate inverse relationship was found between age and balance scores (r(35) = −.524, P = .001), as well as a significant moderate positive relationship between posture and balance (r(35) = .516, P = .001). A Pearson Product Moment Correlation revealed posture scores however, were not significantly different due to physical activity level. Based on the literature and results of this research concerning aging, balance, and physical activity, elders who are currently active have better balance than those whom are not currently active, and that age, as well as posture may affect functional balance.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-39–S-40.

A Study Of The Relationship Between Postural Sway, Navicular Drop, And Ankle Strength In Division I Football Players

JJ Kelly ¹, CG Mattacola ¹, TL Uhl ¹, DL Johnson ¹, JA Madaleno ¹

Abstract

To determine if a relationship exists between postural sway, navicular drop, and ankle strength in Division I football players. Ninety-four University of Kentucky football athletes (age = 20.15 ± 1.40 years; ht = 186.74 ± 6.58 cm; and mass = 104.90 ± 18.53 kg) who were not currently rehabilitating a lower extremity injury, scheduled for or had lower extremity surgery during the time of testing, suffered a concussion in the past month, or experienced any general illness at time of testing volunteered for this study. Each participant was randomly assigned to start with one of the three testing procedures (balance, navicular height, and ankle strength). Subjects were tested prior to preseason competition. The unilateral balance assessment was performed bilaterally and consisted of two conditions: eyes open and eyes closed. Subjects stood bare footed on an Airex balance pad (Alta Vista, CA) placed on the surface of the NeuroCom Smart Balance Master System force plate (Clackamas, OR). The navicular drop was assessed with a Vernier height gauge (Mitutoyo, Japan). Navicular drop was determined by subtracting the value in subtalar joint neutral, from the value in the relaxed position. Ankle muscular strength was assessed in dorsiflexion, eversion, and inversion in each subject with a J-Tech hand-held dynamometer (Salt Lake City, UT). The results were analyzed using Pearson Product Moment Correlations. There was no relationship between Left Eyes Open (LEO) and Left Navicular Drop (LND) (r = 0.079), and Right Eyes Open (REO) and Right Navicular Drop (RND) (r = −0.046). There was no relationship between Left Eyes Closed (LEC) and LND (r = 0.155), and Right Eyes Closed (REC) and RND (r = 0.024). The relationship between Left Dorsiflexion (LDF), Left Inversion (LINV), Left Eversion (LEV), and LND was 0.086, −0.027, and 0.018, respectively. The relationship between Right Dorsiflexion (RDF), Right Inversion (RINV), Right Eversion (REV), and RND was 0.085, −0.086, and 0.043, respectively. The relationship between LDF, LINV, LEV, and LEO was 0.062, −0.219, and −0.122, respectively. The relationship between RDF, RINV, REV, and REO was 0.058, −0.073, and −0.072, respectively. The relationship between LDF, LINV, LEV, and LEC was −0.003, −0.143, and −0.017, respectively. The relationship between RDF, RINV, REV, and REC was −0.089, 0.035, and 0.044, respectively. Our results indicate that there is no relationship between balance, navicular drop, and ankle strength. Further research should examine if any of these factors relate to the incidence of ankle injuries.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-40.

Reliability And Sensitivity Of The Foot And Ankle Disability Index In Subjects With Chronic Ankle Instability Relationships Between Functional Performance Measures For The Ankle

SA Hale ¹, J Hertel ¹

Abstract

Many researchers utilize static balance measures to estimate dynamic balance performance among athletes. This raises the question of whether static dynamic tests accurately reflect dynamic balance performance. The purpose of this study was to examine the relationships between a static balance measure, a dynamic balance measure, and subjective self-reports of function among healthy subjects and subjects with chronic ankle instability (CAI). 50 subjects (29 females/21 males, 31 CAI/19 healthy, age = 21.53 ± 3.59 years, height = 170.35 ± 11.50 cm, weight = 72.94 ± 19.32 kg) participated in this study. Static balance was measured using center of pressure velocity (COPV) measures. Subjects were tested with their eyes open and their eyes closed. Each trial lasted 15 seconds. The star excursion balance test (SEBT) was administered to quantify dynamic balance. The Foot and Ankle Disability Index (FADI) and the Foot and Ankle Disability Index Sports Subscale (FADI-Sport) were selected as the self-reports of function. Bivariate correlations were run to examine the relationship between: 1) COPV and SEBT, 2) COPV and FADI, 3) COPV and FADI-Sport, 4) SEBT and FADI, and 5) SEBT and FADI-Sport. Separate analyses were run for the eyes open and eyes closed trials, each direction of the SEBT, an average SEBT score, involved, and uninvolved limbs. Bivariate correlations were also run to examine the relationship between changes in the above measures following 4 weeks of supervised rehabilitation. No significant relationships were found between 1) COPV and SEBT, 2) COPV and FADI, 3) COPV and FADI-Sport, 4) SEBT and FADI, or 5) SEBT and FADI-Sport. Similarly, there were no significant relationships identified when the change scores were examined. It appears that static and dynamic measures are not related and therefore measure different functions. These balance measures are also different than the subjective reports of function. These findings are important clinically. It is essential that clinicians recognize there is a difference in static and dynamic function and one cannot be used to estimate the other. These results also demonstrate that changes in static balance are not related to changes in dynamic balance suggesting that both most be addressed in rehabilitation paradigms.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-41.

Scapulohumeral Rhythm For Anterior-Posterior Tipping During Dynamic Humeral Rotation

CA Thigpen ¹, DA Padua ¹, SG Karas ¹

Abstract

Scapular kinematics during humeral rotation tasks has not been examined. Scapular anterior-posterior (AP) tipping is the largest scapular motion during a 50° humeral rotation arc performed at 90° of humeral elevation in the frontal plane. Therefore, the purpose of this study was to describe and assess the intra-session reliability of scapulohumeral rhythm (SH) for AP tipping measured during dynamic humeral rotation. Twenty healthy subjects (age=23.3±1.6 yrs, ht=171.9±9.1 cm, wt=72.9±13.0 kg) volunteered for this study. All testing was performed on the subject's throwing dominant arm. Subjects performed three trials of active humeral external and internal rotation while maintaining their humerus at 90° of shoulder abduction in the frontal plane. Kinematic data were collected according to the ISB shoulder protocol for shoulder motion using an electromagnetic tracking system. Scapular AP tipping angles were assessed over two arcs of humeral motion: 0–50° of humeral external rotation and 50-0° of humeral internal rotation. We calculated SH rhythm from the regression slope of humeral rotation versus scapular AP tipping over each motion arc. Intra-session reliability was assessed using intra-class correlation coefficients (ICC_2,1) and associated standard error of the measures (SEM) for each motion arc. The range of scapular AP tipping was 4.6° ±2.3° during the humeral external rotation motion arc and 4.3°±2.0° during the humeral internal rotation motion arc. SH rhythm was was equivalent during humeral external rotation motion arc (13.9 ± 6.6) and humeral internal rotation motion arc (11.1 ± 6.2). There was a strong linear relationship between scapular AP tipping and humeral rotation over each motion arc as R² values ranged from 0.94 to 0.95. SH rhythm demonstrated moderate intra-session reliability during humeral external rotation (ICC=0.76, SEM= 4.1) and good intra-session reliability during humeral internal rotation (ICC = .86, SEM=2.8). Based on these findings, the SH rhythm between scapula AP tipping and humeral rotation demonstrates acceptable intra-session reliability. There is also a strong linear relationship between scapula AP tipping and humeral rotation, similar to scapula upward rotation and humeral elevation. However, SH rhythm values for scapula AP tipping and humeral rotation are considerably larger than for scapula upward rotation and elevation. The limited arc of humeral rotation performed in this study may limit the generalizability of these results. Future studies should evaluate SH rhythm of scapula AP tipping and humeral rotation during larger motion arcs and during elevation tasks. These results should be considered when investigating scapular AP tipping during humeral rotation tasks.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-41.

Comparison Of Three-Dimensional Scapular Kinematics In Pathologic And Non-Pathologic Subjects

BL Tripp ¹, TL Uhl ¹, WB Kibler ¹

Abstract

Patients with shoulder pathologies frequently display abnormal scapular kinematics. Clinical assessment of scapular motion is often performed through bilateral comparisons. Asymmetry and consistency of scapular motions however, are difficult to quantify. The purpose of this study was to compare the consistency and symmetry of three-dimensional scapular motion between pathologic and non-pathologic subjects. We hypothesized that pathologic subjects would display less consistency between trials and less symmetry when compared to non-pathologic subjects. Thirty-nine subjects (24 males and 15 females, 19 non-pathologic, 20 pathologic, age 29.7 ± 9.8 years, mass 75.5 ± 18.25 kg, height 173.0 ± 9.6 cm) volunteered for participation. The diagnosis of an orthopedic surgeon (WBK) was used to classify subjects as pathologic. An electromagnetic tracking device was used to measure bilateral scapular kinematics. Receivers were taped to the posterior acromial angles of both scapula and a reference receiver was taped to the sternum. Investigators digitized subjects creating anatomically relevant, local coordinate axes. Participants performed five repetitions of scapular elevation up to 150 degrees of humeral elevation. A metronome controlled the rate of motion at 4 seconds per repetition. Trials were subdivided into two distinct phases, elevation and lowering. Data were analyzed using Matlab and SPSS; alpha level (p < .05, a priori). Each phase of motion was normalized to 100 data points. Inter-trial consistency and bilateral symmetry were measured through the calculation of coefficients of multiple determination (CMD). These CMD represent similarity of trials, evaluating the magnitude and rate of each scapular motion individually (upward rotation, internal rotation, and posterior tilt). CMD were also calculated to measure bilateral scapular symmetry. The measures of CMD are indicative of the percentage of variance accounted for within the data (i.e., r²). We observed between trial CMD values ranging from .01 to .99 and .02 to .99 in the pathologic and non-pathologic groups respectively. We observed symmetry CMD values ranging from .01 to .99 and .26 to .99 in the pathologic and non-pathologic groups respectively. Multiple pairwise comparisons evaluated differences between groups. Statistically significant results included: 1) between trial CMD of left internal rotation during arm elevation (p=.004), 2) between trial CMD of right internal rotation during arm elevation (p=.037), 3) internal rotation symmetry during the lowering phase (p=.04). Our results indicate that between trial consistency of scapular motions as well as symmetry of scapular motions were similar between pathologic and non-pathologic groups.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-41–S-42.

Reliability Of Scapula Protraction Strength Measures

JA Layton ¹, CA Thigpen ¹, DA Padua ¹, SG Karas ¹

Abstract

The assessment of scapula protraction strength is an important component of shoulder evaluation. Hand held dynamometers (HHD) are used to assess strength in the clinical and research settings. However, a reliable method of assessing scapula protractor strength using a HHD has not been established. Therefore the purpose of this study was to examine the intra-session reliability of two methods for assessing scapula protraction strength using a HHD. Ten subjects (7 females, 3 males, age=23 ± 1.2 yrs, height = 159 ± 29 cm, weight = 69 ± 3 kg), performed three trials of shoulder protraction in two separate testing sessions. All subjects were positioned supine for each trial as described by Kendall et al (1993). Protraction was defined as movement of the scapula which projected the upper extremity anterior. During the first session, the subject lay on the floor and the examiner applied pressure perpendicular and posterior against the subject's fist (Method One). During the second testing session, a handle attached to the dynamometer via a chain was placed in the subject's hand. The chain was positioned parallel to the subject's humerus, and then the subject protracted the scapula while the examiner held the dynamometer stable at the side of the testing table (Method Two). Subjects performed a make test for one practice trial, one sub maximal trial, and three maximal trials for each testing method. Subjects rested 30 seconds between each trial. Average and peak forces (N) for each trial were recorded. Intra-session reliability was assessed using intra-class correlation coefficients (ICC_2,1) and associated SEM values. Average scapula protraction strength was 122 ±7 N for method one and 186 ±21 N for method two. Peak scapula protraction strength was 188 ±6 N for method one and 260 ±27 N for method two. Method one demonstrated poor intra-session reliability for average (ICC= 0.61, SEM= 16.69) and peak (ICC= 0.55, SEM= 15.29) values. Method two demonstrated improved intra-session reliability for average (ICC= 0.84, SEM= 30.08) and peak (ICC= 0.94, SEM= 22.67) values. The results of this study revealed that subjects produced larger average and peak force values during method two. These results also suggest that scapula protractor strength values from method two are more reliable in comparison to method one. These results should be considered when assessing scapula protraction strength using HHD.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-43.

Recruitment And Co-Activation Of The Glenohumeral Force Couples During Functional Upper Extremity Exercises

K Huxel ¹, KA Swanik ¹, CB Swanik ¹, M Patel ¹, J Kelly ¹

Abstract

Optimal stability and function requires the synergistic actions of the force couple muscles that surround the glenohumeral joint. For this reason, co-activation exercises must be incorporated into rehabilitation and injury prevention protocols. Current concepts suggest using closed chain exercises to enhance dynamic shoulder stability. However, this theory is based on examination of isolated muscle firing sequences or exercises that are often performed in the early phases of rehabilitation. Few studies have calculated glenohumeral force couple co-activation during open and closed chain functional activities, specifically in tasks that would be emphasized during later stages of rehabilitation. The purpose of this study was to quantify glenohumeral force couple co-activation during functional open and closed chain tasks commonly prescribed in upper extremity rehabilitation. Seventeen physically active males (age 20.72 ± 1.93 yrs) with no history of upper extremity injury were tested. Indwelling electromyographic (EMG) (Noraxon USA, Inc.) data was collected from the subscapularis, infraspinatus, and teres minor, and surface EMG was recorded from the anterior deltoid. Glenohumeral agonist/antagonist co-activation was calculated for two force couples: anterior deltoid/infraspinatus + teres minor and subscapularis/infraspinatus + teres minor. Each subject performed functional tasks, including pitchback, D1 PNF with tubing, push-up plus, and horizontal abduction/adduction on a slideboard. EMG was time and amplitude normalized to determine differences between exercises and force couple co-activation. A one-way (exercise) MANOVA with repeated measures was performed to analyze data. Results showed no significant difference in the level of force couple co-activation recruitment between the functional exercises (p > 0.05). According to our findings force couple strategies were evident with all the functional tasks (closed chain tasks: 54 – 73% co-activation; open chain tasks: 50–66% co-activation), but not different between the open and closed chain exercises examined in this study. Interestingly, although the level of difficulty for each task varied, all the exercises had similar force couple recruitment levels. This information provides the clinician with a series of validated activities that elicit the force couple co-activation qualities necessary for a comprehensive shoulder prevention program. Further evaluation of co-activation measures during functional tasks in different populations is warranted to more accurately determine implementation into rehabilitation protocols.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-43.

Repetitive Overhead Activity Does Not Affect Anterior Humeral Head Translation

EP Coonradt ¹, CL Docherty ¹, SM Zinder ¹, AM Rijke ¹, EN Saliba ¹, CD Ingersoll ¹

Abstract

The shoulder is the most mobile joint in the human body. In order to achieve such mobility, stability must be sacrificed. Static and dynamic restraints provide some stability to the glenohumeral joint, but are not always able to prevent common injuries like anterior humeral head subluxations/dislocations. Fatigue has been shown to decrease joint position sense, muscle tone, and proprioception. However, no research to date has investigated the effects of repetitive shoulder activity on glenohumeral head movement. The purpose of this study was to determine if repetitive overhead activity influences anterior humeral head translation. The study was performed in Memorial Gymnasium at the University of Virginia. Seventy participants (22.1±2.3 yrs, 170.5±11.6 cm, 75.8±20.0 kg) volunteered for this study. All participants were healthy adults with no prior history of pain or injury to the dominant shoulder. After a 5-minute jogging warm-up, the participants were randomly assigned to the control (non-throwing) or experimental (throwing) group. The throwing group performed a functional throwing protocol, involving 9 bouts of 12 throws at maximum speed while kneeling on both knees, with 3 minutes of rest between each bout. The control group walked on a treadmill for 9 bouts of 90 seconds with 3 minutes of rest between each bout. Using the LigMaster™ device, anterior humeral head translation was tested in 90 degrees of abduction and 90 degrees of external rotation at baseline, following warm-up, and after the 3^rd, 6^th, and 9^th bout. A two-way repeated measures analysis of variance (ANOVA) was used to determine differences between groups (throwing and non-throwing) and time (test 1–5). Follow-up independent t-tests were used to determine differences at each test period. We found that across time the groups had a significant interaction (F_{4, 272}=2.4, p=0.05). However, follow-up independent t-tests revealed that the groups were not statistically different at any individual time. Our findings suggest that exercise does not affect static stability in the glenohumeral joint. This finding may be due to patient anxiety associated with discomfort in the testing device, or the type of activity used in the study. Instead of a short dynamic activity, a more continuous activity may have led to different results.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-43–S-44.

Glenohumeral Joint Stiffness And Laxity Are Influenced By Gender And Athleticism

BM Frye ¹, KA Swanik ¹, CB Swanik ¹, KL Hamstra ¹

Abstract

Laxity and stiffness are often implicated for having a role in glenohumeral joint stability and function but limited data exists concerning the relationship between these characteristics, gender and athleticism. The purpose of this study was to assess the interrelationships between glenohumeral joint stiffness laxity, gender and athleticism. A post-test only control group design was used. The independent variables were group (athlete and non-athlete) and gender. The dependent variables were passive glenohumeral joint stiffness (N·m/radians), a generalized joint laxity score (0–5), and clinical laxity tests. Twenty-nine individuals (15 male, 14 female; mean weight = 78.99 ± 41.82 kg; mean age = 21.34 ± 9.00 years) participated in this study. The experimental group consisted of 8 male and 8 female Division I baseball and softball players. The control group consisted of 7 male and 6 female physically active volunteers. Passive glenohumeral joint stiffness was assessed by measuring the damped natural frequency of oscillation during five pendulum arm swing trials using the PEAK Motus Motion Analysis System (PEAK Performance Technologies, Inc., Englewood, CO). The Noraxon Telemyo System (Noraxon USA, Inc., Scottsdale, AZ) was used to exclude trials with excessive muscle activity. 2 × 2 ANOVA's revealed that males had significantly (p≤.05) greater stiffness (mean = .17 n•m/rad ± .02) than females (mean = 0.16 n•m/rad ± .01); and males (mean = 0.87 ± 1.19) were significantly (p≤.01) less lax than females (mean = 2.21 ± 1.53). Athletes presented with significantly (p≤.01) more glenohumeral joint laxity (mean = 2.13 ± 1.41) than non-athletes (mean = .77 ± 1.30). A stepwise linear regression revealed that 28% of the variance in stiffness was due to deltoid girth measurements (R²=0.28). Pearson correlation coefficients revealed a moderate relationship between stiffness and laxity (Pearson correlation = −.46). There were no significant differences found in the interaction of group and gender for stiffness or laxity. This study confirms gender differences in stiffness and laxity, but these differences may not exist within athletic populations. In the presence of increased laxity, no differences existed in stiffness between athletes and non-athletes, signifying athletes have the ability to regulate passive glenohumeral joint stiffness and control the overall stability of an otherwise mobile shoulder. These results suggest that congenital laxity and/or the ability to regulate stiffness are beneficial for athletic performance in overhead athletes. A more compliant system may extend further and have greater strain energy to accommodate forces acting on the joint, a desirable characteristic for both dynamic restraint and athletic performance.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-44.

Comparison Of Scapulohumeral Rhythm Between Individuals With And Without History Of Shoulder Instability

ME Smith ¹, DA Padua ¹, CA Thigpen ¹, RE Schneider ¹, NM Xu ¹, SG Karas ¹

Abstract

Scapulohumeral rhythm (SHR) is suggested to be altered in individuals with shoulder instability. Dysfunctional SHR in individuals with shoulder instability has only been qualitatively described. Therefore, the purpose of this study was to compare SHR between individuals with and without a history of shoulder instability during dynamic scapular plane elevation. Twenty-two subjects participated in this study. Subjects were assigned to two groups based on history of shoulder instability. There were eleven subjects who reported a history of shoulder instability (age=22.6±3.4 years, height=175.3±8.6 cm, mass=72.8±18.4 kg) and eleven subjects without shoulder instability (age=21.91±2.21 years, height=176.0±9.9 cm, mass=74.2±18.4 kg). Inclusion criteria for subjects who reported a history of shoulder instability were: no surgical intervention, no current rehabilitation, functional shoulder range of motion, and diagnosed shoulder instability by an orthopaedic surgeon. Individuals without shoulder instability were matched for height, weight, activity level, and arm dominance. The American Shoulder and Elbow Surgeons Shoulder Score Index questionnaire was completed as an objective measure of shoulder function. Shoulder kinematics were measured using an electromagnetic tracking system following the ISB protocol for shoulder motion. Individuals performed three separate trials of active scapular plane elevation (0° to 130°) during loaded and unloaded conditions. SHR was calculated from the regression slope of humeral abduction versus scapular upward rotation over three arcs of elevation: 31–60° (SHR_31–60), 61–90° (SHR_61–90) and 91–120° (SHR_91–120). A three way mixed model ANOVA was used to compare SHR between groups, load conditions and elevation arcs. An independent t-test was used to compare ASES scores between groups. Subjects with shoulder instability demonstrated significantly reduced ASES scores compared to those without shoulder instability (P<.001). However, there was no significant main effect or interaction involving group (P>.05) for SHR. Thus, SHR was similar between individuals with and without shoulder instability across loading conditions and elevation arcs. One limitation of this study was the wide range of ASES scores in the subjects with shoulder instability (Range = 42 to 90). This may have contributed to the lack of significance in SHR between groups. Other limitations include a lack of control for injury mechanism (traumatic / atraumatic) and instability direction (anterior/posterior/multi-directional). Future research investigating SHR in subjects with shoulder instability may consider controlling for these variables.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-44–S-45.

The Relationship Between Hip And Shoulder Range Of Motion In Healthy Professional Baseball Players

EL Sauers ¹, MP Johnson ¹, G Keuter ¹, MF Schafer ¹, JL Koh ¹

Abstract

It has been proposed that alterations in hip range of motion may contribute to shoulder pathology in the throwing athlete. Loss of hip internal rotation is theorized to result in a need for greater shoulder external rotation in order to maintain throwing velocity. The purpose of this study was to evaluate the correlation between hip and shoulder range of motion in professional baseball players. Ninety-nine professional baseball players [50 pitchers and 49 position players (22±2.8 years, 187±5.4 cm, 81.6±7.7 kg)] with no present history of hip or shoulder injury volunteered for the study. Each player had both the dominant and non-dominant hip and glenohumeral joint measured for the following passive range of motion variables using standard goniometry: 1) hip internal rotation, 2) hip external rotation, 3) total hip motion (internal + external rotation), 4) isolated glenohumeral internal rotation, 5) isolated glenohumeral external rotation, and 6) total glenohumeral motion (internal + external rotation). The relationships between these variables were then evaluated using Pearson Product Moment Correlations. Correlation analyses were performed under 2 conditions: 1 = all observations (pitchers and position players, dominant and non-dominant extremities), and 2 = pitchers only (dominant hip and shoulder only). These separate analyses were based on the hypothesis that the strongest relationships would be observed between the pitchers dominant hip and shoulder due to the higher forces and repetitive throwing demands. The correlations between hip and glenohumeral joint range of motion for condition 1 (all observations) ranged from r = .006 to .29 (p = .006 to .94). The correlations between hip and glenohumeral joint range of motion for condition 2 [pitchers only (dominant hip and shoulder only)] ranged from r = .005 to .29 (p = .04 to .97). The primary relationship of interest was between hip internal rotation and glenohumeral external rotation, which revealed little or no relationship under both condition 1 (r =.07, p = .33) and condition 2 (r = .04, p = .77). Analysis of variance for each of the hip range of motion variables revealed small differences between positions and sides (0.7° to 3.0°) that we would not consider clinically significant. Collectively, these data suggest little or no relationship between hip and shoulder range of motion and fail to support the presence of chronic hip range of motion adaptations in healthy professional baseball players. Future studies should evaluate the relationship between hip and shoulder range of motion in throwers with active shoulder pathology. Supported by a grant from the NATA Research & Education Foundation.

Special Interest Group #4: Shoulder

Thursday, June 17, 2004, 4:00pm–5:00pm, Room 337; Discussants: Paul Borsa, PhD, ATC, and Eric Sauers, PhD, ATC

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-45.

Prevalence Of The Female Athlete Triad Syndrome Among High School Athletes From Multiple Sports

JF Nichols ¹, MJ Rauh ¹, MJ Lawson ¹, Y Pernick ¹, MY Hoskinson ¹, J Link ¹

Abstract

While prevalence estimates of the female athlete triad (disordered eating, menstrual dysfunction, low bone mineral density) have been reported in collegiate athletes, the prevalence of all three components of the triad has not been reported in high school athletes. The purpose of this study was to determine the prevalence of the female athlete triad syndrome among athletes participating in a variety of high school sports. Menstrual status and disordered eating behaviors (DE) were assessed by interviewer-assisted questionnaires in 451 female athletes (age 15.8±4.1 yr; BMI, 21.9±3.1 kg·m⁻²) representing eight interscholastic sports from six high schools in San Diego County. Bone mineral density (BMD) of the proximal femur (total hip), spine (L1-L4) and total body was determined by DXA in a subsample (n=141) of athletes randomly chosen after stratifying the girls according to risk or non-risk for DE and/or menstrual irregularity [At-risk: primary or secondary amenorrhea and/or DE score of ≥3.0 on the Weight or Shape subscales, or mean Global score of ≥3.0 on the Eating Disorder Examination Questionnaire (EDE-Q)]. Girls were classified as having low BMD if their value was ≥ 1 SD below age-matched reference data at any measurement site. The percentage of athletes meeting criteria for the individual components of the triad were: DE, 35.6% (161/451); menstrual irregularity, 20.2% (91/451); low BMD, 22.7% (32/141). Eight percent of the athletes reported both DE and menstrual irregularity. Of those whose BMD was tested, 10% had low BMD and either DE or menstrual irregularity, while three girls (2%) met all three criteria for the triad. The triad components were compared among girls participating in “aesthetic” sports, i.e., those that emphasize body image and low body weight/structure (cross-country running, track, tennis, swimming; n=289), vs. “non-aesthetic” sports (softball, volleyball, field hockey, lacrosse; n=162). The percentage of athletes with DE (34% vs. 39%) and menstrual irregularity (21% vs. 20%) was similar among aesthetic vs. non-aesthetic sports, respectively. However, all girls with low BMD were from aesthetic sports. These findings indicate that a substantial percentage of female high school athletes may be at risk for potential long-term health consequences of the female athlete triad, including osteoporosis. The data suggest the need for screening female high school athletes for disordered eating behaviors and menstrual irregularities. We recommend that high school coaches and athletic trainers become more aware of this syndrome and inform their female athletes of its potential devastating effects on their long-term health. Supported by a grant from the NATA Research & Education Foundation.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-45–S-46.

Correlates Of Stress Fracture Among Preadolescent And Adolescent Girls

KJ Loud ¹, AE Field ¹, CM Gordon ¹, MW Gillman ¹, AL Frazier ¹, LJ Micheli ¹, GA Colditz ¹

Abstract

Stress fractures are a source of significant morbidity in active populations, particularly among young women athletes and those in the military. Unfortunately, causes of stress fracture have not been explored in those under age 17, nor in the general population. This study examined correlates of stress fracture in a large, population-based national cohort study of preadolescent and adolescent girls. Cross-sectional analysis of 5570 girls age 10–17 in the ongoing Growing Up Today Study (GUTS), an ongoing longitudinal study of the children of female registered nurses participating in the Nurses Health Study II. Mothers provided information on history of stress fracture in their 1998 annual questionnaire. GUTS participants themselves reported their weight and height, menarcheal status, physical activity and disordered eating habits in annual surveys. Generalized estimating equations were used for modeling in order to account for sibling co-variance. In 1998 the mean age of the sample was 13.9 years. Approximately 2.7% of the girls had a history of stress fracture, 3.1% engaged in disordered eating (using fasting, diet pills, laxatives, or vomiting to control weight), and 17% participated in ≥16 hours per week of moderate to vigorous activity. Neither age at menarche nor z-score for body mass index (BMI) in 1998 was a significant correlate of stress fracture; however, independent of age and BMI, girls who participated in ≥16 hrs/wk of activity in 1998 had 1.78 greater odds of a history of stress fracture than girls who participated in < 4 hrs/wk [95% Confidence Interval (CI):1.11–2.84]. Girls who participated in 4–8 hrs/week of activity exhibited a trend toward decreased odds of stress fracture [Odds Ratio (OR)=0.70, 95% CI:0.41–1.21], while those who participated in 8–16 hrs/week had similar odds to those in the lowest activity category. Girls who participated in ≥ 16 hrs/wk of activity were more likely than their peers to engage in disordered eating (4.6% vs. 2.8%, p< 0.01); however, disordered eating did not have an independent association with stress fracture [OR=1.27, 95% CI:0.58–2.78]. These findings suggest that although activity can be beneficial for bone health, there is a threshold over which the risk of stress fracture increases significantly in preadolescent and adolescent girls. Additionally, the prevalence of unhealthy dietary behaviors increases in this high exercise subgroup. Prospective studies are needed to explore the directionality of these relationships.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-46.

An Assessment Of High School Coaches' Knowledge Of Exercise-Induced Asthma

SL Wilson ¹, BL Van Lunen ¹, EA Dowling ¹, L Ridinger ¹

Abstract

Exercise-induced asthma (EIA) is a common disorder that occurs in individuals who compete in recreational activities. Athletic coaches are often the only individuals available to assist an athlete who has an asthmatic episode. The purpose of this study was to determine the knowledge of EIA for high school athletic coaches'. An 18 multiple-choice assessment (modified from Atchison et al. 1994) was used to assess knowledge of prevention, recognition and management of EIA. A 22 question demographic instrument, including questions on gender, number of years coaching, asthmatic status and sports currently coached, was also used. A panel of experts reviewed and modified the survey instruments, which were piloted at a local private high school prior to distribution. The survey was distributed to 250 high school coaches in Eastern Virginia (Hampton Roads area) during their fall coaches meeting and completed by 166 (66.4% return rate). The multiple choice assessment score mean was 48.77/100% ± 14.08, with a range of 5.6 – 94.4%. Independent T-tests were used to determine if selected demographic data had any effect on knowledge of EIA. Females scored higher on the assessment (p = .007) and asthmatics knew more about EIA (.046). An association (Pearson Chi-Square) was found between the number of female coaches and being an asthmatic (p =.000), therefore explaining why there was a difference between genders. It made no difference if the coach had attended a workshop on EIA (p = .844) or had spoken with the Certified Athletic Trainer about EIA (p = .335). Spearman's rho demonstrated no relationship between the number of years coached and overall assessment score (p =.055). A one-way ANOVA revealed no significant differences for educational background and EIA knowledge. However, a strong trend (p=.055) was demonstrated for individuals with a Bachelors degree compared to those with a high school diploma. No relationship existed between age and assessment score. A repeated measures ANOVA was used to analyze differences between subset means for the three sections of the survey. A significant difference was found between all three sections (p = .000) illustrating that coaches knew the most about recognition, followed by management and then prevention. Our results support the need for additional education about EIA for coaches, however the assessment instrument questions may have been at too high of a level for the intended audience. Further research should examine the effectiveness of an EIA workshop on the retention of knowledge for coaches.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-46.

Incidence Of Skin Trauma Associated With Participation In Intercollegiate Baseball

JW Beam ¹, HA Priest ¹

Abstract

Trauma to the skin occurring during participation in intercollegiate athletics has been described in the literature as frequent, often and common. Objective data are limited in the literature to support these statements and descriptions. Complications of skin trauma such as the development of infection and scar tissue and the transmission of HIV and hepatitis B and C can place both the student-athlete and athletic trainer at risk. Little is known regarding the etiology of skin trauma associated with athletic participation and suggestions have been made that impressions about skin trauma are vivid, but knowledge is vague. The purpose of this study was to identify the frequency and injury rate of skin trauma among NCAA Division II baseball student-athletes. For this study, a reportable wound was defined as: occurring in an athletic-related activity (physical conditioning, practice, or competition), requiring attention by an athletic trainer or physician, and resulting either in restriction or non-restriction of student-athlete participation following the injury. All injuries were evaluated and treated by a certified athletic trainer and/or physician. Data were collected over a competitive baseball season. Descriptive statistics were calculated for the data. An average of 33 student-athletes (age: 20.7 + 1.4) participated, totaling 3149 athlete exposures (AE), 2439 in practice and 710 in competition. A total of 27 wounds were documented, 13 occurring in practice and 14 in competition. The overall injury rate was 8.57 injuries/1000 AE, with 5.33 injuries/1000 AE in practice and 19.71 injuries/1000 AE in competition. The most common wounds were abrasions (44.4%), blisters (25.9%), and lacerations (18.5%). The most common mechanism of injury was rubbing/friction (77.8%) through contact with the ground (48.1%) and equipment (29.6%). The reported wounds occurred during competition (51.8%), pre-season practice (25.9%), and in-season practice (22.2%) activities on dirt/clay (74.1%) and grass (14.8%) surfaces. The most frequently injured body locations were the knee (29.6%), fingers (22.2%), and foot (11.1%). Although the data from this study only represented one sport during a competitive season, the incidence of skin trauma among intercollegiate student-athletes warrants further investigation. Studies examining other sports, playing positions, mechanisms of injury, and wound types can lead to the development of prevention programs. When risk factors known to cause skin trauma are identified, strategies to reduce injuries through preventive programs can be implemented. Additionally, with the high incidence of skin trauma, questions regarding cleansing, debridement, and dressing protocols and the cost-effectiveness of wound management techniques should be considered.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-46–S-47.

Incidence Of Injury In A Women's Professional Football Team

BJ Toy ¹, S Rahman ¹

Abstract

Although injury incidence for men's football is well documented, the reporting of similar data for the sport of women's professional football is lacking. Thus, the purpose of this retrospective study was to examine injury incidence for the participants of a professional women's football team. Following the 2003 season injury data, analyzed using descriptive analysis, was examined to determine overall (OA) and time-lost (TL) injury rates, most frequently injured body parts and injury types. The 30 player roster yielded 2010 athlete-exposures (AE) while a certified athletic trainer collected injury data at all practices (n=62) and home games (n=5). Sixty-three injuries occurred producing an OA injury rate of 31.3/1000 AE while 44 of these injuries caused participants to miss at least one practice or game. This yielded a TL injury rate of 21.9/1000 AE and accounted for 333 lost practice and game days (avg TL = 7.6 days/injury). Strains, which most commonly occurred to the hamstring and groin regions, accounted for 25.3% (n=16) of OA injuries and were responsible for 20.5% (n=9) of TL injuries. Sprains to the ankle, thumb and knee accounted for 20.6% (n=13) of OA and 22.7% (n=10) of TL injuries. Seven cases of bi-lateral medial tibial stress syndrome accounted for 11.1%, of OA and 11.4% of TL injuries while patellofemoral syndromes accounted for 9.5% (n=6) and 9.1% (n=4) of OA and TL injuries respectively. Low back pain (n=5) accounted for 7.9% of OA and 11.4% of TL injuries. Four cases of concussion accounted for 6.3% of OA and 4.5% of TL injuries. The most frequently injured body parts included the knee (n=12) which incurred 19% of OA and 22.7% (n=10) of TL injuries; the leg, which sustained 15.9% (n=10) and 15.9% (n=7) OA and TL injuries respectively; and the ankle, which caused 11.1% (n=7) of OA and 11.4% (n=5) of TL injuries. These data indicate that TL injury rate/AE and average TL days/injury for women's professional football players may be significantly higher than injury rates reported for men's football. Lack of playing experience, poor physical condition of participants (avg body fat = 30%; avg Vo2 max = 35ml/kg/min) and utilization of equipment designed for males could be causative factors for increased injury rates. In addition to analyzing the role the certified athletic trainer can play with regard to reducing OA and TL injury occurrence, future prospective investigations should focus on the aforementioned and other potential causative injury factors.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-47.

Effect Of The Simultaneous Application Of NMES And HVPC On Knee Extension Torque

WR Holcomb ¹, MD Rubley ¹, TJ Girouard ¹

Abstract

Different types of electrical stimulating currents may be used for the management of pain, edema, atrophy and strength loss associated with joint injury and surgical repair. The OrthoDx™ (Rehabilicare, New Brighton, MN) is a portable electrical stimulator designed to deliver a simultaneous treatment with neuromuscular electrical stimulation (NMES) and High Voltage Pulsed Current (HVPC). The effect of this simultaneous treatment with two different current types on the resulting force of contraction was not known. Therefore, the primary purpose of this investigation was to compare the effect of NMES in combination with HVPC, with NMES alone on isometric muscular torque production of the quadriceps. A secondary purpose was to compare knee extension torque during three different contraction conditions. Fourteen healthy subjects reported to the athletic training research laboratory and received electrical stimulation with the OrthoDx™ using a within subjects design. Isometric knee extension torque using the two stimulation protocols (NMES in combination with HVPC and NMES alone) was recorded with the Kin-Com™ under three contraction conditions: 1) maximum voluntary isometric contraction (MVIC), 2) MVIC superimposed with electrical stimulation, and 3) electrical stimulation causing passive contraction of quadriceps. Data normalized for body weight were analyzed using a 2 (Stimulation Protocol) × 3 (Contraction Condition) ANOVA with repeated measures. The main effect for Stimulation Protocol was not significant F_1,26 = .01, P = .94 indicating that there was no difference in torque production whether NMES was used alone or in combination with HVPC. Therefore, using a combination of electrical currents for multiple effects has no adverse effect on knee extension torque production as a result of NMES. The main effect for Contraction Condition was significant, F_2,52 = 289.1, P < .0001. Post hoc analysis showed that contraction condition 3 (passive) yielded significantly less torque than contraction conditions 1 (MVIC) and 2 (superimposed). However, contraction condition 3 (passive) produced torque equal to 43% of the MVIC when NMES was combined with HVPC, which is a relatively strong contraction when compared to studies reported in the literature using maximum comfortable stimulation intensities.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-47–S-48.

The Effects Of High Volt Pulsed Current Vs. Russian Current On The Achievable Percentage Of MVIC

MJ Comeau ¹, L Brown ¹, J Landrum ¹, A Wheeler ¹

Abstract

Current therapeutic modality textbooks state that 25% of maximal voluntary isometric contraction is achievable utilizing electrical stimulation. The purpose was to determine if 25% of MVIC is achievable, and to determine if a difference exists between the two types of waveforms [High volt pulsed current (HVPC) vs. Russian current] used. Nineteen college-age males and females (mean ± SD, 21.6 ± 2.7 y) volunteered for the study. Subjects reported one time to the Human Performance Laboratory. Prior to the treatment being administered, subjects completed a medical history questionnaire and consent form in compliance with University policy on human experimentation. Subjects were seated on a Biodex 3 Isokinetic device and the torque arm was aligned with the dominant leg's knee joint line. One electrode was then placed on the proximal thigh as close to the inguinal crease as possible with the other electrode placed over the Vastus Medialis Oblique. The subject's knee was then placed in 10 deg of knee flexion below the horizontal. This was the testing position from which all measurements were taken. The subject was then asked to perform a MVIC for 8 seconds. After completion of the MVIC, the electrical stimulation treatment was then administered to the subject. The type of waveform utilized was randomized between patients. The intensity was increased until the subject experienced a strong contraction, which was visually reinforced with a RPE scale. The strong contraction corresponded to a 5 on a 10-scale. Once a strong contraction was achieved, the intensity was then reset to zero and the testing procedure was completed. The same methodology was utilized on the opposite leg with the other waveform being utilized. Peak torque values were collected during the testing protocol utilizing Labview software with data was collected at 1000 Hz. Paired t-tests (p < 0.05) were used to determine if a significant difference existed between HVPC and Russian current. There was a significant difference (p < 0.007) in the percent of MVIC achieved with Russian level stimulation allowing for a larger percentage being achieved compared to HVPC (21.4% vs. 14.3%), respectively. While the data presented was collected on healthy subjects with no strength deficit or muscle atrophy, one would make the assumption that if a deficit or atrophy were present the overall achievable MVIC would be less. Therefore, the relevance of this data is important when deciding which type of waveform that should be utilized for stimulation.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-48.

The Effects Of Electrical Stimulating Currents On Pain Perception, Plasma Cortisol, And Plasma B-Endorphin For DOMS

MF Norcross ¹, KM Guskiewicz ¹, AA Hackney ¹, DN Hooker ¹, WE Prentice ¹

Abstract

The integration of electrical stimulating currents for pain control into rehabilitation protocols is a common clinical practice. However, proposed theories of action and anecdotal evidence far outnumber the few studies that attempt to identify a causal relationship between specific electrical stimulating current parameters and decreased pain levels. The purpose of this research was to determine if there were differences between four treatment types in subject pain perception, plasma cortisol, and plasma b-endorphin concentrations following an electrical stimulation treatment session for delayed onset muscle soreness (DOMS). We tested subjects over three days utilizing a mixed model, repeated measures design. Subjects included 48 college-aged males (age = 21.15 ± 2.32 years, mass = 79.35 ± 11.32 kg, height = 1.80 ± .062 m) having no upper extremity pain or prior experience receiving electrical stimulation for pain control. We induced delayed onset muscle soreness (DOMS) in the non-dominant elbow flexor musculature using repeated eccentric contractions. Subjects were asked to return 48 hours following the eccentric exercise session, at which time they were randomly assigned to one of four treatment groups: ascending inhibition (sensory level), descending inhibition (noxious level), b-endorphin modulation (motor level), or a control group (sham treatment). Pain perception was assessed using the descriptor differential scale (DDS), and plasma cortisol and b-endorphin levels were measured using radio- or enzyme- immunoassay techniques, respectively, at multiple points pre-and post-treatment. Statistical analysis indicated significant time main effects on the measures of pain perception and plasma cortisol. No significant differences were observed between groups on any measure (p > 0.05), and no associations were observed between pain perception, plasma cortisol, and plasma b-endorphin. We suggest that pain perception is multi-factorial, and that plasma cortisol and b-endorphin levels are not directly related to this perception. It is also suggested that plasma cortisol is not an accurate indicator of plasma b-endorphin and that future studies must measure b-endorphin levels directly. Based on our results, pain is relieved using all of the treatment types, with no treatments being more effective than another. Ultimately, the application of these techniques in the clinical setting should be based upon patient goals, tolerance to the current parameters of a specific treatment, and the setting in which in the patient will be both during and following the treatment session. 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-48.

Microcurrent Treatment On Pain, Edema, And Decreased Muscle Force Associated With Delayed-Onset Muscle Soreness: A Double-Blind, Placebo Study

KA Hewlett ¹, IF Kimura ¹, RK Hetzler ¹, A Nichols ¹, M LaBotz ¹

Abstract

A double-blind, placebo design (two-factor: group and time, with repeated measures over time) was used. The independent variables were three treatment groups: MENS pain, MENS healing, and MENS sham. The dependent variables were perceived pain, palpable tenderness, circumference, resting joint angle (biceps shortening), and biceps isometric force. To investigate the effect of two different microcurrent electrical neuromuscular stimulation (MENS) protocols on delayed onset muscle soreness (DOMS) of the biceps muscles. Microcurrent treatment is gaining popularity for management of acute injuries; however, the effectiveness of this therapeutic modality remains questionable. Subjects were 60 volunteers (22.3 ± 3.6 years of age) without upper extremity pathology. DOMS was administered via eccentric muscle activity at 60°/sec with the Biodex Multi-Joint System 3 dynamometer (Biodex 3). Subjects completed a pretest session (Phase I), which was critical for confirming the acquisition of DOMS symptoms. Following the completion of Phase I, subjects were given a nine-week rest period before Phase II DOMS administration, data collection, and MENS treatments began. DOMS was administered during Phase II with the protocol established in Phase I. Subjects were randomly assigned to the MENS pain (n = 18), MENS healing (n = 22), or MENS sham (n = 20) groups. All groups received 20 min. treatments for five consecutive days. MENS pain and MENS healing groups received 100–600 μA, 30 Hz, and positive polarity and 40 μA, 0.3 Hz and positive polarity microcurrent treatment, respectively. The dependent variables were assessed before DOMS administration and after treatment on day one, as well as pre and post treatment at 24, 48, 72, and 96 hours following eccentric activity. Perceived pain was assessed via a Visual Analogue Scale, palpable tenderness via a Model 75 force gauge probe, edema via circumference and resting joint angle (biceps shortening), and biceps isometric force. Data were analyzed using ANOVAs with repeated measures and Newman-Keuls post hoc tests when main effects were revealed. Statistical analyses revealed no significant differences between treatment groups for any of the dependent variables. Significant differences were indicated between treatment days. Perceived pain decreased between days 1 and 5, 2 and 5, and 3 and 5; palpable tenderness decreased between days 2 and 5; and biceps isometric force increased between days 1 and 5. Within the limitations of the present study, MENS treatment (protocols for pain and healing) does not appear to be an effective treatment of DOMS.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-49.

Effects Of Ibuprofen And High Voltage Electrical Stimulation On Acute Edema Following Blunt Trauma To Hind Limbs Of Rats

MG Dolan ¹, P Graves ¹, C Nakazawa ¹, T Delano ¹, A Hutson ¹, FC Mendel ¹

Abstract

Uncontrolled edema causes increased pain, prolonged immobilization and reduced joint range of motion, all of which extend recovery time following injury. Consequently, clinicians believe that edema management is critical following athletic injuries. Ibuprofen (IBU), a nonsteroidal anti-inflammatory drug (NSAID) available by prescription and over the counter is widely used by clinicians and athletes to manage pain and inflammation following such injuries. Although commonly used, the effectiveness of IBU in the management of acute edema has not been established. High voltage electrical stimulation is another commonly applied, albeit clinically unproven, 'therapy’ used to control edema. Cathodal high voltage pulsed current (CHVPC), at 120 pps and 90% of motor threshold is known to be effective in curbing acute edema formation in laboratory animals. This study examined the effects on acute edema formation of continuous treatment with IBU, CHVPC, and simultaneous application of IBU + CHVPC following injury to limbs of rats. 21 Zucker-lean rats were randomly assigned to one of three treatment groups following blunt trauma to their hind limbs. Prior to injury, volumes of both hind limbs of each subject were determined. Limbs were then injured by dropping a weight from a uniform height onto the plantar aspect of each foot. Limb volumes were measured every 30 minutes during the four-hour experiment. Group 1 received the equivalent of an 800 mg human dose of ibuprofen by gavage. Group 2 received the same dose of IBU and simultaneous application of CHVPC at 120 PPS at 90% motor threshold. One limb of animals in group 3 received CHVPC and the injured contralateral limbs served as controls. Changes in volumes from pretrauma values per kilogram body weight were analyzed by a MANOVA. Volumes of treated limbs were smaller (p<0.05) than volumes of untreated limbs. Calculations indicate a large effect size between the treated and untreated limbs. Treatment groups were not different from each other. IBU, CHVPC, or IBU +CHVPC, as applied here, curbed acute edema formation by roughly 50% relative to untreated but similarly injured control limbs. Potential clinical implications are: 1) Treatment should begin as soon after injury as possible, 2) treatment should be continuously applied while edema is still forming, and 3) Ibuprofen at high doses may be as effective as traditional athletic training therapies in curbing acute edema formation and offers advantages in terms of patient compliance for the physically active.This study was partially funded by the Eastern Athletic Trainers Association, Inc.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-50.

A Collision In A Boy's High School Soccer Game Resulting In Two Traumatic Brain Injuries

AM Roberts ¹, SV Caswell ¹, TE Gould ¹, RG Deivert ¹

Abstract

Two male soccer athletes (Patient A and Patient B) ages 15 and 17 respectively, were involved in a skull-to-skull collision during a soccer game. After the scene was surveyed, EMS was initiated. Patient A exhibited symptoms consistent with severe head trauma. Patient B reported that he was “fine” and appeared lucid. Patient A, weighing 71.8 kg and 174 cm tall had no reported previous history of traumatic brain injury (TBI). After colliding with Patient B, Patient A remained standing and was noticeably disoriented scoring 12/15 on the Glascow Coma Scale (GCS). The ATC assisted Patient A to a supine position and stabilized c-spine. Upon observation, Patient A presented with a large mass on the left side of his head just lateral to the brow line. Baseline vital signs, cranial nerves, dermatomes, and myotomes were assessed and within normal limits. Blood pressure and pulse were approximately 140/76mmHg and 104 bpm five minutes post injury. At seven minutes post injury, Patient A's pulse had slowed to 76 bpm. The patient's pupils were dilated bilaterally. However, the left pupil exhibited a lethargic direct light reflex when compared to the right pupil. Local EMS arrived within 10 minutes. Patient A was spine boarded and transported without complication. The patient's GCS score was now 15/15. Patient A underwent Computed Tomography (CT SCAN) and was diagnosed with a 10 mm left, frontal-parietal hematoma and a small cerebral contusion. No surgical intervention was required. He was monitored in the hospital for two days and released. At one week post-injury, a second CT SCAN presented no change. The patient was instructed to avoid all physical activity. Five weeks post-injury, Patient A underwent a third CT SCAN. The hemorrhage was resolved and the patient was released to full competition. Patient B, weighing 68.2 kg and 168.9 cm tall had reported no previous history of TBI. After the collision with Patient A, Patient B fell to the ground. He appeared alert and oriented to person, place, and time with approximately a 6mm cut over his right frontal bone even with the hairline. The patient walked to the sideline and applied ice to his forehead without assistance. Approximately 25 minutes after Patient A was transported, Patient B was evaluated for signs of head trauma. Vital signs and a cranial nerve exam were normal. No signs of cerebrospinal fluid (CSF) or blood were observed from the ears or nose. However, photophobia, extensive scalp tenderness, and a headache were all present. In addition, the patient described feeling irrational emotions. The ATC advised the patient's parents to take him to the emergency room. The parents complied. A CT SCAN of Patient B indicated the presence of a skull fracture to the frontal bone and an epidural hematoma approximately 12 mm in diameter. The patient was monitored for two days and released. No surgical intervention was required. At one week post-injury, a second CT SCAN indicated that the fracture and hematoma remained. However, a physical exam revealed that Patient B had no additional signs or symptoms of TBI. The physician's orders allowed light exercise with no participation in physical activity until a one month follow-up exam was performed. Five weeks post injury, following a third CT SCAN, patient B was released to full participation with no restrictions and participated for remainder of the season without complications. Both patients have been asymptomatic since the injury occurred. This case study is distinct because the patients displayed two unique reactions to the same collision. Patient A was stuperous and lethargic post-impact showing signs of trauma. Patient A was diagnosed with a small intracranial bleed and still suffers from anterograde amnesia of that day. Conversely, Patient B sustained a serious head injury and showed no symptoms except for a persistent headache. Patient B remembers the collision and is free from retrograde and anterograde amnesia. This case study should serve as re-enforcement that not all head injuries will display signs and symptoms of head trauma. If the ATC on-site had not seen the impact, Athlete B's injury might have been catastrophic. In any situation where such a severe impact occurs, it would be prudent for the ATC to consider hospitalization for both patients.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-50–S-51.

A Mouthpiece Accelerometer Can Accurately Predict Headform Acceleration Upon Impact

MJ Higgins ¹, DH Halstead ¹, DA Barlow ¹

Abstract

The purpose of this study was to determine the relationship between acceleration (g) experienced at the soft palate (mouthpiece) and center of gravity (COG) of a headform (HFCOG). A secondary purpose was to examine if attaching an accelerometer to a mouthpiece is an accurate and reliable way of predicting headform COG acceleration with the potential of using this method to measure on-field head accelerations. A National Operating Committee on Standards for Athletic Equipment (NOCSAE) headform was used for all impacts (N=189). Impact g's of an accelerometer attached to a mouthpiece fitted to a headform was compared with an accelerometer placed at the standard location (COG) of the headform. Severity Index (SI) and peak g were calculated and recorded upon each impact. NOCSAE testing standards were followed for all impact testing. A Pearson Correlation Coefficient (r) was used to determine relationships between the headform COG and mouthpiece acceleration (g) and SI measures upon impact. A Regression analysis coefficient of determination (r²) was calculated to show fit of acceleration levels (g) and SI values experienced at the HFCOG and at the mouthpiece (MP) during impact. Regression analyses facilitated the development of statistical models that predicted the HFCOG g and SI measurements from the mouthpiece g and SI measurements. An Interclass Coefficient Correlation (ICC2,1) was used to determine the reliability of the predicted HFCOG SI and g values versus observed HFCOG SI and g values. For all headform analyses, the HFCOG measurement was the dependent variable and the mouthpiece measurement was the independent variable. Pearson Correlation Coefficients revealed a r = 0.898 for HFCOGSI and MPSI and r = 0.756 for HFCOG g and MP g (p< 0.01). Regression analyses showed r² values for HFCOG g and HFCOG SI of 0.980 and 0.975 respectively (p< 0.01). The predicted HFCOG g and SI measures (ICC's 2, 1) revealed a 0.88 and 0.96 for g and SI respectively. There is a strong relationship between the acceleration (g) and SI measurements at the mouthpiece when compared to the COG of the headform. The use of a mouthpiece fitted with an accelerometer is a reliable predictor of acceleration and SI experienced by HFCOG upon impact. The instrumented mouthpiece has the potential to measure impact acceleration imparted to the head in practice and game situations.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-51.

Facial Trauma In A High School Soccer Goalkeeper

JP Mihalik ¹, TC Sell ¹, JB Myers ¹

Abstract

A 17-year-old male varsity high school soccer player participated in a home contest on natural grass. He was a senior goalkeeper with no previous history of facial or head trauma. The goalkeeper was struck in the face with an opposing player's knee while he attempted to recover a loose ball that the opponent was trying to kick into the goal. After lying still on the field for approximately 10 seconds, the athlete began to go into a seizure that lasted 45 seconds. When the seizure had ended, he had an obstructed airway and subsequently was not breathing. He also had substantial bleeding from the nose, superior lip, and face. A number of teeth also appeared to be displaced. Given the force of impact and resulting effects, possible injuries included a lacerated artery in the superior lip in addition to multiple facial and dental fractures. Massive blood pooling in the athlete's mouth caused a problem in adequately opening the airway. Suction was not available at the contest, and a number of finger sweeps were performed to clear the mouth of pooled coagulated blood. In order to properly secure an airway, the source of the blood loss had to be addressed. His face was quickly cleaned to identify the primary source of the bleeding. A lacerated artery in his superior lip was identified and direct pressure was immediately applied; this was maintained by a parent-volunteer. Attempts to perform a modified jaw thrust to open the airway while maintaining cervical spine alignment failed due to the difficulty in manipulating the jaw in the athlete's post-seizure state. An airway was finally opened by performing a jaw thrust, potentially compromising the athlete's spine. The athlete regained consciousness 4 minutes post-injury while still on the field awaiting ambulance transport. The athlete was transported to a local children's trauma center where he underwent a number of computed tomography (CT) scans which revealed no significant abnormalities of the brain. However, they did reveal a number of facial fractures including both the inferior and superior orbital rim. The athlete had suffered a laceration of the upper lip along with a full laceration of the superior labial artery. In addition, the athlete fractured the alveolar processes of the maxilla at the level of the right central and lateral incisors, canine, and first premolar, causing all 4 teeth to be significantly displaced. The athlete also suffered an anterior maxillary fracture with blood in his sinus and nasal vault. Immediate treatment in the emergency trauma room consisted of plastic surgery to repair his lip and artery, as well as dental surgery to retract the displaced teeth and wire them into their proper positions. He had root canals performed three weeks post-injury. It has been 2 months since his injury and the facial fractures are still being monitored for healing progress. This case is unique given the difficulties posed by the on-field management of injuries of this magnitude in high school athletic environments. As athletic trainers, we are taught to systematically approach all injuries through a primary survey which includes maintenance of airway, breathing check, and signs of circulation. However, athletic trainers must be both prepared and trained to put aside conventional methodologies of “what works” in certain situations with which they are faced. Such circumstances are exemplified in this case report when the athlete's airway could not be cleared and maintained without first addressing severe facial, nasal, and oral blood loss. Classroom education, however, does not always prepare the future athletic trainer for the injuries they may face at athletic events. By presenting this case report, we hope to provide athletic trainers a better understanding of the types of traumatic facial injuries that can be encountered in high school soccer and other sports. By understanding the significance of potential injuries, we strongly feel that athletic trainers can be more adequately and effectively prepared for any on-field medical emergencies.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-51–S-52.

The Effectiveness Of Various Mouthguards In Reducing The Incidence Of Mild Brain Injury In Sport

KL Cameron ¹, KY Peck ¹, CA Yunker ¹

Abstract

During the course of the 2002–2003 academic year a cohort observational study was conducted to evaluate the effectiveness of two different mouthguards in reducing the incidence of Mild Traumatic Brain Injury (MTBI). During the course of the study, 877 subjects provided informed consent and agreed to participate in this study. Of the 877 subjects, 436 were assigned to the control group and were fitted with a traditional Type II boil and bite mouthguard (Shock Doctor EZ Guard) and 441 were assigned to the study group who wore the WIPPS Brain Pad Bimaxillary mouthguard. The subjects for this study consisted of male cadets from the class of 2006 who were enrolled in the compulsory Physical Education Boxing Program at the United States Military Academy (USMA) at West Point during the study period. All episodes of MTBI attributed to participation in the boxing program at USMA were documented using a standardized evaluation protocol which operationally defined MTBI. Additionally, the presence of post concussive symptoms, as well as the duration of those symptoms, were recorded for all injuries. The incidence of MTBI for both groups during the entire study period were calculated using the case rate and an injury rate utilizing an index of exposure. Since participation in the PE boxing program is mandatory at USMA and accountability is recorded daily, the total number of athlete exposures could be calculated. During the course of the study a total of 76 closed head injuries were sustained by cadets participating in the PE boxing program. Of those cadets sustaining head injuries, 44 (57.9%) were wearing the WIPPS Brain Pad mouthguard and 32 (42.1%) were wearing the traditional mouthguard. The case rate for the group wearing the WIPPS Brain Pad mouthguard was 9.98 injuries per 100 athlete seasons and the injury rate utilizing an index of athlete exposure was 5.34 injuries per 1000 athlete exposures. The case rate for the control group wearing the traditional mouthguard was 7.33 injuries per 100 athlete seasons and the injury rate utilizing an index of athlete exposure was 3.91 injuries per 1000 athlete exposures. The results of this study indicate that the WIPPS brain pad did not offer any additional protection from MTBI then the traditional mouthguard. Furthermore, participants wearing the WIPPS Brain Pad were 37% more likely to sustain a MTBI then those participants in the control group.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-52.

Evaluating The Perceived Preventative Qualities Associated With Two Different Types Of Mouthguards

CA Yunker ¹, KL Cameron ¹, KY Peck ¹

Abstract

During the course of the 2002–03 academic year, a between groups study was conducted to evaluate differences in the perceived preventative qualities between subjects wearing two different mouthguards. Subjects for this study consisted of the males enrolled in a 19 lesson Physical Education Boxing program at the United States Military Academy (USMA) at West Point during the first term of instruction of the 2002-03 academic year. Of the 199 subjects who agreed to participate in the study, 99 were assigned to the control group who wore a traditional boil and bite mouthguard (Shock Doctor EZ Guard) and 100 were assigned to the study group who wore the WIPPS Brain Pad Bimaxillary mouthguard. Following the 19^th lesson of boxing, all subjects were asked to complete a twelve item questionnaire designed by the researchers to evaluate their perceptions of the preventative qualities associated with each mouthguard. Each item consisted of a stem and an anchored 100 mm visual analog scale. Reliability estimates for each of the twelve items produced intra-class correlation coefficients from .95 to .99. Results indicated that significantly more participants believed that the traditional mouthguard was more comfortable (F=28.64, df=1, 197, p<.05) and fit better (F=17.05, df=1, 197, p<.05) than the WIPPS mouthguard. When participants were asked if they would use a mouthguard similar to the one they used during boxing while participating in another contact sport (i.e., rugby, football, wrestling) in the future, significantly more individuals using the traditional mouthguard agreed that they would when compared to individuals using the WIPPS mouthguard (F=41.12, df=1,197, p<.05). Similarly, significantly more individuals wearing the traditional mouthguard agreed that they would voluntarily continue to use a mouthguard in the future. (F=10.10, df=1, 197, p<.05). When asked about the ability of the two mouthguards to prevent injuries to the head, neck, and face the following results were noted. Significantly more individuals using the WIPPS mouthguard believed that it would effectively reduce injuries to their head (F=14.11, df=1, 197, p<.05), face (F=3.90, df=1, 197, p<.05), and neck (F=5.14, df=1, 197, p<.05). There were no significant differences noted between the two groups with regard to their perceptions of the effectiveness of either mouthguard to prevent injuries to the teeth (F=.001, df=1, 197, p>.05) and jaw (F=3.10, df=1, 197, p>.05). Finally, both groups felt that using a mouthguard during boxing was equally important for their personal safety (F=.04, df=1, 197, p>.05).

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-52.

Association Between The Incidence Of Cerebral Concussions And Dental Injuries, And Mouthguard Usage Among NCAA Division I Men's Ice Hockey Players

KM Momsen ¹, A Sigurdsson ¹, EW Shields ¹, KM Guskiewicz ¹

Abstract

There is increasing debate among health care professionals regarding the efficacy of mouthguards in protecting athletes from cerebral concussions and dental injuries. Evidence that mouthguards protect against cerebral concussion is scarce and recent studies have generated more questions than answers. The purpose of this study was to examine the association between mouthguard use and the incidence of dental and concussive injuries in hockey players. Letters explaining the study's purpose were sent to the athletic trainers for all NCAA Division I Men's Ice Hockey teams. Athletic trainers choosing to participate in this study conducted a season long web-based injury surveillance of their respective hockey teams. Our interactive web site included the number of practices, games, and injuries as well as the type of mouthguards worn, injuries incurred, and the severity of those injuries. Chi-square analyses and Fisher Exact Tests were used to determine whether significant associations existed between those players who wore mouthguards and those who did not wear mouthguards for the incidence of concussive and dental injuries. A total of 30 certified athletic trainers participated by reporting on 1,058 subjects for the duration of the study. Thirty out of a possible 60 teams (50%) participated. A total of 85,729 athlete-exposures were captured during the study, with 97 concussions and 17 tooth fractures being reported. The incidences of concussion and tooth fractures were 1.13 and 0.20 per 1,000 athlete-exposures, respectively. Observed associations between mouthguard use and incidence or severity of concussion were not significant in practices (P=0.225) or in games (P=0.53). Mouthguard use and severe dental injuries were also not significantly associated (P=0.057). Based on our findings, there appears to be no advantage to wearing a mouthguard for reducing the risk of concussion or the severity of concussion. Mouthguards appear to be marginally beneficial in preventing severe dental injury, however, not to the degree that we expected.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-52–S-53.

An Examination Of Factors That Influence Knowledge And Reporting Of Mild Brain Injuries In Collegiate Football

JM Sefton ¹, K Pirog ¹, A Capitao ¹, D Harackiewicz ¹, ML Cordova ¹

Abstract

Historically, research regarding mild brain injury (MBI) has focused predominantly on neurophysiological mechanisms, epidemiological data, and various assessment techniques to establish return to play criteria for athletes. To date, no data exist examining athletes' specific knowledge of MBI, or the amount of head injuries that go unreported in sport. Thus, the objectives of this study were three-fold: 1) to examine MBI knowledge among collegiate football players and coaches, 2) quantify the number of unreported head injuries during the 2002 football season, and 3) uncover other factors that may influence head injury reporting. Thirty-eight coaches, 457 football players, and 8 certified athletic trainers (ATCs) from 8 NCAA football programs gave informed consent to participate. All football players (ages 18–26) were currently active with a collegiate program, and had at least 2 years of organized football experience. Packets containing: surveys, verbal instruction sheet, consent and general information forms were sent to football programs at the Division I-A (n=1), I-AA (n=5) and II levels (n=2). Surveys were developed for athletes, coaches and ATCs to obtain data on head injury knowledge, head injury reporting, football experience, sources of head injury information, and football program information. The reliability and validity of the instrument was established prior to data collection. Approximately 76% of all football players, 61% of all coaches and 100% of all ATCs returned completed surveys. Of the 391 head injuries incurred by the football players, 80% went unreported to the coaches or medical staff. It was found that coaches and ATCs underestimated the number of unreported head injuries by 91% and 82%, respectively. With respect to MBI knowledge, athlete's MBI knowledge directly correlated to head injury reporting percentages. In addition, 92% of athletes and coaches believed bellringers/dingers and concussions to be different injuries. Of the athletes who provided additional comments, 73% indicated they did not report a head injury because they did not feel it was important or serious enough to do so. Additionally, coaches' knowledge of and attitude toward head injuries were observed to significantly influence the reporting of head injuries to medical personnel. Not surprisingly, athletes who utilized an ATC as a source of head injury information had significantly higher knowledge scores. In conclusion, a large number of head injuries went unreported in the surveyed collegiate football programs. It appears that improved education of athletes and coaches regarding MBI may increase the percentage of head injuries reported to medical personnel.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-53.

Baseline Self-Report Symptomatology

SG Piland ¹, MS Ferrara ¹

Abstract

Summative self-report symptom scales are a common to preseason concussion assessment batteries. They are designed to provide information concerning how an athlete typically experiences symptoms known to be related to concussion. The value and importance of this information may be biased by the presence of other factors (social motivation, sickness, injury, fatigue). The purpose of this study was to evaluate the effects of these factors, and gender on baseline responses to two summative symptom scales. Athletic trainers at 5 NCAA universities conducted a single administration of a 16-item symptom duration scale (Piland, 2003), a 16-item symptom severity scale (Guskiewicz, 2003, Lovell, 1998), two measures of socially motivated response (Eysenck, 1985, Reynolds, 1982), and an investigator developed health questionnaire. Responses (N=956) were collected from non-injured male (n=698) and female (n=258) collegiate athletes (age = 19.72± 1.61 years). The most frequently reported symptoms were fatigue, drowsiness, and headache. Composite duration and severity scores shared a moderate correlation (r =.86) and t-tests demonstrated that composite duration scores were significantly higher than composite severity scores (t = 9.13, p ≤.05). Statistically significant (p <.05), but clinically irrelevant correlations (< .3) were observed between the symptom scales and the two measures of socially motivated response bias. ANOVA indicated that athletes reporting a recent illness, physical injury, and/or fatigue from activities performed prior to the collection of baseline data had higher composite scores for both duration and severity symptom scales than those not reporting the same conditions (F= 80.83, p ≤.001 and F=69.08, p ≤.001, respectively). Based upon these findings, athletes presenting with any of the aforementioned conditions were removed from analysis. We found no sex (N=605, n=426 males, n=179 females) differences in level of composite scores from either symptom measure (p>.05). Also, previous history of concussion significantly affected the composite scores of males, to both symptom duration (F=6.86, p=.009) and severity (F=23.67, p ≤.001) measures, but not in females (p>.05). Our findings suggest that baseline scores on measures of self-report symptoms are not significantly affected by response bias associated with social motivation. But other conditions commonly experienced by athletes do have a tendency to increase composite scores of self-report symptom measures. Also, gender affects how athletes with a previous concussion respond to duration and severity measures of self-report symptoms. Athletic trainers administering baseline concussion symptom scales should note if athletes report with a recent illness or injury or if they have feelings of fatigue, as these conditions may inflate composite scores and decrease their meaningfulness as pre-concussion measures. Supported by a grant from the NATA Research & Education Foundation sponsored by Proctor & Gamble.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-54.

Spinal Cord Shock In A High School Cheerleader

M Kabay ¹, J Brady ¹

Abstract

The athlete is a fifteen-year-old female cheerleader. The injury occurred when she fell from the top of an extension stunt. An extension is when one person is lifted above the ground and held by the feet over the head of three other people as their arms are fully extended (approximately seven feet in the air). When the athlete fell she landed on her buttocks and her neck hyperextended rapidly causing her head to hit the concrete. Immediately following the fall, the girl was fully alert and conscious. She did not complain of any symptoms other than a headache. The first responder was a Cheerleading Instructor who “scooped up” the girl and brought her immediately to the first aid station. Within one minute of the fall, symptoms began to progress showing signs of a cervical injury. She complained of numbness in her upper and lower extremities. At this point, EMS was called and her neck was manually stabilized. Blood pressure and respiration were monitored and normal. Two minutes post incident responsiveness diminished and the athlete was only able to mumble her name. When she was asked what happened she just stared. At the three-minute mark, her only response to verbal communication was with eye blinks. She had lost toe movement and grip strength. Her dermatomes were tested via pinprick. Sensation was lost from S1 to C4 and intact at the mandible, the C3 dermatome, where she blinked her eyes in response to the pinprick. Thirty seconds after this she was no longer able to open or close her eyes on command. The athlete was conscious and breathing throughout the entire time frame. Differential diagnosis: Concussion; Cervical Spine fracture; Skull fracture; Spinal cord lesion-cervical level; Cranial nerve lesion; Epidural/Subdural hematoma; Cervical Spine stenosis; Cervical Spine dislocation. Diagnostic imaging/laboratory tests (verbal report from coach and athlete, specific results unavailable at this time due to HIPPA regulations): X-ray-negative for fracture; MRI-negative fracture, soft tissue swelling cause compression on the cord at C4 level; CT Scan; Blood work. When EMS arrived, a Philadelphia Cervical Collar was applied and the athlete was placed on a spine board. Vital signs continued to be monitored and were normal. She was transported to the closest trauma center via medical helicopter. After going to the hospital, she was diagnosed with spinal cord shock and a concussion. She was in the hospital for 48 hours after the injury for observation. Since this injury took place at a four-day camp, there was no rehabilitation program initiated. The athlete was instructed by the treating physician not to participate in cheerleading for one year due to the nature of the injury. Spinal cord shock is caused by a mild contusion of the spinal cord or by cervical spine stenosis. Symptoms are similar to that of a spinal cord lesion. If a complete lesion were to occur at C1-C3 it will impair respiration and result in death. Lesions below this point would allow for some return of function. With spinal cord shock these symptoms are temporary and the athlete is usually symptom free within 24 hours. In either case, spinal cord lesion or shock, the athlete should be cared for in the same manner used for any severe neck injury. For this athlete there was no lesion of the spinal cord. The girl was up and walking around the hospital 12 hours after the incident. She did suffer anterograde amnesia; she couldn't remember what happened in regards to the incident or her response to the injury, she was able to remember all the cheers and the dances she had learned earlier in the day. This case was successful in the treatment and recovery. Many times in athletics we tend to overlook the seriousness of falls as a mechanism of injury. With the skill and difficulty of cheer techniques increasing, our athletes continue to be put in high-risk situations. As professionals we need to continue our education regarding the risks and care for injuries from a fall.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-54.

Various Types Of Football Helmets, Face Masks, And Face Mask Loop Straps, And Their Effects On The Efficiency Of Face Mask Removal

EE Swartz ¹, SA Norkus ¹, TA Cappaert ¹, LC Decoster ¹

Abstract

The purpose of this study was to analyze the effect of varied helmets, face masks, and loop straps on face mask removal. Fifteen certified athletic trainers reported for two data collection sessions and used a cordless screwdriver (SD) and FM Extractor (FM). Subjects signed an informed consent and were trained in unscrewing or cutting the face mask for all conditions. Conditions included combinations of 3 helmets (Riddell VSR-4 (R4), Riddell Revolution (RV), and Schutt Air Advantage (ST)) 3 face masks (Riddell thin wire, Schutt Armourguard Elite, Riddell Revolution) and 5 loop straps (Riddell standard (RS), Schutt Armourguard (SA), Maxpro Shockblocker (SB), Stabilizer II (SII), Revolution (Rev)). Each subject then removed the face mask two times for all conditions. Trial order was counterbalanced, and data were analyzed for average time (T) in seconds (s) and a rating of perceived exertion (RPE) to indicate the level of difficulty for each condition. Data were analyzed using a MANOVA (alpha = .05) with Bonferonni adjustments and follow-up comparisons when appropriate. When using a SD, a significant effect was detected for T (P=.007). Pairwise comparisons revealed subjects took longer to remove a face mask from an R4 helmet when it was attached using the SII (55.83 ±13.12 s) compared to when it was attached using a SB on both the R4 (43.05±5.54) (P= .023) and ST (40.36±6.52s) (P= .008). There were no differences between conditions in RPE for subjects when using the SD. When subjects used the FM, a significant effect was detected for T (P =.000). Pairwise comparisons revealed subjects took longer to remove the face mask from a RV when attached with Rev (165.67±29.40s) compared to when attached using SB on both R4 (63.08±14.78s) and ST (103.57± 25.86s) (P= .001, P=.047, respectively). Face mask removal took significantly longer using SA (203.33±25.86s) compared to RS (95.00±7.07s) (P=.004), SB when attached to R4 (P=.000), and SB when attached to ST (P=.001). A significant effect was detected for RPE (P=.026) when using the FM, yet follow up tests did not identify differences between specific conditions. Subjects reported the highest RPE when removing the face mask from the RV (6.833±1.02) and lowest RPE when removing the face mask from the R4 when attached with the SB (2.67±.72) These results demonstrate that regardless of type of tool used, football helmet components effect the efficiency of face mask removal. Further research should compare effects on head movement.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-55.

Analysis Of Two Spine Boarding Techniques Utilizing A Motorized Spine Board

HD Ensor ¹, EE Swartz ¹

Abstract

An instance of serious injury often warrants the use of a spine board to transfer the patient. Currently, emergency personnel utilize the log-roll technique with a traditional spine board. The development of a new motorized spine board (MSB) has added a new possibility to the management of the seriously injured patient. The purpose of this study was to evaluate movement at the head and body and time to complete the boarding procedure associated with use of the MSB. Four certified athletic trainers volunteered as subjects and randomly rotated positions with each being first at the head and then at the body for a total of three trials per subject. Twenty-one reflective markers were placed on the victim to track the movement caused during the two techniques: 1) MSB head first (HF), 2) MSB feet first (FF). Each trial began with the victim supine and the subject stabilizing the head while kneeling lateral to the victim. Each trial began with an audio cue from the motion analysis system and ended when the subject stabilizing the head declared the group was “finished”. Time for completion and time of displacement of the head independent from the shoulders was compared. Means were analyzed using an ANOVA (alpha = .05). Results showed no difference in time (P>.05) for FF (30.40±0.66 secs) and HF (31.06±1.30 secs). However, the time of displacement of the head independent from the shoulders was significantly larger (P = .000) for the FF (11.68±0.36) seconds compared to HF (1.62±1.20). These results suggest that the cervical spine is undergoing a longer time interval of movement during the FF loading technique due to motion in the body being created for nearly 12 seconds prior to motion at the head. The MSB could provide an effective alternative to traditional spine boarding techniques. However, initial results of the MSB techniques demonstrate that loading the patient using the HF technique would prove a much safer method compared to FF to minimize potential further injury in the spinal cord. The completion times along with movement data needs to be compared to that of the log-roll technique with the traditional spine board. Further research into this new emergency health management tool is warranted.

J Athl Train. 2004 Apr-Jun;39(Suppl 2):S-55.

Atlanto-Axial Instability In An Intercollegiate Football Player

AJ Warren ¹, CA Vesci ¹, JA Zirkelbach ¹, CL Noll ¹

Abstract

During a strength conditioning workout a 20-year-old intercollegiate football player described a “pop” in his neck while performing eccentric manual cervical extensions. The athlete had no cervical pain prior to this incident, but did sustain multiple brachial plexus injuries in his past. Two days post injury the patient presented with cervical pain and general stiffness with active movement. Additionally, muscular spasm of the upper trapezius, decreased range of motion in all planes, and point tenderness over the posterior cervical spine and base of the occiput were also noted. Increased tenderness to palpation was noted in the area of C1 and C2. The patient denied any associated neurological symptoms at the time of the injury, but did experience neurological symptoms with a compression test. A referral was made to an orthopedic spine specialist upon completion of the initial examination. The pathological possibilities at this time included cervical nerve root compression, cervical facet compression, stenosis of the intervertebral foramen, C1 / C2 stress fracture, and cervical disc herniation. Plain radiographs were negative for an acute cervical fracture, but revealed congenital fusion of C2 / C3 vertebrae. Radiographic examination in flexion and extension showed atlanto-axial cervical instability. The patient was removed from all activity until further imaging studies had been completed. A bone scan was ordered which showed no presence of cervical stress fractures. Magnetic resonance imaging also confirmed the previous finding of congenital fusion of C2 / C3, as well as showed no apparent cord damage. A CT myelogram was then ordered to identify specific bony abnormalities as well as serve as a secondary examination to evaluate the congenital deformity and segmental instability. Results of the CT myelogram also showed fusion at the C2 / C3 level, odontoid hypoplasia with no obvious foraminal stenosis, and revealed only a 9 mm space available for cord (SAC). The patient was diagnosed with congenital fusion of C2 / C3, atlanto-axial instability (AAI), and odontoid hypoplasia. The patient was initially treated by a certified athletic trainer which consisted of ice, cessation of all activities, and immobilization with a soft neck collar. The treatment options were explained by the physician, which consisted of 1) non-surgical treatment with clearance to play, 2) non-surgical treatment with a medical disqualification, 3) surgery and clearance to play, and 4) surgery with a medical disqualification from contact sports. The patient was consented on the possible risks associated with each option, which included paralysis, spinal cord damage, infection, stroke, and death. The latter of the treatment options was selected and the patient underwent surgery with a medical disqualification from all contact and collision sports. Surgery consisted of C1 / C2 fusion which was accomplished by posterior wiring of the segments utilizing a bone graft from the patient's hip. The patient was treated post-operatively with a rigid cervical collar 24 hours/day for six weeks. After immobilization, gradual return of active range of motion was obtained with no cervical resistance for one year. To date the patient's prognosis has been excellent with no report of problems or pain. AAI is characterized by excessive movement at the C1/C2 junction due to either bony or ligamentous abnormality, and is defined as having an atlantodens interval (ADI, distance between odontoid process and the posterior border of the anterior arch of the atlas) of greater than 3 mm in adults. This subject had an ADI of 7mm in neutral, 9mm in flexion, and 4 mm in extension upon radiographical imaging. This particular case involves bony anomalies in the form of congenital shortening of the dens, with a congenital fusion of C2 and C3. While odontoid dysplasia is considered somewhat rare, it is becoming increasingly identified. The clinical importance of this condition is inherent instability of the atlanto-axial segment, which caries the potential of subluxation and dislocation with serious neurological impairment. Although odontoid hypoplasia is a predisposing risk factor for AAI, it is less frequently associated with this problem and seen more often in patients with Down's syndrome. This case is unique in the fact that the etiology of the instability is due to bony abnormalities of the dens, but the instability is also compounded from the fusion of vertebral segments of C2 / C3. Attempts should be made identify this condition prior to involvement in contact activities to decrease the risk of catastrophic injury.

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