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International Journal of Sports Physical Therapy logoLink to International Journal of Sports Physical Therapy
. 2019 Apr;14(2):228–236.

A NOVEL TEST TO ASSESS CHANGE OF DIRECTION: DEVELOPMENT, RELIABILITY, AND REHABILITATION CONSIDERATIONS

Haley Worst 1,✉, Nancy Henderson 1, Ryan Decarreau 1, George Davies 1
PMCID: PMC6449014  PMID: 30997275

Abstract

Background

Several researchers have investigated functional testing with regard to return to sport decision making. Change of direction activities play a role in the advancement of rehabilitation as an athlete progresses towards return to sport. Few studies have assessed tests that measure change of direction tasks.

Purpose

The primary purpose of this study was to establish test-retest and intra- and inter-rater reliability of performing the Change of Lateral Direction (COLD) test. The second purpose was to provide normative data for healthy college aged subjects performing the COLD test. The final purpose of this study was to assess the role of fatigue while performing lateral change of direction tasks.

Study Design

Cross-sectional, descriptive reliability study

Methods

Thirty-three female and 18 male healthy college students (mean age = 25.5) were tested on two occasions, one week apart. Subjects started out standing on a standard 4” step and rapidly altered stepping to tape markers on either side of the step as many times as possible for 30 seconds. The total number of steps achieved in 30 seconds was video recorded and watched later to count steps in order to determine reliability. The effect of fatigue was assessed by subdividing the 30 second trial into three increments: 0-10 seconds (T0-10), 11-20 seconds (T11-20), and 21-30 seconds (T21-30).

Results:

Normative data for session 1 and session 2 were 76.0 (±10.9) and 80.1 (±11.2) steps respectively. Inter-rater (ICC: 0.994-0.996) and intra-rater (ICC: 0.930-0.984) reliability was excellent. Test-retest reliability demonstrated a strong correlation (r = 0.88) between session 1 and session 2. A significant decline (p<0.001) in total number of steps was demonstrated between T0-10 and T21-30, as well as T11-20 and T21-30 during both session 1 and session 2.

Conclusions:

The COLD test demonstrated excellent inter-rater and intra-rater reliability. A possible fatigue effect occurred at T21-30. Because of the ease of administration, minimal equipment required, and excellent intra and inter-rater reliability, the COLD test provides an excellent functional change of direction test. This test could be used for serial reassessment during pre-season screening, rehabilitation, or return to sport.

Level of Evidence:

2c

Keywords: functional testing, lower extremity lateral agility testing, performance testing

INTRODUCTION

Change of direction (COD) and agility drills are commonly used training interventions. Although the terms have been used synonymously, they are distinctly different skills with varied correlation between performance outcomes (r = 0.321-0.70).1–6 COD has been defined as the specific skills and abilities needed to change movement direction or velocity during a preplanned movement pattern.1,6 Conversely, agility is a rapid whole body movement with change of velocity or direction of movement in response to a stimulus. Highlighted in the definition of agility is both the COD component and an added cognitive/perceptual component (visual scanning, anticipation, pattern recognition, and situational awareness).2

Successful completion of COD tasks requires rapid and coordinated force to allow a braking phase (eccentric bias), plant phase (isometric bias), and propulsive phase (concentric bias).7,8 Several physical characteristics have been correlated with faster COD performances. Lower body power,1,9 eccentric and concentric strength,3,5,10,11 reactive strength,7,12,13 and linear speed2,5,6,11 have all been demonstrated to positively correlate with time to complete COD tasks. Although important, several of these physical characteristics cannot be trained in injured or early postoperative populations. Therefore, a progression of change of direction tasks would be required for these individuals during the course of rehabilitation.

The ability to change directions is fundamental to several field based sports, especially those that involve an opponent. Sports specific movement analysis has demonstrated COD activities happening frequently (every two to four seconds) and at high volume (>1000/game) in soccer, tennis, rugby and basketball.14 Given the high prevalence of COD actions in sports, reliable and valid tests of COD ability are important for the rehabilitation and strength and conditioning providers, in order to utilize a low cost and time efficient means to assess the effect of training and rehabilitation programs. Several COD tests have been used as a part of a test battery for athletes returning to sport after injury or surgical procedures (T-test, Pro Agility test, L-Run, 505 and modified 505, Change-of-Direction and Acceleration test (CODAT), and the Illinois agility test).6

Although a wide variety of tests have been described in the literature, a specific progression for COD activities has been difficult to determine in athletes and physically active patients during the course of a rehabilitation program.15,16 With the shift from time-based to criterion-based rehabilitation protocols, specific tests to assess when an athlete is able to progress from their current level of performance to a more advanced skill or exercise will be important for providers.17 The heterogeneity between the current tests used to assess COD (distance, number of cuts, angle of COD, speed of performance) may not allow them to be performed in the early or mid-stages of rehabilitation. A well-designed rehabilitation program to return the athlete/patient back to high level COD tasks should include a progression from submaximal to maximal speed efforts, closed preset skills to open skills that require increasing visual processing, timing, reaction time, perception, and anticipation skills, in order to be successful. A progressive evidence-based COD sequence is needed to accomplish this aforementioned task. The lack of such an evidence-based progression represents a gap in the literature that needs to be explored further.

Commonly used COD tests are generally short in duration (2-18 seconds) and require 1-11 changes of direction.6 Short duration testing is justified in the end stage of rehabilitation and return to sport testing phases as field based sports typically involve short spurts of activity followed by low intensity running or rest.18 The longest COD test currently available is the Illinois Agility Run (IAR), which takes 14-18 seconds to complete. A common criticism of the IAR is the role that fatigue may play on performance due to its extended test duration.19 Despite this, fatigue has been shown to affect performance and biomechanics during return to sport testing and has been identified as a possible avenue to identify deficits after injury.17 In the post-operative Anterior Cruciate Ligament (ACL) reconstruction population, fatigue protocols have demonstrated detrimental effects on hop testing,21 bilateral drop vertical jump,22 and unanticipated landing tasks.23

The effect of fatigue on COD has received less attention and the literature is conflicting. Greig et al. investigated the effect of a fatiguing protocol on COD kinematics via a simulated soccer game.24 As the subjects became more fatigued, knee flexion angle decreased and knee valgus angle increased at touchdown, peaking at the end of both halves. This has important rehabilitation implications as the combination of decreased knee flexion and increased knee valgus has been implicated as an ACL injury mechanism.15 Alternatively, Sanna and O’Connor failed to demonstrate a change in sagittal and frontal plane knee kinetics and kinematics during cutting after a similar fatiguing protocol performed on a 20-meter course.25

The Change of Lateral Direction Test (COLD) is a novel, low intensity lateral COD task performed in a closed environment. It was developed as a way to assess lateral COD performance in a clinical setting. The COLD can be used clinically as a guide for progression of COD tasks while rehabilitating lower extremity injuries in athletic populations. The primary purpose of this study was to establish test-retest and intra- and inter-rater reliability of performing the COLD test. The second purpose was to provide normative data for healthy college aged subjects performing the COLD test. The final purpose of this study was to assess the role of fatigue while performing lateral COD tasks. It was hypothesized that the COLD test would demonstrate good reliability for test-retest, intra- and inter-rater assessments. Additionally, it was hypothesized that the COLD test would demonstrate a decline in scoring from the initial 10 seconds (T0-10) to the final 10 seconds (T21-30) of test performance.

METHODS

The study used a cross-sectional non-experimental study design to establish reliability and provide normative data for the COLD test. The Georgia Southern University Institutional Review Board approved the study and all participants read and signed an informed consent form prior to participation. Fifty-one asymptomatic subjects (35.3% male) were recruited via convenience sampling. Demographic information indicated that 59% of the subjects ran as a form of exercise, 98% had participated in an agility sport in the prior six months, and 57% had sustained a sports related injury at some point in their lifetime. However, none of the participants had sustained an injury within the 12 months prior to their participation in the study. All participants met the inclusion criteria of being physically active as defined by exercising at least three times per week for 60 minutes, involved in running or sport related activities, being between the ages of 18-35 years old, and having no lower extremity pain at the time of the study. Exclusion criteria included a history of lower extremity ligamentous surgery, spine surgery, pregnancy, or other medical conditions that would prevent them from being able to safely perform a COD test as identified on a medical questionnaire.

Prior to testing, subjects performed a five-minute dynamic warm-up that consisted of jogging, lateral shuffles, and cross over carioca that was standardized based on time and intensity. The dynamic warm up was followed by a lower extremity stretching routine for the quadriceps, hamstrings, iliotibial band, and gastrocnemius and soleus complex for a total of five minutes. Subjects were supervised and given a written handout with pictures of the stretches to follow for bilateral lower extremities.

TESTING PROCEDURES

Once the warm up was completed, the same examiner read the standardized script describing the test procedures, including the criteria for stopping the COLD test. Prior to performing the test, each subject watched a brief video demonstrating correct test performance. After listening to the test procedures and viewing the video, each subject was given a 10 second practice session where the examiners provided verbal feedback regarding appropriate test performance. If the subject did not perform the test appropriately, he/she was given a longer orientation session.

A standard fitness step (AW aerobic fitness®, AWinternational Inc. LaPuenta, CA, USA) was used for testing (length: 63.5 cm, wide: 27.94 cm, height: 10.16 cm). A tape marker was placed on the ground 35.56 cm from the center of the step, on either side of the step. (Figure 1a) The subject started with both feet on the step and then rapidly alternated stepping (Figures 1b and 1c) to the tape marker on the right and left sides of the step. The subjects were not required to maintain contact with the step at all times and were able to jump with both feet to facilitate the COD task. Subjects were instructed to alternate touching the tape markers as many times as they could in 30 seconds. The criteria for stopping the test included loss of balance, inability to consistently touch the tape markers for three consecutive trials, or if the subject determined he/she was unable to physically continue the test.

Figure 1.

Figure 1.

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a. Starting position with both feet on the step, b. Start of test with left foot the touching tape on left side of the step, c. Cross over to touch tape on opposite side of step with right foot. The athlete alternates from side to side, touching the tape as many times as they can in 30 seconds.

The subjects performed the testing procedure one time at the initial session (session 1) and then again one week later (session 2), in order to establish between session test-retest reliability. The same study procedures were utilized during the second testing session. A sports video analysis application (Coach's eye®, Techsmith Corp., Okemos, MI, USA) was utilized for 2D image recording on a tablet (Air2®, Apple Inc. Cupertino, CA, USA) for session 1 and session 2 to allow for slow motion counting of the steps at a later time. Coach's eye has been deemed a reliable means of motion analysis to be used clinically.26 The camera was positioned 3.5 m directly in front of the 10.16 cm step and 30 cm from the ground, as done in previous step test research.27 After the test was completed, a single researcher watched the video and steps were counted for the entire 30 second test. Additionally, the effects of fatigue were assessed by subdividing the 30 second trial into three increments: 0-10 seconds (T0-10), 11-20 seconds (T11-20), and 21-30 seconds (T21-30).

Intra-rater and inter-rater reliability of the video assessment was assessed for each of the four researchers by individually evaluating the videos independent of each other using the Coach's eye® video of the first 11 subjects in the sample and each determining the number of steps in the 30 second testing time frame. These procedures were repeated for session 2 for each of the 11 subjects, who were part of the reliability portion, in order to establish intra-rater reliability. The researcher who demonstrated the highest intra-rater reliability was selected to perform the step counting for the remaining subjects.

DATA ANALYSIS

The total number of steps completed in a 30 second trial served as the normative values for the COLD test. Measures of central tendency were calculated for normative data. Data were assessed for normality using the Shapiro Wilk and Kolmogorov Smirnov tests. Intra- and inter-rater reliability for the COLD test was assessed using intraclass correlation coefficients (ICC, model 3). The actual performance of the COLD for test-retest reliability was measured with Pearson's correlation coefficients (r). Minimal detectable change (MDC) values were calculated based on a 95% confidence interval. A Repeated measures ANOVA was conducted to assess the effects of fatigue over the 30 second trial. When sphericity was violated, a Greenhouse-Geisser correction was applied. Alpha level was set a prioi at 0.05 and SPSS version 24 was used for all statistical analyses.

RESULTS

A total sample of 51 subjects participated in the study (mean age  =  25.5 years [range 22-35]). Normative values for the total sample of session 1 and session 2 were 76.0 steps (sd = 10.9; range: 53-101) and 80.7 steps (sd  =  11.2; range: 61-115), respectively. MDC95 values ranged from 2.1-2.3. Inter-rater reliability for the COLD test was excellent (0.994 - 0.996), as was intra-rater reliability (0.930 - 0.984). Test-retest reliability demonstrated a strong correlation between session 1 and session 2 (r  =  0.88). The repeated measures ANOVA showed a significant decline in the number of steps between T11-20 and T21-30 for both session 1 and 2 (p < 0.001; mean difference 2.4-3.6 steps). There was also a significant decline noted between T0-10 and T21-30 for both session 1 and session 2 (p < 0.001; mean difference 2.8-4.3 steps). No significant difference was found between T0-10 and T11-20 for either session 1 or session 2 (p>.05).

DISCUSSION

The primary purpose of this study was to establish test-retest, intra-rater, and inter-rater reliability for the COLD test. The results of this study supported the hypotheses that there would be good reliability of the examiners interpreting the results of the COLD test. This finding is consistent with previous studies looking at inter- and intra-rater reliability with COD tasks with ICC values ranging from 0.73 to 0.99.2,8,9,14,20,28–37

From a clinical perspective, the majority of COD studies have examined tests that can be used in late stage rehabilitation and return to sport testing. Fewer studies have looked at COD tasks that could be evaluated in the early stages of rehabilitation. This is an important step in the safe progression back to high level functional activity. A novel aspect of this study was the use of a hand-held device (smartphone application) to accurately record foot contacts in a COD task. Several options exist to measure patient/athlete movement (force plates, isokinetic dynamometer, 3-D motion analysis systems, etc), but are cost prohibitive and time consuming for use in a clinical setting. Allowing easy and relatively inexpensive options for clinicians may increase the utilization of formal performance testing. This study adds to a body of literature demonstrating the reliable use of smart phones, tablets, or other hand-held devices to measure patient movement in the clinic. Previous studies have demonstrated reliable and valid hand held device measures when evaluating hip and knee mechanics with running,38 jumping and landing technique,15,39–42 movement screening,43 and single leg squatting or step downs.27,44–47

The secondary purpose of this article was to provide normative data for healthy college aged subjects performing the COLD. This test could be used as a COD test for recreational participants or athletes as a progression criterion for return to sport or activity. Athletes who have sustained lower extremity injuries often return to sport before they have been adequately rehabilitated.48,49 Athletes who have undergone anterior cruciate ligament reconstruction (ACLR) are at the highest risk of re-tear in the first 12 months and there is an increased risk of re-injury if the patients are unable to achieve symmetry in strength between the injured and un-injured extremities.48 Additionally, only 30% of post-operative ACLR patients perform agility training as part of their rehabilitation program.48,50 As a result, a low percentage (13.9%) of ACLR subjects demonstrate the ability to meet all strength and COD milestones at return to sport testing.51 The data from these articles serve to demonstrate the importance of assessing COD and agility prior to returning to sport. This is an area that has received limited investigation in the past and would benefit from future research to answer questions regarding the readiness of athletes to perform COD tasks after lower body injury and surgery.

The tertiary purpose of this study was to examine the effects of fatigue on performance on the COLD test. One of the unique features of the COLD test is its ability to assess endurance with the COD testing because it lasts longer than any of the previously described COD tests.1 Although the role of fatigue in biomechanical changes has been questioned,52,53 there is evidence to demonstrate the negative effects of acute fatigue on performance parameters and injury risk biomechanics.25,54,55 Iguchi et al. showed a decline in lower extremity muscle electromyography activation (EMG) with fatigue, which could decrease the protective mechanism of the ACL.54 A study by Liang-Ching et al. found that it took more than 40 minutes of rest for knee kinematics and kinetics during side-step cutting to return to pre-fatigue levels.55 Finally, Edwards et al. used a validated fatigue protocol and demonstrated alterations in lower extremity kinematics due to fatigue during sidestep cutting movements.56

A unique finding of this study was the significant decline in step rate that occurred throughout the COLD test. During the first 0-20 seconds of the test, there was a minimal decrease in the performance of the number of touches, however, after 20 seconds there was a significant decrease in the number of touches indicating a potential fatigue effect had developed. Considering the effects fatigue has on lower extremity kinematics and performance, it is important to know when fatigue possibly occurs in asymptomatic individuals, during this novel COD test. This knowledge will aid clinicians when developing goals for their patients in relation to normative values and fatigue levels. However, more research is required to determine if the decline in step rate was a normal occurrence within the test or a specific effect of fatigue.

LIMITATIONS OF THE STUDY

The COLD test only assesses movement in the frontal plane, which neglects sagittal and transverse plane movements typically seen in sporting activity. The total sample size was relatively small to detect normative data and the majority of participants were female, which may decrease the applicability of this data to males. Although 98% of the subjects participated in an agility sport in the prior six months, none were currently participating in an agility sport at the time of the study. The inclusion of only healthy recreationally active subjects limits the generalizability of the results to athletes that have suffered an injury and those participating in athletics at higher levels of competition.

In the future, it would be beneficial to first perform the COLD test on uninjured athletes of specific sports that involve change of direction. Then, apply the COLD testing to athletes who are recovering from a lower extremity musculoskeletal injury. If the COLD test is to be used as part of a return to play progression, it would be useful to assess lower extremity kinetic data during the performance of the test. This would allow clinicians to evaluate the joint torque and lower extremity muscle forces required to allow proper initiation of this testing/training intervention. It would also be useful to assess COLD test performance in athletes to create valid cut off scores for evaluating the ability to progress to higher level COD/agility tasks.

CONCLUSION

The results of the current study indicate that the COLD test demonstrated good to excellent test-retest, inter-rater, and intra-rater reliability. Additionally, descriptive normative data in healthy college students was included as preliminary data to be used as a reference norm for using the COLD as a COD test in similar populations.

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