The relationship between navicular height and the incidence of self-reported ankle and knee injuries : a grant proposal

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1 The University of Toledo The University of Toledo Digital Repository Master s and Doctoral Projects The relationship between navicular height and the incidence of self-reported ankle and knee injuries : a grant proposal Sarah Marie Hoge The University of Toledo Follow this and additional works at: This Scholarly Project is brought to you for free and open access by The University of Toledo Digital Repository. It has been accepted for inclusion in Master s and Doctoral Projects by an authorized administrator of The University of Toledo Digital Repository. For more information, please see the repository's About page.

2 FINAL APPROVAL OF SCHOLARLY PROJECT Doctor of Physical Therapy Degree The Relationship Between Navicular Height and the Incidence of Self-Reported Ankle and Knee Injuries Submitted by Sarah Marie Hoge In partial fulfillment of the requirements for the degree of Doctor of Physical Therapy Date of Presentation: December 6, 2006 Academic Advisory Committee Major Advisor Clayton Holmes, Ed.D., Ph.T. Department Chairperson Clayton Holmes, Ed.D., P.T. Dean, College of Health Sciences Jerome Sullivan, Ph.D. Senior Associate Dean College of Graduate Studies Michael Bisesi, Ph.D.

3 The Relationship Between Navicular Height and the Incidence of Self-Reported Ankle and Knee Injuries Sarah Hoge 10/14/06 Major Advisor: Clayton Holmes, P.T., Ed.D., A.T.C. 1

4 INTRODUCTION Ankle and knee injuries are among the most common injuries occurring in court sports. [1-3] Ankle sprains, anterior cruciate ligament tears, and anterior knee pain are common injuries affecting these joints. The purpose of this study was to determine if a relationship exists between self-reported knee and/or ankle injuries and navicular height in individuals participating in court sports. Research suggests that ankle and knee injuries could be related to the navicular height of the foot, although many of the studies have yielded conflicting results. [4-9] If ankle and knee injuries are found to be related to navicular height, it would be possible to determine which individuals participating in court sports are at risk for knee and/or ankle injuries by measuring navicular height. The individuals identified could then be fitted for orthotics to help prevent or lower the incidence of knee and/or ankle injuries. It was hypothesized that individuals participating in court sports who have a lower navicular height will sustain more knee injuries than those with a higher navicular height. It was also hypothesized that individuals participating in court sports who have a higher navicular height will sustain more ankle injuries than those with a lower navicular height. LITERATURE REVIEW Athletes playing court sports experience a variety of injuries. Cohen and Metzl reported basketball to be the leading cause of sports-related injury in America, with the ankle and knee being the most common areas of injury. [1] The ankle is the most commonly injured part of the body in volleyball, accounting for approximately 50% of all volleyball injuries. [2] Of all ankle injuries, 85% are sprains. [3] Of all ankle sprains, 85% are inversion sprains. [3] 2

5 Previous research has indicated that abnormal arch height of the foot may be a factor that predisposes athletes to injury. [4-9] Williams et al. found that high-arched runners experienced a greater incidence of ankle, bony, and lateral injuries; whereas, lowarched runners reported more knee, soft tissue, and medial injuries. [4] Wright et al. demonstrated that increased supination during touchdown of a side-shuffling movement created a slight increase in inversion sprain susceptibility, but their results were not significant. [5] Nigg et al. found that eversion of the foot is coupled with internal rotation of the tibia, which is a possible cause of anterior knee pain. The results from Nigg et al. indicated that individuals with a higher arch may be more prone to anterior knee pain. [6] Jones and Cowan found that those with high arches experienced increased training related injuries. [7] Loudon et al. reported that females with excessive navicular drop (> 9 mm) had a greater incidence of anterior cruciate ligament injury. [8] Dahle et al. found that individuals with either high or low arches had greater incidences of knee injuries than individuals with normal arches. [9] In order to examine the effect of arch height on ankle and knee injuries, a consistent method is needed to measure the position of the weight bearing foot. Many studies have been done to test the reliability of different methods of measuring arch height of the foot. [10-13] Most measuring techniques involve taking a measurement of the foot in subtalar joint neutral (STJN), which is when the foot is neither pronated nor supinated. STJN measurements can be taken with the patient in an open kinetic chain (OKC) (non-weight-bearing position) or closed kinetic chain (CKC) (weight-bearing position). A measurement of the foot may also be taken with the patient in a relaxed position. The navicular drop test (NDT) involves calculating the distance the navicular drops when moving into a relaxed position from CKC STJN. 3

6 Picciano et al. found that OKC and CKC STJN yield poor reliability and NDT yields poor to moderate intratester reliability when measurements were performed by inexperienced testers. [10] Menz and Keenen demonstrated that the angle finder and digital goniometer were unreliable for CKC rearfoot measurement. [11] Sell et al. compared the methods of using an inclinometer to measure standing calcaneal angle and a ruler to measure standing navicular drop. [12] They found the navicular drop method to be most reliable in both intrarater and interrater reliability. Due to the high ICC values reported by Sell et al., the navicular drop method was chosen for use in this study. Holmes et al. developed a tool to measure arch height of the foot in a weight bearing position. [13] The tool consisted of a ruler imbedded into a foam block, which ensured the ruler was flat against the measuring surface and projected straight up for each measurement. They demonstrated that this device produced reliable data when measuring relaxed stance and STJN. Problem Injuries to the ankle and knee are among the most common injuries occurring in court sports. [1-3] Ankle injuries account for up to one sixth of all time lost from sport due to injury. [14] Many knee injuries are severe, requiring surgery, and are the most common cause of permanent disability. [4,6,8] The height of the navicular has been linked to increased risk of certain injuries. [4-9] However, studies examining the relationship between navicular height and lower extremity injuries do not yield definitive findings. Purpose The purpose of this study was to determine if a relationship exists between selfreported knee and/or ankle injuries and navicular height in individuals participating in court sports. 4

7 Hypotheses It was hypothesized that individuals participating in court sports who have a lower navicular height will sustain more knee injuries than those with a higher navicular height. It was also hypothesized that individuals participating in court sports who have a higher navicular height will sustain more ankle injuries than those with a lower navicular height. Significance If the hypotheses are supported by the study, it would be possible to determine which inidividuals participating in court sports are at risk for knee and/or ankle injuries by measuring navicular height. The individuals identified could then be fitted for orthotics to help prevent or lower the incidence of knee and/or ankle injuries. METHODS Design This will be a mixed design study involving measurement of the navicular height of individuals and collection of self-reported data relating to previous incidences of knee and ankle injuries while participating in court sports. Subjects Thirty-two college-aged subjects participated in this study. This resulted in 64 ankles for observation. The researcher recruited subjects by asking for student volunteers from the Medical University of Ohio. All subjects were required to provide their signature of informed consent before participating in this study. The study was approved by the Institutional Review Board for the Protection of Rights of Human Subjects at the Medical University of Ohio at Toledo (IRB #104830). Measurement 5

8 The measurements of the palpated navicular height were taken using the Johnson Level 406EM 6" English/Metric Metal Combination Square device. The technique simulated that used by Holmes et al.; however, the Johnson Level was used in place of the ruler embedded in the foam block with the goal of improving reliability. 11 The subjects navicular was palpated in a weight bearing position, and the most prominent point was marked by the measurer with a marker. The subjects were asked to march in place several steps and then stand relaxed. The subjects navicular height was measured in millimeters in relaxed stance and STJN while standing on a platform. The navicular height was recorded as the distance from surface of the platform to the dot marking the most prominent portion of the subjects navicular. STJN was found by palpating the subject s tali anteromedially and anterolaterally using the hand closest to the patient s midline. The measurer s hypothenar eminence rested on top of the subject s first ray to ensure that the subject s great toe did not come off the support surface during supination. The measurer actively assisted the subjects in rotating their leg into internal and external rotation, pronating and supinating the foot, respectively. STJN was determined to be the point when the talar head was felt equally between the measureer s thumb and index finger. For consistency, the determined STJN was when the medial head was no longer prominent when moving the subject s foot from pronation to supination. Procedure The researchers visited multiple classes at the Medical University of Ohio to explain the purpose of the study. All students in the classes visited were asked to participate in the study. After the presentation, the potential subjects were given time to 6

9 ask any questions related to participation in the study. Students were then given a personal consent form to allow participation in the study. Subjects turned in their consent forms at the time of measurement. Prior to measurement, subjects were asked to complete a written form stating whether they had ever experienced any of the following injuries while participating in court sports: chronic knee pain, acute knee injury, inward ankle sprain, or outward ankle sprain. If subjects answered yes to any of these injuries, they were asked to provide more specific information related to the injury. Specific information regarding injuries included: the sport in which the injury occurred, which side of the body was involved, if the subject saw a doctor for the injury, the specific diagnosis, and the number of times the injury occurred. The form utilized to collect this data is available in the Appendix. Subjects were also asked to record their gender, age, height, weight, and shoe size on a separate form. Once subjects had completed the previously mentioned paperwork, they were taken in groups of four to be measured. The measurer was blinded from the subjects by a sheet. Two measurements were taken for each subject in both relaxed stance and STJN while the subject stood with full weight bearing. Subjects were randomly switched between the first and second measurements, and all data was recorded by a separate researcher in order to prevent bias of the second measurement. Measurements were taken from the surface of the platform to the marking placed on the most prominent portion of the navicular. Once all the data was collected, pronation data was calculated for all subjects using the following formula: STJN - relaxed stance = pronation. Data was analyzed to determine reliability and to see which subjects sustained knee and/or ankle 7

10 injuries, which subjects did not sustain knee or ankle injuries, and compare those to the navicular heights of each group. Data Analysis The reliability of the data are reported using the ICC (2,1) with a 95% confidence interval. This study used two-factor ANOVA to test for differences in measures of relaxed stance, STJN, and/or pronation between subjects who sustained a specific injury versus subjects who did not sustain the same injury. The specific injuries analyzed were inversion ankle sprains, eversion ankle sprains, acute knee injuries, and chronic knee injuries. The p-value was set at <.05. The hypotheses under analysis were as follows: 1. Individuals participating in court sports who have a lower navicular height will sustain more knee injuries than those with a higher navicular height. 2. Individuals participating in court sports who have a higher navicular height will sustain more ankle injuries than those with a lower navicular height. RESULTS The researcher took repeated measurements, which were separated by time, of the navicular height of 32 subjects, for a total of 64 feet, in relaxed stance and STJN in order to test intra-rater reliability. This study estimates the reliability of the data using the intraclass correlation coefficient (2,1). Reliability was obtained for all measurements as demonstrated in Table 1. The single rater ICC value was 0.98 for measurement of left foot relaxed stance, which indicates excellent reliability. The 95% confidence interval was 0.96 to The single rater ICC value was 0.97 for measurement of left foot STJN, which again indicates excellent reliability. The 95% confidence interval was 0.93 to The single rater ICC value was 0.96 for measurement of right foot relaxed stance, which indicates excellent reliability. The 95% confidence interval was 0.92 to 8

11 0.98. The single rater ICC value was 0.82 for measurement of right foot STJN, which indicates good reliability. The 95% confidence interval was 0.66 to Table 1. Intraclass Correlation Coefficient values for the four variables, with 95% confidence intervals Measure ICC Lower Upper Left relaxed stance Left STJN Right relaxed stance Right STJN Thirty-two subjects participated in this study. Females accounted for 75.0% (n=24) while males accounted for 25.0% (n=8) of the subjects. The subjects were all college-aged students from the Medical University of Ohio at Toledo. Descriptive statistics for males are shown in Table 2. The mean age of the males was years (SD=3.314). The mean height was inches (SD=2.563). The mean weight was pounds (SD=14.745). The mean shoe size of the males was (SD=1.225). Table 2. Descriptive Statistics Males N Minimum Maximum Mean Std. Deviation AGE HEIGHT WEIGHT Shoe Size Descriptive statistics for females are shown in Table 3. The mean age of the females was years (SD=1.103). The mean height was inches (SD=2.413). 9

12 The mean weight was pounds (SD=26.688). The mean shoe size was 8.33 (SD=1.100). Table 3. Descriptive Statistics Females N Minimum Maximum Mean Std. Deviation AGE HEIGHT WEIGHT Shoe Size With a total of 32 subjects, there were 64 knees/ankles analyzed for injuries. The incidence of injury was established by self-report, and injuries were only considered if the injuries occurred while participating in court sports. There were a total of 20 inversion sprains reported. There were three eversion sprains. There were five acute knee injuries reported. There were four chronic knee injuries. Descriptive statistics for acute knee injuries are shown in Table 4. The mean height of the navicular in relaxed stance for subjects reporting no history of acute knee injury was mm (SD=6.396). The mean height of the navicular in relaxed stance for subjects reporting a previous acute knee injury was mm (SD=5.771). The mean height of the navicular in STJN for subjects reporting no history of acute knee injury was mm (SD=5.581). The mean height of the navicular in STJN for subjects reporting a previous acute knee injury was mm (SD=7.225). The mean amount of pronation in subjects with no history of acute knee injury was 2.14 mm (SD=3.020). The mean amount of pronation in subjects reporting a previous acute knee injury was 1.60 mm (SD=2.074). Table 4. Descriptive Statistics Acute knee injury Relaxed stance acute knee injury Mean Std. Deviation N no yes Total

13 STJN Pronation no yes Total no yes Total It was hypothesized that individuals participating in court sports who have a lower navicular height will sustain more knee injuries than those with a higher navicular height. A two-factor ANOVA was used to test for differences in measures between those who had an acute knee injury and those who did not have an acute knee injury. No significant differences were found in relaxed stance, STJN, or pronation measures between those who had acute knee injuries and those who did not (p>.05). The statistical values found for this two-factor ANOVA test are shown in Table 5. A graphical representation of the results is shown in Figure 1. Table 5. ANOVA table for comparison of measures in acute knee injury and non-acute knee injury groups Source Type III Sum of Squares df Mean Square F Sig. Partial Eta Squared Noncent. Parameter Observed Power(a) Intercept KNEE ACUTE Error

14 Figure 1. Mean values of positional measures for acute knee injured and non-acute knee injured groups 60 Estimated Marginal Means Acute knee injury no yes 0 Relaxed STJN Pronation Position Descriptive statistics for chronic knee injuries are shown in Table 6. The mean height of the navicular in relaxed stance for subjects reporting no history of chronic knee injury was mm (SD=6.303). The mean height of the navicular in relaxed stance for subjects reporting previous chronic knee injury was mm (SD=5.560). The mean height of the navicular in STJN for subjects reporting no history of chronic knee injury was mm (SD=5.733). The mean height of the navicular in STJN for subjects reporting previous chronic knee injury was mm (SD=4.726). The mean amount of pronation in subjects with no history of chronic knee injury was 2.02 mm (SD=3.011). The mean amount of pronation in subjects reporting previous chronic knee injury was 3.25 mm (SD=1.500). 12

15 Table 6. Descriptive Statistics Chronic knee injury Relaxed STJN Pronation chronic knee injury Mean Std. Deviation N no yes Total no yes Total no yes Total It was hypothesized that individuals participating in court sports who have a lower navicular height will sustain more knee injuries than those with a higher navicular height. had a chronic knee injury and those who did not have a chronic knee injury. No significant differences were found in relaxed stance, STJN, or pronation measures between those who had chronic knee injury and those who did not (p>.05). The statistical values found for this two-factor ANOVA test are shown in Table 7. A graphical representation of the results is shown in Figure 2. A two-factor ANOVA was used to test for differences in measures between those who Table 7. ANOVA table for comparison of measures in chronic knee injury and non- chronic knee injury groups Type III Sum of Mean Partial Eta Noncent. Observed Source Squares df Square F Sig. Squared Parameter Power(a) Intercept KNEE CHRONIC Error

16 k Figure 2. Mean values of positional measures for chronic knee injured and non-chronic knee injured groups 60 Estimated Marginal Means chronic knee injury no yes 0 Relaxed STJN Pronation Position Descriptive statistics for inversion ankle sprains are shown in Table 8. The mean height of the navicular in relaxed stance for subjects reporting no history of inversion ankle sprain was mm (SD=6.602). The mean height of the navicular in relaxed stance for subjects reporting a previous inversion ankle sprain was mm (SD=6.027). The mean height of the navicular in STJN for subjects reporting no history of inversion ankle sprain was mm (SD=5.753). The mean height of the navicular in STJN for subjects reporting a previous inversion ankle sprain was mm (SD=5.823). The mean amount of pronation in subjects with no history of inversion ankle sprain was 2.33 mm (SD=3.050). The mean amount of pronation in subjects reporting a previous inversion ankle sprain was 1.71 mm (SD=2.789). 14

17 Table 8. Descriptive Statistics Inversion ankle sprain Rrelaxed STJN Pronation INVERSION Mean Std. Deviation N no yes Total no yes Total no yes Total It was also hypothesized that individuals participating in court sports who have a higher navicular height will sustain more ankle injuries than those with a lower navicular height. A two-factor ANOVA was used to test for differences in measures between those who had an inversion ankle sprain and those who did not have an inversion ankle sprain. No significant differences were found in relaxed stance, STJN, or pronation measures between those who had an inversion ankle sprain and those who did not (p>.05). The statistical values found for this two-factor ANOVA test are shown in Table 9. A graphical representation of the results is shown in Figure 3. Table 9. ANOVA table for comparison of measures in inversion ankle sprain and noninversion ankle sprain groups Source Type III Sum of Squares df Mean Square F Sig. Partial Eta Squared Noncent. Parameter Observed Power(a) Intercept Inversion ankle sprain Error

18 Figure 2. Mean values of positional measures for inversion ankle sprain and non-inversion ankle sprain groups 60 Estimated Marginal Means Inversion ankle sprains no yes 0 Relaxed STJN Pronation Position Descriptive statistics for eversion ankle sprains are shown in Table 10. The mean height of the navicular in relaxed stance for subjects reporting no history of eversion ankle sprain was mm (SD=5.864). The mean height of the navicular in relaxed stance for subjects reporting a previous eversion ankle sprain was mm (SD=1.500). The mean height of the navicular in STJN for subjects reporting no history of eversion ankle sprain was mm (SD=5.346). The mean height of the navicular in STJN for subjects reporting a previous eversion ankle sprain was mm (SD=2.062). The mean amount of pronation in subjects with no history of eversion ankle sprain was 2.20 mm (SD=2.956). The mean amount of pronation in subjects reporting a previous eversion ankle sprain was 0.50 mm (SD=2.646). 16

19 Table 10. Descriptive Statistics Eversion ankle sprain Relaxed STJN Pronation EVERSION Mean Std. Deviation N no yes Total no yes Total no yes Total It was also hypothesized that individuals participating in court sports who have a higher navicular height will sustain more ankle injuries than those with a lower navicular height. A two-factor ANOVA was used to test for differences in measures between those who had an eversion ankle sprain and those who did not have an eversion ankle sprain. Significant differences were found (p<.05) using the two-factor ANOVA, so an independent samples t-test was performed to find which measurements showed the significant differences. Specifically, relaxed stance measures (t=3.94, p<.05) and STJN measures (t=3.69, p<.05) were found to have significant differences between those who had an eversion ankle sprain and those who did not by performing the independent samples t-test. Pronation measures did not show significant differences between the two groups (p>.05). The statistical values found for the independent samples t-test are shown in Table 11. Equal variances could be assumed for all three measures (p>.05). A graphical representation of the results is shown in Figure 4. Table 11. Independent samples t-test table showing differences of measures between eversion ankle sprain and non-eversion ankle sprain groups Levene's Test for Equality of Variances F Sig. t df t-test for Equality of Means Sig. (2- tailed) Mean Diff. 95% Confidence Interval of the Difference Std. Error Diff. Lower Upper 17

20 Relaxed STJN Pronation Equal variances assumed Equal variances not assumed Equal variances assumed Equal variances not assumed Equal variances assumed Equal variances not assumed Figure 4. Mean values of positional measures for eversion ankle sprain and non-eversion ankle sprain groups 60 Estimated Marginal Means EVERSION no yes 10 0 Relaxed STJN Position Pronation DISCUSSION It was hypothesized that individuals participating in court sports who have a lower navicular height will sustain more knee injuries than those with a higher navicular height. The results found in this study did not demonstrate statistical significance to support this hypothesis. In both acute and chronic knee injury groups the mean relaxed stance and 18

21 STJN measures were lower than the mean measures for the non-injured group, but the differences were not significant. It was also hypothesized that individuals participating in court sports who have a higher navicular height will sustain more ankle injuries than those with a lower navicular height. The eversion ankle sprain injury results of this study supported this hypothesis; however, the inversion ankle sprain data did not show significant differences. The results indicate that subjects with a higher navicular height in relaxed stance and STJN are more likely to have had a previous eversion ankle sprain than subjects with a lower navicular height. Although the data relating to eversion ankle sprains showed significant differences in relaxed stance and STJN measures between injured and non-injured groups, the findings are not very powerful because out of 64 ankles, only 4 eversion ankle sprains were reported. The findings of this study related to eversion ankle sprains conflict with biomechanical analysis of arch height and ankle injury. Having a higher arch height places the foot in a more inverted position, which can cause excessive inversion at heel contact of the gait cycle as force is increased through the subtalar joint. [5] This hypothetically creates an increased possibility of sustaining an inversion ankle sprain. There are similarities and differences between the findings of this study and those reported in the literature. Out of all the ankles sprains reported in this study (n=23), 87.0% were inversion sprains, which is similar to the 85.0% report in the literature. [3] Most subjects reporting ankle sprain reported multiple sprains to the same ankle. The results of this study are consistent with those reported by Williams et al. regarding the finding that increased arch height relates to increased incidence of ankle injury, and decreased arch height relates to increased incidence of knee injury. [4] Nigg et al. reported 19

22 a positive relationship between high arches and anterior knee pain, which is contradictory to the results of this study as those in the chronic knee injury group showed a lower mean navicular height than the non-injured group. [6] The results of this study add to the variability of findings reported from other similar studies in the literature. Major strengths of this study were that the data were determined to be extremely reliable, and strict measures were taken to make sure that the researchers were properly blinded when measuring subjects. A weakness of the study was that the subjects gave self-reported injury data. This allows for error due to false or inaccurate reporting of injuries. Another weakness was that the injury data was collected retrospectively, meaning that a previous injury could have affected the height of the navicular. Future research should focus on establishing reliability with the new measuring device before conducting data collection. A large multi-site study would help increase the chance of finding significant differences, as well as increase the power of the results. Ideally, subjects should be measured before the sports season, and injury data should be collected throughout the season. These changes to the study would make the results more meaningful. If a consistent relationship is found, measurements of navicular height can be taken as part of pre-season physical examinations to screen for players that are at increased risk for knee and/or ankle injury. It would then be possible to provide those athletes identified as at increased risk with preventative devices, such as orthotics, to decrease their risk of injury. CONCLUSION No significant differences were found between measures of navicular height and self-reported ankle and knee injuries in this study, with the possible exception of eversion ankle sprains since there were only 4 eversion ankle sprains reported which lowers the 20

23 statistical power of this finding. The height of the navicular is thought to be related to the incidence of ankle and knee injury, but results of previous studies on this topic have been variable. More research is needed which compares navicular height to the incidence of ankle and knee injuries in order to see if a true relationship exists. If a consistent relationship is found, measurements of navicular height can be taken as part of pre-season physical examinations to screen for players that are at increased risk for knee and/or ankle injury. It would then be possible to provide those athletes identified as at increased risk with preventative devices, such as orthotics, to decrease their risk of injury. REFERENCES 1. Cohen AR, Metzl JD. Sports-specific concerns in the young athlete: basketball. Pediatr Emerg Care. 2000;16: Bahr R, Bahr IA. Incidence of acute volleyball injuries: a prospective cohort study of injury mechanisms and risk factors. Scand J Med Sci Sports. 1997;7: Rimando MP. Ankle sprain. emedicine Available at: com/pmr/topic11.htm. Accessed February 15, Williams DS, McClay IS, Hamill J. Arch structure and injury patterns in runners. Clinical Biomechanics. 2001;16: Wright IC, Neptune RR, van den Bogert AJ, Nigg BM. The influence of foot positioning on ankle sprains. J Biomechanics. 2000;33: Nigg BM, Cole GK, Nachbauer W. Effects of arch height of the foot on angular motion of the lower extremities in running. J Biomechanics. 1993;26: Jones BH, Cowan DN. Foot morphologic characteristics and the risk of exercise related injury. Arch Fam Med. 1993;2:

24 8. Loudon JK, Jenkins W, Loudon KL. The relationship between static posture and ACL injury in female athletes. J Orthop Sports Phys Ther. 1996;24: Dahle LK, Mueller M, Delitto A, Diamond JE. Visual assessment of foot type and relationship of foot type to lower extremity injury. J Orthop Sports Phys Ther. 1991;14: Picciano AM, Rowlands MS, Worrell T. Reliability of open and closed kinetic chain subtalar joint neutral positions and navicular drop test. J Orthop Sports Phys Ther. 1993;18: Menz HB, Keenan A. Reliability of two instruments in the measurement of closed chain subtalar joint positions. The Foot: International Journal of Clinical Foot Science. 1997;7: Sell KE, Verity TM, Worrell TW, Pease BJ, Wigglesworth J. Two measurement techniques for assessing subtalar joint position: a reliability study. J Orthop Sports Phys Ther. 1994;19: Holmes CF, Wilcox D, Fletcher JP. Effect of a modified, low-dye medial longitudinal arch taping procedure on the subtalar joint neutral position before and after light exercise. J Orthop Sports Phys Ther. 2002;32: Garrick JG. The frequency of injury, mechanism of injury, and the epidemiology of ankle sprains. Am J Sports Med. 1977;5:

25 APPENDIX Injury Form Subject # Have you ever experienced any of the following injuries while participating in court sports (basketball, vollyball, tennis, indoor track, etc.): Doctor Injury Sport Which side visit Specific DX # of times injury occurred Chronic knee pain R L Yes No Acute knee injury R L Yes No Inward ankle sprain R L Yes No Outward ankle sprain R L Yes No 23