Journal of Sport Rehabilitation, 2014, 23, 44-55 http://dx.doi.org/10.1123/JSR.2012-0132 © 2014 Human Kinetics, Inc.
www.JSR-Journal.com ORIGINAL RESEARCH REPORT
Concurrent and Discriminant Validity of the Star Excursion Balance Test for Military Personnel With Lateral Ankle Sprain Maude Bastien, Hélène Moffet, Laurent Bouyer, Marc Perron, Luc J. Hébert, and Jean Leblond The Star Excursion Balance Test (SEBT) has frequently been used to measure motor control and residual functional deficits at different stages of recovery from lateral ankle sprain (LAS) in various populations. However, the validity of the measure used to characterize performance—the maximal reach distance (MRD) measured by visual estimation—is still unknown. Objectives: To evaluate the concurrent validity of the MRD in the SEBT estimated visually vs the MRD measured with a 3D motion-capture system and evaluate and compare the discriminant validity of 2 MRD-normalization methods (by height or by lower-limb length) in participants with or without LAS (n = 10 per group). Results: There is a high concurrent validity and a good degree of accuracy between the visual estimation measurement and the MRD gold-standard measurement for both groups and under all conditions. The Cohen d ratios between groups and MANOVA products were higher when computed from MRD data normalized by height. Conclusion: The results support the concurrent validity of visual estimation of the MRD and the use of the SEBT to evaluate motor control. Moreover, normalization of MRD data by height appears to increase the discriminant validity of this test. Keywords: functional test, motor control, metrological properties, musculoskeletal disorder Lateral ankle sprain (LAS) is one of the most common injuries in military and athletic populations.1,2 The prevalence of LAS in these populations was found to be 5 times greater than in the general population.1,3 Injured individuals usually return to sports and functional activities quickly—within 6 weeks of LAS.4 However, the high rate of recurrence and often persistent nature of ankle instability experienced by injured individuals suggest that this localized injury affects overall motor control.5,6 Indeed, perturbations in motor control among ankle-instability populations, such as increased postural sway in single-leg static stance, have been demonstrated, in addition to impairment in ankle proprioception and sensorimotor function as plantar vibrotactile detection deficits.7,8 Reduced performance in functional tests like the Star Excursion Balance Test (SEBT9–13), the single-leg jump,8 and other balance tests9,14 has also been documented in the population with ankle instability. Finally, and more convincingly, lack of motor control has been demonstrated not only in the injured limb but also in the uninjured limb6,15,16 during both early and long-term stages of recovery.10 It is therefore important to use functional tests with good metrological properties to monitor the quality of whole-body motor control after LAS. The authors are with the CIRRIS Research Centre and the Faculty of Medicine, Laval University, Quebec City, QC, Canada.
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The SEBT has frequently been used to measure motor control and residual functional deficits at different stages of LAS recovery in various populations.9–12,17–19 This functional test is actually a goal-oriented task requiring motor control over all parts of the body such as the trunk and limbs. The participant has to plan a maximal reach with 1 lower limb while maintaining balance on the other lower limb. It requires a high level of functional skill in terms of muscle strength (unilateral squat20), proprioception, joint range of motion,21 and neuromuscular control.22 It is therefore an appropriate test for measuring motor control in our target population. In addition, the SEBT has already demonstrated good metrological properties with regard to reliability, responsiveness, and content validity.12,18,23–25 More specifically, the intrarater and interrater reliability (within and between sessions) were very good (excellent intraclass correlation coefficients [ICC] >.8423,24) to good (ICC .67–.8726). The SEBT showed discriminant validity with regard to gender.25 It also has been able to detect changes after interventions in various populations.18,19 The SEBT was also identified as a predictive test for future injuries to the lower limb.27 However, the validity of the measure used to characterize performance—the maximal reach distance (MRD) measured by visual estimation—is still unknown. There is a need to confirm the concurrent validity of the MRD estimated visually against a gold-standard measure and quantify its accuracy before
Validity of the Star Excursion Balance Test 45
using it more extensively, even though it has already been used in many studies and clinical settings. In this study, MRD measured by a 3D motion-capture system was the gold-standard measure. The chosen system, the Optotrak 3020 system, exhibits high validity,28 excellent reliability: ICC >.9 during human gait,29 an accuracy of .05). a Mann-Whitney exact test measuring group differences. b [(Healthy group mean – LAS group mean) ÷ healthy group mean] ´ 100%. c Mean of anteromedial, medial, and posteromedial mean performance.
Validity of the Star Excursion Balance Test 51
the LAS group the height-adjusted R2 = .24 and LLLadjusted R2 = .17). There was no significant difference between Pearson correlation coefficients for MRD with either height or LLL (CORDIF, P = .19). Second, using normalization of the MRD by LLL seemed to result in an overlap of each group’s performance more than did using normalization by height (Figures 4[A] and [B]). In addition, using normalization by LLL diminished differences between groups for all directions compared with using normalization by height (Table 3). Indeed, all Cohen d ratios have medium to high effect size46 for both normalization methods (effect size > 0.57; see Table 3). The mean differences of these ratios between groups for each direction computed were higher with normalization by height (1.17 ± 0.24) than with normalization by LLL (0.98 ± 0.27). Finally, in the third step of this analysis it was shown by MANOVA that groups were significantly different when using normalization by height (Wilks’ Λ = 6.859, P = .001; partial η2: AM = .316, M = .180, PM = .220; observed power: AM = .983, M = .820, PM = .890). A difference was also found using normalization by LLL, although the η2 was smaller with this second method (Wilks’ Λ = 5.404, P = .004; partial η2: AM = .285, M = .128, PM = .136; observed power: AM = .966, M = .634, PM = .663). Overall, these analyses favor normalization by height insofar it reveals greater differences between groups that have different functional abilities as determined by the functional-ability questionnaires. Figure 4 — Box plots of maximal reach distance (MRD) normalized by (A) lower-limb length (LLL) or (B) body height for AM, M, and PM reaching directions and overall score for each group (n = 10 per group). (A) The 75th percentile of the gray boxplot representing the healthy group is close to the 25th and the 50th percentiles of the white boxplot representing the lateral-ankle-sprain group. (B) These boxplots overlap each other less than with normalization by LLL. Abbreviations: AM, anteromedial; M, medial; PM, posteromedial.
Effects of MRD-Normalization Methods To evaluate the effect of each MRD-normalization method (by height or LLL) on the discriminative properties of the SEBT between groups, the following parameters were calculated and compared between normalization methods: bivariate correlation coefficients between MRD and anthropometric characteristics, Cohen ratio coefficients to highlight the differences between group performance, and MANOVA statistics (Wilks’ Λ, p, partial η2, and observed power), which indicate the strength of the differences between groups. First, the relationship between body height and LLL revealed a very high correlation with an adjusted R2 of .88 for the entire sample. For both groups the relationship between overall performance on the SEBT (all directions combined) and body height was stronger than the relationship with LLL (for the healthy group the height-adjusted R2 = .60 and LLL-adjusted R2 = .52, for
Discussion Our study’s primary finding is the excellent concurrent validity and high degree of accuracy between MRD measurements made by the visual estimation and goldstandard methods. Our results also demonstrate the capacity of the SEBT to discriminate between populations with different functional abilities and that MRD data normalized with respect to participant height better differentiate individuals with and without LAS.
Concurrent Validity and Accuracy of MRD Measured by Visual Estimation Visual estimation of the MRDs performed in a standardized manner shows a high concurrent validity when compared with the gold-standard measure. This result is particularly fortuitous given that visual estimation of distance does not require specialized equipment—the proposed procedure is easy to set up and may be implemented at very low cost in any clinical setting. Moreover, the proposed method uses the same instructions to the participant as the original test does, which is to reach the MRD using natural control strategies. The high concurrent validity between the standardized visual estimation and the Optotrak measure validates the use of SEBT in clinical practice. Using a simple standardized procedure (6 graduated tapes secured to the floor) minimizes possible mistakes with the visual-estimation procedure.
52 Bastien et al
Indeed, the proposed procedure decreases the number of manipulations required when compared with the original test version, where the evaluator must lay down a measuring tape for every single trial to obtain the MRD. To simplify the MRD measurement, 1 study47 suggested pushing blocks along the floor, which in our estimation would hamper the ability of participants to reach their limits of stability. The principle of abiding by an intuitive strategy and avoiding any manipulation that might influence it is important because previous studies suggest that a reaching task like the SEBT employs centrally mediated control mechanisms.6,15,16 These mechanisms are involved in the early stage of planning and movementstrategy choice.48 It is therefore essential to avoid any interaction with participant performances so that their intuitive strategies can be observed. The accuracy of the MRD measurement by visual estimate was good and did not significantly differ from that of the gold-standard measurement—a confirmation of its concurrent validity. The accuracy was found to be similar between groups and between different reachdistance lengths. In both groups, the difference due to measurement method in more than 90% of the trials did not exceed 2.32 cm. This difference is within the standard error of measurement (SEM = 1.64–3.7 cm) reported by Lanning et al.49 Furthermore, it was 57% lower than the smallest detectable difference (5.41–7.04 cm).24 It is interesting that this high degree of accuracy was observed in all reaching directions. The evaluator’s estimation varied, however, with test direction. The evaluator tended to overestimate the MRD in the PM direction more than in other directions. These variations in the difference distributions between methods for the PM direction as compared with the other 2 directions may be attributable to the evaluator’s position (which was restricted by the placement of the Optotrak cameras) during the test and by the rotated position of the participant’s leg, which partially hides the foot tip. Because of this effect of the evaluator’s position, it is especially important to collect data for several trials and base the performance measurement on the mean of those trials. This was done in the current study and was also recommended by other authors.17,42,43 In addition, the evaluator must be correctly positioned to see the foot tip and must always make sure to adopt the same position for all trials and sessions. Finally, the similarity between accuracy of visual estimation between groups and the fact that accuracy was stable across the different MRDs were indications of the evaluator’s ability to adapt his or her position accordingly. We can thus conclude that the difference between the 2 methods was negligible with regard to the smallest detectable difference in the SEBT (standardized procedure) and so does not lead to inappropriate conclusions about differences between populations.
Discriminant Validity of the SEBT This study demonstrates the ability of the SEBT to discriminate between healthy and LAS groups based
on their performance on the test (Figure 4). Discrimination is higher in the AM direction and is enhanced with the use of MRD data normalized by height. This suggests that such normalization may help, in the future, highlight differences between groups or even within the same group across time. Both functional ability, quantified by the LEFS and FADI questionnaires, and SEBT performance (raw and normalized values by LLL and height) were found to be different between groups. The finding of poorer SEBT performance in the LAS group confirmed their motor-control deficit compared with healthy participants.9 Poorer SEBT performance has previously been attributed to a modification in strategy that involved less flexion at the knee and hip joints of the stance limb of healthy participants.13,48 Further work is needed to more carefully characterize the SEBT task and determine which biomechanical variables, in conjunction with MRD, are the best indicators of the quality of motor control in both populations. In our study, we saw no evidence of interlimb differences in SEBT performance for either group. As regards the LAS group, these results may suggest that there are bilateral alterations in motor control15,16 or that this group is predisposed to LAS injury due to motor control that had been compromised before injury.27 However, the absence of an interlimb difference in the LAS group can be attributed to a lack of statistical significance due to the small sample size. The greatest differences between LAS and healthy groups were seen with the AM reaching direction. This result may be attributable to the fact that a large range of dorsiflexion is needed for this particular condition. Indeed, a previous study indicated that the range of ankle dorsiflexion required for weight bearing has a strong impact on reaching performance in the anterior reaching direction.21 It was observed in some studies that a limited range of dorsiflexion when weight bearing on the injured limb remained 8 weeks after injury50—we did not observe this dorsiflexion limitation in our LAS group. A more detailed kinematics and kinetics analysis should be done to better understand this result.
Effect of the Normalization by Height Normalization by height seems to yield a more interesting and thorough understanding of the anthropometric characteristics associated with SEBT performance than does normalization by LLL—the more widely used approach. Indeed, normalization by height is interesting in consideration of the overall task at hand (ie, all body segments move during the task) and the trunk’s contribution to maintaining balance while the individual reaches his or her limit of stability. To limit the influence of the participant’s individual characteristics on SEBT performance, it has been suggested that normalization be used when comparing different groups.25 Gribble and Hertel25 chose to normalize by LLL rather than height, although both approaches show a high degree of correlation. In the current study, the adjusted R2 of the correlation
Validity of the Star Excursion Balance Test 53
between the MRD and height was slightly higher than the one that used for LLL for both groups. Finally, height is easy to measure and does not require specific skills like palpation of bony landmarks.51 Normalization by height takes into consideration the significant influence of the trunk on overall body CoM movement over the support base during SEBT motor-skills tasks. From Dempster values as reported by Winter,52 the trunk CoM accounts for a high percentage (67.8%) of total body mass and may strongly influence the body CoM during motor tasks. Trunk and hip movements play an integral role in motor control and significantly contribute to recovery strategies that minimize body CoM acceleration under more challenging conditions.32,33 The control of the body’s CoM displacement mainly involves trunk stabilization in the direction opposite that of the perturbation or voluntary movement.32,53 LLL normalization would represent an adequate anthropometric tool to evaluate a reaching task in studies where participants remain seated or where the trunk is fixed.
Limitations The first limitation to point out in the current study is that several variables were measured using a small sample (2 groups of 10 participants). There were also some data-collection limitations related to the use of Optotrak technology in concert with visual estimation, as well as limitations inherent in the study design itself. First, the accuracy of visual estimation of the MRD may have been influenced by the evaluator’s restricted position. To avoid hiding Optotrak markers during testing, the evaluator had to sometimes adopt suboptimal positions, especially while testing in the PM direction. As a consequence, the accuracy of the visual estimation may have been compromised. A second limitation in the current study involved the difficulty in drawing conclusions about concurrent and discriminant validity using only 3 directions, insofar as we evaluated 3 reaching directions out of a total of 8 possibilities in the initial test. These 3 directions were chosen because they furnish unique and specific information about participants with ankle injuries. Finally, the homogeneity of the population, like its gender homogeneity, may limit the external validity of our results related to the second objective—to measure the discriminative ability of the MRD methods. It would be of interest to investigate this discriminant validity by studying other populations such as sedentary or elderly populations.
Conclusion Visual estimation of the MRD in the SEBT is a highly valid and accurate measurement when a standardized procedure is employed. The high degree of accuracy of the MRD measurement was evident in both healthy and LAS groups. The MRD, when estimated visually, tends to be overestimated in the PM reaching direction, so caution is advised regarding the evaluator’s position for this particular test direction. Normalization of MRD by
height increases discriminant validity between groups with or without LAS. This result supports the use of MRD normalization by height in future studies when assessing the quality of motor control. MRD is, however, the endpoint (outcome) of a series of complex motor strategies put in place to perform such a task. Future studies should analyze, in more detail, not only the endpoints of these strategies (namely, the MRD) but also the strategies themselves and the impact of the different reaching directions on motor control. Acknowledgments The authors acknowledge the support of Guy St-Vincent and Émilie Michaud for their help with data collection, Chantal Gendron and the team of physiotherapists at the Valcartier military base for recruiting participants, and Isabelle Lapointe, Joanie Bédard, and Joannie Huot for their assistance during data acquisition. We also want to thank Stéphanie Bernard for revising the manuscript. Maude Bastien was supported by studentships from the Canadian Institutes of Health Research (CIHR), the CIRRIS, and the OPPQ. The project was funded by the Ordre professionnel de la physiothérapie du Québec (OPPQ) and the Quebec Rehabilitation Research network (REPAR).
References 1. Cameron KL, Owens BD, Deberardino TM. Incidence of ankle sprains among active-duty members of the United States Armed Services from 1998 through 2006. J Athl Train. 2010;45(1):29–38. PubMed doi:10.4085/10626050-45.1.29 2. Fong DT, Hong Y, Chan LK, Yung PS, Chan KM. A systematic review on ankle injury and ankle sprain in sports. Sports Med. 2007;37(1):73–94. PubMed doi:10.2165/00007256-200737010-00006 3. Waterman BR, Owens BD, Davey S, Zacchilli MA, Belmont PJ, Jr. The epidemiology of ankle sprains in the United States. J Bone Joint Surg Am. 2010;92(13):2279– 2284. PubMed doi:10.2106/JBJS.I.01537 4. Jones MH, Amendola AS. Acute treatment of inversion ankle sprains: immobilization versus functional treatment. Clin Orthop Relat Res. 2007; (455):169–172. PubMed doi:10.1097/BLO.0b013e31802f5468 5. Hiller CE, Nightingale EJ, Lin CW, Coughlan GF, Caulfield B, Delahunt E. Characteristics of people with recurrent ankle sprains: a systematic review with metaanalysis. Br J Sports Med. 2011;45(8):660–672. PubMed doi:10.1136/bjsm.2010.077404 6. Hass CJ, Bishop MD, Doidge D, Wikstrom EA. Chronic ankle instability alters central organization of movement. Am J Sports Med. 2010;38(4):829–834. PubMed doi:10.1177/0363546509351562 7. Hoch MC, McKeon PO, Andreatta RD. Plantar vibrotactile detection deficits in adults with chronic ankle instability. Med Sci Sports Exerc. 2012;44(4):666–672. PubMed doi:10.1249/MSS.0b013e3182390212 8. Munn J, Sullivan SJ, Schneiders AG. Evidence of sensorimotor deficits in functional ankle instability: a systematic
54 Bastien et al
review with meta-analysis. J Sci Med Sport. 2010;13(1):2– 12. PubMed doi:10.1016/j.jsams.2009.03.004 9. Arnold BL, De La MS, Linens S, Ross SE. Ankle instability is associated with balance impairments: a metaanalysis. Med Sci Sports Exerc. 2009;41(5):1048–1062. PubMed doi:10.1249/MSS.0b013e318192d044 10. Wikstrom EA, Naik S, Lodha N, Cauraugh JH. Balance capabilities after lateral ankle trauma and intervention: a meta-analysis. Med Sci Sports Exerc. 2009;41(6):1287– 1295. PubMed doi:10.1249/MSS.0b013e318196cbc6 11. Olmsted LC, Carcia CR, Hertel J, Shultz SJ. Efficacy of the Star Excursion Balance Tests in detecting reach deficits in subjects with chronic ankle instability. J Athl Train. 2002;37(4):501–506. PubMed 12. Gribble PA, Hertel J, Plisky PJ. Using the Star Excursion Balance Test to assess dynamic postural-control deficits and outcomes in lower extremity injury: a literature and systematic. J Athl Train. 2012;47(3):339–357. PubMed 13. Gribble PA, Hertel J, Denegar CR. Chronic ankle instability and fatigue create proximal joint alterations during performance of the Star Excursion Balance Test. Int J Sports Med. 2007;28(3):236–242. PubMed doi:10.1055/s-2006-924289 14. Wikstrom EA, Fournier KA, McKeon PO. Postural control differs between those with and without chronic ankle instability. Gait Posture. 2010;32(1):82–86. PubMed doi:10.1016/j.gaitpost.2010.03.015 15. Evans T, Hertel J, Sebastianelli W. Bilateral deficits in postural control following lateral ankle sprain. Foot Ankle Int. 2004;25(11):833–839. PubMed 16. Wikstrom EA, Naik S, Lodha N, Cauraugh JH. Bilateral balance impairments after lateral ankle trauma: a systematic review and meta-analysis. Gait Posture. 2010;31(4):407–414. PubMed doi:10.1016/j.gaitpost.2010.02.004 17. Hertel J, Braham RA, Hale SA, Olmsted-Kramer LC. Simplifying the Star Excursion Balance Test: analyses of subjects with and without chronic ankle instability. J Orthop Sports Phys Ther. 2006;36(3):131–137. PubMed doi:10.2519/jospt.2006.36.3.131 18. Hale SA, Hertel J, Olmsted-Kramer LC. The effect of a 4-week comprehensive rehabilitation program on postural control and lower extremity function in individuals with chronic ankle instability. J Orthop Sports Phys Ther. 2007;37(6):303–311. PubMed doi:10.2519/ jospt.2007.2322 19. Sefton JM, Yarar C, Hicks-Little CA, Berry JW, Cordova ML. Six weeks of balance training improves sensorimotor function in individuals with chronic ankle instability. J Orthop Sports Phys Ther. 2011;41(2):81–89. PubMed doi:10.2519/jospt.2011.3365 20. Earl JE, Hertel J. Lower-extremity muscle activation during the Star Excursion Balance Tests. J Sport Rehabil. 2001;10(2):93–104. 21. Hoch MC, Staton GS, McKeon PO. Dorsiflexion range of motion significantly influences dynamic balance. J Sci Med Sport. 2011;14(1):90–92. PubMed doi:10.1016/j. jsams.2010.08.001
22. Norris B, Trudelle-Jackson E. Hip- and thigh-muscle activation during the Star Excursion Balance Test. J Sport Rehabil. 2011;20(4):428–441. PubMed 23. Clark RC, Saxion CE, Cameron KL, Gerber JP. Associations between three clinical assessment tools for postural stability. N Am J Sports Phys Ther. 2010;5(3):122–130. PubMed 24. Munro AG, Herrington LC. Between-session reliability of the Star Excursion Balance Test. Phys Ther Sport. 2010;11(4):128–132. PubMed doi:10.1016/j. ptsp.2010.07.002 25. (25) Gribble PA, Hertel J. Considerations for normalizing measures of the Star Excursion Balance Test. Meas Phys Educ Exerc Sci. 2003;7(2):89–100. 26. Kinzey SJ, Armstrong CW. The reliability of the StarExcursion test in assessing dynamic balance. J Orthop Sports Phys Ther. 1998;27(5):356–360. PubMed doi:10.2519/jospt.1998.27.5.356 27. Plisky PJ, Rauh MJ, Kaminski TW, Underwood FB. Star Excursion Balance Test as a predictor of lower extremity injury in high school basketball players. J Orthop Sports Phys Ther. 2006;36(12):911–919. PubMed doi:10.2519/ jospt.2006.2244 28. Monaghan K, Delahunt E, Caulfield B. Ankle function during gait in patients with chronic ankle instability compared to controls. Clin Biomech (Bristol, Avon). 2006;21(2):168–174. PubMed doi:10.1016/j.clinbiomech.2005.09.004 29. McGinley JL, Baker R, Wolfe R, Morris ME. The reliability of three-dimensional kinematic gait measurements: a systematic review. Gait Posture. 2009;29(3):360–369. PubMed doi:10.1016/j.gaitpost.2008.09.003 30. Schmidt J, Berg DR, Ploeg H-L. Precision, repeatability and accuracy of Optotrak optical motion tracking systems. Int J Exp Comput Biomech. 2009;1(1):114–127. doi:10.1504/IJECB.2009.022862 31. Cote KP, Brunet ME, Gansneder BM, Shultz SJ. Effects of pronated and supinated foot postures on static and dynamic postural stability. J Athl Train. 2005;40(1):41–46. PubMed 32. Hughey LK, Fung J. Postural responses triggered by multidirectional leg lifts and surface tilts. Exp Brain Res. 2005;165(2):152–166. PubMed doi:10.1007/s00221-0052295-9 33. Blackburn JT, Riemann BL, Myers JB, Lephart SM. Kinematic analysis of the hip and trunk during bilateral stance on firm, foam, and multiaxial support surfaces. Clin Biomech (Bristol, Avon). 2003;18(7):655–661. PubMed doi:10.1016/S0268-0033(03)00091-3 34. Alonso A, Khoury L, Adams R. Clinical tests for ankle syndesmosis injury: reliability and prediction of return to function. J Orthop Sports Phys Ther. 1998;27(4):276–284. PubMed doi:10.2519/jospt.1998.27.4.276 35. Magee D. Orthopedic Physical Assessment. Philadelphia, PA: Elsevier; 2008. 36. Terry MA, Winell JJ, Green DW, et al. Measurement variance in limb length discrepancy: clinical and radiographic assessment of interobserver and intraobserver variability. J Pediatr Orthop. 2005;25(2):197–201. PubMed doi:10.1097/01.bpo.0000148496.97556.9f
Validity of the Star Excursion Balance Test 55
37. Geeta A, Jamaiyah H, Safiza MN, et al. Reliability, technical error of measurements and validity of instruments for nutritional status assessment of adults in Malaysia. Singapore Med J. 2009;50(10):1013–1018. PubMed 38. Bennell KL, Talbot RC, Wajswelner H, Techovanich W, Kelly DH, Hall AJ. Intra-rater and inter-rater reliability of a weight-bearing lunge measure of ankle dorsiflexion. Aust J Physiother. 1998;44(3):175–180. PubMed 39. Hale SA, Hertel J. Reliability and sensitivity of the Foot and Ankle Disability Index in subjects with chronic ankle instability. J Athl Train. 2005;40(1):35–40. PubMed 40. Martin RL, Irrgang JJ. A survey of self-reported outcome instruments for the foot and ankle. J Orthop Sports Phys Ther. 2007;37(2):72–84. PubMed doi:10.2519/jospt.2007.2403 41. Binkley JM, Stratford PW, Lott SA, Riddle DL. The Lower Extremity Functional Scale (LEFS): scale development, measurement properties, and clinical application. North American Orthopaedic Rehabilitation Research Network. Phys Ther. 1999;79(4):371–383. PubMed 42. Hertel J, Miller SJ, Denegar CR. Intratester and intertester reliability during the Star Excursion Balance Tests. J Sport Rehabil. 2000;9:104–116. 43. Robinson RH, Gribble PA. Support for a reduction in the number of trials needed for the Star Excursion Balance Test. Arch Phys Med Rehabil. 2008;89(2):364–370. PubMed doi:10.1016/j.apmr.2007.08.139 44. Portney LG, Watkins MP. Foundations of Clinical Research Applications to Practice. 3rd ed. Upper Saddle River, NJ: Pearson Prentice Hall; 2013. 45. Munro BH. Statistical Methods for Health Care Research. 3rd ed. Philadelphia, PA: JB Lippincott; 1997.
46. Cohen J. Statistical Power Analysis for the Behavioral Sciences. Hillsdale, NJ: Lawrence Erlbaum; 1988. 47. Plisky PJ, Gorman PP, Butler RJ, Kiesel KB, Underwood FB, Elkins B. The reliability of an instrumented device for measuring components of the Star Excursion Balance Test. N Am J Sports Phys Ther. 2009;4(2):92–99. PubMed 48. Robinson R, Gribble P. Kinematic predictors of performance on the Star Excursion Balance Test. J Sport Rehabil. 2008;17(4):347–357. PubMed 49. Lanning CL, Uhl TL, Ingram CL, Mattacola CG, English T, Newsom S. Baseline values of trunk endurance and hip strength in collegiate athletes. J Athl Train. 2006;41(4):427–434. PubMed 50. van Rijn RM, van Os AG, Bernsen RM, Luijsterburg PA, Koes BW, Bierma-Zeinstra SM. What is the clinical course of acute ankle sprains?: a systematic literature review. Am J Med. 2008;121(4):324–331. PubMed doi:10.1016/j. amjmed.2007.11.018 51. Geeta A, Jamaiyah H, Safiza MN, et al. Reliability, technical error of measurements and validity of instruments for nutritional status assessment of adults in Malaysia. Singapore Med J. 2009;50(10):1013–1018. PubMed 52. Winter DA. Biomechanics and Motor Control of Human Movement. 2nd ed. New York, NY: John Wiley & Sons; 1990. 53. Carpenter MG, Allum JH, Honegger F. Directional sensitivity of stretch reflexes and balance corrections for normal subjects in the roll and pitch planes. Exp Brain Res. 1999;129(1):93–113. PubMed doi:10.1007/ s002210050940
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www.JSR-Journal.com ORIGINAL RESEARCH REPORT
Concurrent and Discriminant Validity of the Star Excursion Balance Test for Military Personnel With Lateral Ankle Sprain Maude Bastien, Hélène Moffet, Laurent Bouyer, Marc Perron, Luc J. Hébert, and Jean Leblond The Star Excursion Balance Test (SEBT) has frequently been used to measure motor control and residual functional deficits at different stages of recovery from lateral ankle sprain (LAS) in various populations. However, the validity of the measure used to characterize performance—the maximal reach distance (MRD) measured by visual estimation—is still unknown. Objectives: To evaluate the concurrent validity of the MRD in the SEBT estimated visually vs the MRD measured with a 3D motion-capture system and evaluate and compare the discriminant validity of 2 MRD-normalization methods (by height or by lower-limb length) in participants with or without LAS (n = 10 per group). Results: There is a high concurrent validity and a good degree of accuracy between the visual estimation measurement and the MRD gold-standard measurement for both groups and under all conditions. The Cohen d ratios between groups and MANOVA products were higher when computed from MRD data normalized by height. Conclusion: The results support the concurrent validity of visual estimation of the MRD and the use of the SEBT to evaluate motor control. Moreover, normalization of MRD data by height appears to increase the discriminant validity of this test. Keywords: functional test, motor control, metrological properties, musculoskeletal disorder Lateral ankle sprain (LAS) is one of the most common injuries in military and athletic populations.1,2 The prevalence of LAS in these populations was found to be 5 times greater than in the general population.1,3 Injured individuals usually return to sports and functional activities quickly—within 6 weeks of LAS.4 However, the high rate of recurrence and often persistent nature of ankle instability experienced by injured individuals suggest that this localized injury affects overall motor control.5,6 Indeed, perturbations in motor control among ankle-instability populations, such as increased postural sway in single-leg static stance, have been demonstrated, in addition to impairment in ankle proprioception and sensorimotor function as plantar vibrotactile detection deficits.7,8 Reduced performance in functional tests like the Star Excursion Balance Test (SEBT9–13), the single-leg jump,8 and other balance tests9,14 has also been documented in the population with ankle instability. Finally, and more convincingly, lack of motor control has been demonstrated not only in the injured limb but also in the uninjured limb6,15,16 during both early and long-term stages of recovery.10 It is therefore important to use functional tests with good metrological properties to monitor the quality of whole-body motor control after LAS. The authors are with the CIRRIS Research Centre and the Faculty of Medicine, Laval University, Quebec City, QC, Canada.
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The SEBT has frequently been used to measure motor control and residual functional deficits at different stages of LAS recovery in various populations.9–12,17–19 This functional test is actually a goal-oriented task requiring motor control over all parts of the body such as the trunk and limbs. The participant has to plan a maximal reach with 1 lower limb while maintaining balance on the other lower limb. It requires a high level of functional skill in terms of muscle strength (unilateral squat20), proprioception, joint range of motion,21 and neuromuscular control.22 It is therefore an appropriate test for measuring motor control in our target population. In addition, the SEBT has already demonstrated good metrological properties with regard to reliability, responsiveness, and content validity.12,18,23–25 More specifically, the intrarater and interrater reliability (within and between sessions) were very good (excellent intraclass correlation coefficients [ICC] >.8423,24) to good (ICC .67–.8726). The SEBT showed discriminant validity with regard to gender.25 It also has been able to detect changes after interventions in various populations.18,19 The SEBT was also identified as a predictive test for future injuries to the lower limb.27 However, the validity of the measure used to characterize performance—the maximal reach distance (MRD) measured by visual estimation—is still unknown. There is a need to confirm the concurrent validity of the MRD estimated visually against a gold-standard measure and quantify its accuracy before
Validity of the Star Excursion Balance Test 45
using it more extensively, even though it has already been used in many studies and clinical settings. In this study, MRD measured by a 3D motion-capture system was the gold-standard measure. The chosen system, the Optotrak 3020 system, exhibits high validity,28 excellent reliability: ICC >.9 during human gait,29 an accuracy of .05). a Mann-Whitney exact test measuring group differences. b [(Healthy group mean – LAS group mean) ÷ healthy group mean] ´ 100%. c Mean of anteromedial, medial, and posteromedial mean performance.
Validity of the Star Excursion Balance Test 51
the LAS group the height-adjusted R2 = .24 and LLLadjusted R2 = .17). There was no significant difference between Pearson correlation coefficients for MRD with either height or LLL (CORDIF, P = .19). Second, using normalization of the MRD by LLL seemed to result in an overlap of each group’s performance more than did using normalization by height (Figures 4[A] and [B]). In addition, using normalization by LLL diminished differences between groups for all directions compared with using normalization by height (Table 3). Indeed, all Cohen d ratios have medium to high effect size46 for both normalization methods (effect size > 0.57; see Table 3). The mean differences of these ratios between groups for each direction computed were higher with normalization by height (1.17 ± 0.24) than with normalization by LLL (0.98 ± 0.27). Finally, in the third step of this analysis it was shown by MANOVA that groups were significantly different when using normalization by height (Wilks’ Λ = 6.859, P = .001; partial η2: AM = .316, M = .180, PM = .220; observed power: AM = .983, M = .820, PM = .890). A difference was also found using normalization by LLL, although the η2 was smaller with this second method (Wilks’ Λ = 5.404, P = .004; partial η2: AM = .285, M = .128, PM = .136; observed power: AM = .966, M = .634, PM = .663). Overall, these analyses favor normalization by height insofar it reveals greater differences between groups that have different functional abilities as determined by the functional-ability questionnaires. Figure 4 — Box plots of maximal reach distance (MRD) normalized by (A) lower-limb length (LLL) or (B) body height for AM, M, and PM reaching directions and overall score for each group (n = 10 per group). (A) The 75th percentile of the gray boxplot representing the healthy group is close to the 25th and the 50th percentiles of the white boxplot representing the lateral-ankle-sprain group. (B) These boxplots overlap each other less than with normalization by LLL. Abbreviations: AM, anteromedial; M, medial; PM, posteromedial.
Effects of MRD-Normalization Methods To evaluate the effect of each MRD-normalization method (by height or LLL) on the discriminative properties of the SEBT between groups, the following parameters were calculated and compared between normalization methods: bivariate correlation coefficients between MRD and anthropometric characteristics, Cohen ratio coefficients to highlight the differences between group performance, and MANOVA statistics (Wilks’ Λ, p, partial η2, and observed power), which indicate the strength of the differences between groups. First, the relationship between body height and LLL revealed a very high correlation with an adjusted R2 of .88 for the entire sample. For both groups the relationship between overall performance on the SEBT (all directions combined) and body height was stronger than the relationship with LLL (for the healthy group the height-adjusted R2 = .60 and LLL-adjusted R2 = .52, for
Discussion Our study’s primary finding is the excellent concurrent validity and high degree of accuracy between MRD measurements made by the visual estimation and goldstandard methods. Our results also demonstrate the capacity of the SEBT to discriminate between populations with different functional abilities and that MRD data normalized with respect to participant height better differentiate individuals with and without LAS.
Concurrent Validity and Accuracy of MRD Measured by Visual Estimation Visual estimation of the MRDs performed in a standardized manner shows a high concurrent validity when compared with the gold-standard measure. This result is particularly fortuitous given that visual estimation of distance does not require specialized equipment—the proposed procedure is easy to set up and may be implemented at very low cost in any clinical setting. Moreover, the proposed method uses the same instructions to the participant as the original test does, which is to reach the MRD using natural control strategies. The high concurrent validity between the standardized visual estimation and the Optotrak measure validates the use of SEBT in clinical practice. Using a simple standardized procedure (6 graduated tapes secured to the floor) minimizes possible mistakes with the visual-estimation procedure.
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Indeed, the proposed procedure decreases the number of manipulations required when compared with the original test version, where the evaluator must lay down a measuring tape for every single trial to obtain the MRD. To simplify the MRD measurement, 1 study47 suggested pushing blocks along the floor, which in our estimation would hamper the ability of participants to reach their limits of stability. The principle of abiding by an intuitive strategy and avoiding any manipulation that might influence it is important because previous studies suggest that a reaching task like the SEBT employs centrally mediated control mechanisms.6,15,16 These mechanisms are involved in the early stage of planning and movementstrategy choice.48 It is therefore essential to avoid any interaction with participant performances so that their intuitive strategies can be observed. The accuracy of the MRD measurement by visual estimate was good and did not significantly differ from that of the gold-standard measurement—a confirmation of its concurrent validity. The accuracy was found to be similar between groups and between different reachdistance lengths. In both groups, the difference due to measurement method in more than 90% of the trials did not exceed 2.32 cm. This difference is within the standard error of measurement (SEM = 1.64–3.7 cm) reported by Lanning et al.49 Furthermore, it was 57% lower than the smallest detectable difference (5.41–7.04 cm).24 It is interesting that this high degree of accuracy was observed in all reaching directions. The evaluator’s estimation varied, however, with test direction. The evaluator tended to overestimate the MRD in the PM direction more than in other directions. These variations in the difference distributions between methods for the PM direction as compared with the other 2 directions may be attributable to the evaluator’s position (which was restricted by the placement of the Optotrak cameras) during the test and by the rotated position of the participant’s leg, which partially hides the foot tip. Because of this effect of the evaluator’s position, it is especially important to collect data for several trials and base the performance measurement on the mean of those trials. This was done in the current study and was also recommended by other authors.17,42,43 In addition, the evaluator must be correctly positioned to see the foot tip and must always make sure to adopt the same position for all trials and sessions. Finally, the similarity between accuracy of visual estimation between groups and the fact that accuracy was stable across the different MRDs were indications of the evaluator’s ability to adapt his or her position accordingly. We can thus conclude that the difference between the 2 methods was negligible with regard to the smallest detectable difference in the SEBT (standardized procedure) and so does not lead to inappropriate conclusions about differences between populations.
Discriminant Validity of the SEBT This study demonstrates the ability of the SEBT to discriminate between healthy and LAS groups based
on their performance on the test (Figure 4). Discrimination is higher in the AM direction and is enhanced with the use of MRD data normalized by height. This suggests that such normalization may help, in the future, highlight differences between groups or even within the same group across time. Both functional ability, quantified by the LEFS and FADI questionnaires, and SEBT performance (raw and normalized values by LLL and height) were found to be different between groups. The finding of poorer SEBT performance in the LAS group confirmed their motor-control deficit compared with healthy participants.9 Poorer SEBT performance has previously been attributed to a modification in strategy that involved less flexion at the knee and hip joints of the stance limb of healthy participants.13,48 Further work is needed to more carefully characterize the SEBT task and determine which biomechanical variables, in conjunction with MRD, are the best indicators of the quality of motor control in both populations. In our study, we saw no evidence of interlimb differences in SEBT performance for either group. As regards the LAS group, these results may suggest that there are bilateral alterations in motor control15,16 or that this group is predisposed to LAS injury due to motor control that had been compromised before injury.27 However, the absence of an interlimb difference in the LAS group can be attributed to a lack of statistical significance due to the small sample size. The greatest differences between LAS and healthy groups were seen with the AM reaching direction. This result may be attributable to the fact that a large range of dorsiflexion is needed for this particular condition. Indeed, a previous study indicated that the range of ankle dorsiflexion required for weight bearing has a strong impact on reaching performance in the anterior reaching direction.21 It was observed in some studies that a limited range of dorsiflexion when weight bearing on the injured limb remained 8 weeks after injury50—we did not observe this dorsiflexion limitation in our LAS group. A more detailed kinematics and kinetics analysis should be done to better understand this result.
Effect of the Normalization by Height Normalization by height seems to yield a more interesting and thorough understanding of the anthropometric characteristics associated with SEBT performance than does normalization by LLL—the more widely used approach. Indeed, normalization by height is interesting in consideration of the overall task at hand (ie, all body segments move during the task) and the trunk’s contribution to maintaining balance while the individual reaches his or her limit of stability. To limit the influence of the participant’s individual characteristics on SEBT performance, it has been suggested that normalization be used when comparing different groups.25 Gribble and Hertel25 chose to normalize by LLL rather than height, although both approaches show a high degree of correlation. In the current study, the adjusted R2 of the correlation
Validity of the Star Excursion Balance Test 53
between the MRD and height was slightly higher than the one that used for LLL for both groups. Finally, height is easy to measure and does not require specific skills like palpation of bony landmarks.51 Normalization by height takes into consideration the significant influence of the trunk on overall body CoM movement over the support base during SEBT motor-skills tasks. From Dempster values as reported by Winter,52 the trunk CoM accounts for a high percentage (67.8%) of total body mass and may strongly influence the body CoM during motor tasks. Trunk and hip movements play an integral role in motor control and significantly contribute to recovery strategies that minimize body CoM acceleration under more challenging conditions.32,33 The control of the body’s CoM displacement mainly involves trunk stabilization in the direction opposite that of the perturbation or voluntary movement.32,53 LLL normalization would represent an adequate anthropometric tool to evaluate a reaching task in studies where participants remain seated or where the trunk is fixed.
Limitations The first limitation to point out in the current study is that several variables were measured using a small sample (2 groups of 10 participants). There were also some data-collection limitations related to the use of Optotrak technology in concert with visual estimation, as well as limitations inherent in the study design itself. First, the accuracy of visual estimation of the MRD may have been influenced by the evaluator’s restricted position. To avoid hiding Optotrak markers during testing, the evaluator had to sometimes adopt suboptimal positions, especially while testing in the PM direction. As a consequence, the accuracy of the visual estimation may have been compromised. A second limitation in the current study involved the difficulty in drawing conclusions about concurrent and discriminant validity using only 3 directions, insofar as we evaluated 3 reaching directions out of a total of 8 possibilities in the initial test. These 3 directions were chosen because they furnish unique and specific information about participants with ankle injuries. Finally, the homogeneity of the population, like its gender homogeneity, may limit the external validity of our results related to the second objective—to measure the discriminative ability of the MRD methods. It would be of interest to investigate this discriminant validity by studying other populations such as sedentary or elderly populations.
Conclusion Visual estimation of the MRD in the SEBT is a highly valid and accurate measurement when a standardized procedure is employed. The high degree of accuracy of the MRD measurement was evident in both healthy and LAS groups. The MRD, when estimated visually, tends to be overestimated in the PM reaching direction, so caution is advised regarding the evaluator’s position for this particular test direction. Normalization of MRD by
height increases discriminant validity between groups with or without LAS. This result supports the use of MRD normalization by height in future studies when assessing the quality of motor control. MRD is, however, the endpoint (outcome) of a series of complex motor strategies put in place to perform such a task. Future studies should analyze, in more detail, not only the endpoints of these strategies (namely, the MRD) but also the strategies themselves and the impact of the different reaching directions on motor control. Acknowledgments The authors acknowledge the support of Guy St-Vincent and Émilie Michaud for their help with data collection, Chantal Gendron and the team of physiotherapists at the Valcartier military base for recruiting participants, and Isabelle Lapointe, Joanie Bédard, and Joannie Huot for their assistance during data acquisition. We also want to thank Stéphanie Bernard for revising the manuscript. Maude Bastien was supported by studentships from the Canadian Institutes of Health Research (CIHR), the CIRRIS, and the OPPQ. The project was funded by the Ordre professionnel de la physiothérapie du Québec (OPPQ) and the Quebec Rehabilitation Research network (REPAR).
References 1. Cameron KL, Owens BD, Deberardino TM. Incidence of ankle sprains among active-duty members of the United States Armed Services from 1998 through 2006. J Athl Train. 2010;45(1):29–38. PubMed doi:10.4085/10626050-45.1.29 2. Fong DT, Hong Y, Chan LK, Yung PS, Chan KM. A systematic review on ankle injury and ankle sprain in sports. Sports Med. 2007;37(1):73–94. PubMed doi:10.2165/00007256-200737010-00006 3. Waterman BR, Owens BD, Davey S, Zacchilli MA, Belmont PJ, Jr. The epidemiology of ankle sprains in the United States. J Bone Joint Surg Am. 2010;92(13):2279– 2284. PubMed doi:10.2106/JBJS.I.01537 4. Jones MH, Amendola AS. Acute treatment of inversion ankle sprains: immobilization versus functional treatment. Clin Orthop Relat Res. 2007; (455):169–172. PubMed doi:10.1097/BLO.0b013e31802f5468 5. Hiller CE, Nightingale EJ, Lin CW, Coughlan GF, Caulfield B, Delahunt E. Characteristics of people with recurrent ankle sprains: a systematic review with metaanalysis. Br J Sports Med. 2011;45(8):660–672. PubMed doi:10.1136/bjsm.2010.077404 6. Hass CJ, Bishop MD, Doidge D, Wikstrom EA. Chronic ankle instability alters central organization of movement. Am J Sports Med. 2010;38(4):829–834. PubMed doi:10.1177/0363546509351562 7. Hoch MC, McKeon PO, Andreatta RD. Plantar vibrotactile detection deficits in adults with chronic ankle instability. Med Sci Sports Exerc. 2012;44(4):666–672. PubMed doi:10.1249/MSS.0b013e3182390212 8. Munn J, Sullivan SJ, Schneiders AG. Evidence of sensorimotor deficits in functional ankle instability: a systematic
54 Bastien et al
review with meta-analysis. J Sci Med Sport. 2010;13(1):2– 12. PubMed doi:10.1016/j.jsams.2009.03.004 9. Arnold BL, De La MS, Linens S, Ross SE. Ankle instability is associated with balance impairments: a metaanalysis. Med Sci Sports Exerc. 2009;41(5):1048–1062. PubMed doi:10.1249/MSS.0b013e318192d044 10. Wikstrom EA, Naik S, Lodha N, Cauraugh JH. Balance capabilities after lateral ankle trauma and intervention: a meta-analysis. Med Sci Sports Exerc. 2009;41(6):1287– 1295. PubMed doi:10.1249/MSS.0b013e318196cbc6 11. Olmsted LC, Carcia CR, Hertel J, Shultz SJ. Efficacy of the Star Excursion Balance Tests in detecting reach deficits in subjects with chronic ankle instability. J Athl Train. 2002;37(4):501–506. PubMed 12. Gribble PA, Hertel J, Plisky PJ. Using the Star Excursion Balance Test to assess dynamic postural-control deficits and outcomes in lower extremity injury: a literature and systematic. J Athl Train. 2012;47(3):339–357. PubMed 13. Gribble PA, Hertel J, Denegar CR. Chronic ankle instability and fatigue create proximal joint alterations during performance of the Star Excursion Balance Test. Int J Sports Med. 2007;28(3):236–242. PubMed doi:10.1055/s-2006-924289 14. Wikstrom EA, Fournier KA, McKeon PO. Postural control differs between those with and without chronic ankle instability. Gait Posture. 2010;32(1):82–86. PubMed doi:10.1016/j.gaitpost.2010.03.015 15. Evans T, Hertel J, Sebastianelli W. Bilateral deficits in postural control following lateral ankle sprain. Foot Ankle Int. 2004;25(11):833–839. PubMed 16. Wikstrom EA, Naik S, Lodha N, Cauraugh JH. Bilateral balance impairments after lateral ankle trauma: a systematic review and meta-analysis. Gait Posture. 2010;31(4):407–414. PubMed doi:10.1016/j.gaitpost.2010.02.004 17. Hertel J, Braham RA, Hale SA, Olmsted-Kramer LC. Simplifying the Star Excursion Balance Test: analyses of subjects with and without chronic ankle instability. J Orthop Sports Phys Ther. 2006;36(3):131–137. PubMed doi:10.2519/jospt.2006.36.3.131 18. Hale SA, Hertel J, Olmsted-Kramer LC. The effect of a 4-week comprehensive rehabilitation program on postural control and lower extremity function in individuals with chronic ankle instability. J Orthop Sports Phys Ther. 2007;37(6):303–311. PubMed doi:10.2519/ jospt.2007.2322 19. Sefton JM, Yarar C, Hicks-Little CA, Berry JW, Cordova ML. Six weeks of balance training improves sensorimotor function in individuals with chronic ankle instability. J Orthop Sports Phys Ther. 2011;41(2):81–89. PubMed doi:10.2519/jospt.2011.3365 20. Earl JE, Hertel J. Lower-extremity muscle activation during the Star Excursion Balance Tests. J Sport Rehabil. 2001;10(2):93–104. 21. Hoch MC, Staton GS, McKeon PO. Dorsiflexion range of motion significantly influences dynamic balance. J Sci Med Sport. 2011;14(1):90–92. PubMed doi:10.1016/j. jsams.2010.08.001
22. Norris B, Trudelle-Jackson E. Hip- and thigh-muscle activation during the Star Excursion Balance Test. J Sport Rehabil. 2011;20(4):428–441. PubMed 23. Clark RC, Saxion CE, Cameron KL, Gerber JP. Associations between three clinical assessment tools for postural stability. N Am J Sports Phys Ther. 2010;5(3):122–130. PubMed 24. Munro AG, Herrington LC. Between-session reliability of the Star Excursion Balance Test. Phys Ther Sport. 2010;11(4):128–132. PubMed doi:10.1016/j. ptsp.2010.07.002 25. (25) Gribble PA, Hertel J. Considerations for normalizing measures of the Star Excursion Balance Test. Meas Phys Educ Exerc Sci. 2003;7(2):89–100. 26. Kinzey SJ, Armstrong CW. The reliability of the StarExcursion test in assessing dynamic balance. J Orthop Sports Phys Ther. 1998;27(5):356–360. PubMed doi:10.2519/jospt.1998.27.5.356 27. Plisky PJ, Rauh MJ, Kaminski TW, Underwood FB. Star Excursion Balance Test as a predictor of lower extremity injury in high school basketball players. J Orthop Sports Phys Ther. 2006;36(12):911–919. PubMed doi:10.2519/ jospt.2006.2244 28. Monaghan K, Delahunt E, Caulfield B. Ankle function during gait in patients with chronic ankle instability compared to controls. Clin Biomech (Bristol, Avon). 2006;21(2):168–174. PubMed doi:10.1016/j.clinbiomech.2005.09.004 29. McGinley JL, Baker R, Wolfe R, Morris ME. The reliability of three-dimensional kinematic gait measurements: a systematic review. Gait Posture. 2009;29(3):360–369. PubMed doi:10.1016/j.gaitpost.2008.09.003 30. Schmidt J, Berg DR, Ploeg H-L. Precision, repeatability and accuracy of Optotrak optical motion tracking systems. Int J Exp Comput Biomech. 2009;1(1):114–127. doi:10.1504/IJECB.2009.022862 31. Cote KP, Brunet ME, Gansneder BM, Shultz SJ. Effects of pronated and supinated foot postures on static and dynamic postural stability. J Athl Train. 2005;40(1):41–46. PubMed 32. Hughey LK, Fung J. Postural responses triggered by multidirectional leg lifts and surface tilts. Exp Brain Res. 2005;165(2):152–166. PubMed doi:10.1007/s00221-0052295-9 33. Blackburn JT, Riemann BL, Myers JB, Lephart SM. Kinematic analysis of the hip and trunk during bilateral stance on firm, foam, and multiaxial support surfaces. Clin Biomech (Bristol, Avon). 2003;18(7):655–661. PubMed doi:10.1016/S0268-0033(03)00091-3 34. Alonso A, Khoury L, Adams R. Clinical tests for ankle syndesmosis injury: reliability and prediction of return to function. J Orthop Sports Phys Ther. 1998;27(4):276–284. PubMed doi:10.2519/jospt.1998.27.4.276 35. Magee D. Orthopedic Physical Assessment. Philadelphia, PA: Elsevier; 2008. 36. Terry MA, Winell JJ, Green DW, et al. Measurement variance in limb length discrepancy: clinical and radiographic assessment of interobserver and intraobserver variability. J Pediatr Orthop. 2005;25(2):197–201. PubMed doi:10.1097/01.bpo.0000148496.97556.9f
Validity of the Star Excursion Balance Test 55
37. Geeta A, Jamaiyah H, Safiza MN, et al. Reliability, technical error of measurements and validity of instruments for nutritional status assessment of adults in Malaysia. Singapore Med J. 2009;50(10):1013–1018. PubMed 38. Bennell KL, Talbot RC, Wajswelner H, Techovanich W, Kelly DH, Hall AJ. Intra-rater and inter-rater reliability of a weight-bearing lunge measure of ankle dorsiflexion. Aust J Physiother. 1998;44(3):175–180. PubMed 39. Hale SA, Hertel J. Reliability and sensitivity of the Foot and Ankle Disability Index in subjects with chronic ankle instability. J Athl Train. 2005;40(1):35–40. PubMed 40. Martin RL, Irrgang JJ. A survey of self-reported outcome instruments for the foot and ankle. J Orthop Sports Phys Ther. 2007;37(2):72–84. PubMed doi:10.2519/jospt.2007.2403 41. Binkley JM, Stratford PW, Lott SA, Riddle DL. The Lower Extremity Functional Scale (LEFS): scale development, measurement properties, and clinical application. North American Orthopaedic Rehabilitation Research Network. Phys Ther. 1999;79(4):371–383. PubMed 42. Hertel J, Miller SJ, Denegar CR. Intratester and intertester reliability during the Star Excursion Balance Tests. J Sport Rehabil. 2000;9:104–116. 43. Robinson RH, Gribble PA. Support for a reduction in the number of trials needed for the Star Excursion Balance Test. Arch Phys Med Rehabil. 2008;89(2):364–370. PubMed doi:10.1016/j.apmr.2007.08.139 44. Portney LG, Watkins MP. Foundations of Clinical Research Applications to Practice. 3rd ed. Upper Saddle River, NJ: Pearson Prentice Hall; 2013. 45. Munro BH. Statistical Methods for Health Care Research. 3rd ed. Philadelphia, PA: JB Lippincott; 1997.
46. Cohen J. Statistical Power Analysis for the Behavioral Sciences. Hillsdale, NJ: Lawrence Erlbaum; 1988. 47. Plisky PJ, Gorman PP, Butler RJ, Kiesel KB, Underwood FB, Elkins B. The reliability of an instrumented device for measuring components of the Star Excursion Balance Test. N Am J Sports Phys Ther. 2009;4(2):92–99. PubMed 48. Robinson R, Gribble P. Kinematic predictors of performance on the Star Excursion Balance Test. J Sport Rehabil. 2008;17(4):347–357. PubMed 49. Lanning CL, Uhl TL, Ingram CL, Mattacola CG, English T, Newsom S. Baseline values of trunk endurance and hip strength in collegiate athletes. J Athl Train. 2006;41(4):427–434. PubMed 50. van Rijn RM, van Os AG, Bernsen RM, Luijsterburg PA, Koes BW, Bierma-Zeinstra SM. What is the clinical course of acute ankle sprains?: a systematic literature review. Am J Med. 2008;121(4):324–331. PubMed doi:10.1016/j. amjmed.2007.11.018 51. Geeta A, Jamaiyah H, Safiza MN, et al. Reliability, technical error of measurements and validity of instruments for nutritional status assessment of adults in Malaysia. Singapore Med J. 2009;50(10):1013–1018. PubMed 52. Winter DA. Biomechanics and Motor Control of Human Movement. 2nd ed. New York, NY: John Wiley & Sons; 1990. 53. Carpenter MG, Allum JH, Honegger F. Directional sensitivity of stretch reflexes and balance corrections for normal subjects in the roll and pitch planes. Exp Brain Res. 1999;129(1):93–113. PubMed doi:10.1007/ s002210050940
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