The University of Toledo The University of Toledo Digital Repository Theses and Dissertations 2013 An examination of contributing factors to star excursion balance test in individuals with and without chronic ankle instability Sara E. Carey The University of Toledo Follow this and additional works at: http://utdr.edu/theses-dissertations Recommended Citation Carey, Sara E., "An examination of contributing factors to star excursion balance test in individuals with and without chronic ankle instability" (2013). Theses and Dissertations. This Thesis is brought to you for free and open access by The University of Toledo Digital Repository.
It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of The University of Toledo Digital Repository. For more information, please see the repository's About page. A Thesis entitled An Examination of Contributing Factors to Star Excursion Balance Test in Individuals with and without Chronic Ankle Instability by Sara E. Carey, ATC Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Masters of Science Degree in Exercise Science _________________________________________ Dr.
Phillip Gribble, Committee Chair _________________________________________ Dr. Brian Pietrosimone , Committee Member _________________________________________ Dr. Kate Pfile, Committee Member _________________________________________ Dr. Komuniecki, Dean College of Graduate Studies The University of Toledo May 2013 Copyright 2013, Sara Elizabeth Carey This document is copyrighted material.
Under copyright law, no parts of this document may be reproduced without the expressed permission of the author. An Abstract of An Examination of Contributing Factors to Star Excursion Balance Test in Individuals with and without Chronic Ankle Instability by Sara E. Carey, ATC Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Masters of Science Degree in Exercise Science The University of Toledo May 2013 Objective: The purposes of this study were to determine if differences exist in sagittal plane strength at the ankle and knee, static and dynamic postural control, ankle dorsiflexion range of motion (DFROM), and ankle laxity between individuals with and without chronic ankle instability (CAI) as well as to determine which factors contribute the most to Star Excursion Balance Test (SEBT) performance in the CAI and healthy control groups. Design: A case-control study.
Setting: Research laboratory. Participants: Twenty healthy control participants (M=6, F=14, 20.) and eighteen CAI participants (M=10, F=8, 20.) volunteered for this study. Interventions: Dynamic postural control was assessed with the three directions of the SEBT. After four practice trials, participants performed four testing trials.
Concentric strength of the sagittal plane movers of the ankle and the knee was assessed on an isokinetic dynamometer. Static postural control was assessed during a single-leg static balance on a force plate under eyes-closed (EC) conditions. Center of pressure (COP) displacements were recorded in the anteroposterior (AP) and mediolateral (ML) directions during 3, 15-second trials. Ankle DFROM was assessed using the weight-bearing lunge test (WBLT).
Ankle joint laxity was evaluated using the iii instrumented ankle arthometer in the AP and Inversion-Eversion (IE) directions. Main Outcome Measures: Dynamic postural control was represented as the average of the three reach distances (cm) normalized by leg length (cm) and represented as a percentage score (MAXD). Static balance was calculated as the center of pressure velocity (COPV, m/s2) and time-to-boundary (TTB). Ankle dorsiflexion from the WBLT is represented by the distance away from the wall (cm) the foot can slide and still allow the knee to touch the wall while performing closed-chain dorsiflexion.
Ankle dorsiflexion and plantar flexion, and knee flexion and extension strength was normalized to body mass and represented as average peak torque (Nm/kg) from five trials. AP and IE ankle laxity were quantified in millimeters and degrees, respectively. Statistical Analysis: Independent t-tests were used to compare each dependent variable between the CAI and control groups. A Cohen’s d effect size along with 95% confidence intervals (CI) was calculated for each comparison between groups.
A backward regression analysis was performed to determine which dependent variables influence the SEBT performance of both groups. Significance was set a priori at p<0. Results: Significant differences were observed in static postural control measures between the groups in the static postural control (p < 0. All other variables were not statistically significant (p > 0.
The regression model showed that ankle plantar flexion and WBLT predicted SEBT performance in the CAI group whereas knee strength and static postural control predicted SEBT performance in the control group. Conclusion: Participants with CAI had decreased postural control compared to the healthy controls, indicating that the presence of CAI may be associated with altered sensorimotor control. Ankle dorsiflexion and plantar flexor strength were significant predictors of SEBT performance in the CAI group, while knee strength and static balance iv were the major contributors to the SEBT performance. When deficits in dynamic postural control is detected using the SEBT, our data suggests the need to address ankle DFROM and plantar flexor strength for individuals with CAI as well as knee strength and static balance for those without any lower extremity injury in order to improve their dynamic function.
v Acknowledgements Mom, Dad, Meg: Thank you for encouraging me throughout this whole process. You helped me through the stressful times and made them not seem so bad. Thanks for believing in me and helping me to get to this point. I love you guys! Liz and Heather: Over the past two years I have spent countless hours with you guys doing research, testing, data processing, and generally stressing out.
I’m not sure I would have been able to make it to now without you guys! Masafumi: I would have not been able to finish this process without you. Thank you for always being encouraging even when you could tell I was struggling. I appreciate and will never forget all the help you gave to me. You spent tons of hours in the lab and on the computer and I am forever grateful.
Pfile: Thank you for being on my committee and helping me to create the best paper and project I could. Thank you for all the hard work and dedication to my thesis project. I will never forget how much you helped me on this journey. vi Table of Contents Abstract iii Acknowledgements vi Table of Contents vii List of Tables x List of Figures xii List of Abbreviations xiii 1.1 Statement of Problem .2 Statement of Purpose .4 Significance of Study .1 Purpose of Literature Review .3 Lateral Ankle Prevalence .4 Chronic Ankle Instability.1 Pathomechanics of Chronic Ankle Instability .1 Risk Factors for Ankle Sprains .2 Risk Factors for Chronic Ankle Instability .1 Potential contributing factors to the Star Excursion Balance Test .7 Summary of Literature Review .5 Data Collection and Processing .1 Star Excursion Balance Test .2 Static Postural Control .5 Range of Motion .1 Comparison of the CAI and Control Groups .1 Sensorimotor Outcome Measures .1 Dynamic Postural Control: Star Excursion Balance Test .2 Static Postural Control .2 Mechanical Joint Integrity Outcome Measures .1 Anterior Reach of Star Excursion Balance Test .2 Posteromedial Reach of Star Excursion Balance Test .3 Posterolateral Reach of Star Excursion Balance Test .4 Composite Score of Star Excursion Balance Test .1 Discussion of Main Outcome Measures .56 References 57 Appendices Appendix A 73 Appendix B 80 Appendix C 83 Appendix D 84 Appendix E 87 ix List of Tables 3.1 Ankle Injury Questionaries’ .2 Star Excursion Balance Test Variables for Chronic Ankle Instability (CAI) and control groups.3 COPV (cm/s) and TTB measures (s) in an eyes closed condition evaluating Static Postural control……………………………………………….4 Ankle and knee average peak torque (N·m-1·kg-1) in the sagittal plane for the CAI and control groups.5 Mechanical joint integrity assessed using the Weight Bearing Lung Test (WBLT) and Instrumented Ankle Joint Laxity for the Chronic Ankle Instability (CAI) and control groups.6 Backward Regression of predictors of variance in the CAI and control groups for the anterior reach.7 Backward Regression of predictors of variance in the CAI and control groups for the posteromedial reach.8 Backward Regression of predictors of variance in the CAI and control groups for the posterolateral reach…………………………………………….9 Backward Regression of predictors of variance in the CAI and control groups for the composite score.45 xi List of Figures 3-1-A Star Excursion Balance Test Anterior Reach .28 3-1-B Star Excursion Balance Test Posteromedial Reach .29 3-1-C Star Excursion Balance Test Posterolateral Reach .29 3-2 Static Postural Control .33 3-5 Weight Bearing Lunge Test .35 xii List of Abbreviations % MAXD…………………….Normalized Percentage of the Reach Distance CAI…………………………….Chronic Ankle Instability CKC……………………………….Closed Kinetic Chain COP ……………………………….Center of Pressure) DF.
Effect Size FAAM.Foot and Ankle Ability Measure PL. Range of Motion SEBT. Star Excursion Balance Test TTB………………………………….Time to Boundary WB. Weight Bearing WBLT.
Weight Bearing Lunge Test xiii Chapter 1 Introduction Lateral ankle sprains are one of the most common injuries in the physically active population.1-4 In the 2005-2006 academic years, there were 4,350 sports injuries reported in high school athletes in the United States.5 Of these injuries, 52.8% were lower extremity injuries, and an ankle sprain was the most common injury in the lower extremity.5 Lateral ankle sprains result in time loss from sports participation5,6, cause long-term disability such as recurrent ankle sprains and ankle osteoarthritis3,4,7,8 and have a major impact on health care costs and resources.9 Therefore, lateral ankle sprains are a critical issue in public health, especially the physically active Yeung et al.4 reported that 73% of athletes with an initial ankle sprain had repeated ankle sprains and 59% of those had significant residual disability and symptoms with functional and mechanical impairments. The condition associated with recurrent ankle sprains is commonly known as chronic ankle instability (CAI7). Functional and mechanical impairments associated with CAI have been related to the development of post-traumatic osteoarthritis.8 Therefore, there is a need to develop effective intervention and prevention programs for decreasing the prevalence of CAI and the associated long- term complications. 1 Important steps in decreasing the prevalence of CAI are identifying modifiable risk factors and the development of intervention strategies to target these risk factors.
The leading risk factor and predictor for recurrent ankle sprains is a previous history of an ankle sprain.10 Additionally, altered arthrokinematics and neuromuscular control have been previously observed following an ankle sprain, manifesting as restricted ankle dorsiflexion (DF) range of motion (ROM),11 increased ankle laxity,12,13 decreased strength in the proximal and distal segment,12,14 and poor postural control12,15-18. There does not appear to be a single factor that accounts for clinical deficits associated with recurrent ankle sprain and a multi-factorial approach for determination of risk factors and intervention has been suggested.12,15 Therefore, it is important to identify which factors are associated with the existence and risk of ankle pathology, and then determine which are modifiable with clinical intervention. Specifically, previous studies14,19,20 found reductions in torque production of the ankle plantarflexors and evertors as well as knee flexors and extensors in individuals with CAI. Furthermore, Friel et al,21 observed hip abductor weakness in those with CAI.
However, McHugh et al.22 reported that hip weakness did not predict ankle sprains in high school athletes. Together, these findings suggest that strength deficits may develop in the entire lower extremity following an initial ankle sprain rather than exist prior to initial ankle sprain. Another factor related to CAI is static postural control. Static postural control requires the individual to maintain the base of support for a given amount of time.
Measurements of static postural control include time to boundary (TTB) and center of 2 pressure (COP). Hertel et al.23 found decreased TTB in CAI participants compared to healthy participants. Pope et al.24 evaluated COP in CAI and healthy participants and observed that the CAI group had a more anterior and lateral displacement of their COP than the healthy group.24 These findings showed that alterations in static postural control are likely associated with CAI. Mechanical impairments have been observed in CAI population, including ankle joint laxity and restricted DF-ROM.
Hubbard et al.25 found increased laxity in functional unstable ankles compared to uninjured ankles. Increased ankle laxity can cause a change in the support of the ankle joint and altered healing of the ligament.