A Comparison of Strength, ROM, Laxity, and Dynamic and Static Postural Control Between Those At-Risk and Healthy

Objective: The purposes of this study were to compare strength, ankle joint laxity, ankle dorsiflexion range of motion (DF-ROM), and static balance between individuals with poor and good performance on the Star Excursion Balance Test in the anterior reach direction (SEBT-A), as well as to identify what combination of factors contribute the most to SEBT-A performance. Design: A single-blinded, case-control design. Setting: Research laboratory. Participants: Twenty three participants with no self-reported injury were recruited from the University of Toledo community. These individuals were assigned to either at-risk (M = 4, F = 9, 21.00 ± 2.61 yrs, 74.78 ± 15.94 kg, 165.99 ± 10.28 cm) or healthy control group (M = 3, F = 7, 20.60 ± 1.51 yrs, 65.82 ± 17.27 kg, 169.36 ± 11.43 cm) based on their performance on the SEBT-A. Interventions: Participants completed five testing activities, including the SEBT-A, a single-lag balance task, the Weight Bearing Lunge Test (WBLT), concentric strength of sagittal-plane ankle and knee movers using the Biodex, and ankle laxity using an instrumented ankle arthrometer. Main Outcome Measures: The normalized reach distance of the SEBT-A was calculated as the average of the three reach distances (cm) divided by leg length (cm) and represented as a percentage score (MAXD). Static postural control was examined with the center of pressure velocity (COPV, m/s2) and time-to-boundary (TTB, s). 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 weight-bearing dorsiflexion. The average of five peak torque productions of the sagittal-plane ankle and knee movers was normalized to body mass and represented as average peak torque (Nm/kg) from the five trials. Total anterior-posterior (AP) and inversion-eversion (IE) laxities were quantified in millimeters and degrees, respectively. Statistical Analysis: Independent t-tests were used to compare each dependent variable between the at-risk and healthy groups. Cohen’s d effect sizes with 95% confidence intervals (CI) were calculated for each comparison between groups. Additionally, a multiple linear backward regression analysis was performed to determine which dependent variables contributed to the variance of SEBT-A. Significance was set a priori at p<0.05. Results: There were statistically significant differences in the SEBT-A (t18 = -5.961, p = 0.001) and the WBLT (t18 = -2.632, p = 0.016) between the at-risk and healthy groups. There were no significant results for other outcome measures (p > 0.05). For the at-risk group, the combination of knee extensor strength, static postural control, and the WBLT explained 75% of the variance in SEBT-A (R2 = 0.750, p = 0.004). Conclusion: Participants with shorter anterior reaching distance in the SEBT had significantly less DF-ROM compared to controls. The results of the regression analyses showed that sagittal-plane knee strength, static postural control, and AP laxity predict the most to SEBT-A performance. Sagittal-plane knee strength, static postural control, and weight-bearing ankle DF-ROM may represent clinically modifiable factors for a targeted prevention program when decreased functional performance is identified with the SEBT-A.

Name thesis:degree_name

Master of Science in Exercise Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Exercise Science

Grantor dc:publisher

University of Toledo

Year dc:date

2013

Author dc:creator

• Rullestad, Elizabeth A.

Contributors dc:contributor

• Gribble, Phillip

• Kinesiology

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=toledo1364464324

OAI identifier oai:identifier

oai:etd.ohiolink.edu:toledo1364464324