A comparison of performance in steadiness tasks for the knee and ankle muscles in elderly
Crowley, Z, Zhou, S & Bezerra, P 2009, 'A comparison of performance in steadiness tasks for the knee and ankle muscles in elderly', Journal of Science and Medicine in Sport, vol. 12, suppl. 1, p. S37.
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Publisher's version of article available at http://dx.doi.org/10.1016/j.jsams.2008.12.090
Introduction: Steadiness in force production has been used as an indicator for the ability in control of muscles. Little research has been conducted to compare steadiness performance between different muscles. This study aimed to compare steadiness of knee extensors (KE) and flexors (KF), ankle plantarflexors (AP) and dorsiflexors (AD) in elderly. Methodology: Ten males and ten females, age range 60–77 years, performed isometric maximal voluntary contractions (MVC), then isometric KE, KF, AP, and AD steadiness tasks at 5, 15, and 25% MVC levels. Steadiness was quantified by coefficient of variation (CV) of force production around the target levels. Results: ANOVA analysis demonstrated that males’ MVC was significantly greater (P < 0.05) than females in all the muscle groups. No gender difference was observed in CV. The pooled results from all subjects showed that, in KF, CV at 5% MVC was higher than that at 15% (P < 0.05). In AD, CV at 5% was higher than that at 15 and 25% MVC (P < 0.05). However, in AP, CV at 25% was higher than that at 5 and 15% MVC (P < 0.05). No difference in CV was found for KE at these target levels. Comparisons between muscles found that AP was the steadiest except at 5% MVC with KE. AD was the least steady at 5% MVC. Conclusions: No significant correlations existed between either agonist/antagonist pairs in steadiness performance at 5–25% MVC levels. The AP appeared to be the steadiest muscle group. These between-muscle differences should be further examined and considered when muscle steadiness is assessed for neuromuscular function of the elderly.