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Sources of Variability in Musculo-Articular Stiffness Measurement
The assessment of musculo-articular stiffness (MAS) with the free-oscillation technique is a popular method with a variety of applications. This study examined the sources of variability (load applied and frequency of oscillation) when MAS is assessed. Over two testing occasions, 14 healthy men (27....
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2013
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3648525/ https://www.ncbi.nlm.nih.gov/pubmed/23667662 http://dx.doi.org/10.1371/journal.pone.0063719 |
Sumario: | The assessment of musculo-articular stiffness (MAS) with the free-oscillation technique is a popular method with a variety of applications. This study examined the sources of variability (load applied and frequency of oscillation) when MAS is assessed. Over two testing occasions, 14 healthy men (27.7±5.2 yr, 1.82±0.04 m, 79.5±8.4 kg) were measured for isometric maximum voluntary contraction and MAS of the knee flexors using submaximal loads relative to the individual's maximum voluntary contraction (MAS(%MVC)) and a single absolute load (MAS(ABS)). As assessment load increased, MAS(%MVC) (coefficient of variation (CV) = 8.1–12.1%; standard error of measurement (SEM) = 51.6–98.8 Nm(−1)) and frequency (CV = 4.8–7.0%; SEM = 0.060–0.075 s(−1)) variability increased consequently. Further, similar levels of variability arising from load (CV = 6.7%) and frequency (CV = 4.8–7.0%) contributed to the overall MAS(%MVC) variability. The single absolute load condition yielded better reliability scores for MAS(ABS) (CV = 6.5%; SEM = 40.2 Nm(−1)) and frequency (CV = 3.3%; SEM = 0.039 s(−1)). Low and constant loads for MAS assessment, which are particularly relevant in the clinical setting, exhibited superior reliability compared to higher loads expressed as a percentage of maximum voluntary contraction, which are more suitable for sporting situations. Appropriate sample size and minimum detectable change can therefore be determined when prospective studies are carried out. |
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