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Measurement and reproducibility of strength and voluntary activation of lower‐limb muscles
Author(s) -
Todd Gabrielle,
Gorman Robert B.,
Gandevia Simon C.
Publication year - 2004
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.20027
Subject(s) - isometric exercise , reproducibility , ankle , physical medicine and rehabilitation , coefficient of variation , medicine , physical therapy , muscle contraction , triceps surae muscle , stride , electromyography , anatomy , chemistry , chromatography
Accurate measurement of muscle strength and voluntary muscle activation is important in the assessment of disorders that affect the motor pathways or muscle. We designed a multipurpose system to assess the variability and reproducibility of isometric torque measurements obtained during maximal voluntary efforts of the knee flexor, knee extensor, ankle dorsiflexor, and ankle plantarflexor muscles on each side. It used two isometric myographs mounted on an adjustable frame. Measurements of maximal voluntary torque (range, 25–188 Nm) displayed low variability within a testing session and over five testing sessions (coefficient of variation range, 5–11%). We used the same equipment to measure voluntary activation of the triceps surae muscles. Voluntary activation, measured with a sensitive twitch interpolation method, increased with increasing voluntary contraction torque ( P < 0.001) and was very high during maximal efforts (mean, 97.8 ± 2.1%; median, 98.5%). Furthermore, measurements of voluntary activation during maximal efforts were reproducible across testing sessions with very little variability (coefficient of variation, <2%). The myograph system and the testing procedures should allow accurate measurement of strength and voluntary drive in longitudinal patient studies. Muscle Nerve 29: 834–842, 2004