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Variability and distribution of muscle strength and its determinants in humans
Author(s) -
Stebbings Georgina K.,
Morse Christopher I.,
Williams Alun G.,
Day Stephen H.
Publication year - 2014
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.24075
Subject(s) - isometric exercise , fascicle , physical medicine and rehabilitation , muscle strength , coefficient of variation , anatomy , medicine , mathematics , physical therapy , statistics
ABSTRACT Introduction : Inter‐individual variability in measurements of muscle strength and its determinants was identified to: (1) produce a normative data set describing the normal range and (2) determine whether some measurements are more informative than others when evaluating inter‐individual differences. Methods : Functional and morphological characteristics of the vastus lateralis were measured in 73 healthy, untrained adult men. Results : Inter‐individual variability (coefficient of variation) was greater for isometric maximal voluntary contraction (MVC) torque (18.9%) compared with fascicle force (14.6%; P = 0.025) and physiological cross‐sectional area (PCSA; 17.2%) compared with anatomical cross‐sectional area (ACSA, 13.0%; P < 0.0005). The relationship between ACSA and isometric MVC torque ( r 2 = 0.56) was weaker than that between PCSA and fascicle force ( r 2 = 0.68). Conclusions : These results provide a normative data set on inter‐individual variability in a variety of muscle strength‐related measurements and illustrate the benefit of using more stringent measures of muscle properties. Muscle Nerve 49 : 879–886, 2014