Premium
Postural activation of the human medial gastrocnemius muscle: are the muscle units spatially localised?
Author(s) -
Vieira Taian M. M.,
Loram Ian D.,
Muceli Silvia,
Merletti Roberto,
Farina Dario
Publication year - 2011
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2010.201806
Subject(s) - motor unit , anatomy , gastrocnemius muscle , motor unit recruitment , human muscle , electrode , electrophysiology , myocyte , muscle contraction , electromyography , chemistry , biomedical engineering , medicine , biology , skeletal muscle , neuroscience
Non‐technical summary In the medial gastrocnemius muscle of cats, the longitudinal size (3–4 cm) of the territory of motor units is large (∼60%) relative to the muscle length. In the human medial gastrocnemius, the size of motor unit territories is unknown. By comparing intramuscular and surface electromyograms we show that, when subjects stand at ease, the motor units active in the medial gastrocnemius have small territories. They extend no longer than 4 cm and no less than 1 cm along the longitudinal axis (∼25 cm long) of the muscle. Physiologically, the small territories of motor units give the nervous system a mechanism for the independent activation of sub‐volumes of the medial gastrocnemius muscle.