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Electrically induced torque decrease reflects more than muscle fatigue
Author(s) -
Papaiordanidou Maria,
Stevenot JeanDamien,
Mustacchi Valerie,
Vacini Michele,
Martin Alain
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.24276
Subject(s) - muscle fatigue , triceps surae muscle , muscle contraction , intensity (physics) , contraction (grammar) , stimulation , medicine , physical medicine and rehabilitation , transcranial magnetic stimulation , electromyography , cardiology , physics , quantum mechanics
The aim of the study was to compare the fatigue induced by different electrical stimulation (ES) protocols. The triceps surae muscle of 8 healthy subjects was fatigued with 4 protocols (30 H z −500 μs, 30 H z −1 ms, 100 H z −1 ms, and 100 H z −500 μs), composed of 60 trains (4 s on–6 s off), delivered at an intensity evoking 30% of maximal voluntary contraction (MVC). Fatigue was quantified by ES and MVC torque decreases. The amplitude of the twitch delivered at the intensity and pulse width used in each fatiguing protocol (twitch at I stim ) was analyzed. All parameters decreased significantly after all protocols. The ES torque decrease correlated positively with the twitch decrease elicited at I stim only for the 30‐H z protocols. Results show that, during the 100‐H z protocols, phenomena not related to the fatigue of the solicited motor units may occur, including changes in the excitability threshold of the axonal terminal branches. Muscle Nerve 50: 604–606, 2014