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Specific joint angle dependency of voluntary activation during eccentric knee extensions
Author(s) -
Doguet Valentin,
Rivière Valentin,
Guével Arnaud,
Guilhem Gaël,
Chauvet Lucile,
Jubeau Marc
Publication year - 2017
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.25515
Subject(s) - isometric exercise , concentric , eccentric , contraction (grammar) , medicine , knee joint , anatomy , muscle contraction , physical medicine and rehabilitation , mathematics , physics , surgery , geometry , quantum mechanics
This study compared voluntary activation during isometric, concentric, and eccentric maximal knee extensions at different joint angles. Methods Fifteen participants performed isometric, concentric, and eccentric protocols (9 contractions each). For each protocol, the central activation ratio (CAR) was randomly measured at 50°, 75°, or 100° of knee joint angle (0° = full knee extension) using superimposed supramaximal paired nerve stimulations during contractions. Results CAR increased between 50° and 100° during isometric (93.6 ± 3.1 vs. 98.5 ± 1.4%), concentric (92.4 ± 5.4 vs. 99.2 ± 1.2%), and eccentric (93.0 ± 3.5 vs. 96.6 ± 3.8%) contractions. CAR was lower during eccentric than both isometric and concentric contractions at 75° and 100°, but similar between contraction types at 50°. Conclusions The ability to activate muscle maximally is impaired during eccentric contractions compared with other contraction types at 75° and 100°, but not at 50°. Muscle Nerve 56 : 750–758, 2017