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Facilitation of quadriceps activation is impaired following eccentric exercise
Author(s) -
Hedayatpour N.,
ArendtNielsen L.,
Falla D.
Publication year - 2014
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/j.1600-0838.2012.01512.x
Subject(s) - eccentric , medicine , eccentric exercise , electromyography , physical medicine and rehabilitation , physical therapy , knee flexion , muscle damage , physics , quantum mechanics
Contracting the knee flexor muscles immediately before a maximum voluntary contraction ( MVC ) of knee extension increases the maximal force that the extensor muscles can exert. It is hypothesized that this phenomenon can be impaired by muscle fiber damage following eccentric exercise [delayed onset muscle soreness ( DOMS )]. This study investigates the effect of eccentric exercise and DOMS on knee extension MVC immediately following a reciprocal‐resisted knee flexion contraction. Electromyography ( EMG ) was recorded from the knee extensors and flexors of 12 healthy men during knee extension MVC s performed in a reciprocal (maximal knee extension preceded by resisted knee flexion), and nonreciprocal condition (preceded by relaxation of the knee flexors). At baseline, knee extension MVC force was greater during the reciprocal condition ( P < 0.001), whereas immediately after, 24 and 48 h after eccentric exercise, the MVC force was not different between conditions. Similarly, at baseline, the EMG amplitude of the quadriceps during the MVC was larger for the reciprocal condition ( P < 0.001). However, immediately after, 24 and 48 h postexercise the EMG amplitude was similar between conditions. In conclusion, eccentric exercise abolished the facilitation of force production for the knee extensors, which normally occurs when maximum knee extension is preceded by activation of the knee flexors.