Affiliations: [a] Laboratory of Health and Sports Sciences, Meiji Gakuin University, Yokohama, Japan | [b] Training Center, Nippon Sport Science University, Tokyo, Japan | [c] Laboratory of Hygiene and Community Hygiene, Nippon Sport Science University, Tokyo, Japan | [d] Graduate School of Education, Okayama University, Okayama, Japan
Correspondence:
[*]
Corresponding author: Yosuke Tsuchiya, Laboratory of Health and Sports Sciences, Meiji Gakuin University, 1518 Kamikurata, Totsuka, Yokohama 244-8539, Japan. Tel.: +81 90 8026 6846; E-mail:[email protected]
Abstract:
BACKGROUND: Eccentric contractions (ECC)-induced muscle damage and
activation pattern are not fully understood. OBJECTIVE: To investigate the activation level and damage in each muscle and
site after ECC. METHODS: Eleven men performed 30 isokinetic ECC of
the elbow flexors. Maximal voluntary isometric contraction (MVC) torque,
range of motion of the elbow joint (ROM), delayed onset muscle soreness
(DOMS), transverse relaxation time (T2), and cross-sectional area (CSA) were
measured immediately before, immediately after, and 1, 3, 5 days after ECC. RESULTS: MVC and ROM significantly decreased while DOMS significantly
increased until 3 days after ECC. The CSA of the brachialis significantly
increased after ECC. The T2 in biceps brachii and middle and distal
brachialis increased significantly at post (p< 0.01) day 1 (middle; p< 0.01,
distal; biceps brachii, p< 0.05, brachialis, p< 0.01), and day 3 (middle;
p< 0.01, distal; biceps brachii, p< 0.05, brachialis, p< 0.01). In addition,
after 5 days only the distal brachialis has shown a significant increase
(p< 0.01). CONCLUSIONS: Following maximal ECC the activation pattern and muscle damage
differ among the elbow flexors depending upon the individual muscle and site
of recording.
Keywords: Lengthening, transverse relaxation time, elbow flexors, site-specific activation
