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Advisor(s)
Abstract(s)
This study investigates the effects of eccentric
exercise and delayed onset muscle soreness (DOMS) of the
quadriceps on agonist–antagonist activity during a range of
motor tasks. Ten healthy volunteers (age, mean ± SD,
24.9 ± 3.2 years) performed maximum voluntary contractions
(MVC) and explosive isometric contractions of
the knee extensors followed by isometric contractions at
2.5, 5, 10, 15, 20, and 30% MVC at baseline, immediately
after and 24 h after eccentric exercise of the quadriceps.
During each task, force of the knee extensors and surface
EMG of the vasti and hamstrings muscles were recorded
concurrently. Rate of force development (RFD) was computed
from the explosive isometric contraction, and the
coefficient of variation of the force (CoV) signal was
estimated from the submaximal contractions. Twenty-four
hours after exercise, the subjects rated their perceived pain
intensity as 4.1 ± 1.2 (score out of 10). The maximum
RFD and MVC of the knee extensors was reduced immediately
post- and 24 h after eccentric exercise compared to
baseline (average across both time points: 19.1 ± 17.1%
and 11.9 ± 9.8% lower, respectively, P\0.05). The CoV
for force during the submaximal contractions was greater
immediately after eccentric exercise (up to 66% higher
than baseline, P\0.001) and remained higher 24 h postexercise
during the presence of DOMS (P\0.01). For the
explosive and MVC tasks, the EMG amplitude of the vasti
muscles decreased immediately after exercise and was
accompanied by increased antagonist EMG for the explosive
contraction only. On the contrary, reduced force
steadiness was accompanied by a general increase in EMG
amplitude of the vasti muscles and was accompanied by
increased antagonist activity, but only at higher force levels
([15% MVC). This study shows that eccentric exercise
and subsequent DOMS of the quadriceps reduce the maximal
force, rate of force development and force steadiness
of the knee extensors, and is accompanied by different
Description
Keywords
Electromiografia Exercício excêntrico Fadiga neuromuscular
Citation
Vila-Chã, Carolina; Hassanlouei, H.; Farina, D.; Falla, D. (2012). Eccentric exercise and delayed onset muscle soreness of the quadriceps induce adjustments in agonist–antagonist activity, which are dependent on the motor task. Experimental Brain Research. ISSN 0014-4819. 216:3, p. 385-395
Publisher
Springer