Alteration of neuromuscular function in squash
Data(s) |
2010
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Resumo |
The alteration in neuromuscular function of knee extensor muscles was characterised after a squash match in 10 trained players. Maximal voluntary contraction (MVC) and surface EMG activity of vastus lateralis (VL) and vastus medialis (VM) muscles were measured before and immediately after a 1-h squash match. M-wave and twitch contractile properties were analysed following single stimuli. MVC declined (280.5+/-46.8 vs. 233.6+/-35.4 Nm, -16%; P<0.001) after the exercise and this was accompanied by an impairment of central activation, as attested by decline in voluntary activation (76.7+/-10.4 vs. 71.3+/-9.6%, -7%; P<0.05) and raw EMG activity of the two vastii (-17%; P<0.05), whereas RMS/M decrease was lesser (VL: -5%; NS and VM: -12%; P=0.10). In the fatigued state, no significant changes in M-wave amplitude (VL: -9%; VM: -5%) or duration were observed. Following exercise, the single twitch was characterised by lower peak torque (-20%; P<0.001) as well as shorter half-relaxation time (-13%; P<0.001) and reduced maximal rate of twitch tension development (-23%; P<0.001) and relaxation (-17%; P<0.05). A 1-h squash match play caused peripheral fatigue by impairing excitation-contraction coupling, whereas sarcolemmal excitability seems well preserved. Our results also emphasise the role of central activation failure as a possible mechanism contributing to the torque loss observed in knee extensors. Physical conditioners should consider these effects when defining their training programs for squash players. |
Identificador |
http://serval.unil.ch/?id=serval:BIB_F648846495AD isbn:1878-1861[electronic] pmid:19231287 doi:10.1016/j.jsams.2008.11.002 |
Idioma(s) |
en |
Fonte |
Journal of Science and Medicine In Sport / Sports Medicine Australia, vol. 13, no. 1, pp. 172-177 |
Palavras-Chave | #Adult; Electromyography; Exercise Test; Humans; Knee Joint/physiology; Male; Muscle Contraction/physiology; Muscle Fatigue/physiology; Muscle, Skeletal/physiopathology; Neuromuscular Junction/physiopathology; Racquet Sports/physiology; Tremor/physiopathology; Young Adult |
Tipo |
info:eu-repo/semantics/article article |