Alteration of neuromuscular function in squash


Autoria(s): Girard O.; Micallef J.P.; Noual J.; Millet G.P.
Data(s)

2010

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