Alteration of neuromuscular function in squash
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- 作者：Olivier Girard ; Jean-Paul Micallef ; Julien Noual ; Gré ; goire P. Millet
- 关键词：Central activation ; EMG ; Neuromuscular fatigue ; Racquet sports ; Twitch
- 刊名：Journal of Science and Medicine in Sport
- 出版年：2010
- 出版时间：January 2010
- 年：2010
- 卷：13
- 期：1
- 页码：172-177
- 全文大小：192 K
文摘
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 N m, −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.