Interaction of Central and Peripheral Factors during Repeated Sprints at Different Levels of Arterial O2 Saturation
Interaction of Central and Peripheral Factors during Repeated Sprints at Different Levels of Arterial O2 Saturation
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DOI：
10.1371/journal.pone.0077297
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发表时间：
2013-10-14
期刊：
影响因子：
3.7
通讯作者：
Bishop, David J.
中科院分区：
文献类型：
--
作者：
Billaut, Francois;Kerris, Jarrod P.;Bishop, David J.
目的：探讨重复冲刺运动 (RSE) 期间外周运动肌疲劳、肌肉募集和表现之间的相互作用。方法：在单盲、随机和交叉设计中，10 名男性团体运动运动员在常氧和急性中度缺氧 (FIO2 0.138) 下进行了两次 RSE（15 次 5 秒的自行车冲刺，中间有 25 秒的休息；功率自行选择）。每次冲刺都计算机械功、总肌电强度（股四头肌肌电图总和，RMSsum）和肌肉（股外侧肌）和前胎儿皮层近红外光谱 (NIRS) 参数。在整个方案中测量血乳酸浓度（[Lac(-)]）。通过运动前与运动后对超最大磁股神经刺激的增强股四头肌抽搐力 (Delta Q(tw,pot)) 的变化来评估周围股四头肌疲劳。中枢激活率（Q（CAR））用于量化股四头肌激活的完整性。结果：与常氧相比，缺氧降低了动脉氧饱和度（-13.7％，P=0.001）、股四头肌RMSsum（-13.7％，P=0.022）、Q（CAR）（-3.3％，P=0.041）和总机械功（-8.3％， P=0.019）。然而，RSE 引起的股四头肌疲劳程度在两种情况下相似（Delta Q(tw),(pot)：-53.5% 和 -55.1%，P=0.71）。尽管代谢（肌肉 NIRS 参数和血液 [Lac(-)]）和功能（抽搐和 M 波）肌肉状态相似，但缺氧时的骑行表现较低。 结论：结果表明，中枢神经系统调节股四头肌的募集，从而限制间歇性短冲刺期间肌肉疲劳的发展。这一发现强调了冲刺运动期间肌肉扰动和神经调整之间复杂的相互作用，并进一步支持间歇冲刺运动期间起搏的存在。
Purpose: To investigate the interaction between the development of peripheral locomotor muscle fatigue, muscle recruitment and performance during repeated-sprint exercise (RSE).Method: In a single-blind, randomised and cross-over design, ten male team-sport athletes performed two RSE (fifteen 5-s cycling sprints interspersed with 25 s of rest; power self-selected) in normoxia and in acute moderate hypoxia (FIO2 0.138). Mechanical work, total electromyographic intensity (summed quadriceps electromyograms, RMSsum) and muscle (vastus lateralis) and pre-fontal cortex near-infrared spectroscopy (NIRS) parameters were calculated for every sprint. Blood lactate concentration ([Lac(-)]) was measured throughout the protocol. Peripheral quadriceps fatigue was assessed via changes in potentiated quadriceps twitch force (Delta Q(tw,pot)) pre- versus post-exercise in response to supra-maximal magnetic femoral nerve stimulation. The central activation ratio (Q(CAR)) was used to quantify completeness of quadriceps activation.Results: Compared with normoxia, hypoxia reduced arterial oxygen saturation (-13.7%, P=0.001), quadriceps RMSsum (-13.7%, P=0.022), Q(CAR) (-3.3%, P=0.041) and total mechanical work (-8.3%, P=0.019). However, the magnitude of quadriceps fatigue induced by RSE was similar in the two conditions (Delta Q(tw),(pot):-53.5% and -55.1%, P=0.71). The lower cycling performance in hypoxia occurred despite similar metabolic (muscle NIRS parameters and blood [Lac(-)]) and functional (twitch and M-wave) muscle states.Conclusion: Results suggest that the central nervous system regulates quadriceps muscle recruitment and, thereby, performance to limit the development of muscle fatigue during intermittent, short sprints. This finding highlights the complex interaction between muscular perturbations and neural adjustments during sprint exercise, and further supports the presence of pacing during intermittent sprint exercise.