Noakes Timothy D
Department of Human Biology, University of Cape Town, Sports Science Institute of South Africa, Cape Town, South Africa.
Sports Med. 2007;37(4-5):374-7. doi: 10.2165/00007256-200737040-00026.
Two popular models hold that performance during exercise is limited by chemical factors acting either in the exercising muscles or in the brain producing either 'peripheral' or 'central' fatigue, respectively. A common feature of both models is that neither allows humans to 'anticipate' what will happen in the future and modify their exercise response accordingly. The peripheral fatigue model predicts that exercise terminates only after there has been catastrophic failure in one or more body systems and only when all the available motor units in the active muscles have been activated. The marathon race provides evidence that human athletes race 'in anticipation' by setting a variable pace at the start, dependent in part on the environmental conditions and the expected difficulty of the course, with the capacity to increase that pace near the finish. Marathoners also finish such races without evidence for a catastrophic failure of homeostasis characterised by the development of a state of absolute fatigue in which all the available motor units in their active muscles are recruited. These findings are best explained by the action of a central (brain) neural control that regulates performance in the marathon 'in anticipation' specifically to prevent biological harm.
两种流行的模型认为，运动表现受化学因素限制，这些化学因素分别作用于运动肌肉或大脑，产生“外周”或“中枢”疲劳。这两种模型的一个共同特点是，它们都不允许人类“预测”未来会发生什么，并相应地调整运动反应。外周疲劳模型预测，只有在一个或多个身体系统发生灾难性故障之后，并且只有当活跃肌肉中所有可用的运动单位都被激活时，运动才会终止。马拉松比赛提供了证据，表明人类运动员在比赛开始时通过设定一个可变的速度“提前预测”比赛，这部分取决于环境条件和赛程的预期难度，并且有能力在接近终点时加快速度。马拉松运动员完成比赛时，也没有证据表明存在内环境稳态的灾难性故障，这种故障表现为出现绝对疲劳状态，即其活跃肌肉中所有可用的运动单位都被募集。这些发现最好用中枢（大脑）神经控制的作用来解释，这种控制专门“提前预测”调节马拉松比赛中的表现，以防止生物损伤。
