期刊
JOURNAL OF APPLIED PHYSIOLOGY
卷 100, 期 4, 页码 1361-1369出版社
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/japplphysiol.00945.2005
关键词
maximal voluntary contraction; hyperthermia; fatigue; neuromuscular activation; triceps surae
Fatigue during hyperthermia may be due in part to a failure of the central nervous system to fully activate the working muscles. We investigated the effects of passive hyperthermia on maximal plantar flexor isometric torque ( maximal isometric voluntary contraction) and voluntary activation to determine the roles of local skin temperature, core temperature, and peripheral muscle temperature in fatigue. Nine healthy subjects were passively heated from 37.2 to 39.5 degrees C ( core temperature) and then cooled back down to 37.9 degrees C using a liquid-conditioning garment, with the right leg kept at a thermoneutral temperature throughout the protocol, whereas the left leg was allowed to heat and cool. Passive heating resulted in significant decreases in torque from [mean (SD)] 172 N center dot m (SD 39) to 160 N center dot m (SD 44) and in voluntary activation from 96% (SD 2) to 91% (SD 5) in the heated leg, and maximal isometric voluntary contraction decreased similarly from 178 N center dot m (SD 37) to 165 N center dot m (SD 38) and voluntary activation from 97% (SD 2) to 94% (SD 5) in the thermoneutral leg. The initiation of cooling, which produced a rapid decrease in skin temperature and cardiovascular strain [heart rate reserve decreased from 58% (SD 12) to 31% (SD 12)], did not immediately restore either torque or voluntary activation. However, when core temperature was lowered back to normal, torque and voluntary activation were restored to baseline values. It was concluded that an increase in core temperature is a factor responsible for reducing voluntary activation during brief voluntary isometric contractions and that temperature-induced changes in the contractile properties of muscle and local thermal afferent input from the skin do not contribute significantly to the decrement in torque.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据