Acceptability of Intermittent Handgrip Contractions Based on Physiological Response
研究了7名男性进行不同间歇模式的等长握拳运动时的生理反应，发现基于疲劳和恢复时间可判断运动可接受性，间歇收缩强度≥17%最大随意收缩或持续收缩≥10%时不可接受。
Our aim was to study physiological response and acceptability of intermittent muscle contractions. Seven male subjects performed eight isometric handgrip exercises with altered contraction-relaxation periods but identical tension-time products. Local blood flow (BF), heart rate, blood pressure, electromyography, maximal voluntary handgrip contraction (MVC), and venous concentration of potassium and lactate of both forearms were followed during and up to 24 hours after the exercises. Wrist force response to electrical stimulation of a forearm muscle was used to investigate low-frequency fatigue (LFF). Ratings of perceived exertion were recorded during exercise. LFF was associated with a decreased functional capacity, which may be explained by a net potassium loss. Recovery BF was linearly related to mean contraction intensity of the experiments. Physiological criteria for acceptability of isometric exercise are suggested, based on the absence of fatigue during exercise and the return to baseline values within four hours of the recovery period. Based on these physiological criteria, intermittent handgrip contractions at (or higher than) a mean contraction intensity of 17% MVC and continuous handgrip contractions at (or higher than) 10% MVC were considered unacceptable.