Fitts R H, Holloszy J O
Am J Physiol. 1977 Sep;233(3):C86-91. doi: 10.1152/ajpcell.1977.233.3.C86.
The effects of exercise training and fatique on the contractile properties of rat soleus muscles have been investigated. Prolonged exercise, consisting of 2 h or daily treadmill running, induced small but significant decrease in contraction time, one-half relaxation time, and maximum tetanic tension (Po), and increase in the peak rate of tension development (dP/dt) during a twitch, and an increase in maximum shortening velocity (Vmax). The 20% increase in Vmax was proportional to the previously reported increase in actomyosin ATPase induced by 2 h of daily running. These results indicate that prolonged training can induce modifications of the neurally determined contractile properties of skeletal muscle. To investigate the effects of fatigue, soleus muscles were stimulated in situ with 250-ms trains of 100 Hz at a rate of 110 trains per minute for 30 min. This resulted in a 32% decrease in Po, a 48% decline in peak tetanic dP/dt, and a 12% decrease in Vmax in muscles of untrained animals. Muscles that had adapted to exercise were significantly protected against the decrease in Po (only an 8% decrease) and Vmax (no significant decrease) but not against the decline in peak dP/dt.
已经研究了运动训练和疲劳对大鼠比目鱼肌收缩特性的影响。持续运动，包括每天2小时的跑步机跑步，导致收缩时间、半松弛时间和最大强直张力（Po）出现微小但显著的下降，单收缩期间张力发展的峰值速率（dP/dt）增加，以及最大缩短速度（Vmax）增加。Vmax增加20%与先前报道的每天跑步2小时诱导的肌动球蛋白ATP酶增加成比例。这些结果表明，长期训练可诱导骨骼肌神经决定的收缩特性发生改变。为了研究疲劳的影响，比目鱼肌在原位以每分钟110次的频率用100 Hz的250毫秒串刺激30分钟。这导致未训练动物肌肉的Po下降32%，强直峰值dP/dt下降48%，Vmax下降12%。适应运动的肌肉对Po下降（仅下降8%）和Vmax下降（无显著下降）有显著的保护作用，但对峰值dP/dt下降没有保护作用。
