Lepers Romuald, Maffiuletti Nicola A, Rochette Ludovic, Brugniaux Julien, Millet Guillaume Y
Groupe Analyse du Mouvement, Faculté des Sciences du Sport, Université de Bourgogne, 21078 Dijon Cedex, France.
J Appl Physiol (1985). 2002 Apr;92(4):1487-93. doi: 10.1152/japplphysiol.00880.2001.
The effects of prolonged cycling on neuromuscular parameters were studied in nine endurance-trained subjects during a 5-h exercise sustained at 55% of the maximal aerobic power. Torque during maximal voluntary contraction (MVC) of the quadriceps muscle decreased progressively throughout the exercise (P < 0.01) and was 18% less at the end of exercise compared with the preexercise value. Peak twitch torque, contraction time, and total area of mechanical response decreased significantly (P < 0.05) after the first hour of exercise. In contrast, changes in M-wave characteristics were significant only after the fourth hour of the exercise. Significant reductions (P < 0.05) in electromyographic activity normalized to the M wave occurred after the first hour for the vastus lateralis muscle but only at the end of the exercise for the vastus medialis muscle. Muscle activation level, assessed by the twitch interpolation technique, decreased by 8% (P < 0.05) at the end of the exercise. The results suggest that the time course is such that the contractile properties are significantly altered after the first hour, whereas excitability and central drive are more impaired toward the latter stages of the 5-h cycling exercise.
在9名耐力训练受试者中，研究了以最大有氧功率的55%持续进行5小时运动期间，长时间骑行对神经肌肉参数的影响。股四头肌最大自主收缩（MVC）时的扭矩在整个运动过程中逐渐降低（P<0.01），与运动前相比，运动结束时降低了18%。运动开始1小时后，单收缩峰值扭矩、收缩时间和机械反应总面积显著降低（P<0.05）。相比之下，M波特征的变化仅在运动4小时后显著。外侧股四头肌在运动开始1小时后，以M波标准化的肌电图活动显著降低（P<0.05），而内侧股四头肌仅在运动结束时显著降低。通过单收缩内插技术评估的肌肉激活水平在运动结束时降低了8%（P<0.05）。结果表明，时间进程如下：在运动开始1小时后，收缩特性显著改变，而在5小时骑行运动的后期，兴奋性和中枢驱动受到的损害更大。
