Laboratoire activité physique, performance et santé (EA 4445), université de Pau et des Pays de l'Adour, département STAPS, ZA Bastillac Sud, 65000 Tarbes, France.
Neurophysiol Clin. 2012 Dec;42(6):377-83. doi: 10.1016/j.neucli.2012.08.002. Epub 2012 Sep 2.
This study aim was to compare the effects of unilateral knee extensor fatigue induced by electrically stimulated (ES) and voluntary (VOL) contractions on postural control during bipedal stance.
Seventeen healthy active males (21.5±2 years) completed these two fatiguing exercises of the quadriceps femoris muscle. Both exercises were of equal duration (130 repetitions of 5 seconds, each separated by a rest period of 2 seconds) and intensity (20% isometric maximal voluntary contraction [MVC]). Both MVC and postural control were recorded using an ergometer and a force platform that registered the centre of foot pressure (COP). We analyzed the spatiotemporal COP parameters (in eyes closed condition) and the spectral power density given by the wavelet transform. Recordings were performed before (PRE condition) and after the completion of each fatiguing task (immediately: POST condition; and after a 5-minute recovery: POST 5 condition).
In the POST and POST 5 conditions, the ES exercise affected MVC more than the VOL exercise but the bipedal postural control was similarly deteriorated for both exercises.
The disturbance of the bipedal postural control after unilateral knee muscle fatigue is not only related to a reduction in muscle strength but also (especially) to an impairment of the effectiveness of sensory inputs. Unilateral knee muscle fatigue induced by ES similarly degrades the bipedal postural control as that induced by VOL, and the duration of the recovery of postural control did not differ between both fatiguing exercises.
本研究旨在比较电刺激（ES）和自主（VOL）收缩引起的单侧膝关节伸肌疲劳对双足站立姿势控制的影响。
17 名健康活跃的男性（21.5±2 岁）完成了这两种股四头肌的疲劳运动。两种运动的持续时间相同（130 次 5 秒，每次休息 2 秒），强度相同（20%等长最大自主收缩[MVC]）。使用测功计和力平台记录 MVC 和姿势控制，力平台记录足底压力中心（COP）。我们分析了在闭眼条件下的 COP 时空参数（spatiotemporal COP parameters）和由小波变换给出的谱功率密度。在每个疲劳任务完成之前（PRE 条件）和之后（立即：POST 条件；5 分钟恢复后：POST 5 条件）进行记录。
在 POST 和 POST 5 条件下，ES 运动对 MVC 的影响大于 VOL 运动，但双足姿势控制在两种运动中都同样恶化。
单侧膝关节肌肉疲劳后双足姿势控制的干扰不仅与肌肉力量的降低有关，而且（特别是）与感觉输入的有效性受损有关。ES 引起的单侧膝关节肌肉疲劳同样会降低双足姿势控制，而两种疲劳运动之间的姿势控制恢复时间没有差异。
