The motor control and muscle activities during the voluntary rhythmic movement task

为了解站立过程中的运动控制，本研究采用视觉引导跟踪任务，在测力平台上对健康青少年和老年人的下肢运动性能和肌肉活动进行了研究。运动任务的运动方向、幅度和速度对运动成绩有影响。特别是运动成绩与运动速度之间存在U型关系，两组均存在最佳运动速度。年龄差异被证实在肌肉活动的膝屈肌，这是双关节肌肉。这表明，双关节肌肉功能的丧失可能会缩小老年人的姿势策略的选择范围。

To understand the motor control during standing, this study investigated the motor performance and muscle activities of lower limbs in healthy youths and elders by using the visually guided tracking task on the force platform. The motor performance was influenced by the movement direction, the amplitude and the velocity of the motor task. Especially, there was the U shape relation between the motor performance and the motor velocity, and the optimum motor velocity for the motor task was shown in both groups. Age differences were confirmed in muscle activities of knee flexors which were biarticular muscles. This suggested that the functional loss of biarticular muscles might narrow elder's range of choice for the postural strategy by aging.