Seidler-Dobrin R D, He J, Stelmach G E
Motor Control Laboratory, Arizona State University, Tempe, AZ 85287, USA.
Motor Control. 1998 Oct;2(4):314-30. doi: 10.1123/mcj.2.4.314.
The aim of this experiment was to determine whether elderly persons exhibit reciprocal phasing of muscle activity and scale EMG burst amplitude in the same manner as young people. Seven young and 7 elderly adults performed 30( elbow flexion movements at 800 ms duration to a visual target against varying inertial loads. The elderly were not able to achieve the required movement duration as frequently and spent a greater portion of the movement accelerating than the young. The young and the elderly subjects scaled EMG burst amplitude to the increasing loads in the same fashion, although the elderly subjects coactivated the agonist/antagonist muscles more than did the young subjects and thus did not accelerate the limb as rapidly. We hypothesized that the elderly used coactivation to reduce movement variability, and we developed a single-joint model with two muscles to examine this hypothesis. The model simulation correctly predicted the variability reduction due to coactivation. It appears, however, that this reduces the capability to accelerate rapidly.
本实验的目的是确定老年人是否与年轻人一样表现出肌肉活动的相互相位变化以及按比例调整肌电图爆发幅度。7名年轻人和7名老年人针对不同的惯性负荷，在800毫秒的持续时间内朝着视觉目标进行了30次肘部弯曲运动。老年人无法像年轻人那样频繁地达到所需的运动持续时间，并且在运动加速阶段所花费的时间比例比年轻人更大。尽管老年受试者比年轻受试者更多地共同激活了主动肌/拮抗肌，因此肢体加速没有那么快，但年轻和老年受试者以相同的方式按比例调整肌电图爆发幅度以应对增加的负荷。我们假设老年人通过共同激活来减少运动变异性，并开发了一个具有两块肌肉的单关节模型来检验这一假设。模型模拟正确地预测了由于共同激活导致的变异性降低。然而，这似乎降低了快速加速的能力。
