Miyaguchi Shota, Kojima Sho, Kirimoto Hikari, Tamaki Hiroyuki, Onishi Hideaki
Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata, Japan.
Front Hum Neurosci. 2016 Apr 29;10:159. doi: 10.3389/fnhum.2016.00159. eCollection 2016.
We conducted two experiments to determine how differences in muscle contraction levels, muscle contraction types, and movement duration affect degree of post-exercise depression (PED) after non-exhaustive, repetitive finger movement. Twelve healthy participants performed repetitive abduction movements of the right index finger at 2 Hz. In experiment 1, we examined the effects of muscle contraction levels at 10, 20, and 30% maximum voluntary contraction and the effects of muscle contraction types at isotonic and isometric contraction. In experiment 2, we examined the effects of movement duration at 2 and 6 min. Motor-evoked potentials (MEPs) were recorded from the right first dorsal interosseous muscle before movement tasks and 1-10 min after movement tasks. MEP amplitudes after isotonic contraction tasks were significantly smaller than those after isometric contraction tasks and decreased with increasing contraction levels, but were independent of movement duration. This study demonstrated that the degree of PED after non-exhaustive repetitive finger movement depended on muscle contraction levels and types. Thus, the degree of PED may depend on the levels of activity in the motor cortex during a movement task. This knowledge will aid in the design of rehabilitation protocols.
我们进行了两项实验，以确定在非疲劳性重复性手指运动后，肌肉收缩水平、肌肉收缩类型和运动持续时间的差异如何影响运动后抑郁程度（PED）。12名健康参与者以2赫兹的频率进行右手食指的重复性外展运动。在实验1中，我们研究了最大自主收缩的10%、20%和30%时的肌肉收缩水平的影响，以及等张收缩和等长收缩时的肌肉收缩类型的影响。在实验2中，我们研究了2分钟和6分钟运动持续时间的影响。在运动任务前以及运动任务后1至10分钟，从右手第一背侧骨间肌记录运动诱发电位（MEP）。等张收缩任务后的MEP波幅显著小于等长收缩任务后的MEP波幅，且随收缩水平的增加而降低，但与运动持续时间无关。本研究表明，非疲劳性重复性手指运动后的PED程度取决于肌肉收缩水平和类型。因此，PED程度可能取决于运动任务期间运动皮层的活动水平。这一知识将有助于康复方案的设计。
