Graduate School of Education, Naruto University of Education, Naruto, Japan.
Hum Mov Sci. 2010 Jun;29(3):339-48. doi: 10.1016/j.humov.2009.11.006. Epub 2010 May 5.
The present study examined the control of force and timing during periodic isometric force production of the right index finger. Ten right-handed male participants performed three tasks cycling between lower levels (5-40%) of maximum voluntary force with a target peak-to-peak or valley-to-valley interval of 500 ms. The analysis showed that the valley force was markedly more variable than the peak force over all tasks. Participants further exhibited a greater magnitude of negative constant error at the target valley force than at the target peak force, indicating that decreasing isometric force to achieve the lower force goal resulted in underachievement of force production. This study thus confirmed that decreasing isometric force to achieve the lower force goal results in greater force variability and revealed that the linear relationship between force level and variability does not hold at lower force levels. On the other hand, the valley-to-valley interval was more variable than the peak-to-peak interval, indicating that switching from increasing force to decreasing force produced higher timing variability than switching in the opposite direction.
本研究考察了右食指周期性等长力产生过程中的力和时间控制。10 名右利手男性参与者完成了三个任务，即在最大自主力的较低水平（5-40%）之间循环，目标峰峰值或谷谷值间隔为 500 毫秒。分析表明，在所有任务中，山谷力的变异性明显大于峰值力。参与者在目标山谷力处表现出比目标峰值力更大的负常误，这表明为了达到较低的力目标而降低等长力会导致力产生的不足。因此，本研究证实，为了达到较低的力目标而降低等长力会导致更大的力变异性，并揭示了力水平和变异性之间的线性关系在较低力水平下并不成立。另一方面，谷谷值间隔比峰峰值间隔更具变异性，这表明从增加力切换到减小力产生的定时变异性高于相反方向的切换。
