Yoneda T, Oishi K, Fujikura S, Ishida A
Brain Res. 1986 Apr 30;372(1):89-94. doi: 10.1016/0006-8993(86)91461-7.
The motor unit discharges in human hand muscles were recorded during voluntary isometric contraction. Bipolar wire electrodes were inserted in the right adductor pollicis muscle (AP) and first dorsal interosseous muscle (FDI) for the recordings. Motor unit activities from these muscles were investigated when subjects exerted voluntary force to each target force at various speeds. On 27 motor units of AP and 28 motor units of FDI, ramp RTF and ballistic RTF were compared. Furthermore, RTF changes of motor units with the different force speeds were investigated. It is clear that the RTF of the motor units during ballistic contractions were lower than those during ramp contraction. The processes of motor unit RTF changes were classified into 3 types: RTF of type I motor units were relatively low and decreased slightly even when force speed increased widely; RTF of type II motor units were relatively high and decreased irregularly; and RTF of type III motor units, which appeared rarely, decreased their relatively high RTF with increases of force speed increment. It is suggested that the volitional outflow related with the force speed change to the spinal motor pool might cause the different RTF change effects in the various motor units.
在自愿等长收缩过程中记录了人类手部肌肉的运动单位放电情况。将双极线状电极插入右手拇收肌（AP）和第一背侧骨间肌（FDI）进行记录。当受试者以不同速度向每个目标力施加自愿力量时，研究了这些肌肉的运动单位活动。对AP的27个运动单位和FDI的28个运动单位比较了斜坡反应时间（RTF）和弹道反应时间。此外，还研究了不同力速下运动单位的RTF变化。很明显，弹道收缩期间运动单位的RTF低于斜坡收缩期间的RTF。运动单位RTF变化过程分为3种类型：I型运动单位的RTF相对较低，即使力速大幅增加也略有下降；II型运动单位的RTF相对较高且不规则下降；III型运动单位很少出现，随着力速增加，其相对较高的RTF下降。提示与力速变化相关的意志性传出至脊髓运动池可能在不同运动单位中引起不同的RTF变化效应。
