Peeters M, Svantesson U, Grimby G
Department of Rehabilitation Medicine, Göteborg University, Sahlgrenska University Hospital, Sweden.
Eur J Appl Physiol Occup Physiol. 1995;71(2-3):272-5. doi: 10.1007/BF00854990.
The influence of different levels of prior isometric muscle action on the concentric torque output during plantar flexion was examined at two angular velocities (60 degrees.s-1 and 120 degrees.s-1) in ten healthy female subjects. The levels of the prior muscle actions were 25%, 50%, 75% and 100% of the maximal voluntary isometric contraction (MVIC). A KINetic-COMmunicator II dynamometer was used to measure torque output during plantar flexion within a range of motion of 78 degrees-120 degrees of the ankle joint. Simultaneous recordings of electromyograms (low-pass filtered and rectified) were obtained from the gastrocnemius medialis muscle and the soleus muscle. Torque-angle curves were made for the plantar flexions using different prior muscle actions. Up to 75% of MVIC, the torque output in the first part of the range of motion increased with the level of the prior isometric muscle action; at higher levels of MVIC the torque did not appear to increase any further. Later in the range of motion, after 24 degrees in the plantar flexion at a velocity of 60 degrees.s-1 and 31 degrees at 120 degrees.s-1, the prior muscle actions had no further influence. No increase was found in the electromyograms, with one exception, during the concentric movements when preceded by higher levels of MVIC. It would seem therefore that the increase in torque output early in the range of motion cannot be explained on the basis of differences in electrical muscle activation in this study.
在10名健康女性受试者中，研究了在两种角速度（60度·秒⁻¹和120度·秒⁻¹）下，不同水平的预先等长肌肉动作对跖屈过程中向心扭矩输出的影响。预先肌肉动作的水平分别为最大自主等长收缩（MVIC）的25%、50%、75%和100%。使用KINetic-COMmunicator II测力计在踝关节78度至120度的运动范围内测量跖屈过程中的扭矩输出。同时记录腓肠肌内侧头和比目鱼肌的肌电图（低通滤波和整流）。利用不同的预先肌肉动作绘制跖屈的扭矩-角度曲线。在达到MVIC的75%之前，运动范围第一部分的扭矩输出随预先等长肌肉动作水平的增加而增加；在更高的MVIC水平下，扭矩似乎不再增加。在运动范围的后期，以60度·秒⁻¹的速度进行跖屈时，在24度之后，以及以120度·秒⁻¹的速度进行跖屈时，在31度之后，预先肌肉动作不再有进一步影响。在较高水平的MVIC之后进行向心运动时，除了一个例外，肌电图没有增加。因此，在本研究中，运动范围早期扭矩输出的增加似乎不能基于肌肉电激活的差异来解释。
