Hirono Tetsuya, Ikezoe Tome, Taniguchi Masashi, Yamagata Momoko, Miyakoshi Kosuke, Umehara Jun, Ichihashi Noriaki
Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan.
Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo, 102-0083, Japan.
Eur J Appl Physiol. 2020 May;120(5):1075-1082. doi: 10.1007/s00421-020-04346-0. Epub 2020 Mar 14.
This study was aimed at determining the relationship between ankle plantar flexor force steadiness and postural control during single leg standing on stable and unstable platforms.
For the thirty-three healthy participants, force steadiness, at target torques of 5%, 20%, and 50% of the maximum voluntary torque (MVT) of the ankle plantar flexors, was measured. Force steadiness was calculated as the coefficient of variation of force. Single leg standing on stable and unstable platforms was performed using the BIODEX Balance System SD. The standard deviation of the anteroposterior center of pressure (COP) displacements was measured as the index for postural control. During both measurements, muscle activities of the soleus were collected using surface electromyography.
On the stable platform, the COP fluctuation significantly correlated with force steadiness at 5% of MVT (r = 0.512, p = 0.002). On the unstable platform, the COP fluctuation significantly correlated with force steadiness at 20% of MVT (r = 0.458, p = 0.007). However, the extent of muscle activity observed for a single leg standing on both stable and unstable platforms was significantly greater than the muscle activity observed while performing force steadiness tasks at 5% and 20% of MVT, respectively.
Postural stability during single leg standing on stable and unstable platforms may be related to one's ability to maintain constant torque at 5% and 20% of MVT regardless of the muscle activity. These results suggest that the required abilities to control muscle force differ depending on the postural control tasks.
本研究旨在确定在稳定和不稳定平台上单腿站立时踝关节跖屈肌力量稳定性与姿势控制之间的关系。
对33名健康参与者，测量踝关节跖屈肌在最大自主扭矩（MVT）的5%、20%和50%目标扭矩下的力量稳定性。力量稳定性计算为力的变异系数。使用BIODEX Balance System SD在稳定和不稳定平台上进行单腿站立。测量前后压力中心（COP）位移的标准差作为姿势控制指标。在两次测量期间，使用表面肌电图收集比目鱼肌的肌肉活动。
在稳定平台上，COP波动与MVT的5%时的力量稳定性显著相关（r = 0.512，p = 0.002）。在不稳定平台上，COP波动与MVT的20%时的力量稳定性显著相关（r = 0.458，p = 0.007）。然而，在稳定和不稳定平台上单腿站立时观察到的肌肉活动程度分别明显大于在MVT的5%和20%时执行力量稳定性任务时观察到的肌肉活动。
在稳定和不稳定平台上单腿站立时的姿势稳定性可能与一个人在MVT的5%和20%时保持恒定扭矩的能力有关，而与肌肉活动无关。这些结果表明，控制肌肉力量所需的能力因姿势控制任务而异。
