Department of Life Science, The University of Tokyo, Meguro, Tokyo, Japan.
J Musculoskelet Neuronal Interact. 2023 Mar 1;23(1):84-89.
The purpose of this study was to investigate the effect of relaxation time on tendon hysteresis.
Subjects exerted isometric plantar flexion torque from rest to maximal voluntary isometric contractions within around 0.5 s, followed by relaxation with six different times (0.3, 0.5, 0.7, 1, 3, and 5 s). During each trial, tendon elongation in the medial gastrocnemius muscle was measured by ultrasonography. The area within the exerted torque-tendon elongation loop, as a percentage of the area beneath the curve during ascending phase, was calculated as tendon hysteresis.
Between the 0.3 and 1 s relaxation time conditions, the hysteresis values were significantly greater for the shorter relaxation time conditions (except between the 0.5 and 0.7 s conditions). In contrast, no significant differences in tendon hysteresis were found between 1 and 5 s of relaxation time conditions. Furthermore, the relationship between relaxation time and tendon hysteresis showed a significantly negative correlation under 1 s or less of relaxation time, but no significant correlation was observed under conditions of 1 s or more.
These results suggest that relaxation time greatly affects tendon hysteresis under condition that relaxation time was less than 1 s.
本研究旨在探讨弛豫时间对肌腱滞后的影响。
受试者在大约 0.5 秒内从休息状态到最大随意等长收缩状态下进行等长足底屈肌扭矩，然后以六种不同时间（0.3、0.5、0.7、1、3 和 5 秒）进行放松。在每次试验中，通过超声测量内侧腓肠肌中的肌腱伸长。将施加扭矩-肌腱伸长环内的面积，作为上升阶段曲线下面积的百分比，计算为肌腱滞后。
在 0.3 和 1 秒弛豫时间条件之间，较短弛豫时间条件下的滞后值显著更大（0.5 和 0.7 秒条件之间除外）。相比之下，在 1 和 5 秒的弛豫时间条件之间，肌腱滞后没有显著差异。此外，在弛豫时间小于 1 秒的情况下，弛豫时间与肌腱滞后之间的关系呈显著负相关，但在 1 秒或更长时间的条件下没有观察到显著相关性。
这些结果表明，在弛豫时间小于 1 秒的情况下，弛豫时间会极大地影响肌腱滞后。
