Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, 1398 Shimami-cho, Kita-ku, Niigata, Niigata, 950-3198, Japan.
Exp Brain Res. 2019 Dec;237(12):3409-3417. doi: 10.1007/s00221-019-05689-7. Epub 2019 Nov 14.
Repetitive passive movement (RPM) activates afferent Ia fibers. The input of afferent Ia fibers from antagonist muscle may modulate the extent of spinal reciprocal inhibition (RI). However, effects of RPM on RI remain unknown. We aimed to clarify these effects in 20 healthy adults. Four RPM tasks (40°/s, 80°/s, 120°/s, and 160°/s), with the range of ankle joint movement set to 40°, ranging from 10° in dorsiflexion to 30° in plantar flexion, were performed for 10 min. For measuring RI, a deep peroneal nerve as a conditioning stimulus, tibial nerve as a test stimulus, and three condition-test stimulus intervals (CTIs; single, 2 ms, and 20 ms) were used. The stimulation frequency was 0.3 Hz for 36 times (3 stimulation conditions × 12 sets). RI was measured before, immediately after, and 5, 10, 15, and 20 min (Pre, Post 5, 10, 15, and 20, respectively) after the task. The extent of reciprocal Ia inhibition (CTI 2 ms) significantly increased in Post 5 and 10 at RPM speed of ≥ 120°/s. The extent of D1 inhibition (CTI 20 ms) significantly increased in Post 5 and 10 at RPM speed of ≥ 80°/s, and continued to increase until Post 15 at RPM speed of 160°/s. The extent of RI was the highest at RPM speed of 160°/s for both Ia and D1. Therefore, high RPM may increase the extent of reciprocal Ia inhibition and D1 inhibition, suggesting that rapid movements affect RI by increasing the firing frequency from the muscle spindle to afferent Ia fibers.
反复被动运动（RPM）激活传入 Ia 纤维。来自拮抗肌的传入 Ia 纤维的输入可能调节脊髓交互抑制（RI）的程度。然而，RPM 对 RI 的影响尚不清楚。我们旨在澄清 20 名健康成年人的这些影响。进行了四项 RPM 任务（40°/s、80°/s、120°/s 和 160°/s），踝关节运动范围设定为 40°，从背屈的 10°到跖屈的 30°。进行了 10 分钟。为了测量 RI，使用深腓神经作为条件刺激，胫神经作为测试刺激，以及三个条件-测试刺激间隔（CTI；单、2ms 和 20ms）。刺激频率为 0.3Hz 36 次（3 种刺激条件×12 组）。在任务之前、之后立即以及 5、10、15 和 20 分钟（分别为 Pre、Post 5、10、15 和 20）测量 RI。在 RPM 速度≥120°/s 时，在 Post 5 和 10 时，CTI 2ms 的反向 Ia 抑制程度显著增加。在 RPM 速度≥80°/s 时，在 Post 5 和 10 时，CTI 20ms 的 D1 抑制程度显著增加，并在 RPM 速度为 160°/s 时一直增加到 Post 15。Ia 和 D1 的 RI 程度在 RPM 速度为 160°/s 时最高。因此，高速 RPM 可能会增加反向 Ia 抑制和 D1 抑制的程度，这表明快速运动通过增加来自肌梭的传入 Ia 纤维的发射频率来影响 RI。
