2017 年 17 巻 p. 55-62
Acupuncture stimulation suppresses some proprioceptive reflexes, such as the stretch reflex. On the other hand, the stretch reflex plays a certain role during movements utilizing the stretch-shortening cycle (SSC). This study evaluated the degree to which acupuncture stimulation impacts the ability to perform SSC movements. The subjects were 11 young males who were subjected to low-frequency electroacupuncture (2 Hz, 15 min.) of the triceps surae muscle, randomly selecting between the left and the right side. Immediately before, immediately after, and 1, 24, 48, and 72 hours after, the subjects performed five single-legged rebound jumps (RJ), and we calculated an RJ index (jump height/ground contact time). At the same time, we also measured the range of ankle dorsiflexion, the muscle stiffness of the medial and lateral head gastrocnemius muscles (medial and lateral muscle stiffness), and subjective sensations according to a visual analogue scale (VAS). The measurements were performed bilaterally (stimulated side and non-stimulated side). In any of the measured variables, no interaction was observed between which side was stimulated and the measurement opportunity. We performed Dunnett's method of multiple comparisons for the stimulated side and the non-stimulated side. As a result, on the stimulated side we found a significant decrease immediately before and immediately after stimulation in the RJ index and the medial and lateral muscle stiffness. In addition, we found a similarly significant increase in the sense of discomfort according to a VAS. On the non-stimulated side, we found a similar difference only in the medial muscle stiffness. Consequently, this suggested that the timing of clinical implementation of acupuncture therapy requires consideration.