Activation of Human Stretch Reflex by Experimental Muscle Pain.

, Sohn, Min Kyun; , Cho, Kang Hee; , Lee, Hye Jin

Original Article

Journal of the Korean Academy of Rehabilitation Medicine 2004;28(3):240-246.

Sohn, Min Kyun , Cho, Kang Hee , Lee, Hye Jin

Department of Rehabilitation Medicine, Chungnam National University College of Medicine, Korea. milkycat7@hanmail.net

실험적 근육통에 의한 신장반사의 증가

손민균, 조강희, 이혜진

충남대학교 의과대학 재활의학교실

Abstract

Objective
This study was performed to investigate the effect of experimental muscle pain on the stretch reflex through electrophysiologic measuring of H-reflex and ankle tendon reflex.
Method
Muscle pain was produced by the continuous infusion of 5% hypertonic saline into the soleus and tibialis anterior muscles respectively in the fourteen healthy, male volunteers. Control was made with infusion of 0.9% isotonic saline. H-reflex and ankle tendon reflex were recorded at the soleus before, during and 30 minutes after infusion of saline.
Results
The amplitude of ankle tendon reflex increasedsignificantly during soleus and tibialis anterior muscle pain by the infusion of hypertonic saline as compared with those of before and after injection. But the H-reflex showed no significant changes during the infusion in either muscles.
Conclusion
These results have demonstrated a muscle pain increased the amplitude of the stretch reflex without a corresponding increase of the H-reflex amplitude. One explanation could be an increased dynamic sensitivity of the muscle spindles during muscle pain caused by an increased firing of the dynamic γ-motor neurons. (J Korean Acad Rehab Med 2004; 28: 240-246)

Key Words: Stretch reflex, H-reflex, Ankle tendon reflex, Experimental muscle pain