Repeated bouts of fast eccentric contraction produce sciatic nerve damage in rats.

ABSTRACT

INTRODUCTION: We evaluated sciatic nerve impairment after eccentric contractions (ECs) in rat triceps surae. METHODS: Wistar rats were randomly assigned to different joint angular velocity 180°/s (FAST), 30°/s (SLOW), or nontreated control (CNT). FAST and SLOW groups were subjected to multiple (1-4) bouts of 20 (5 reps, 4 sets) ECs. Nerve conduction velocity (NCV) and isometric tetanic ankle torque were measured 24 h after each ECs bout. We also assessed nerve morphology. RESULTS: After 4 ECs bouts, NCVs and isometric torque in the FAST group were significantly lower than those in the CNT (NCV 42%, torque 66%; P < 0.05). After 4 bouts, average nerve diameter was significantly smaller in the FAST group [2.39 ± 0.20 µm vs. 2.69 ± 0.20 µm (CNT) and 2.93 ± 0.24 µm (SLOW); P < 0.05] than that in other two groups. CONCLUSIONS: Chronic ECs with high angular velocity induce serious nerve damage. Muscle Nerve 54 936-942, 2016.