Effects of eccentric exercise on different slopes.

Objectives: Eccentric contraction occurs when the muscle lengthens under tension. Damage-induced responses seen in the muscle after eccentric exercise usually experienced by sedentary individuals. This study aims to investigate muscle damage on different slopes.

Methods: 32 male Wistar albino rats randomly divided into four groups: sedentary, horizontal running, and eccentric exercise (-8°, -16°) groups. Animals ran for 90 min with the speed of 25 m/s for five days. After 48h from the last exercise, rats were sacrificed, and plasma creatine kinase (CK), heat shock protein 70 (HSP70) levels were examined. Plasma and soleus total oxidant/antioxidant status (TOS-TAS) and histological changes of soleus muscle assessed.

Results: CK and HSP70 significantly increased in 16° EE group. TOS increased at 16° EE and 8° EE, but oxidative stress index (OSI) was only high at 8° EE group. Mononuclear cell infiltration and the angiogenesis increased in soleus after eccentric exercise, and there was a correlation with slope. Sarcomere breaks were detected in 16° EE group also in a correlation with slope.

Conclusions: Consequently, sedentary individuals are vulnerable to injuries induced by eccentric contraction. Therefore, our study provides information for reconsidering rehabilitation and training programs.