Effect of Contraction Velocity of Eccentric Exercise-Induced Muscle Damage on Running Economy in Trained Young Females

Purpose: Unique activation strategy of eccentric contraction predisposes the muscle to damage. Type II muscle fibers are more susceptible to muscle damage, therefore, it seems that velocity interferes in mechanical stress and muscle damage. The purpose of this study was to investigate the effect of contraction velocity of eccentric exercise- induced muscle damage of dominant knee extensor on running economy in trained young females. Methods: Sixteen trained young females randomly assigned into two groups: high velocity (240°.s-1) and low velocity (60°.s-1). In order to induce muscle damage, subjects in high and low velocity groups performed 20 and 5 sets of 15 eccentric contractions respectively, with a load equal to 150Ua of the maximal voluntary isometric torque (MVIT) of dominant knee extensors. Muscle damage indices (MVC, perceived pain, thigh circumference) were recorded before, 1 and 48 hours and running economy were recorded 24 h before and 48 h after eccentric exercise. Statistical analysis was performed with SPSS16, using the between-subject repeated-measures ANOVA, independent t-test and Mann-Whitney U test. Results: All muscle damage indicators significantly changed one and 48 hours after damage in both groups (p<0.05) in a way suggestive of muscle damage. There were no significant differences for any of the muscle damage indicators (except perceived pain) and running economy at different running intensity between groups. Conclusion: With regard to the same tension time in muscle, contraction velocity (Four-fold difference) of eccentric exercise-induced muscle damage of dominant knee extensor was not a determining factor of changes in running economy in trained young females.