Effects of Concentric and Eccentric Strength Training on Fatigue Induced by Concentric and Eccentric Exercises

Purpose : To compare the concentric and eccentric training effects on fatigue induced by eccentric and concentric protocols. Methods : A total of 22 men and women (22 [3.6] y) were assigned to concentric (GCON, n = 11) or eccentric training (GECC, n = 11). The concentric (CON) and eccentric (ECC) protocols were composed of 4 sets of 20 knee-extension/flexion repetitions. Force losses were analyzed by comparing 10 repetitions’ mean torques during the protocols and by verifying the maximal voluntary contraction and rate of torque development before and after the protocols. Muscle damage was assessed using echo intensity of the vastus lateralis 48 h after the protocols. Training consisted of 6 wk of isokinetic exercise at 60°/s (concentric or eccentric) twice weekly. Results : Before training, both protocols resulted in dynamic and isometric force losses in GCON and GECC ( P