Specific effects of eccentric training on muscular fatigability.

This study was designed to test the hypothesis that an eccentric training period induces a reduction of neuromuscular fatigability following an eccentric exercise. Before (Pre-T) and after (Post-T) a 7-wks sub-maximal eccentric training, ten active males performed a fatiguing exercise consisting of five sets of ten maximal eccentric elbow flexions. Before (Pre-T-1 and Post-T-1) and after (Pre-T-2 and Post-T-2) each fatiguing exercise, the voluntary torque and its associated agonistic electromyographic activity (RMS), assessed at four angular velocities (-60 degrees x s (-1); 0 degrees x s (-1); 60 degrees x s (-1); 240 degrees x s (-1)) were measured. The isometric voluntary activation level and twitch contractile properties were measured. The training period induced significant eccentric and isometric torque gains. While isometric and concentric torque decreases were similar Pre-T-2 and Post-T-2, the eccentric torque loss was significantly lower Post-T-2 than Pre-T-2 (-11.7 +/- 10.2 % and -20.5 +/- 6.5 %, respectively; p < 0.05). The reduction of the twitch maximal rate of torque rise was also significantly lower Post-T-2 (-49.4 +/- 11.9 %) than Pre-T-2 (-65.2 +/- 9.8 %) (p < 0.05). The loss of maximal voluntary activation and RMS were similar Pre-T-2 and Post-T-2. The present experiment showed that a 7-wks eccentric training period produced contraction-type specific adaptations that significantly reduced the exercise-induced torque loss during eccentric muscle actions.