Eccentric training

Patent Granted Eccentric training is defined as active contraction of a muscle occurring simultaneously with lengthening of the muscle. For example, in a biceps curl the action of lowering the dumbbell back down from the lift is the eccentric phase of that exercise — as long as the dumbbell is lowered slowly rather than letting it drop (i.e., the biceps are in a state of contraction to control the rate of descent of the dumbbell).