However, in studies where fast training and testing movements have been performed the evidence supports dynamic training over isometric training. It is difficult to draw any conclusion about one form of resistance training being better than the other with regard to functional performance. Concentric versus Eccentric Resistance Training Upper-body research indicates that eccentric training is superior for developing eccentric strength but there is little evidence to support concentric training being better for developing concentric strength. In the lower body the specificity of training type emerges. Eccentric trains eccentric and concentric trains concentric strength.
Eccentric strength is trained more specifically by eccentric training.
On the other hand, concentric actions are frequently trained and have less room for improvement. That difference could account for the more dramatic effects in eccentric as opposed to concentric training studies. Neither concentric nor eccentric training is superior for developing isometric strength. The two normal mechanisms for strength improvement are classified as hypertrophic or neural. There is insufficient evidence to attribute one or both to observed changes.