ABSTRACT
Specificity Principle is a widely accepted principle, that suggests that the adaptive effects of training, such as the improvement of strength, power and endurance tend to be highly specific to the training method employed. This principle tells us that the training programe should mimic the mode(Eccentric, Concentric or Isometric) of action at which the desired function works. For example – In quadriceps muscle a negative work has been shown to exist throughout the gait cycle. The only exception being when the knee extends slightly during midstance. As a result of these findings, the quadriceps muscle appears to be functioning primarily via eccentric contractions. So, the therapeutic implications should concentrate mostly on eccentric type of strengthening in quadriceps muscle.