How to train the subscapularis and why it's important

The subscapularis muscle is the only rotator cuff muscle that's both an internal rotator and posteroinferior translator of the humeral head. It prevents anterior glide and superior motion (impingement) of the shoulder joint. Many either train it wrong by either over-using the pecs and lats, or don't train it at all (e.g if client is already too internally rotated). Both are mistakes! it's important to train all four rotator cuff muscles. Training the subscap will ABSOLUTELY NOT increase postural I.R. The strength of the subscap. should be approximately 13% of 1RM push or pull. For ER, 10% of 1RM push or pull (whichever is strongest). Internal rotation should be approx. 30% stronger than E.R, hence the 13% rather than 10%.