Keith used to work alongside the late strength and conditioning coach Charles Poliquin, here is his story and some of what he learnt while working with him. Listen to the episode wherever you get your podcast.
This exercise is a MUST for upper back development.
The eccentric supinated chin up has superior mass building qualities and and develops high levels of functional strength. Bring you chin over the bar and hold for 30secs. Then lower yourself in a slow and controlled manner.