What muscle is the primary one targeted in a pull up?

Answer 1

The traditional pull up is a so-called `compound` exercise, which means it targets most of the muscle groups of the upper body (so basically it trains your entire upper body fairly equally). In my experience though, the muscles which grew tired the most after every pull up workout and in long-term grew the most were the obliques and shoulder muscles.

Answer 2

It depends on the grip you use. Palms away from body and wide grip targets back and shoulders. Palms facing you with wide grip targets chest and close grip targets biceps.