Differences In Which Muscles Get Trained

Again, both exercises will primarily train your back/lats and biceps no matter what. However, there are some slight differences in the degree in which those muscles get trained.

Since chin ups put your biceps in a stronger line of pull, they’ll typically hit your biceps a bit harder than pull ups will.

Conversely, pull ups may hit your lats a bit harder, mostly as a result of your biceps being in a slightly weaker position.

Grip width also plays a role here too. The narrower your grip is, the more it will train your biceps. The wider the grip, the less it will train your biceps.

Now, it was always believed that the difference in lat/biceps usage between pull ups vs chin ups was pretty significant. However, recent EMG testing shows that, while these differences definitely do exist, it’s not that significant and definitely not worthy of being the sole deciding factor in picking one exercise over the other.

I will mention though that if you tend to have a problem actually feeling and using your back during back exercises instead of your biceps, you may benefit from using pull ups instead of chin ups when trying to correct this problem, at least initially.