A pull-up is an upper-body strength exercise. The pull-up is a closed-chain movement where the body is suspended by the hands and pulls up. As this happens, the elbows flex and the shoulders adduct and extend to bring the elbows to the torso.
The term chin-up, traditionally referring to a pull-up with the chin brought over the top of a bar, was used in the 1980s to refer to a pronated, or overhand, grip, with a supinated, or underhand, grip being called a "reverse-grip" chin-up. [1][2][3][4] In later decades, this usage has inverted, with some using "chin-up" to refer to a pull-up done with a supinated hand position[5], while "pull-up" refers specifically to the exercise done with a pronated hand position.[6]
Pull-ups use many different muscles of the upper body, including the latissimus dorsi and the biceps brachii.[7]
