<P> It is a form of pull - up in which the range of motion is established in relation to a person's chin . </P> <P> In the 1970s and 1980s, the term chin - up not only included an overhand / pronated ("palms away") grip, but some authors used it as the default meaning of the term, with an underhand / supinated ("palms toward") grip called a "reverse" grip . Even in the 2010s "chin - up" still includes palms - away lifting . The term "chin - up" is still regularly used refer to pulling using an overhand - grip . </P> <P> Both pull - ups and chin - ups are among the best exercises for back and overall upper body conditioning . However, they target the muscles a bit differently . Both exercises will work the latissimus dorsi and biceps, but standard chin - ups--with an underhand grip--place more emphasis on the biceps . </P> <P> A chin - up is named by bringing the chin up through space, specifically in relation to its position with the bar or other hand grips . This can be either touching the bar (more easily done by extending the neck, though that could be considered cheating) or by bringing the chin over the bar . This exercise is easier for males than females because of the male tendency to have stronger and larger biceps . </P>

What is the origin of the primary muscle used in a chin up