The pullup is a closed kinetic chain calisthenic upperbody exercise that works the Latissimus Dorsi and biceps muscles primarily, as well as several other muscles, such as the midsection. It is considered the gold standard for working the back (for bodyweight). The pullup utilizes a pronated, or overhand, grip, as opposed to the chinup which is similar in nature but utilizes a supinated (underhand) grip.