A pull-up is a kind of exercise that uses the weight of the body (body weight) to make a person stronger. To do this exercise one holds something that is high above the head with both hands so their body is hanging free under it. Then one pulls oneself up and stops when the chin is above the hands. This mostly helps the back muscles but also uses the muscles on top of the arms (biceps) and stomach (abdominals). It is an exercise that does not need any special equipment except something high that a person can hold on to.