Beginning by hanging from the bar, the body is pulled up vertically. From the top position, the participant lowers their body until the arms and shoulders are fully extended. Pull-ups are a
closed-chain, compound movement involving
flexion at the elbow and adduction or extension of the
shoulder joint. The
trapezius,
infraspinatus, and
brachialis muscles are most active at the beginning of the pull-up; the
latissimus dorsi,
teres major, and
biceps brachii reach peak activity during the middle of the movement, and the
triceps brachii and
subscapularis experienced maximum activity at the top of the movement. Muscle activation is significantly different depending on whether the pull-up is completed individually or in a set without resting between repetitions, which is more efficient due to muscle and tendon stretch-shortening rebound. Overhead movements such as pull-ups reduce the subacromial space and create a risk of
shoulder impingement. According to one study, the pronated grip pull-up with hands at shoulder width apart led to less risk of impingement than other variations studied. ==Variations==