Hang from a chin-up bar with your legs and feet together using an overhand grip (palms facing away from you) that is slightly wider than shoulder width. Tip: You may use wrist wraps in order to facilitate holding on to the bar.
Now bend your knees at a 90 degree angle and bring the upper legs forward so that the calves are perpendicular to the floor while the thighs remain parallel to it. This will be your starting position.
Pull your legs up as you exhale until you almost touch your shins with the bar above you. Tip: Try to straighten your legs as much as possible while at the top.
Lower your legs as slowly as possible until you reach the starting position. Tip: Avoid swinging and using momentum at all times.
Repeat for the recommended amount of repetitions.
Variations: You can perform this exercise with ankle weights in order to make it more challenging.