HOS-N24 Seated Leg Curl To perform the seated leg curl, you start by adjusting the machine according to your height and comfort level. Once properly set up, you sit on the machine with your back against the backrest and your legs extended in front of you. Your ankles should be resting against the padded lever of the machine. To begin the exercise, you contract your hamstrings to pull the lever towards your buttocks, bending your knees in the process. Slowly return to the starting position and repeat for the desired number of repetitions.