The traditional variation of the standing leg curl requires a cable weight machine, but you can perform the same exercise using ankle weights or a resistance band as long as you're not concerned about building maximal strength. Consult a personal trainer to ensure that you're performing the exercise correctly, and talk to your doctor if you feel any pain during or after a workout.
Anatomy and Biomechanics
The standing leg curl targets the three hamstring muscles -- the biceps femoris, semimembranosus and semitendinosus -- which serve as the major knee flexors. The exercise also works the muscles that assist with knee flexion, including the gastrocnemius, gracilis, popliteus and sartorius. These muscles contract concentrically, as the muscle fibers shorten, during the upward-movement phase of the exercise, and eccentrically, as the fibers lengthen, during the downward-movement phase.
Wear an ankle weight on each leg to perform this variation of the standing leg curl. Stand facing a wall with your feet about 6 inches apart and your toes directed forward. Place your hands on the wall for balance, then flex your left knee, moving your heel toward your buttocks to lift the weight. Reverse to the starting position slowly, then repeat with your right leg. Continue alternating legs for your desired number of repetitions.
Tie one end of a resistance band to a sturdy object near the floor, or have a partner stand on it, and the other end around your left ankle to perform the resistance-band variation of the standing leg curl. Stand facing the object and back away from it until the band is taut, then flex and extend your knee repeatedly, executing the same movement as for the ankle-weight variation. Complete your desired number of repetitions, then switch legs. Place a chair nearby and hold onto it if you have trouble keeping your balance.
Whether you're performing the ankle-weight or resistance-band variations of the standing leg curl, do the exercise at least three times a week. Complete three sets of 10 to 20 repetitions per leg during each session. Increase the amount of resistance progressively if you have a set of ankle weights or resistance bands of varying tensions, but decrease the number of repetitions each time you do so. Start by performing 10 repetitions and gradually add more if you aren't able to increase the resistance. Rest for one to two minutes between sets.