Strong legs are important for walking, climbing stairs and sports activities. The hamstring muscles -- located along the back of your thighs -- move your hips backward and bend your knees. The hamstrings consist of three separate muscles -- semitendinosus, semimembranosus and biceps femoris. Standing leg curls strengthen your hamstrings, targeting the lower part of the muscle that bends your knee. Perform standing leg curls at home to strengthen knee flexion.
Stand facing the back of a chair with your feet shoulder-width apart. Hold the back of the chair with one or both hands to maintain your balance.
Bend your right knee and lift your heel up toward your buttock. Hold for two to three seconds, then lower back down.
Repeat 10 leg curls on each side. Work up to three sets of 10 repetitions. As strength improves, add ankle cuff weights to increase resistance.