Gently flex your feet. Contract your abdominals and tuck your hips to press your hipbones into the pad. Exhale as you bend your knees to lift the ankle bar until your calves are perpendicular to the floor. Do not bring the ankle bar all the way to your butt. Hold briefly and then slowly return to starting position.
Squats are also good for the hamstrings.
See description in Glutes section. Stand with feet together, hands holding a dumbbell on each hip. Inhale as you step forward with your right leg and bend your front knee until a 90-degree angle is formed. Keep your knee directly above your toes during the downward movement to avoid overstressing the knee joint. Exhale as you push off your toes to return to starting position.