Closed chain hamstring exercises provide a functional way to strengthen the hamstrings. A closed chain exercise means the hand or foot is in constant contact with a surface. Hamstrings are often trained as a knee flexor (bends the knee) with hamstring curls. However, in athletic use (running, jumping or skating), the hamstrings extend the hip. According to Michael Boyle in "Functional Training for Sports," "Hamstrings are only knee flexors in nonfunctional settings. In running, jumping, or skating, the function of the hamstrings and glutes is not to flex the knee but to extend the hip."
Stiff-Leg and Bent-Leg Deadlifts
A balanced hamstring program includes exercises that use straight leg, bent leg and one-leg exercises.
The stiff-leg (or straight-leg) deadlift is done by standing up straight with your feet approximately shoulder width apart and your toes straight ahead. The weight (dumbbells or barbell) is held in front of the body with the palms facing inward. Keeping your shoulders back and your legs straight (do not lock the knees), bend over at the waist pushing the butt back. The back should be straight throughout the exercise. Then, contracting your hamstrings and glutes, straighten your body upwards again.
The bent-leg deadlift starts identically to the stiff-legged deadlift. However, during the descent, you will bend your knees and during the ascent you will straighten the knees back out.
One-leg straight leg deadlifts are important in training the hamstrings since many athletic activities require power from one leg at a time. Examples of this include the push-off phase of running or a lay-up jump in basketball. Besides training the hamstrings, one-leg deadlifts train your balance and should be done first only with body weight and then progressed to add additional weight when you are able to easily do three sets of 12 repetitions. To do a one-leg deadlift, begin by standing with your feet shoulder width apart and your toes straight ahead. Come to a balance on one foot and bend over at the waist reaching your hands down toward the floor. Return to a standing position and do all of the repetitions on one leg and then repeat on the opposite side. As in all deadlifts, the back should always remain straight. If balance is a challenge, you may simply place your foot down in between repetitions.
Stability Ball Hamstring Curls
The stability ball (also know as a gym or Swiss ball) hamstring curl is a closed chain hamstring exercise (despite being a hamstring curl) because your feet are in contact with the ball at all times. Lie down flat on your back with your arms at your sides and your feet placed on top of a stability ball. Squeeze your glutes and raise your hips up off of the floor. Once the hips are lifted, contract your hamstrings and pull the ball in towards you and then roll it back out. This exercise may be progressed to a one leg exercise.
Putting It All Together
These exercises may be done together in one workout or may be alternated within your workout routine. Start with two to three sets of five to 12 repetitions of each exercise using a weight that is challenging, but does not cause you to lose good form.