Hamstrings & Deceleration During a Lunge

There are tons of lower body exercises, but few as readily available as the lunge. You can do them with dumbbells, barbells or just your body weight. Lunges use nearly all the muscles of your lower body, but the hamstrings play an important role. The hamstrings let you safely decelerate your body during the lunge. The deceleration phase is what transitions you from lowering to rising out of the lunge.

  1. Hamstring Function

    • The hamstrings are composed of four muscles on the backs of the thighs. The four muscles are the short and long head of the biceps femoris, semitendinosus and semimembranosus. The hamstrings perform knee flexion and hip extension -- bending the knee, moving your leg backward. Because the hamstrings extend over the hip and knee joint, it can perform actions at both joints at the same time. This means the hamstring can shorten at one joint and lengthen at the other during exercises like lunges and squats.

    Lunges Defined

    • The lunge is a basic strength exercise that targets the glutes and the quadriceps, and is dynamically stabilized by the hamstrings. The muscles of your inner thigh, small muscles in your back and even your core contribute to stabilize the motion. To perform the lunge, start with both feet side by side. Take a step forward and let your back knee slowly come toward the ground. Once the the back knee gets close to the ground, push off your front foot to get back to the starting position. Perform the same motion on the opposite leg.

    Hamstring's Slow it Down

    • The hamstring dynamically stabilizes your lunge motion by controlling your hip function during the lunge. The hamstrings slowly lengthen to allow slow deceleration to the bottom position of the lunge. However, this doesn't mean the the hamstrings aren't working. Decelerating an exercise places great strain on the muscle because it uses an eccentric muscle action. An eccentric muscle action is the simultaneous lengthening and contracting of a muscle. This deceleration stress is increased when external weight, like a barbell, is added.

    Lunging for Safety

    • To reduce the likelihood of injury, warm up thoroughly before you begin to exercise. Do five to ten minutes of cardio to build a light sweat and then do some active stretching for your hamstrings, glutes and quadriceps. Drink plenty of water beforehand to prevent cramping and stop if the lunges cause pain. During your lunges, don't let your front knee go over your toes, which can put unnecessary stress on the knee. Also, never use so much weight that it compromises your technique.