The hamstring muscle is composed of three separate muscles (and their associated tendons): the biceps femoris, semitendinosus, and semimembranosus. They are located on the posterior (back) of the upper leg. The hamstrings are attached to the tibia (shinbone). These muscles act on the hip joint and the knee joint. They flex the knee joint and extend the hip, while also adducting the leg.
There are three muscles of the hamstring: the biceps femoris, semitendinosus, and semimembranosus. They are located on the pelvic bone just below the gluteus maximus (the buttock muscle), and extend to the thigh on either side of the back of the knee. The noticeable tendons at the back of the knees are part of the hamstring muscles.
These hamstring muscles are connected to muscles that flex (bend) the knee joint and extend (straighten) the hip when the trunk is stationary. They also medially (inwardly) and laterally (outwardly) rotate the lower leg when the knee is bent. The long head of the biceps femoris extends the hip when a person begins to walk.
These hamstring muscles, all except the short head of the biceps femoris, cross the hip and knee joints. The short head of the biceps femoris crosses only the knee joint. Consequently, this short head does not participate in extending the hip.
There are different types of exercises that benefit the hamstring muscles. Common exercises include:
Hamstring exercises should be performed on a regular basis to help maintain a fit and healthy body. Unfortunately, people in developed countries are not as physically active as they used to be at home, school, and work. Thus, weakness and inflexibility occur much more frequently in their hamstring muscles. Because many people are not involved in labor-intensive jobs (such as farming and manufacturing), but rather sit at a desk for eight hours a day, they do not bend over as much as they used to do. Consequently, the hamstring is not as frequently stretched and strengthened. Exercise experts state that the hamstring muscle should be at least 56%–80% as strong as the quadriceps muscles.
The purpose of the hamstring muscles is primarily to bring the heel of the foot toward the buttocks (called knee flexion) and to move the leg to the rear (hip extension). For movements like walking and running, the hamstring is used to slow down the lower leg. Exercises for the hamstring include the leg curl exercise, which benefits knee flexion, and the deadlift exercise, which helps hip extension. Exercising of the hamstring muscle is very important to maintain and add to the overall flexibility of the body. When the hamstring is not well exercised, injuries are more likely to occur. A common athletic injury is a pulled hamstring muscle.
Hamstrings can be stretched various ways. One way is to lie on the floor near a doorframe or the outer corner of a wall. Raise the right leg and rest its heel against the wall. Keep the right knee slightly bent. Slowly straighten the right leg until a stretch is felt along the back of the right thigh. Hold this position for about 30 seconds. Repeat with the left leg. This stretching exercise will add flexibility to the hamstring muscle. As this flexibility increases, move closer to the wall to allow more stretching of the hamstring.
Pain can occur in the leg muscles when they are pulled or torn. It occurs when a portion of the muscle is stretched beyond its ability. Cramps in the leg muscles can also occur. Treatment for a minor injury to the chest muscles usually requires rest. Anti-inflammatory medication can help to reduce the pain. A medical professional should be consulted if the pain remains after a few days.
Risks from leg exercises can be minimized by gradually building up an exercise routine. If the exercise feels comfortable, then it is appropriate for one's level. Never do too much and risk injuring the muscles in the leg. Never perform exercises if pain is present. Mild discomfort is natural when doing exercises, especially when the muscle is being stretched.
A hamstring strain can be a serious injury. It can impair the ability to walk and may take several weeks to heal. To minimize the risk of a hamstring injury:
Leg exercises, in combination with a total resistance training routine and regular aerobic exercise, will help to maintain a proper body weight because many calories are burned during the physical activity of exercising the leg muscles, especially the muscles in the thighs because they have more muscle mass. In addition, strong leg muscles allow people to perform better in sports and in the accomplishment of everyday activities such as climbing stairs and walking.
See also Leg exercises .
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American Council on Exercise, 4851 Paramount Dr., San Diego, CA, 92123, (858) 576-6500, (888) 825-3636, Fax: (858) 576-6564, firstname.lastname@example.org, http://www.fitness.gov .
National Coalition for Promoting Physical Activity, 1150 Connecticut Ave., NW, Ste. 300, Washington, DC, 20036, (202) 454-7521, email@example.com, http://www.ncppa.org .
President's Council on Fitness, Sports & Nutrition, 1101 Wootton Pkwy., Ste. 560, Rockville, MD, 20852, (240) 276-9567, Fax: (240) 276-9860, firstname.lastname@example.org, http://www.presidentschallenge.org .
SHAPE America, 1900 Association Dr., Reston, VA, 20191-1598, (800) 213-7193, Fax: (703) 476-9527, http://www.shapeamerica.org .
William A. Atkins, BB, BS, MBA