What Causes Hamstring Tightness?

Hamstring muscles are located along the back of the thigh, from the hip area to just below the knee, and make it possible for a person to straighten his leg behind his body and bend his knee. A person with hamstring tightness may feel like he has a cramp. Hamstring tightness can be caused by participating in sports such as weightlifting and gymnastics, which put too much pressure on the lower back bones.

Too Much Sitting

• Too much sitting in an office chair during the workday can cause hamstring tightness. Sitting causes the hamstring muscles to be inactive, and kept at a shortened length, which causes tightness. Children often experience hamstring tightness at the age of 5 or 6, when they begin school and sit in a chair for long periods at a time. Sitting up tall and practicing good posture during the workday keeps the spine in proper alignment and can help prevent hamstring tightness. Modifying work stations by proper placement of the keyboard, and using an office chair with back support, can help maintain proper posture.

Stress Fracture

• Another condition that causes hamstring tightness is spondylolysis, which shows up on an X-ray as a stress fracture in a spinal vertebra bone. Spondylolysis is most commonly seen in adolescent athletes. This condition typically affects the fifth lumbar vertebra in the lower back, or less commonly, the fourth lumbar vertebra. If the stress fracture causes the bone to become too weak, the vertebra can start to slip out of place, press on nerves, and cause spasms that result in a stiff back and hamstring tightness, resulting in changes in posture and walking gait. Causes of spondylolysis include rapid growth spurts in adolescence and heredity.

Age

• As people age and become less active, hamstrings can become shortened, and hamstring tightness can develop, felt during activities that require flexion of the hip and during knee extensions, such as bending over to put on shoes. Hamstring tightness while performing these activities may be caused by standing with the knees slightly flexed, which is a common change in posture as people age.