The ins and outs of the hamstring muscle group
Lisa Lehman, MS, LAT
Katie Fara, DPT
Many of us have heard of, know or have experienced a problem with the hamstring muscle group. Located on the back side of the upper leg, the hamstring group is comprised of three different muscles – the semimembranosis, semitendinosis and biceps femoris.
This muscle group attaches to the pelvis, crossing behind the hip joint, and runs downward toward the knee to attach on the inside and outside portion of the lower leg, just below the knee joint. Based on its many attachments, the hamstring influences motions/actions at the hip, knee, and back.
Mechanism of hamstring injury
Hamstring strains or "pulls" are usually non-contact in nature. Common causes of hamstring strains include decreased flexibility, decreased strength, inadequate warm-up and muscle fatigue. To help prevent injury or to ensure full recovery following a strain, each of these conditions must be addressed.
A hamstring strain can occur in a variety of ways. This muscle group is often injured in high-speed activities like running, jumping, pivoting or exploding out of a stance. Since the hamstring crosses multiple joints, it is involved in motions or affects movement at each of these joints. Although its primary influence centers around the hip and knee joints, it can often impact back alignment and function.
The hamstring muscle group is contracting during many activities in various phases. For example, during running, when the leg is not in contact with the ground, the hamstring acts to slow down or decelerate the lower leg, which may lead to injury. Another method of injury can occur when the foot contacts the ground. During this phase, the hamstring must control motion at the knee joint while also controlling motion of the trunk to prevent it from bending forward too far. In this action, the muscle is being pulled at both ends, like a rubber band, which may lead to a muscle strain if the force is too much.
Strengthening and stretching the hamstring
To avoid injuring a hamstring, one needs to have a balance of strength and flexibility in the hamstring muscle group. A simple and effective strengthening exercise is a forward lunge.
- Step forward with involved leg's foot pointing straight ahead.
- Maintain alignment of kneecap with second toe.
- Lower the back knee to a position of two inches off the ground.
- Stand up to regain upright position. Repeat 10 times with each leg leading.
The lunge is a great exercise because it trains more than just the hamstrings; it also helps to strengthen the quadriceps and gluteal muscles.
A simple stretch one can do to maintain hamstring flexibility is called the hurdler stretch.
- Sit on floor with one leg stretched out in front of you with toes up.
- Bend other leg and place sole of foot against knee of the straightened leg.
- Slowly bend forward from hips, keeping your back and head straight.
- Lean forward to feel a stretch, not pain, behind the knee or thigh.
- Hold 20 – 30 seconds. Repeat three times on each leg
While strengthening and stretching activities are important for avoiding or recovering from a hamstring injury, they are only part of the entire rehabilitation process. Restoring full range of motion, normalizing walking/running pattern, decreasing pain and improving function of the entire leg are just as important.
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