A hamstring tendon strain (also known biceps femoris strain or rupture) is a tear or rupture of one of the hamstring tendons at the point where they insert into the back of the knee.
Sudden sharp pain may be felt at the time of injury with possible swelling and soreness. A hamstring avulsion strain occurs when the tendon pulls a small fragment of bone with it.
On this page:
- Symptoms & diagnosis
- Causes & anatomy
Symptoms of hamstring tendon strain
Symptoms include a sudden sharp pain in the back of the knee. There may be swelling, tenderness and heat coming from the point where the tendon inserts into the back of the knee. The athlete may feel pain when bending the knee against resistance as the hamstring muscle is put under stress. An avulsion strain (or fracture) has similar symptoms consisting of a sudden sharp pain at the back of the knee. An avulsion fracture is known to be particularly painful so continuing to play on is not usually an option.
Swelling will appear at the point of injury where the tendon attaches to the bone at the outside back of the knee. The athlete will feel a significant loss in hamstring muscle strength and attempting to bend the knee against resistance will also be painful. It will be tender when pressing in (palpating) at the point of injury. With an avulsion strain, it may even be possible to feel the bone fragment through the skin. If an avulsion injury is suspected then seek professional medical advice immediately as an X-ray will be needed to confirm the diagnosis.
Hamstring tendon strain causes & anatomy
The hamstring muscles consist of three muscles called the biceps femoris, semitendinosus, and semimembranosus. Their function is to bend the knee (knee flexion) and they are also involved in moving the thigh backward (hip flexion). The muscles insert at the back of the knee via tendons which join muscle to bone.
It is possible for these tendons to be torn during an explosive movement or kicking action, in particular, the biceps femoris tendon or the semitendinosus tendon. When sprinting at high speed, a great deal of force is put through the hamstring muscles as they work hard to slow down the lower as it comes through and strike the ground. If the athlete might have been suffering from hamstring tendon inflammation which failed to heal properly then this could be a weak point, more susceptible to injury.
Treatment of hamstring tendon strains
What can the athlete do?
Apply cold therapy or PRICE principles (protection, rest, ice, compression, elevation) as soon as possible. Ice can be applied for 10 minutes every hour during the acute stage which is usually 24 to 48 hours depending on how bad the injury is. Do not apply ice or a gel ice pack directly to the skin but wrap in a wet tea towel. Even better is to use a commercially available cold therapy and a compression wrap. Seek professional advice if an avulsion strain or a complete rupture of the tendon is suspected.
If the injury is to the semitendinosus muscle on the inside back of the knee then it is likely this will be treated conservatively, meaning without surgery. However, in more severe cases a torn biceps femoris tendon may require an operation to fix it.
After the first 2 or 3 days when the tendon has started to calm down alternating hot and cold can be done. Commercially available gel packs are ideal for this purpose as they can be warmed in hot water or carefully in the microwave, or frozen. Wear knee support to support to protect the tendon and retain the bodies heat which will aid the healing process. When returning to running a heat retainer or support can be worn. Tendons work better when they are warm but as a precaution applying ice after a training session can help reduce any inflammation.
What can a sports injury specialist or doctor do?
A doctor may prescribe anti-inflammatory medication such as ibuprofen to help with the pain and inflammation in the early stages. Do not take Ibuprofen if you have asthma or other contraindications, always check with a medical professional first. Anti-inflammatory medication may not be as effective in the later stages and may even restrict healing.
For very severe tendon strains and complete ruptures, the knee may be immobilized in a plaster cast or a surgeon may operate to repair the damaged tendon.
Sports massage may be beneficial in remodeling the scar tissue and improving the condition of the hamstring muscles themselves. Cross friction massage is applied by rubbing transversely across the tendon.
A full rehabilitation program consisting of stretching, strengthening exercises should be done to restore the athlete to full fitness.
In the case of mild tendon injuries, stretching and strengthening exercises for the hamstring muscles can begin when pain allows. But beginning exercises too soon, or if an avulsion fracture is present could make the injury worse. Stretching, strengthening and finally functional or sports specific exercises all play a part in the rehabilitation of hamstring tendon strains.
See hamstring strain rehabilitation exercises for more detailed information.