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The Injury Clinic - The Baker Injury

My heart sunk when I saw Sam Baker limping to the sidelines on Saturday with a hamstring injury. This is another one of those injuries that can affect any athlete at any time and only time and rest will make it fully heal. We have all had a hamstring strain at some point in our lives so this is not foreign to any of us. Severity is always the key to this injury as you will see below.

The Hamstring Muscle Group

Hamstring injuries are common among athletes. The hamstring muscles run down the back of the leg from the pelvis to the lower leg bones, and an injury can range from minor strains to total rupture of the muscle. The three muscles that make up the hamstrings are the biceps femoris, semitendinosus and semimembranosus. A hamstring injury is recognized by a sudden, sharp pain in the back of the thigh that may stop you mid-stride. After such an injury, the knee may not extend more than 30 to 40 degrees short of straight without intense pain.


Hamstring injuries are easier to prevent than cure. But to understand what causes a hamstring injury, you first have to know how muscles work.

All muscles work in pairs to perform a task. One set of muscles shortens (contracts) to exert force, while the other set of muscles relaxes. The hamstring muscles, located at the back of the thigh, work with the quadriceps muscles in the front of the thigh. When you bend your leg, the hamstring muscles contract and the quadriceps muscles relax. Conversely, when you straighten your leg, the quadriceps muscles contract and the hamstring muscles relax.

When one muscle group is much stronger than its opposing muscle group, the imbalance can lead to a strain. This frequently happens with the hamstring muscles. The quadriceps muscles are usually much more powerful, so the hamstring may become fatigued faster than the quadriceps. A fatigued muscle cannot relax as easily when its opposing muscle contracts, leading to strains.

Muscle strains are overuse injuries that result when the muscle is stretched without being properly warmed up. It's like pulling a rubber band too long. Eventually, the rubber band will either lose its shape or tear apart. The same thing happens with muscles.

Hamstring strain in young people often occurs because bones and muscles do not grow at the same rate. During a growth spurt, the bones may grow faster than the muscles. The growing bone pulls the muscle tight, and a sudden jump, stretch, or impact can tear the muscle away from its connection to the bone.

Sometimes, a muscle that tears away from a bone will pull a piece of bone with it. This is called an avulsion injury. If the hamstring tears near the hip, where it attaches to the pelvis, it may pull a piece of hip bone (ischium) away. This is a serious injury that may require surgery to reattach the muscle.

Classifications of the Injury

Sprains and strains are caused by excessive stretching (tearing) of muscle fibers soft tissues. Hamstring strains are classified as Grade I (mild), Grade II (moderate), or Grade III (severe) degree strains depending on the severity.

The Grade III Avulsed Hamstring
Grade 1: Consists of minor tears within the muscle.

* May have tightness in the posterior thigh.

* Probably able to walk normally however will be aware of some discomfort.

* Minimal swelling.

* Lying on front and trying to bend the knee against resistance probably won't produce much pain.

Grade 2: Is a partial tear in the muscle.

* Gait will be affected-limp may be present .

* May be associated with occasional sudden twinges of pain during activity.

* May notice swelling.

* Pressure increases pain.

* Flexing the knee against resistance causes pain.

* Might be unable to fully straighten the knee.

Grade 3: Is a severe or complete rupture of the muscle.

* Walking severely affected- may need walking aids such as crutches

* Severe pain- particularly during activity such as knee flexion.

* Noticeable swelling visible immediately.

Common Causes of Hamstring Injuries

Some of the more common reasons for hamstring injuries are:

  • Doing too much, too soon or pushing beyond your limits.
  • Poor flexibility.
  • Poor muscle strength.
  • Muscle imbalance between the quadriceps and hamstring muscle groups.
  • Muscle fatigue that leads to over exertion
  • Leg Length Differences. A shorter leg may have tighter hamstrings which are more likely to pull.
  • Improper or no warm-up.
  • History of hamstring injury.

Hamstring injuries are usually readily apparent.

  • Mild strains may involve a simple tightening of the muscle that you can feel.
  • More severe injuries may result in a sharp pain in the back of the thigh, usually in full stride.
  • A rupture or tear may leave you unable to stand or walk. The muscle may be tender to the touch, and it may be painful to stretch your leg. Within a few days after a tear, bruising may appear.

Treatment may depend upon the severity of the injury, with third degree strains requiring a doctor's evaluation. In general the following tips are used for most muscle strains.

  • After an injury it's important to rest the injured muscle, sometimes for up to two or three weeks.
  • RICE - Rest, apply Ice and Compression. Elevate the leg if possible.
  • An anti-inflammatory can be helpful to reduce pain and inflammation.
  • A stretching program can be started as soon as the pain and swelling subsides.
  • A strengthening program should be used to rebuild the strength of the injured muscle in order to prevent re-injury. Make sure you increase this gradually.
  • A thigh wrap can be applied to provide support as the muscle heals.
Surgical Treatment

Avulsion Repair

Surgery is rarely needed for hamstring injuries. However, it may be needed for an avulsion to reattach the torn hamstring tendon to the pelvis. If surgery is delayed after an avulsion, the tendon may begin to retract further down the leg, and scar tissue may form around the torn end of the tendon. Both of these factors make it more difficult to do the surgery.

To begin the operation, an incision is made in the skin over the spot where the hamstring tendon normally attaches to the pelvis. The surgeon locates the torn end of the hamstring tendon. Forceps are inserted into the incision to grasp the free end of the torn hamstring tendon. The surgeon pulls on the forceps to get the end of the hamstring back to its normal attachment. The surgeon cuts away scar tissue from the free end of the hamstring tendon.

The original attachment on the pelvis, the ischial tuberosity, is prepared. An instrument called a burr is used to shave off the surface of the tuberosity. Large sutures or staples are used to reattach the end of the hamstring tendon to the pelvis.

When the surgeon is satisfied with the repair, the skin incisions are closed.

Muscle Repair

Surgery may be needed to repair a complete tear of a hamstring muscle. An incision is made over the back of the thigh where the hamstring muscle is torn. The muscle repair involves reattaching the two torn ends and sewing them together.


  • Warm up thoroughly. This is probably the most important muscle to warm-up and stretch before a workout.
  • Stretching after the workout may be helpful.
  • Try adding a couple sessions per week of retro-running or backward running which has been should decrease knee pain and hamstring injuries.
  • Follow the "Ten Percent Rule" and limit training increases in volume or distance to no more than ten percent per week.
  • Other ways to prevent injury are to avoid doing too much, too soon, avoid drastic increases in intensity or duration, and take it easy if you are fatigued.
Information taken from, the AAOS and the Sports Injury

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