Hamstring Injury: Strains, Tears and Returning to Sport

Hamstring Injury: Strains, Tears and Returning to Sport

How do hamstring injuries happen? The difference between a strain and a tear, what to do in the first days, diagnosis, rehabilitation, when surgery is needed and return-to-sport criteria.

A hamstring injury is a strain or tear of the muscle group at the back of the thigh, usually caused by sprinting or overstretching. It typically announces itself as a sudden sharp pain or pulling sensation at the back of the thigh mid-sprint, followed by pain when walking. Most mild strains heal well without surgery through a structured rehabilitation programme, but hamstring injuries have a strong tendency to recur, so a rushed return to sport is a common mistake. In the less common case where the tendon tears completely away from the pelvis, early surgical assessment may be needed.

Below we explain how hamstring injuries happen, the difference between a strain and a tear, what to do in the first few days, how they are diagnosed and treated, and which criteria guide a safe return to sport.

What are the hamstrings and how do they get injured?

The hamstrings are three muscles at the back of the thigh. They start at the sitting bone at the bottom of the pelvis, cross behind the knee and attach to the lower leg bones. They extend the hip and bend the knee, and because they cross two joints they are particularly vulnerable during fast running.

Injuries usually happen in one of two ways:

• Sprinting injuries: as the leg swings forward, the muscle is stretched while contracting hard to brake it. This is the classic mechanism in football, athletics, rugby and basketball.
• Stretching injuries: in dance, gymnastics, high kicks or slipping into a split, the hip bends sharply while the knee stays straight. These injuries tend to affect the upper part of the muscle and its tendon and often take longer to heal.

Fatigue, a poor warm-up, a previous hamstring injury, older age, strength imbalances and sudden increases in training load are the main risk factors.

Strain or tear? Grades of hamstring injury

• Grade 1 (strain): a small number of fibres are damaged; there is tightness and mild pain, and walking is usually normal.
• Grade 2 (partial tear): more fibres are involved, with clear pain, limping, weakness and sometimes bruising after a few days.
• Grade 3 (complete tear or tendon avulsion): the muscle or tendon is fully torn, with severe pain, real difficulty walking, extensive bruising and sometimes a palpable gap.

For an overview of muscle injuries in general, see our article on muscle tears and strains.

Symptoms of a hamstring injury

• A sudden stabbing or pulling pain at the back of the thigh while running or stretching
• Sometimes a pop felt or heard at the moment of injury
• Pain when walking, climbing stairs or bending forward
• Weakness when bending the knee or lifting the straight leg
• Tenderness and bruising that may appear within one to three days
• Pain at the sitting bone when sitting for long periods, especially on hard surfaces, in higher injuries

What to do in the first few days

1. Stop straight away: playing on through pain can make the damage worse.
2. Protect the muscle: avoid movements that clearly increase the pain for the first few days; short-term crutches can help if you are limping badly.
3. Cold and gentle compression: a towel-wrapped ice pack for 15–20 minutes and an elastic bandage may limit swelling.
4. Avoid aggressive stretching and deep massage early on, as they can disturb healing.
5. Keep moving within comfort: short, pain-free walks are generally better than complete bed rest.

Our guide to first aid for sports injuries covers the general steps on and off the pitch.

How is it diagnosed?

Diagnosis starts with an examination. Your doctor will ask how the injury happened and assess where it hurts, muscle strength, range of motion and the length of the tender area. Mild strains often need no further tests.

If a more serious injury is suspected, in professional athletes, or when the tendon may have pulled off the bone, MRI or ultrasound is used. MRI is particularly helpful for showing the location and extent of the damage, whether the tendon is involved and how far a torn tendon has retracted. That information is key in deciding between non-surgical and surgical treatment.

Treating a hamstring injury

Rehabilitation without surgery

The great majority of hamstring injuries are treated without surgery, usually in stages:

1. Early phase: gentle isometric contractions within comfort, short-stride walking and hip and trunk exercises.
2. Strengthening: bridges, single-leg hip hinges and resisted knee bends with bands, progressed gradually.
3. Eccentric work: exercises in which the muscle works while lengthening, such as the Nordic hamstring curl, are added when pain allows.
4. Running programme: from easy jogging to faster running, with sprinting added last.
5. Sport-specific training: cutting, acceleration and a controlled return to team sessions.

Mild strains may allow a return to sport within a few weeks, while partial tears and injuries involving the tendon can take several months. Recovery time depends on the location and size of the injury and on the individual. In some prolonged or recurrent cases, supportive treatments such as PRP may be discussed, although evidence for their benefit in muscle injuries is still limited.

When is surgery needed?

Surgery is considered when the hamstring tendons have pulled completely away from the sitting bone and retracted. In active patients, particularly when more than one tendon is torn and there is clear weakness, early reattachment may be recommended. Timing matters, because delayed repairs can be technically more difficult, so severe pain at the sitting bone with extensive bruising and obvious weakness should be assessed promptly.

Returning to sport and preventing re-injury

Re-injury is one of the biggest problems with hamstring injuries, and it most often happens in the first weeks after returning. Return should therefore depend on criteria rather than simply the absence of pain:

• Full, comfortable range of motion
• A largely closed strength gap between the two legs
• No pain or hesitation during full-speed sprinting and cutting
• Full team sessions completed without problems and feeling ready

Keeping exercises such as the Nordic hamstring curl in your weekly routine, warming up properly and increasing training load gradually can help reduce the risk of recurrence. Our article on when an injured athlete should return to sport covers the general principles.

When should you see an orthopedic surgeon?

• A clear pop or tearing sensation at the moment of injury
• Major difficulty walking or being unable to bear weight
• Extensive bruising, a gap or a change in shape at the back of the thigh
• Severe pain at the sitting bone and difficulty sitting
• Pain that has not clearly improved within a few weeks, or repeated injuries
• Numbness, tingling or burning in the leg

At Prof. Dr. Gökhan Polat's clinic, hamstring injuries are managed after examination and any necessary imaging, taking into account the grade of injury, the sport and the athlete's goals. You can read more on our sports injuries page.

In summary

• A hamstring injury is a strain or tear of the back-of-thigh muscles, usually during sprinting or overstretching.
• Most mild and moderate injuries are treated without surgery through staged rehabilitation.
• A complete tendon tear from the sitting bone may need early surgical assessment.
• Return to sport should be criteria-based, and ongoing strength work helps lower the risk of re-injury.

This article is for general information only; diagnosis and treatment decisions are made individually after examination and the necessary tests.