Muscle Tear and Strain

Traditional grading by size predicts return time poorly: in 176 athletes with hamstring injuries, MRI grading systems explained only a small share of the variation in return time 1. Where the tear sits also matters: in elite track and field athletes, hamstring injuries extending into the tendon took longer to return from and re-tore more often 2. A patient told "grade two, three weeks" is often being misled.

Proximal hamstring injuries near the sitting bone are the clearest example — they behave differently and are frequently underestimated.

Protection lasts days, not weeks. In a randomised trial of 50 recreational athletes with severe thigh or calf strains, starting rehabilitation early rather than after a delay led to a faster return to sport, although healing on MRI and strength recovery were similar in both groups 3. The programme moves through range, then strength through range, then speed, then sport-specific movement.

Eccentric strengthening — lengthening the muscle under load — has good evidence for speeding recovery: in a meta-analysis of rehabilitation trials, lengthening exercises shortened the time to return to play, although they did not change the re-injury rate 4.

Return is decided on measured criteria: symmetrical strength across the range, full pain-free lengthening, completed sprint progression, and confidence at speed. Pain-free walking is not a criterion for returning to sprinting, and treating it as one is why re-injury rates stay high.

We run this as objective testing rather than clinical impression, because the difference between the two is what a patient is travelling for.

Injuries involving the tendon itself take longer to return from and re-tear more often than those confined to the muscle 2.

Grading systems describe severity, but neither grade nor location on MRI predicts an individual's return time well 1. A scan in a significant tear is still useful, above all to show whether the tendon is involved, but the return decision rests on how the muscle performs in testing.

It varies more than most athletes are told. In a randomised trial of 75 elite footballers with MRI-confirmed hamstring injuries, return to full training took a mean of 28 days with a programme built on lengthening exercises and 51 days with conventional exercises, and individual times ranged from about one week to three months 5. In both groups, injuries caused by overstretching took longer than those caused by sprinting 5. Because the calendar is so variable, an international panel of 58 experts recommended deciding on criteria instead, including no pain on palpation or during strength, flexibility and functional tests, hamstring flexibility similar to the other side, field-test performance and psychological readiness 6.

The risk can be reduced substantially. A 2019 meta-analysis of 15 studies with 8,459 athletes found that injury-prevention programmes including the Nordic hamstring exercise roughly halved the rate of hamstring injuries, and the effect held when only the randomised trials were pooled 7. The studies covered different sports and age groups, in both women and men 7.

In the exercise, the athlete kneels with the ankles held and lowers the body forwards slowly, so the hamstrings work while they lengthen. It belongs in training after return to sport as well, rather than being stopped once the injury has healed.