Early versus delayed lengthening exercises for acute hamstring injury in male athletes

The inclusion of hamstring lengthening exercises to a rehabilitation programme for acute hamstring injuries reduces the time to return to sport and re-injuries. However, it is unknown whether introducing these exercises early or later in rehabilitation is optimal.

A research study from Qatar evaluated the efficacy of early versus delayed introduction of lengthening or eccentric strengthening exercises in addition to an established rehabilitation programme on return to sport duration for acute hamstring injuries. The study was published in British Journal of Sport medicine.

The study recruited 90 male participants (age: 18–36 years, median 26 years) with an acute hamstring injury (MRI-confirmed). They were randomised into an early lengthening (at day 1 of rehabilitation) group or a delayed lengthening (after being able to run at 70% of maximal speed) group. Both groups received an established rehabilitation programme.

The results show that the return to sport (time from injury to full unrestricted training and/or match play) in the early lengthening group was 23 days (between 16–35 days) in contrast to 33 days (between 23–40) in the delayed lengthening group. However after adjusting other conditions, there was no significant difference in the return to sport. In addition, there was no significant difference between groups for re-injury rates within 2 months.

The authors concluded that accelerating the introduction of lengthening exercises in the rehabilitation of hamstring injuries in male athletes did not improve the time to return to sport nor the risk of re-injury. The authors added that early introduction of lengthening exercises in hamstring strain injury is safe, although not associated with meaningful improvements in the primary outcome (time to return to sport).