How long does a pulled hamstring take, and when can you sprint again?

How long does a pulled hamstring take to recover?

Average return times in the studies below run from about a week for the mildest strains to around ten weeks for the most severe, with a longer tail for tendon and stretch-type injuries. The research points to three things that change the outlook: how much of the muscle is damaged, whether the tendon is involved, and how you got hurt (sprinting or overstretching).

The studies also measure different end points. Some count days to full training, some to match play and some to your previous performance level, which takes longer. In a case series of 18 elite sprinters with first-time strains, the median time to get back to pre-injury level was 16 weeks, with a range of 6 to 50. Average return-to-sport times in trials are shorter. Erickson and Sherry's 2017 review reports an average of 25.2 days for a rehab programme built on agility and trunk stabilization and 28.8 days for one built on progressive running and eccentric strengthening, a difference that wasn't significant.

The hamstring injury prevention guide covers why sprinters strain hamstrings in the first place. This guide is about the time after it happens.

Recovery time by grade (including grade 1 hamstring strains)

What "grade 1" means depends on the grading system. Some clinics grade on symptoms and examination, while research and elite sport usually grade on MRI. In a UEFA study of 23 European professional soccer teams, 516 hamstring injuries were recorded and 58% had an MRI. Grades 0 and 1 showed no fibre disruption, and grades 2 and 3 did. Average layoffs by grade:

A later UEFA study of 255 grade 1 and 2 injuries found a similar gap: 18 ± 15 days for grade 1 and 24 ± 13 for grade 2. The spread around each average is wide, so two grade 1 strains can keep players out for very different lengths of time.

The British Athletics classification

British Athletics grades muscle injuries on MRI from 0 to 4 by extent, and adds a letter for where the injury sits: (a) at the muscle's outer fascia, (b) at the junction of muscle and tendon, or (c) inside the tendon. In a 4-year study of 65 hamstring injuries in elite British track athletes, grade 3 injuries and "c" injuries took longer to return to full training, grade 0 injuries took less, and intratendinous injuries recurred more often.

After the team built its rehab around the classification, a second 4-year study followed 70 hamstring injuries in 46 World Class Programme athletes:

The overall reinjury rate in that group was 2.9%, with no reinjuries among the intratendon injuries.

Sprint-type vs stretch-type strains

Carl Askling's research split hamstring strains into two types. The sprint type happens during fast running and usually hits the biceps femoris long head. All 18 sprinters in his first study had strained that muscle during competitive sprinting. The stretch type happens in slow movements that take the hip into deep flexion with the knee straight, as in dance or stretching.

Stretch-type strains are slower to heal. In 15 professional dancers injured this way, the semimembranosus was involved in 87%, always including its proximal free tendon, and the median time back to pre-injury level was 50 weeks (range 30–76). In Swedish elite football, stretch-type strains took 43 days against 23 for sprint-type with the lengthening protocol, and 74 against 41 days with a conventional protocol.

If you were hurt mid-sprint, the sprint type is the likely one. Tell your clinician exactly what you were doing when it went, because the mechanism changes the outlook.

What predicts a longer layoff

Lost knee range of motion in the first 48 hours

In 165 track and field athletes with first-time strains, a clinician measured how far each athlete could straighten the knee 48 hours after injury, compared with the other leg. The 81% with a deficit under 20° were back to full performance at 2 weeks. The 3.6% with a deficit over 30° took more than 6 weeks.

Tendon involvement and a higher injury

In the sprinter series, injuries that involved the proximal free tendon or sat closer to the sit bone took longer. In a trial of 56 Swedish elite sprinters and jumpers, injuries that involved the free tendon averaged 73 days against 31 without it on the lengthening protocol, and 116 against 63 on the conventional one.

Early signs and size on MRI

Erickson and Sherry list early signs linked to a return taking more than 40 days: pain above 6 out of 10, pain in everyday activities for more than 3 days, a popping sound at the time of injury, bruising, and a difference of more than 15° when the knee is passively straightened. Australian football players who took more than a day to walk without pain were 4 times more likely to need longer than 3 weeks. In a trial comparing two rehab programmes, a longer injury on MRI before rehab started correlated with a longer return to sport. In British track athletes, more pain on walking and on resisted hamstring contraction, and a bigger loss of knee extension with the hip bent, were associated with a longer time to full training.

Checks clinicians use before full-speed sprinting

There is no single agreed test battery. In a worldwide Delphi study, 58 experts agreed on these criteria to support a return-to-play decision after a hamstring injury:

• Clearance from the medical staff
• No pain when the injured area is pressed
• No pain during strength and flexibility testing
• No pain during or after functional testing
• Hamstring flexibility similar to the other leg
• Performance on field testing
• Psychological readiness

They also agreed the decision should be shared between the athlete, sports physician, physiotherapist, fitness trainer and coach.

Strength and the H-test

A systematic review of nine studies and 601 acute strains found that every study used the athlete's pain to guide progression. Studies that used isokinetic strength testing in the return decision had the shortest return times (12–25 days), and those using the Askling H-test, a fast straight-leg raise, had the lowest reinjury rates (1.3–3.6%). Erickson and Sherry describe the approach from Askling's trials: an athlete who feels insecure on the H-test gets another 1–2 weeks of rehab, then retests.

Strength often isn't fully back at clearance. In 25 athletes tested at return to sport, the injured leg was 9.6% down on peak knee flexion torque at 60°/s, and 20.4% of the muscle cross-section still showed swelling on MRI. Both had resolved 6 months later. In the two-programme trial, no athlete's MRI showed complete healing at return, even with pain gone and strength back on clinical testing.

Sprint speed itself

Passing clinic tests doesn't mean you are back to full speed. Soccer players tested on the day they were cleared were moderately slower over 50 m than uninjured teammates and produced less horizontal force, and their acceleration had improved when retested about two months later. For a sprinter, timed runs are part of the return. Erickson and Sherry's return algorithm ends with sport-specific movements, including sprinting, done near maximum speed without pain, limitation or hesitation.

How a return to sprinting is typically staged

This is general information about how published programmes are structured. Your own plan should come from the clinician who examined you, because the right speed for each step depends on the injury.

Erickson and Sherry's guideline has three phases, each with criteria to move on. The British Athletics team tracks milestones such as pain-free jogging, full pain-free strength on manual testing, a negative H-test and full passive range of motion, all of which were associated with the time to full training.

Running is part of rehab

One of the two programmes in the trial Erickson and Sherry describe (PRES) was built on progressive running, and the British Athletics milestones start with jogging. In a trial of 48 soccer players, a criteria-based programme that trained sprint performance from early in rehab took slightly longer (25.5 against 23.2 days) but had 1 reinjury in 6 months against 6 in the standard group. Those players also had faster 10 m times and higher maximal sprinting speed at return.

Which exercises the trials used

In Askling's two trials, a protocol built on exercises that load the hamstrings at long lengths returned athletes faster than a conventional protocol: 49 against 86 days in elite sprinters and jumpers, and 28 against 51 days in elite footballers. In Sherry and Best's trial of 24 athletes, a programme of progressive agility and trunk stabilization returned athletes in 22.2 days on average against 37.4 for stretching and isolated hamstring strengthening. That difference wasn't significant, but the reinjury difference was (below).

Working into some discomfort

In a trial of 43 men, rehab done within a pain threshold (some discomfort allowed) didn't shorten the time to clearance compared with strictly pain-free rehab (median 17 against 15 days, not significant). It did bring back 15% more isometric strength and kept more fascicle length, with two reinjuries in each group. How much discomfort is acceptable is a call for your clinician.

Once you are cleared, keep the strength work going. The Nordic hamstring curl guide has a build-up and a maintenance dose, and hamstring exercises for sprinters covers the hip and knee exercises that go with it. Build your sprint volume back in steps. The speed training guide shows how fast sessions are spaced through a week.

Reinjury risk

Nearly one third of hamstring strains recur within the first year after return to sport, and the second injury is often worse than the first. A systematic review of five prospective studies found recurrence rates of 13.9% to 63.3% from the same season up to 2 years after the first injury. In the first UEFA study, re-injuries made up 16% of hamstring injuries, all in the biceps femoris.

A 2020 meta-analysis of 78 studies found that any previous hamstring strain raised the risk of another 2.7-fold, and a recent one 4.8-fold.

What predicted a reinjury

In a study of 64 athletes, 17 (27%) were reinjured within 12 months. None of the MRI findings from the time of injury predicted it. Findings from tests done just after return did. Athletes who still had localised discomfort when the hamstring was pressed were almost four times more likely to be reinjured. More previous hamstring injuries, a bigger loss of knee extension and a strength deficit with the knee nearly straight also predicted reinjury.

Rehab content

In Sherry and Best's trial, 6 of 11 athletes (54.5%) on the stretching and isolated strengthening programme were reinjured within 2 weeks of returning, against none of 13 on the agility and trunk stabilization programme. At one year it was 7 of 10 (70%) against 1 of 13 (7.7%). Both were small groups, and later trials with different programmes have found lower rates in both arms.

Common mistakes

Going by the calendar

Average return times hide a wide spread. Clinicians clear athletes on criteria such as pain on pressing, strength, flexibility and field tests, not on days since injury.

Treating no pain as fully healed

At return to sport, strength was still 9.6% down and MRI still showed swelling in one study. Keep the strength work going after you are cleared.

Racing straight after clearance

Cleared soccer players were still slower than uninjured teammates. Rebuild acceleration and top-speed volume in steps before racing.

Ignoring a tender spot

Discomfort when the hamstring was pressed just after return made reinjury almost four times as likely. Tell your physio about it.

Self-diagnosing the grade

Tendon involvement and stretch-type strains can mean months instead of weeks. Get an assessment instead of guessing from how it feels.