Hamstring injury: rehabilitation and returning to running

The hamstrings are the muscles at the back of the thigh. The NHS describes sudden sharp pain at the back of the leg during sport or exercise, sometimes a snapping sensation or a pop in a severe injury, followed by tenderness and swelling or bruising within a few hours, and difficulty standing or walking on the affected leg.

Scoping-review authors describe hamstring muscle injury as the most prevalent injury in sports involving sprinting at maximal acceleration or velocity, such as football, rugby and athletics. That is why return to running, and especially sprinting, is the stage most closely watched.

For the first 2 to 3 days the NHS recommends protection, rest, ice for up to 20 minutes every 2 to 3 hours, a snug elastic bandage removed before sleep, and elevation. It advises avoiding heat, massage and alcohol for the first 3 days to limit swelling, and asking a pharmacist about pain relief. When you can move the leg without pain stopping you, the NHS says to keep moving it so the hamstring does not stiffen.

Get help from NHS 111 if the injury is very painful or getting worse, there is a large amount of swelling or bruising that is increasing, it hurts to walk or stand, the leg is very stiff or hard to move, it is not improving with self-care, or you have a very high temperature or feel hot but shivery, which can signal infection.

The NHS says if the injury is taking longer to heal than expected, or you have had previous hamstring injuries, you may need to see a physiotherapist who can show specific exercises to speed recovery and prevent further injury. NHS physiotherapy is free but there may be a long waiting list, and staff at your GP surgery may be able to advise on local access.

Physiotherapy is also the usual route for anyone who plans to return to running or sport at a higher level, because the reviews described below show that the way a person is judged ready matters as much as the exercises they do.

The scoping review identified 137 articles and 40 different rehabilitation strategies, and noted wide variety, limited high-level evidence and poor reporting of programme details. Across primary and secondary research, the components reported most often were eccentric-based strengthening, flexibility exercises, and progressive running and agility protocols, with neuromuscular control and lumbar stability work also common.

Eccentric strengthening means loading the muscle as it lengthens, as in controlled hamstring curls on the way down. Progressive running means building from walking to jogging to faster running in steps. The review is clear that programmes differ so much that no single plan is proven best, so your physiotherapist's choices will reflect your sport, your injury and your history.

A systematic review of 22 studies on return to activity found that the most commonly used criterion was pain, with flexibility and range of movement, strength, functional tests and imaging also used. It recommends combining pain with strength, flexibility and the ability to perform sport-specific movements at maximum speed. Another finding was that walking without pain was the most frequently cited basic requirement before advanced stages begin.

The same review reports a consensus pointing to a maximum deficit of 10 percent in flexibility and strength compared with the other leg, and a more conservative approach to progression for people who have had previous hamstring injuries. The scoping review adds that return-to-sport criteria were reported in fewer than half of the primary studies and were often based on pain resolution alone, which the authors regard as a gap.

• Pain-free walking and everyday movement comes first.

• Strength and flexibility are compared with the uninjured leg.

• Sport-specific, high-speed movement is tested before sprinting or competition.

• A past hamstring injury calls for a more cautious progression.

No published source used here gives a standard calendar for return to running, and the reviews stress that readiness depends on the injury grade and the sport. A typical outline, which the programmes in the reviews follow in various forms, is to move from pain-free walking to straight-line jogging, then to faster running and changes of direction, then to sport-specific drills and finally competition, with each step attempted only when the previous one is comfortable the next day.

The NHS advice on prevention fits this approach: build fitness gradually if you have not exercised for a while, warm up before exercise, stop if you feel pain in the hamstrings, and avoid exercising when tired, because tired muscles are more prone to injury.

Severe hamstring injuries can take weeks or months to heal. The NHS says surgery may be needed for the most serious injuries where the muscle has torn completely, repaired using stitches or plastic clasps, with several months of recovery afterwards. A suspected severe tear is a reason to seek assessment early, not to wait and see.