A hamstring strain is an overstretch or tear of one of the three muscles that run down the back of the thigh, from the sitting bone to below the knee. They bend the knee and control the leg as it swings forwards, and they are under most tension at the moment the heel is about to strike the ground - which is exactly when most strains happen.
The usual mechanism is a flash of speed or a big stretch: sprinting, a long stride for a ball, an awkward slide, or a sudden lunge. Most people feel a sharp pull or grab at the back of the leg and stop immediately. Fatigue late in a game, little preparation for sprinting, and a previous hamstring injury all raise the risk.
In the days afterwards it is sore to stretch, sore to accelerate, and often tender to press, and bruising may appear a little way down the thigh. Walking is usually possible, sometimes with a limp. Most strains are low grade and the day-to-day soreness settles well over a few weeks.
The important part is what comes next. The hamstring has a high re-injury rate if you go back to sport before it is genuinely ready, and re-injuries are usually worse than the original. That is why this programme is staged and finishes with clear, testable markers rather than a fixed number of weeks. It moves from calming the muscle and restoring easy movement, through progressive strength work that emphasises the lengthened position, into running speed and change of direction, and finally a return-to-play checklist.
People who have felt a sudden pull at the back of the thigh during running or sport and can walk, even if with a limp. If you cannot take weight, saw heavy bruising appear quickly, or felt a pop high up near the buttock bone, get assessed before starting - that can be a more serious tear.
Quick movement tests you can try at home to see what your symptoms might point towards. A guide, not a diagnosis.
The first few days to two weeks. Protect the muscle, keep walking within comfort, and start very gentle range and low-load activation. Avoid aggressive stretching and anything that reproduces a sharp pull.
Begin when walking is pain-free and gentle contraction no longer hurts. Load the hamstring progressively, including work with the hip flexed and knee straighter, two to three times a week.
Add these once you can do slow strength work at good load with no next-day soreness. Introduce faster, higher-force work, jogging building to strides, and controlled direction changes.
You are ready to return when: you have full, pain-free hamstring range compared with the other side; single-leg bridge and Nordic strength feel equal left to right; you can sprint at near maximum without holding back or feeling the muscle; and you have completed sport-specific drills and a full training session without a next-day reaction. If any of these are not yet true, or you are unsure, get assessed before you go back.
A low-grade strain often settles enough for a graded return to running in 2 to 4 weeks, with full return to sport around 4 to 8 weeks. Higher-grade tears, or pain near the sitting bone, can take several months. Progress is guided by the return-to-play markers, not the calendar.
Move up a stage only when the current work is comfortable both during and the day after. Use a simple rule for running: if a session leaves the hamstring more than mildly sore for over 24 hours, repeat the previous level before progressing. Re-injury usually happens when the last two stages are rushed.
Once you can walk fast and lengthen the muscle without a sharp pull, and gentle strength work is pain-free - often around the 2 to 3 week mark for a minor strain. Start with a walk-jog plan and build speed gradually over one to two weeks.
Not early on. Aggressive stretching in the first week or two can irritate the healing tissue. Gentle range within comfort is fine; the muscle regains length mainly through progressive strength work in longer positions.
The main reasons are returning to sprinting before strength and range are fully restored, and skipping high-speed running in rehab. Completing all four stages, including the return-to-play checklist, lowers the re-injury risk considerably.
Most strains do not need imaging. A scan is worth considering if you cannot weight-bear, the pain is high up near the buttock bone, or the injury is not improving as expected, as these can point to a tear that changes the plan.
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