The short answer
- A hamstring strain happens suddenly at speed. Proximal hamstring tendinopathy builds over weeks and hurts deep in the buttock, especially when sitting.
- Stretching feels like the obvious answer and is the wrong instinct for both, for different reasons.
- For acute strains, a rehab protocol built on lengthening exercises returned Swedish elite sprinters and jumpers in 49 days against 86 for conventional exercises.
- Whether the free tendon inside the muscle is involved matters more than how bad it felt on the day.
- The first proper trial of tendon treatment found individualised physiotherapy and shockwave therapy equally effective, so anyone selling you one as the answer is going beyond the evidence.
There are two ways a runner's hamstring goes wrong, and they have almost nothing in common.
One announces itself. You are doing strides or the last repetition of a session, something catches at the back of the thigh, and you stop running immediately. The other never announces anything. It appears as a deep ache under the sit bone, gets worse over a couple of months, and the thing that finally makes you notice it is a long drive or a desk chair.
Both get called a hamstring problem. Almost every decision after that depends on which one you have.
Telling them apart
- Onset
- Acute strainA single moment you can name, usually at speed.
- Proximal hamstring tendinopathyGradual, over weeks or months, with no clear start.
- Where
- Acute strainIn the belly of the muscle, anywhere down the back of the thigh.
- Proximal hamstring tendinopathyDeep in the buttock, right where the hamstring attaches to the sit bone.
- Sitting
- Acute strainUncomfortable, but not the main problem.
- Proximal hamstring tendinopathyOften the worst part of the day, and worse on hard seats.
- Speed
- Acute strainSprinting is impossible early on.
- Proximal hamstring tendinopathyFaster running and hills hurt most, easy running is often fine.
- Stretching
- Acute strainFeels tight, so stretching is tempting.
- Proximal hamstring tendinopathyFeels tight, and stretching usually makes the next day worse.
- Direction of travel
- Acute strainImproves week by week from a bad start.
- Proximal hamstring tendinopathyGrumbles along at the same level for months.
Proximal hamstring tendinopathy shows up as deep buttock pain at the common hamstring origin, and it tends to be long-standing and limiting in both athletic and non-athletic people1. That description matches what distance runners get far more often than the dramatic version.
The stretch that feels right
If it is a strain
The most useful trial in this area compared two ways of rehabilitating the same injury.
Two things to take from that. Lengthening work under control beats general strengthening, by a margin that is worth having. And the single biggest determinant of how long this takes is something you cannot feel: whether the tendon inside the muscle was involved.
Where it stops applying: these were elite sprinters and jumpers, and the injuries were the explosive kind. A distance runner who tweaked a hamstring on a tempo run is a different case, and the day counts will not transfer.
If it is the tendon
Here the honest answer is uncomfortable.
For years the honest answer was that nobody had tested anything properly. When Goom and colleagues reviewed the condition in 2016, there was limited evidence on diagnosis, assessment and management, and no randomised controlled trials of rehabilitation for it at all, so the whole approach was carried over from tendons that had been studied better, such as the Achilles and the patellar1.
That has started to change, and the first proper answer is not the one most clinics would like.
Two treatments, no difference, and both groups improved. The same authors note that a recent systematic review found insufficient evidence to recommend any one intervention over another, and that what experts most commonly recommend is education and exercise4.
What we do: load the tendon in positions that do not compress it, build up to heavy slow strength work, and reintroduce hip flexion range and speed last. Running usually continues in some form, kept flat and easy, because the tendon responds to a steady moderate load better than to a long rest followed by a return to hills.
The timeline is the part runners most need warning about. In the Achilles, where the same loading logic comes from, improvement appeared as early as two weeks and went on climbing to about 12 weeks5. A hamstring tendon is not an Achilles, but the shape of the curve is the honest expectation to hold: months, not weeks, with the early progress arriving before the tissue has caught up.
What actually lowers the odds of the next one
One exercise has a genuinely strong prevention record.
The caveat matters for you specifically. Almost all of those athletes play sports built on repeated sprinting, and the injury being prevented was the explosive kind. Nobody has shown the same effect in distance runners, and the umbrella review of running injury risk puts the large effects in training characteristics, health and lifestyle, and biomechanics rather than in any single exercise7.