The short answer
- Pain at the bone you sit on, deep in the buttock, that is worse sitting than standing, fits proximal hamstring tendinopathy.
- It is not a hamstring strain. A strain has a moment you can name and sits in the muscle belly. This builds over weeks and sits at the attachment.
- Bending the hip pulls the tendon around that bone and presses it against it. Sitting, driving, deep forward folds, deadlifts and hamstring stretches all do this.
- Stopping the stretching is the single change that most often turns it around.
- There is very little trial evidence here. Anyone who gives you a confident protocol with a timeline is going beyond what has been tested.
Most running injuries announce themselves while you run. This one announces itself in a chair. If the worst part of your day is a two-hour drive or a long meeting, and the run itself is merely uncomfortable, you are probably looking at the tendon where the hamstrings attach to the bone you sit on.
Where it sits
All three hamstring muscles share one attachment at the base of the pelvis, on the ischial tuberosity, which is the bony point you can feel under each buttock when you sit on a hard surface. Proximal hamstring tendinopathy is a sensitised tendon at that attachment1.
The pain is deep, felt high in the buttock rather than in the back of the thigh, and you can usually get a finger fairly close to it. It rarely travels below the knee. It came on over weeks, not in one moment.
Why bending the hip is the problem
The tendon wraps around the sitting bone on its way to the muscles. Bending the hip pulls it tighter around that bone and presses it against it. The further the hip bends, the harder the squeeze1.
Standing
Barely any
Sitting upright
Some
Low seat or car
More
Hamstring stretch
Most
That ranking is the whole management plan in one picture. It tells you why a hard low chair is worse than a high firm one, why a car seat is worse than an office chair, and why the two exercises most often prescribed for a sore hamstring are the two worst things you can do to this one.
Hamstring stretches take the hip to the far end of that range and hold it there. A deadlift or a kettlebell swing loads the tendon hard while the hip is bent. A yoga forward fold does both. Every one of those is a compression exercise for this tendon, whatever it was intended to be1.
Testing it yourself
Three provocation tests have been checked against MRI in athletes.
Two of those need a second person. The one you can do alone is the Puranen-Orava: stand, put the heel of the sore leg on a support at about hip height with the knee straight, and lean forward over it. Reproducing your pain at the sitting bone is a positive. That is a stretch position, so do it once to check, not as an exercise.
Do not go by the scan
This is one of the strongest examples in running medicine of imaging finding something in nearly everyone.
A report describing tendinosis at your hamstring origin is therefore not, on its own, an explanation for your pain. It describes something most people have. The reason to scan is a different question: a suspected tear, bone involvement, or a picture that does not fit.
What the treatment evidence actually says
Here is the part most articles about this condition leave out.
There is no rehabilitation trial to point to. The clinical guidance that does exist is a narrative review built on the principles established in Achilles and patellar tendinopathy, adapted to a tendon that is also being compressed1. Even the way outcomes are measured is still being settled: a 2023 review found that of twenty-eight measurement instruments used in the research, only one had been validated in this population5.
Building it back
Because the provocation is a position rather than a distance, the useful way to plan this is to rank what you do by how much it compresses, then move up and down that list.
For most runners the bottom of the ladder is flat easy running and standing work, the middle is longer runs and loaded hip hinges through a small range, and the top is hills, speed work and deep-range loading. Hills and faster running are consistently near the top, because both ask the hamstring to work hard while the hip is bent1.
1During the run, it stays at five out of ten or below.
2By the next morning, it is back where it started.
Surviving the chair
Sitting pain is usually the last symptom to go, and it is the one that wears people down, so it is worth managing rather than enduring.
A higher, firmer seat bends the hip less than a low soft one. Moving a car seat slightly forward and raising it helps for the same reason. A cushion spreads the pressure on the bone. Standing up every twenty minutes resets it.
What does not help is avoiding sitting altogether. Tolerance for sitting is itself something you can lose, and it takes a long time to get back1.
How long it takes
Longer than you want, and the honest answer is that nobody has measured it properly in a trial. What the clinical guidance describes, and what we see, is meaningful change over a couple of months and a full return to hills and speed taking longer than that1. Sitting pain lags behind running comfort, so you will probably be racing again while a long drive is still annoying.
Progress is not linear, and a flare after a step up is information rather than a setback.
When to get it looked at
Buttock pain has several possible sources, and the attachment of a tendon, the bone it attaches to, and the nerve that runs nearby all sit within a few centimetres of each other. That is a good reason to have it named rather than assumed7.