Hamstring Origin Tendinosis

The tendons at the sitting bone. The hamstring muscles at the back of the thigh start from the sitting bone (the ischial tuberosity), the part of the pelvis you sit on. Two of them, semitendinosus and the long head of biceps femoris, share one tendon there, and semimembranosus attaches beside it. Reports call this area the hamstring origin. The sciatic nerve runs close beside it, so a report on the tendons may mention the nerve as well.

Tendinosis, tendinopathy, tendonitis. Tendinosis means the tendon’s structure has changed: it looks thicker, or a patch inside it looks different on the scan. Tendinopathy is the general word for a painful tendon that is sensitive to load, the condition covered on the proximal hamstring tendinopathy page. Tendonitis, also spelled tendinitis, is the older word; it suggests inflammation alone, which is not the whole picture.

The words that come with it. These are the terms you are most likely to see with it on a hip, pelvis or buttock report.

It is common in people with no symptoms there. In 253 consecutive patients aged 13 to 89 whose hamstring origins caused no symptoms, only 35 percent looked normal on both sides on MRI. The rest had tendinosis or a tear on at least one side: about a quarter had tendinosis alone and about a third had a partial tear (15 percent on both sides). The groups with changes were older: the middle (median) age was 51 with normal tendons, 56 with tendinosis on both sides and 63 with partial tears on both sides (Thompson et al., 2017).

Brighter signal inside the tendon says little about pain. In 118 people who had a pelvic MRI and a clinical examination, 21 of them with hamstring tendinopathy on one side, more than 90 percent of hamstring tendons showed brighter signal inside, and it was not linked with symptoms. A larger tendon, fluid signal around it with a feathery look lower down, and edema in the sitting bone were each more common in the hamstrings with symptoms, but all of them were also seen without symptoms (De Smet et al., 2012).

Age changes what the picture means. In a study of 31 people with symptoms and 31 without, matched for age and sex, the curved fluid line of a partial tear was seen in 10 of those with symptoms, all over 45. Seven of the people without symptoms, all over 45, showed it too, and four of the younger people without symptoms had signal change inside the tendon. The authors concluded that a tendon that looks abnormal after 45 may or may not be the source of symptoms, while changes in younger patients usually are (Bowden et al., 2018).

A normal-looking scan does not rule the tendon out. In the same study, 8 of the 31 people with symptoms had tendons that looked normal on MRI (Bowden et al., 2018). The diagnosis is made mainly from the history and the examination; the 2025 trial described below enrolled people on those alone, without a scan (Rich et al., 2025).

When the report mentions the sciatic nerve. The nerve runs close beside the hamstring origin, so an irritable tendon can sometimes irritate it. In 14 people with long-standing sciatica whose nerve scans showed a change in the sciatic nerve at the sitting bone, 8 had tissue changes beside the hamstring origin, and 7 of the 9 with a detailed history had injured that area before. The authors still describe a hamstring injury as a cause of sciatica to accept only once other causes are excluded (Bucknor et al., 2014). The hamstring tendinopathy or piriformis syndrome comparison covers deep buttock pain with nerve symptoms.

It does not decide the treatment. What decides the plan is where the pain is, what sets it off and what the examination shows. Pain in one spot on the sitting bone that is worse on hard seats, with hills or faster running and with deep hamstring stretches fits the tendon. Pain that travels below the knee with numbness, pins and needles or weakness points to the lower back or the nerve instead, and the sciatica or hamstring tendinopathy comparison sets out the differences. A complete tear after a sudden injury is the main exception, covered below.

The tendons carry pulling forces when the hamstrings work, and at the sitting bone they are also pressed against the bone. That pressure comes with deep hip bending, as in squatting and lunging, with sitting, and with stretching the hamstrings, and these loads commonly bring on the pain in people with this condition (Rich et al., 2025). A hard seat or a long period without a break presses on the same spot, and a deep toe-touch stretch adds pressure at the sitting bone to the stretch.

Running asks for a strong pull instead: the hamstrings work hard as the leg swings forward and the body moves over the planted foot, and speed and slope raise the demand. That matches the usual triggers, which are hills, faster running, lunges, a long drive and a hard chair. Pain with sitting does not mean that sitting has stopped the tendon from repairing. A supportive seat, a cushion that spreads pressure and standing up every 30 to 45 minutes may make sitting easier while strength is built up.

The research on this tendon is thin. A 2021 review found 12 studies, only two of them randomised trials, and too little evidence to recommend any one treatment over another (Nasser et al., 2021). Treatment builds how much load the tendon can take, with other options fitted around that.

• Progressive loading. The usual plan moves in stages: holds that do not move the joint (isometric exercise), then heavy, slow strength work, then faster, spring-like exercise, with sitting and stretching adjusted along the way (Goom et al., 2016). It borrows principles from Achilles and patellar tendon rehabilitation that are less well documented for this tendon, and research has not established one best program.
• Physiotherapy compared with shockwave. In a trial of 100 adults with at least three months of symptoms, most of them recreational distance runners, six sessions of individualised physiotherapy built on progressive strengthening were compared with six sessions that included four shockwave treatments and no prescribed exercise, with the same advice and education in both groups. Function and overall change did not differ significantly at any point up to a year. With no sham or untreated group, the trial cannot show how much either treatment added to advice and time (Rich et al., 2025).
• Shockwave. An earlier trial in 40 professional athletes compared four weeks of shockwave with anti-inflammatory medication, physiotherapy and a hamstring exercise program. Three months after treatment, 17 of 20 in the shockwave group had at least 50 percent less pain, against 2 of 20 in the other group (Cacchio et al., 2011). The 2021 review rated that evidence as very low certainty (Nasser et al., 2021). Taken with the 2025 trial, the evidence is mixed. Shockwave may help. It is offered alongside the loading program, although neither trial tested the two together.
• Injections. In a series of people with high hamstring tendinopathy given a cortisone (corticosteroid) injection guided by ultrasound, half improved for more than a month and 24 percent for more than six months (Zissen et al., 2010). For platelet-rich plasma (PRP), one small trial found no difference from an injection of the person’s own whole blood. The review rated the evidence for every type of injection as low or very low and could not recommend one injection over another, or over none (Nasser et al., 2021). An injection is a medical decision, weighed with a physician.
• Tendinosis and partial tears. Reviews of injuries at the hamstring origin report that tendinopathy and partial-thickness tears can often be managed without surgery, with surgery kept for those that do not respond (Degen, 2019; Sheean et al., 2021). The studies of surgery for tendinopathy are case series with no comparison group, rated very low certainty, and surgery had the most complications of the treatments reviewed (Nasser et al., 2021).
• Complete tears and avulsions. Surgical repair is considered for a sudden tear with more than 2 centimetres of retraction and for an old retracted tear, and early repairs do better than late ones (Sheean et al., 2021). Not every avulsion needs surgery: in a trial of 119 adults aged 30 to 70 whose hamstring tendons had pulled off the sitting bone, function two years later was no worse with non-surgical treatment than with surgery (Pihl et al., 2024). The choice is made with a surgeon, which is why a suspected avulsion needs that opinion within days.
• How long it takes. Recovery is usually measured in months. A staged program may extend over 3 to 6 months or longer, but that is a planning guide, not a deadline. Sitting comfort, strength and return to faster running may improve at different rates. It can be persistent: half the people in the 2025 trial had already had symptoms for more than a year when they joined (Rich et al., 2025).

I start with where the pain is and how it began. Pain in one spot on the sitting bone that crept in over weeks and is worst on hard seats, with hills or faster running and with deep hamstring stretches points to the tendon. A sharp pull at one moment you can name points to a strain instead, and the hamstring strain or tendinopathy comparison sets out the differences. A pop at the sitting bone with bruising or difficulty walking is different: check the warning signs on this page first.

On examination I press on the sitting bone, test the hamstring against resistance with the hip and knee in different positions, and use stretch tests done with the knee bent, which often bring on the familiar pain when the tendon is the source. I check the lower back and run nerve tension tests, because the back and the sciatic nerve can send pain to the same area. Then I read the report alongside what I found. I cannot order imaging; when imaging would change the plan, I flag it to your family doctor or a sports medicine physician and refer you.

For tendinosis and most partial tears the plan is the same. Early on, the sitting set-up changes and hard hamstring stretches are eased off, and loading often starts with holds, such as a bridge with the heels on a low step. Slow, heavy strength work follows, beginning with a shallow hip hinge and adding depth and weight as the tendon copes. Hills, speed or the demands of your sport come back in small steps, and easy, flat running can often stay in at a reduced dose. The proximal hamstring tendinopathy page sets out the stages in detail.

If progress stalls, I reassess the plan before adding more effort. Shockwave can be added alongside the exercise, and an injection is a decision for your family doctor or a sports medicine physician. A report that shows a complete tear, or a tendon pulled back from the bone, after a recent injury needs a surgical opinion within days. Tendinosis or a partial tear that still limits you after a fair course of non-surgical care is also a reason to ask your family doctor about a surgical opinion.