The Buttock Pain Everyone. Thought Was a Hamstring Problem.
Nobody expects a year long mystery to end with a simple walking test. That's exactly why it's worth paying attention.
A few weeks ago someone came to see me with pain that had been there for more than a year. Deep in the lower buttock. Worse with walking worse with running. He'd been told it might be a hamstring problem. Sciatica had also been considered. His X-ray hadn't provided an explanation.
Then I asked him a simple question "What happens when you sit ? "Nothing " he said. In fact sitting felt better. That answer caught my attention proximal hamstring tendinopathy one of the conditions I'd normally consider here is usually aggravated by sitting. His pain behaved differently.
So I looked at what happened when he walked. A shorter stride was comfortable. A longer stride taking the hip further into extension reproduced the familiar pain. Now there was another possibility worth considering ischiofemoral impingement.
After almost four decades in clinical practice, I've learned that the location of pain doesn't always tell you where the problem is coming from. Sometimes the useful clue is something that doesn't hurt at all.
A small space deep behind the hip
Deep in the hip is a space between the ischium the bone we sit on and the lesser trochanter of the femur. This is the ischiofemoral space, and the quadratus femoris muscle lies within it. In ischiofemoral impingement or IFI structures in this space can become compressed during certain hip movements.
The condition isn't new. But a 2026 clinical masterclass by Alison Grimaldi, Charlotte Ganderton and Anthony Nasser describes it as an under recognised source of lower buttock pain. What stood out to me wasn't the anatomy it was the reasoning. Where exactly is the pain? Does sitting make it better or worse? Does a long stride reproduce it? What happens when the hip moves into extension and adduction? Those four questions can change the direction of an examination.
Why it gets mistaken for something else
Deep buttock pain can come from several structures. Proximal hamstring tendinopathy causes pain around the sitting bone and is often aggravated by sitting. Gluteal tendinopathy produces pain on the outside of the hip around the greater trochanter. Lumbar problems can refer pain into the buttock and sometimes further down the leg. Hip joint disorders can also produce pain in this region.
IFI belongs on that list too. One useful clue is pain provoked by positions that narrow the ischiofemoral space a long stride for instance. There are also clinical tests designed to provoke this specific region. In one small diagnostic study of 30 patients the long-stride walking test had 94% sensitivity and 85% specificity. The ischiofemoral impingement test had 82% sensitivity and 85% specificity.
Those are useful numbers but 30 patients is a small study. I wouldn't diagnose someone from one test alone.
What about MRI?
MRI can show narrowing of the ischiofemoral space and changes within the quadratus femoris muscle. But an MRI finding isn't the same as a diagnosis. A 2025 study examined 256 hips in young patients being evaluated for joint-preserving hip surgery. MRI findings consistent with IFI were present in 9% of the hips associated with female sex increased femoral torsion and a larger ischial angle. But this was a selected specialist population. It does not mean that 9% of everyone with buttock pain has IFI. Imaging can support the clinical picture. It shouldn't replace it.
So what do you actually do about it?
The first step isn't an injection an operation or complete rest. It's identifying which movements are repeatedly provoking the area. For someone whose symptoms appear with a long stride temporarily shortening the stride reduces hip extension and can make walking more comfortable straight away. Other aggravating positions may need to be modified for a period too.
Then comes rehabilitation. Progressive strength training is part of conservative management strengthening the muscles that control the hip and pelvis and gradually progressing from simpler exercises to single-leg loading. The goal isn't just a stronger muscle it's enough capacity to walk run and move through daily life without repeatedly provoking the painful position.
How the hip moves during walking running or sport influences symptoms too so rehabilitation often includes movement and gait retraining alongside strength work with the aggravating activity gradually reintroduced as tolerance improves.
This isn't a quick process, and there isn't yet a large body of randomized trials telling us exactly which exercise program works best for IFI. That's worth being clear about.
The current evidence supports a conservative approach built around education modifying provocative positions movement retraining and progressive exercise. For persistent cases that don't respond, image guided injections may be considered. Surgery exists too but for carefully selected cases not as a starting point.
What happened to him
We shortened his stride on the treadmill and the pain eased within the same session. That gave us a clear direction temporary stride modification hip strengthening progressed from double-leg to single-leg work and a gradual return to his normal running distance. Six weeks in he was running his usual route again pain-free. No injection. No scan needed to start. That was his outcome. Every case is different and the same approach or timeline won't be right for everyone.
What this case reminded me
I've worked with back hip and musculoskeletal problems for almost four decades. One lesson keeps returning the location of pain doesn't always tell you where the problem is coming from. Sometimes the useful clue is something that doesn't hurt.
In this case sitting was comfortable. Walking with a longer stride wasn't. That difference changed what I wanted to examine.
So when someone comes in with unexplained deep buttock pain one of the simplest questions I can ask is "What happens when you sit?" Then I want to see them walk. Neither gives me a diagnosis on its own. But together with the rest of the history and examination they can point me in a direction that might otherwise be missed.
Research behind this newsletter: Grimaldi A, Ganderton C, Nasser A. (2026). Clinical masterclass on ischiofemoral impingement. Musculoskeletal Science and Practice. · Gómez-Hoyos J, et al. (2016). Accuracy of 2 clinical tests for ischiofemoral impingement. Arthroscopy. · 2025 study of 256 hips undergoing evaluation for joint-preserving hip surgery.
This newsletter is for general education. Persistent or unexplained buttock or hip pain should be individually assessed.
Until the next signal,
Dr Erik Rudberg, DC
Most people wait for pain. The attentive ones notice the signal.
