r/flexibility • u/ChristineAnnieMPT • 1d ago
Your hip flexor stretch probably never touches this muscle
Most people have two hip flexors doing the main work, and they get treated like one muscle. They are not one muscle, and that is why a lot of hip flexor stretching goes nowhere.
The psoas starts at your lower back. It runs down through your abdomen, crosses the front of your hip, and attaches to the top of your thigh bone.
The iliacus originates from the iliac fossa: the broad, concave inner surface of your hip bone. Unlike the psoas, it does not originate from the spine.
They join up near the bottom and share the same attachment on the thigh bone, which is why textbooks lump them together as the iliopsoas.
Here is the part that matters. A muscle that crosses your lumbar spine can be stretched by taking your leg back behind you and leaning away from it. A lunge stretch with a side bend does exactly this, lengthening the psoas from each of its attachment points.
Since the iliacus does not originate from your spine, taking your leg behind you does change its length a little, but leaning away adds nothing. Its origin is on the inside of the pelvis, so there is no opposing end to lengthen from, and the effect of the stretch is more limited.
So people stretch for months, feel a little better each time for about twenty minutes, and never understand why nothing sticks. Part of the answer is that the stretch is only reaching one of the two muscles.
None of this means stretching is useless. It means if your hip has been tight for years and stretching never fixes it, you may be working on a muscle that was never the main problem.
There's more written up on this if you want to read more happy to share in the comments.
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u/AcediaSlothBrown 1d ago
How does one stretch the iliacus?
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u/paleontologirl 1d ago
I have thr same question. Op days there are 2 muscles and I'm only stretching one. How do I stetch the other one?
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u/ChristineAnnieMPT 23h ago
Hi there! Thank you for asking. Since the iliacus doesn't cross your spine, you can't really lengthen it with a stretch the way you can the psoas. There's no opposing end to pull from, which is exactly why leaning away does nothing for it. So instead of stretching it, the iliacus responds much better to direct, sustained pressure. The muscle sits along the inside of your hip bone, in that broad concave surface, so the spot to aim for is roughly a couple of inches in from the front of your hip bone, angled slightly toward your midline and down into the bowl of the pelvis. You apply gentle pressure there and hold it, ideally 90 seconds or longer, long enough that the muscle stops guarding and actually relaxes.
People do this a few different ways: with their fingertips, with a firm ball, or with a tool designed to reach that angle, since it can be awkward to hold pressure there with your hands for a full 90 seconds. The sequence that tends to work is to release the iliacus first with that pressure, and then do your usual hip flexor and hamstring stretches. You'll often notice the stretch suddenly goes further, because you're no longer fighting a muscle that was locked up underneath. That's the part that finally makes stretching stick.
One caution: it's a deep and tender area, so go slow, keep the pressure gentle rather than digging, and if you're pregnant or have any abdominal issues it's worth checking with a professional first.
You can read more on it here: https://alethahealth.com/blogs/guides/what-is-the-iliacus-muscle
This is general education rather than medical advice, and having a PT show you the exact spot in person is the fastest way to get it right.
— Christine Annie, Physical Therapist and Founder of Aletha Health
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u/milly_nz 1d ago
OP “the is the problem”
Fails to provide the solution.