ExRx.net

I'm new to your fine website, so I must be missing something, but I can't find any info on one of the largest muscles in the body- the psoas. It's not listed in the muscle section, nor in the exercise section. I thought the "V up" and related exercises would heavily activate that muscle. It's not mentioned in "hip flexors" which, I thought it was a part of. I know it's not a visible muscle, so some body builders might not be interested in it, but I'm an athlete looking for total body fitness for functional movement. I do some weightlifting, yoga, run, hike, bike, and ski and am presently looking at potential muscle imbalances and ways to correct them. I assume that the psoas is often overlooked, especially since I can't find one mention of it on your site! Oh, I love the little videos of each exercise- makes it easy to understand.

http://exrx.net/Lists/ExList/HipsWt.html#anchor1938598
http://exrx.net/Muscles/Iliopsoas.html

You couldn't find it because you were looking for the individual muscle. The Iliopsoas is a group of muscles that work together:
psoas major
psoas minor
iliacus

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Let thy food be thy medicine, and thy medicine be thy food.~Hippocrates
Strength is the adaptation that leads to all other adaptations that you really care about - Charles Staley
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Thanks TimD

That was a quick reply, thanks. I see "psoas" was hiding in "illiopsoas". Ha, I feel pretty stupid, but I would guess many weightlifters have not heard of either one. I'm wondering if it tends to be a weak link in many athletes that don't specifically train it. I've heard that alpine skiers can have relatively weak hip flexors compared to extensors, possibly contributing to injury.

I can see how skiers may need stronger hip flexors. It's usually the other way around, strong Psoas overpowering weak abs due to sitting all day is a common contributor to lower back pain. There's some discussion about that here:
http://www.exrx.net/Questions/DangerousExercises.html

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Let thy food be thy medicine, and thy medicine be thy food.~Hippocrates
Strength is the adaptation that leads to all other adaptations that you really care about - Charles Staley
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Thanks TimD

Hip flexion is really interesting. Well, to some people anyway..

I definitely agree that short/stiff "hip flexors" can overpower glutes and abs causing an anterior tilt and contribute to lower back pain. However, I think when you look "within" the hip flexors, it's not as simple as that.

I think the psoas has got a bad rap due to it being lumped into the same category as all the other hip flexors. However, the psoas is distinct from the others. The other hip flexors all attach at the iliac crest (think, pelvis) but, the psoas is attached to the lumbar spine. This is important because, well, it's the lumbar spine, so it has direct control over it, to an extent. Also, and more so, the lumbar spine is higher than the pelvis. This means the psoas pulls the femur higher than the hip or, beyond 90degrees of flexion whilst the others are at a mechanical disadvantage to do so.

Beyond 90degrees of hip flexion is basically parallel and lower in a squat. Not many untrained people - men especially - can squat below parallel without rounding the spine or tucking the pelvis (which just precedes rounding...).

If we go back to Psoas and consider it's attachment on the lumbar spine, then for example sake, assume it's "weak" during hip flexion. In order to get beyond 90degrees, the only place left go to take the movement further is lumbar flexion/lower back rounding. Therefore, if the psoas is weak, the lower back will flex in compensation. This is actually very, very common.

I would bet that the psoas is more commonly weak/underactive than overactive in most. The psoas is essentially what "pulls" you into the hole in a squat, and not many people can get into the hole in a squat without compromising the stable position of the lower back (forcing it to move/flex).

I would say the psoas also flies in the face of the sometimes over simplified (but still largely effective) theory that, lengthened muscles = weak/underactive, short muscles = stiff/overactive. I don't think it's always either/or and the psoas is a great example. We need length AND we need strength, AND we need function.

A good way to test this is stand up tall in a good military posture and pull one knee up towards your chest. Keep the chest up, then let go of the knee, maintaining that posture and trying to keep the knee as high as possible (above the hip) for 15 seconds. If it falls to or below 90degrees instantly or before 15 seconds, or the anterior hip cramps up, or you get a big tilt to one side, then your psoas is likely weak and you need to train hip flexion above 90degrees... You probably also need to learn how to use them to pull you into a squat (the "function" aspect).

Also, it's much easier to think movements not muscles - just make sure hip flexion is good, particularly above 90degrees...

KPj

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Thanks TimD

KPj, how would you go about strengthening a weak psoas?

You just need to get the knee above the hip with a neutral spine and good posture (watch for lower back rounding and chest caving forward - your torso should be like a pillar and not change position). There are various ways to do this and the approach really depends on the individual but i've got some basic progressions...

Activation: I'll put this in a warm up for those who can barely hold the knee above the hip. Get an aerobic step at a height that, when you put your foot on it, your knee is just about level, or a little below the hips. So, right now you look like you're about to do a step up with your foot on the step. Then just "brace", and lift the knee as high as possible without losing form for 5 seconds, and that's one rep. As a starting point, we'll do 3-5 holds per side before every session after mobilising the hips.

You can't strengthen the muscle(s) if you can't switch it on so, no point looking for resistance initially. I do the above and retest every couple of weeks using the assessment mentioned above. When they can hold the knee up for 15 seconds, I then put them on their back, choke a light band around something (normally a resistance machine in our warm up area), and loop the other side of the band around your foot. We place one hand/forearm under the lower back to force the arch to stay put, and we flex the hips/lift the knee towards the chest against the band. I like to "stick" at the top i.e. hold for a second or 2.

You can do with cables, too, which is shown here with 2 feet at a time, but I prefer to do one at a time initially,

http://exrx.net/Articulations/Hip.html#anchor845056

At this point i'll also add the kneeling rock back to the warm up, great example of how to do and not to do it in the following blog by tony gentilcore (this movement also highlights the relevance to hip flexion above 90, squatting, and a maintaining a neutral spine). I love this for teaching people how to "feel" the hip flexors "pull" you into a squat.

http://www.tonygentilcore.com/blog/q-a- ... g-part-ii/

When the band is no problem and your hip no longer goes on fire from it, you want to move to your feet. This is where the likes of "high knee walks/skips" bring it all together into an athletic movement (and still during the warm up), and ideally you should be able to squat deeper and better at this point and therefore also using flexion above 90degrees in movement...... Remember the challenge can lie in taking what you can do on the floor and doing it on your feet. It's much easier doing things on the floor. You can nail it on the floor then stand up, move around, and crumble into the same old dysfunction that caused the issues in the first place.

So, at this point, you want to move to your feet. One example is standing with your back to a cable, with a D-handle on the low cable. You loop this round your foot/toes and then flex the hip whilst standing against the resistance of the cable. I don't go crazy with this i.e. i won't give it a 5-3-1 progression or anything. I just want people to be able to get that knee above the hip with good form and with ease.

At this point, i've not seen anything miraculous happen from maintaining a dedicated focus on it and i suspect this because you are now putting the new found function to good use in things like squats and lunges. This is the point where a formerly bad squatter will now be squatting deep with good form and lunging off steps etc, and this is really what the function of flexing above the hip is for (as well as sprinting and jumping.. even kicking....).

KPj

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Thanks TimD

interesting post there Kenny. I'll add psoas strengthening to my list of stuff I should...

It's a long list

Do the test mentioned and see how you do. BTW, this is very related to the "hurdle step" in Athletic Body in Balance.

Also, "long list" depends on how you look at it. I would just list it as, "Improve movement" - if for anything else, it makes life a lot more straight forward.

KPj

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Thanks TimD

Somebody stole my copy of Athletic Body in Balance at my gym

The psoas is a bit of a sticky wicket when it comes to pain free movement. The hip flexors are a commonly tight structure that can cause painful or restricted movement, but the most common attack patterns are not only pretty useless, but reductionist to an absurd degree. The body as a whole is a structure supported by tensional integrity, like a geodesic dome or a circus tent. Focusing on -- or perhaps more accurately blaming -- a single point in an enormous complex system is a recipe for a... tent collapse? My metaphor is getting a bit long in the tooth. The point is, look at the tent, not individual poles.

Don't train your psoas to achieve a particular movement goal, train movements. You'll get a lot more mileage. And, uh, clowns in your tent...?

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that's just god when he's drunk

Thanks so much for everyone's input!