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Hip Flexors for Squatting...


Can anyone tell me the real significance of the hip flexors during squatting? I am a pre-PT student and I read tons of orthopaedics / biomechanics stuff, and I really can't figure it out. Some say pelvic stability and other stuff, but so many people talk about how their hip flexors are so weak and it hurts their squat. How? When guys say that they are weak off the box during box squats, I don't get that. How are the hip flexors the issue during active hip extension? Flexiability; sure, but strength????


good question, all I know is that on the concentric of a squat, which if I am mistaken, hip flexion I feel them all the time. Tight hip flexors can be a pain in the ass, espeically for me, i have trouble getting out of the hole on both sqauts and deads. Not because my glutes are weak but because my HF's are so overactive that my glutes are lengthen, recipical inhibition

But yes the concetric of a squats is hip flexion


No; the eccentric is hip flexion. The concentric hip extension. Thats why I put in my post; "active hip extension". You sit back into hip flexion on the eccentric and then EXTEND the hip and back on the concentric.


The concentric is hip extension, the eccentric is hip flexion.


From a kinesiology standpoint, it remains difficult for me to explain. However, the best advice I received regarding the squat is to have the hip flexors pull you down rather than the weight on your shoulders pushing you down. Second, in the famous words of Dan John, your torso is slung between your legs and all you do is sit between them. Amazing how this little visualization can make all the difference in the world.



hmmm I always thought it was the other way around


AFAIK, hip flexion plays no active role while squatting. the fact that the eccentric phase involves hip flexion is no matter because the hip extensors are still the ones bearing the load.

AFAIK, one of the hip flexors is also a knee extensor. so that guy will be active while squatting.

the whole thing about how tight enough hip flexors will keep somebody from squatting deep enough irks me (unless they're talking about the hip flexor that is actively involved during squats; but then the "tight" inhibition would apply for all active squatting muscles). i just dont get how a muscle that is shortened causes ROM problems cuz it's too "tight." although, this is true with the active muscles.


They also play a role in hip abduction (moving the leg away from the body) so they come in to play during wider (power) squats. I think this is one of the ways you get a bigger stretch reflex out of wide squats; you'll definately feel you hips after some wide and low squats.


Well, as you go down (sitting back) the hip is going into flexion. As you come up (standing) the hip is extending.


The rectus femoris (part of quad) also acts as a hip flexor; however, my people are referring mainly to the iliopsoas (illiacus and psoas major).


Best I can figure, it's because the tight hip flexors would pull the back/pelvis forward a bit when trying to maintain an erect torso. So, while it wouldn't stop downward motion like tight hamstrings would, tight hip flexors would cause too much of a forward pitch of the torso, basically turning the deep squat into a good morning.

That'd be pretty much just the rectus femoris, though, unless we're talking EXTREME tightness of the others.



they would have to be so tight that they'd shorten your trunk flexors. i dont think this is the case. full squats have complete hip flexion to begin with, the "coming forward" is a trunk thing. a "rounded back" is necessary with full squats. if you didn't round your back you'd fall backwards because the weight would be quite a bit behind your center of gravity.

the whole "tight hip flexors causes squat depth problems" sounds made up to me. maybe we can get Cressey or Robertson in here...


the rectus femoris is what i mean, then, when i say "a hip flexor that acts as a quad extensor." i tend to know movements better than muscles.


The hip flexors are mainly for stability and balance during the squat. Especially during the transition from the eccentric (going down) to the concentric (going up). If someone were to have tight hip flexors, such as some sprinters may, they wouldn't be able to extend completely during their stride which would cause them speed.

If guys in the gym say they have troulbe getting out of the box then its probably because they're loading improperly and not using their glutes as much as they should. When the glutes aren't loaded you lose stabiltiy which may be why they relate it to their hip flexors. Also you should never round your back, you lean forward some but ALWAYS keep your back straight or slightly arched.


apparently the terms are being confused. because trunk flexion is a MUST for full squatting. trunk flexion=back rounding.

how are hip flexors mainly for stability during squats? how do they even play an active role during squats? how are they anything other than hip flexors which dont bear any of the load during squats?


Good thread guys. I love the psoas so here are my 2 cents.

The role of the hip flexors, particularly the psoas, during any squatting movement, if squatting correctly, is to actively "pull," or draw, the femur toward the trunk/pelvis during the descent. This allows for a flatter back position and if performed correctly, maintains a relatively neutral pelvic postion.

This "active negative" as Pavel Tsatsouline calls it, allows for a greater contraction of the glutes during the concentric portion of the squat. This allows for increased stability of the lumbar spine actually preventing excessive anterior pelvic tilt which is commonly associated with "pushing the hips out" to squat. (You'll also feel increased innervation of the "fabled" lower abdominals, which also contribute to the neutral pelvic postion.)

I suspect that because the psoas major attaches on the lesser trochanter of the femur, this active negative actually changes the angle/glide of the femur's head in the acetabulum--creating a slight bit more external rotation of the femur. (I have 2 torn labrums--1 in each hip and this is the only way I can full squat without flaring those bad-boys up--very painful--hard to walk!)

As far as trunk flexion when squatting--there should be ZERO. If there is, you are pulling out your spine's double-s curvature which is essential for proper weight distribution and proper execution of the lift. If the low back rounds (tale tucks under) in the full/olympic squat position, you are performing it incorrectly and are setting yourself up for a posterior disc herniation sometime in the future. If your low back rounds, it's an indication of tight hamstrings and/or adductors and sometimes calves.

Hope that contributes something positive.


Oh! My favorite topic - squats.

The rectus femoris is the only (primary) hip flexor that is likely to have a large influence on your range-of-motion in the squat. Its influence will be greater as the squat becomes deeper.

To reiterate what some others have said: There should be no trunk flexion/back rounding in a squat of any depth.

If you are unable to maintain neutral curvature of the spine, gaining flexibility in the limiting structures should be your priority. The usual culprits are rectus femoris, gluteus maximus, and soleus. It also wouldn't hurt to strengthen (statically) the erector spinae group, rectus abdominus, and quadratus lumborum. Throw away that belt!


i still think the terms are being confused because panterarosa claims that there should be no trunk flexion/back rounding in a full squat, and claims the spine should be neutral. technically, spinal flexion and a "neutral" spine are not the same thing.

now, hearing you guys say that trunk flexion has no role in full squatting makes me think that you A) have never done them, B) have done them but haven't consciously noticed trunk flexion (since you're trying to maintain a "neutral" spine), or C) haven't ever even thought about it because lots of "gurus" say the trunk should never be under flexion during a full squat (actually, they tend to use the word "neutral" but it seems that word has been used interchangeable with the thought "fully extended").

personally, my full squats are two inches shy of ass touching floor. i recently just finished doing a three week cycle of full squats, 3 second pause in the hole, taking 3 reps to near failure. and i can assure you, my trunk was under flexion in the hole, and my good form was quite enviable. if it wasn't under flexion then i would've fallen backwards (actually, it's a good thing that the trunk flexes once you reach a certain depth because if it didn't it would be really fecking hard, if not impossible, to dump the bar behind you).

if you dont believe me then try this experiment: grab a broomstick, stand beside a mirror (like a profile), get into full squat stance, hold broom in overhead squat position; now slowly descend into a full squat while keeping your trunk completely extended. if you do this right, you'll find out that you fell backwards before you even reach parallel. for me this happens about 3-4 inches shy of PLers' measurement of parallel. depending on your leverages it may vary.

still dont believe me? try this: get in the same position as before, but squat down to the deepest depth you can. you should notice that your back is straight, but because of the postion of your hips it is, technically, flexed. now, while sitting in the hole and without moving any other part of your body, slowly extend your back. if you do this right you'll find that you fell backwards quite a ways before you were able to completely extend your back.

still dont believe me? well then, i'll reference, the one and only, Pyrros Dimas...


here's Pyrros in a full squat. notice the angle of his back.


another of Pyrros in a full squat (ahem, almost a full squat). notice the angle of his back.