What you’re getting yourself into

~2,400 words. 6-10 minute read time.

Key points:

1) When you miss a squat, it’s not because one muscle or muscle group failed – they all failed sequentially; what you perceive as your limiting factor is just the last thing that failed.

2) The quads are “maxed out” earlier in the movement than the hip extensors.

3) When you don’t purposefully rely on your quad strength and don’t try to lead with your chest out of the hole instead of your hips, you run the risk of shifting extra load to your hip extensors. Since they are the last thing that fail you, increasing the proportion of the load they’re handling can limit your ability to squat as heavy as you’d otherwise be able to.

Before we get into this post, I want to let you know about our giant How to Squat guide. It covers everything you need to know about every aspect of the squat – from biomechanics to correcting weaknesses to technique. Click here to open it in a new tab so you can check it out after you’ve finished reading this article.

In the last article about squat technique, there was some confusion about the section labeled “Intent.” The purpose of this article is to flesh out that point a bit more rigorously so you’ll see why, in spite of your hip extensors (glutes, adductors, hamstrings) being stronger than your quads, it is wise to rely on your quads in the squat to the greatest degree possible. If you haven’t read it yet, I’d suggest you do so. Otherwise, this one may feel like you’re stepping in on the middle of a conversation.

Out of necessity, there’s a decent amount of math in this one as well, but – just as in the last one – the numbers themselves aren’t as important as simply understanding “less” and “more.”

First things first, we need to talk about what happens when you miss a squat. People like looking at video of a missed lift and trying to pick out what failed them. Maybe their back started rounding. Maybe their hips shot up, putting them in a bad position, etc. However, if you try to pick out THE thing that failed you, you’re going to come up with the wrong answer (provided you didn’t do something like simply misgroove the lift or lose your balance). Why? Because everything failed you – just at different times. When you look for the limiting factor, you’re typically mistakenly looking for what failed you last.

Here’s what I mean:

At the bottom of the squat, the quads are maximally challenged. This is both when their EMG readings are highest and their relative muscular effort peaks. (Bryanton and Wilk).

Relative muscular effort for the hip extensors, with heavy loads, remains elevated from the bottom of the lift through the sticking point, but there’s a sequencing in how they work. At the bottom of the squat, glute EMG reaches maximal (disclaimer: that study is a little wonky, but I haven’t been able to find any better ones about this particular subject), with more of the work shifting toward the hamstrings through the sticking point (again, see Wilk, 1996 above).

This is what I mean by only seeing what fails last: When you see someone miss a squat, usually they get folded over, whether that means their back started rounding, or the bar just starts pushing their chest toward the floor and their hips flex again. However, that was just the last thing that failed. How did they get there in the first place?

Well, out of the bottom of the lift, the quads “max out” (hopefully – we’ll get to that later), shifting more of the work to the hip extensors. Coming out of the hole, if the glutes and adductors can handle the extra work, the back angle should remain consistent from around parallel to the sticking point. If the glutes and adductors can’t handle the extra load, the hips flex a bit further, lengthening the hamstrings so they can take over as a prime mover sooner in the movement (functioning primarily in force transfer out of the hole, then functioning as more of an active hip extensor as the lift progresses). Once you make it to the sticking point, the quads are doing a bit less work (shorter moment arm and lower EMG, though they’re still contracting hard to stabilize the tibia for the hamstrings to contract against), and the hip extensors are straining to get your back upright. Finally, if your hip extensors or your spinal erectors fail at the sticking point, you’re folded over and you miss the lift.

On video, any of those scenarios would end up looking like your back or hip extensors were the limiting factor. In reality, they were simply the last things to fail. The quads had already “failed,” shifting more work to the posterior chain. The glutes and adductors may have failed (this doesn’t always happen – again, this usually shows up as increased forward lean on the concentric between parallel and the sticking point), and the hamstrings (with other hip extensors still contributing, obviously) and back are simply the last things to go.

Now that we’ve laid that groundwork, let’s talk about why relying as much as possible on your quads and trying to lead with your chest instead of your hips coming out of the hole is the best route to lift more weight.

Here’s our friendly neighborhood squatting stick figure again, at the sticking point of a squat. The picture on the far left is the “average” position in the sticking point again, as established in research on competitive powerlifters. We’ll assume that the sticking point in this study is the strongest position to be in through the sticking point. It’s not an assumption we have to make – any arbitrary position slightly above parallel with the hips doing the bulk (but not all) of the work will do, but we need numbers for the sake of comparison, so the sticking point established in this study will work as well as any.

The middle figure represents a more “quad-dominant” position, and the figure on the right represents a more “hip-dominant” position with the bar at the exact same place vertically. Just to give us some numbers, this guy is 1.8m tall and has average body proportions, and he’s squatting low bar (though bar position is largely irrelevant here).

The figure on the far left in the “optimal” position squats 250kg, and this is a true max. Based on the moment arm lengths for his quads and hip extensors, he has to produce ~254Nm of knee extension torque and ~676Nm of hip extension torque (net torque, factoring in the contractions of antagonist muscles).

The figure in the middle, if he had 250kg on the bar, would need to produce ~571Nm of hip extension torque (less than “optimal man”) and ~368Nm of knee extension torque (more than “optimal man”). Think back to what we’ve discussed already, though. Coming out of the hole, the quads should be the first thing to hit their limit and “fail,” shifting more of the load back to the hip extensors. Meaning, if a lifter is striving for this position, their failure to attain it will wind them up in the “optimal” position.

The figure on the far right, if he had 250kg on the bar, would need to produce ~791Nm of hip extension torque (more than “optimal man”) and ~112Nm of knee extension torque (less than “optimal man”). Thinking back on what we already discussed, the final thing to fail when you miss a lift is the hip extensors or spinal erectors at the sticking point. Meaning, since 250kg was a true max for “optimal man,” the fact that this figure needs to produce more hip extension torque than “optimal man” means that he would fail a squat with 250kg. In fact, he’d only be able to squat about 213kg in this position (213kg is the load at which, in this position, he’d only have to produce the same 676Nm of hip extension torque “optimal man” could).

This illustration used the sticking point, but the same basic set of factors applies in the hole or around parallel also. The strongest position will be the one at which the quads are doing as much as possible, and the hip extensors are doing as little as possible. To rephrase slightly:

What is the last thing that fails?

The hip extensors or back (for the purposes of this article, the distinction doesn’t matter, as the factors that would cause the hip extensors to be the last thing to fail are the same factors that would cause the back to be the last thing to fail; it will almost always be one or the other – and the cause is the same: the interaction of the weight on the bar and the distance of the hips behind the bar).

What work are they doing?

Whatever work the quads can’t do. A shorter knee extensor moment arm means a longer hip extensor moment arm, and vice versa.

Stated another way, every bit of work the quads could be doing that they aren’t doing is more work the hips must do to pick up the slack, leading to failing a lift with a load you’d have been able to lift otherwise (in the example above, the figure on the far right squatting 213kg to “optimal man’s” 250kg).

Now, a few anticipated questions:

“Why not just try to go to the ‘optimal’ position right away, rather than fight to attain a position that’s unattainable?”

Because of how loads naturally shift to the hips when the quads reach their limit. By attempting to force yourself back upright and lead with your chest out of the hole, you ensure that whatever weight your hip extensors eventually fail with is simply the first weight that’s too heavy. Since they’re doing as little as possible, when “as little as possible” is too much, that’s a pretty good guarantor that you couldn’t have lifted any more.

However, the opposite is not true. While the body will naturally shift more of the load to the hips when the quads hit their failure point, the hips don’t naturally shift more of the load to the quads in the squat if the quads are being under-utilized. I can’t pretend like I have any empirical evidence to support that last claim, but I’ve seen a lot of missed squats, and never once have I seen someone’s hips shoot up into an atrocious position, followed by a natural and effortless shift of more of the weight to the quads. Conversely, I’ve seen many, many weightlifters squatting while trying to stay as upright as possible, shifting more and more of the load to their hips as the bar gets heavier.

When you try to go to the “optimal” position right away under heavy loads by leading with your hips, only two things can happen: 1) you get it right. 2) you “overshoot” on the hips and “undershoot” on the quads coming out of the hole, meaning the hips end up having to do more work, decreasing the weight at which you ultimately fail. Conversely, when you try to keep a squat as quad-dominant as possible (trying to get upright coming out of the hole as fast as possible – leading with your chest and shoulders, not your hips), only one thing can happen: The quads do everything they can, and the hips “pick up the slack,” ensuring that the “slack” (the required hip extension torque through the sticking point that will ultimately cause you to miss the lift) is minimized as much as possible.

“Since the hip extensors are stronger than the quads and are the last thing to fail when you ultimately miss a lift, why would you squat in a manner that prioritizes the quads instead?”

Keep in mind, this is simply about cuing – what you’re trying to make happen, not what actually happens. Assuming you’re squatting with relatively heavy weights and pushing your sets relatively close (within 2-3 reps) to failure, by trying to stay as upright as possible and use your quads as much as possible, you’re still going to wind up in quite a “hip-dominant” position – just not one that’s more “hip-dominant” than in needs to be, which would ultimately limit performance. We’re talking about a difference of a few degrees here, not an entirely different movement.

“I thought more upright, ‘quad-dominant’ squats were worse for your knees. Won’t my ACL or patella tendon explode?”

Probably not. Squats of all shapes and sizes cause stress to the soft tissues of the knee FAR below what those tissues are capable of handling in healthy knees. The anterior shear force (what you’d be increasing with a more knee-dominant squat) tends to be considerably lower than the posterior shear force anyways.

That being said, if squatting in a certain manner causes you pain, don’t do it. Squatting comfortably is obviously much more important than optimizing the mechanics of the lift.

“I feel stronger and more comfortable leading with my hips out of the hole.”

Okay, then do that. I make no claim that anything I say applies to all people at all times in all circumstances – just that this is a generally helpful model for understanding the cues/intentions when squatting that tend to produce the most favorable set of circumstances for squatting a ton.

Caveats:

I’m assuming here that I’m talking to pretty experienced squatters interested in doing whatever they can to maximize performance. If you’re a fairly new lifter, none of this is really relevant to you. Just put a bar on your back and squat. Once you’ve gotten stronger and you’re comfortable with the movement, you may want to think about giving this a shot. I realize this isn’t a new idea. For years, people have been saying “lead with your chest,” “drive your traps back into the bar,” or any number of other cues designed to get the lifter to use their quads as much as possible and get back upright as fast as possible. I’d just never come across an acceptably good explanation for it, so I wrote one.

Getting yourself in a good position:

I’m not a huge fan of the “lead with your chest” or “chest up” cue. I used to say “show someone in front of you the logo on your shirt,” and it worked okay as a cue. Of late, however, I’ve preferred to think to myself/cue others “traps back, hips under” – driving your traps back accomplishes the same purpose as “chest up” without as many people naturally wanting to hyperextend their spines. The “hips under” cue gets people to perform the maneuver seen in this article and this recent squat video I took – getting their hips back forward and under the bar as the lift slows to make it through the sticking point with ease.

Since your hip extensors or spinal erectors are what’s most apt to ultimately fail at the sticking point, by cuing yourself to get your hips forward and back under the bar, you shorten that moment arm and make sure to get any extra “juice” out of your quads. Again, shifting weight to the hips when the quads hit a failure point in the hole comes naturally. Shifting more of the load back to the quads through the sticking point doesn’t tend to come as naturally, and needs to be cued. It’s not unlike doing an Olympic-style pull with double knee bend.

So again, two key takeaways from this article and the last one:

The quads should do what they can. The hips should do what they must. Traps back, hips forward.

Want more squat content? Check out How to Squat: The Definitive Guide, a giant, free guide to everything you could ever want to know about the squat.

Edit/correction 2-24 from Bret Contreras (PhD(c)). Thanks for the catch, Bret!

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