Squats don’t train what you think they train

Chapters:

00:00 Intro

00:50 Calves

01:50 Hamstrings

02:43 Glutes

03:38 The most underrated squatting muscle

04:27 My Online PT Course

04:51 Quads

05:35 Erector spinae

05:54 Summary

06:15 Differences between squat variants are overrated

08:43 Squatting heavier emphasizes the glutes, study finds

11:16 Conclusion

Transcript:

Squats make your balls and your booty bigger. Everyone knows this. However, other conventional wisdom about what it is exactly that you’re training when you’re squatting is sorely lacking. Bodybuilders often lump squats into the “lower body” category. Squats definitely don’t train the entire lower body. There’s also widespread belief that different variations of squats have radically different effects on which muscles you train, with high bar squats, for example, preferentially training the quads and low bar squats training the booty more. Wrong again. So let’s look at exactly which muscles you train when you squat and how this is affected by different squat variations. And at the end of this video I’ll go into a new study that suggests the rep range we squat at affects which muscles we train more.

Let’s start at the bottom and look at the calves. The calves are trained by squats, but not in their entirety. The long, thin soleus muscle underneath the calves is probably trained quite well by squats. At least if the knee comes forward and you’re doing a deep type squat that involves movement at the ankle. The gastrocs however, the big two headed big bulging parts on top of the soleus are not trained very well by squats at all. That’s because while they help plantar flex, so they help move the ankle and press you up as you would do during a calf raise, they also flex the knee. So if they contract they will help you push the knee back as you would do during a squat, but they will also pull your upper leg back down into a deeper squat, which would be counterproductive. As a result the body doesn’t recruit the gastrocs nearly as much during a squat as for example, during a calf raise. We see this in EMG research, biomechanical analysis and also long term research on muscle growth. The gastrocnemius does not grow nearly as much from squatting as, say, the quads or the glutes.

Moving up to the hamstrings we face a similar problem. The hamstrings are, again, a muscle that is active at both the knee and, in this case, at the hip. The hamstrings are very beneficial for squatting in the sense of being hip extensors. Hip extension is very important for squats. It helps you move the trunk up and get out of the hole, get back up out of the squat, however, when the hamstrings contract they also contract at the knee. At the knee they are flexors, so they basically pull you back down into the squat. So again we have this bi-articulate muscle conflict that the muscle will not be recruited because it has one function that is pulling you back down and the other function that is helping you squat up. As a result, we see in EMG research and biomechanical analyzes that the hamstring activity during a squat is very low and consequently, in long term research, we see that the growth of the hamstrings during squats is also very low. So I recommend that you don’t count the hamstrings as being effectively trained by your squats at all.

So what then is extending the hips when you squat? What is moving the trunk up? It’s the glutes primarily. The glutes are very effectively trained by squats. There’s no dispute. We see this clearly in EMG research, biomechanical analysis and long term studies. And yes, even if you don’t feel them. The glutes are the primary hip extensor. The hamstrings have very limited contribution. So when you are squatting and you’re moving the weight up the glutes are highly active. It doesn’t matter if you don’t feel them. We did a study comparing hip thrusts to squats and we found that they stimulated equal hypertrophy in the glutes in all regions, even though all participants said that they felt the hip thrusts activate their glutes a lot more. We also had another study, which I recently posted about, showing that there is a very little correlation between someone’s subjective and objective muscle activity. So whether you feel a muscle or not, and whether it’s actually objectively activating or not, those are very different things in some cases.

That said, there is another hip extensor that is extremely underrated. It’s very unlikely to completely take over the role of the glutes, but many people don’t realize that they’re training this muscle. It’s actually very big and it contributes a significant amount of force during squats. This muscle is the adductor magnus. It’s a huge muscle in the inside of your thigh that’s basically going all the way to the back and the front. It’s a very large part of the inner thigh musculature and it’s producing a lot of the force. Known as the adductor magnus, but it’s role as a hip extensor may actually be more potent than its role as a hip adductor. A new study, in fact, concluded: “The potential contribution of the adductor magnus in human movements has often been overlooked so far. The present study would motivate us to redefine the functional role of the adductor magnus and accordingly rename this muscle, for example, “Extensor magnus”.”

Moving to the front of the body we have the quads. The quadriceps is trained very effectively by squats, but not in its entirety. Squats are a great exercise for the vasti muscles at the sides of the quads. They give you a good quad sweep, they give you good teardrop, but they don’t train the rectus femoris in the middle very well. For that you need something like leg extensions. The rectus femoris in the middle, again has a bi-articulate muscle conflict. Lower body muscles are somewhat complex. The rectus femoris is not just a knee extensor, helping the other quads extend the knee and pushing you up during a squat, it is also the hip flexor, and the hip flexor would basically drag you down back into the hole during a squat. So just like the hamstrings the rectus femoris is barely recruited and barely grows from squatting.

And then finally, we have the erector spinae. The erector spinae are very effectively trained by squats. Although they are contracting only isometrically, they do not change muscle length very much, most lifters have found that if they squat and deadlift heavy they actually get pretty decent lower back development, even without spending other additional time doing specific exercises for the lower back.

So in summary, squats train the calves, but only the soleus, not the gastrocnemius. They basically do not train the hamstrings. They train the glutes very effectively. They train the quads, but again, not in their entirety. They do not train the rectus femoris, only the vasti muscles. And they train the lower back, specifically the erector spinae. Those are the muscles that are very effectively trained by barbell squats.

Now, how does this change when you do, say, a front squat or a high bar squat or a low bar squat? Maybe even a split squat? How about a lunge? Well, most people would say the differences are quite profound and there are tons of analyzes analyzing what exactly is the difference between a high bar squat, a low bar squat… The conventional wisdom is that if you do a more upright type squat, say a high bar squat, you preferentially train the quads and you reduce the stimulus for the glutes. If you do a more low bar type squat, more bent over, more hip dominant, then you train the hip muscles, specifically the glutes more and you train the quads substantially less.

Research does not support this. It’s not that there’s no difference at all. There are biomechanical differences and they do have substantial impacts on which joints you load more, they can also change the range of motions a little bit of muscles, but by and large the differences in force production and range of motion are probably too small to substantially affect muscle hypertrophy outcomes over at least short periods. In the end, it’s still very similar movements that you’re producing, and it’s only the leverages that change. Whether you do a front squat, a high bar squat or a low bar squat, it’s still essentially the same movement pattern that is done by the same muscles. The position of the weights primarily affects the leverages, which affects how much you can lift and whether you are a little bit more bent over or a little bit more upright. But in the end, almost all the muscles will be contracting to their full potential, especially if you train close to failure and consequently, in electromyography research, we see no significant differences between front squats, high bar squats and low bar squats in the activity of all the target musculature.

Accordingly in the long term research we have, we see no significant differences in muscle growth between squats and leg presses, front squats and back squats, back squats and bodyweight single leg squat-type movements and lunges and squats. Now I will say all of these studies have very significant limitations and I wouldn’t say any of these studies is excellent, but at least a study on front squats versus back squats was quite well conducted, and I think quite representative of what we can expect in practice. So it’s not that there are most certainly no differences, but the biomechanical differences that we can expect are probably very small. Maybe over the course of a year in well-trained athletes we will see a few percent difference in growth. But by and large, most squat variants are probably interchangeable. Again, it’s still the same broad movement pattern that you’re doing and the position of the weights primarily changes the leverage, not the primary functions of the target musculature or how much they are involved, especially if you’re training close to failure.

Surprisingly, what might actually matter is the rep range that you squat at. A new study found that the force production of the quads is very high regardless of which intensity you squad at. The contribution of the glutes, however, increases substantially with heavier loads. This suggests that squats are a great exercise for the quads and the quads are always recruiting to a high extent, even if you are far away from failure or not using a very heavy weight, but the glutes kick in more when you get closer to failure and lift heavier loads. Anecdotally, this does fit with people having more forward lean and relying on their hips a little bit more when they’re squatting heavier. When people do sets of 12, for example, most people can stay relatively upright, at least during the first repetitions, but when people start getting very close to failure you see that people start engaging the hips more, they get more of a squat morning position, which, by the way, is natural and often efficient as long as it’s not excessive.

There are always a lot of assumptions with the type of mathematical modeling that was employed in this study to calculate the force outputs of all the musculature, but this was a well-conducted study and a very representative sample of high level powerlifters. The differences also seemed meaningful enough to potentially affect long term hypertrophy outcomes. The contribution of the glutes increased about twice as much as the contribution of the quads to total force production, as the powerlifters used a higher percentage of their 1RM.

However, a big limitation is that they only did a single repetition with each percentage of their 1RM, so while we have data from 70 to 90% of 1RM, it would be interesting to see what actually happens during a full set or even multiple sets. Because when you get closer to failure it’s all hands on deck, essentially, for many muscles, and these small differences between which muscles are more active and less active might not matter as much. But an argument could be made that if you’re doing, say, sets of 10 or 20, the quads from the beginning already achieve a very high stimulus, so maybe in the long term this would mean that the quads get a higher stimulus for muscle hypertrophy when you do higher reps, and when you do lower reps the glutes also fully contribute.

In most research, we see that the glutes and quads grow approximately equally, and they both grow very well. So this is definitely a matter of fine tuning, but it’s interesting to test in a future long term study. For powerlifters it’s also important to realize that a heavy squat and a light squat are technically a slightly different exercise. The biomechanics are not the same in part because of the degree of forward lean. So powerlifters should spend much of their time squatting with sets of 1 to 5 repetitions, being relatively close to their 1RM. If you’re using 60% of your 1RM, for example, you’re technically doing a slightly different exercise, which is probably not going to optimize the neural motor optimization patterns that make your technique better for squats. So if your primary goal is strength, you want to do mostly heavy squatting.

So in summary: squats train the soleus but not the gastrocnemius. They basically don’t train the hamstrings. They train the vasti of the quads, but not the rectus femoris. They train the glutes, the erector spinae and they train the adductor magnus. The specific variant of squats you do, or even a lunge, or a split squat does not seem to significantly affect muscle hypertrophy in long term research. Except that single leg squats probably grow the erector spinae less because of the lower degree of spinal loading, which can also be beneficial if you have a back injury. An emerging new research tentatively suggests that if you do high rep squats you train the quads more and you need to squat heavy to fully engage the glutes. I hope you found this video useful. If you like this type of evidence based content, I’d be honored if you like and subscribe.