The short answer to muscles used in squats, depending on which type of squat you’re doing, is primarily the quadriceps muscles and the hamstrings, with varying degrees of lower back involvement, depending on height and form.
If you want a longer answer based on my own experiences, read on.
If you ever happen to glimpse through a bodybuilding magazine, I can guarantee you that the leg workouts are going to demand that you do squats, particularly if the goal is bigger legs. Do you have to do squats? I would say that it depends on what your goals are, of course. Mark Rippetoe would simply tell you that anyone not squatting is a P*ssy and leave it at that.
My own interest in the squat has grown in the last couple of months, largely due to the amount of box squatting I have been doing. At my height of 6’8″ I let myself believe that my leverage was just never going to allow me to be a good squatter, at least not in the barbell back squat variety.
I did front squats with kettlebells, rocks, sandbags, and barbells, but had pretty much given up on the idea of ever putting the bar on my back again. At the time my best back squat was only a meager 225. But I was fine with that because I had convinced myself that I just wasn’t a squatter. Still, it nagged at me that I could get stronger at anything I chose, except for this. I felt like I was making excuses.
On a whim I decided to test out box squats after reading a few articles by Louie Simmons. It is just what it sounds like: you put the barbell on your back and squat down onto a box. Here is Dave Tate from Elite FTS with a brief tutorial:
After a couple of weeks of box squatting, I felt stronger than I ever had, and I was able to knock out easy reps with 315. That’s nothing special to anyone but me, but it was HUGE for me considering that I just thought I wasn’t capable of squatting well.
One interesting thing about Mr. Simmons’ article was his suggestion that the quad muscles can actually shrink if the box squat is the squat of choice. This makes sense once you try it: there is a lot more emphasis placed on the hamstrings, because the squatting motion comprises sitting back instead of sitting down.
If you’re not familiar with Simmons, Tate, or the Westside methods, they are powerlifters and their style of squat is used to move the most weight possible, not simply to build muscle.
If you sit down, however, like an Olympic squatter, the quads get hammered. They’ll get stronger, larger, and people still put up freakish amounts of weight with this style.
So currently I am working on box squatting, and I also do a fair amount of squats with the Ironmind Hip Squat Belt, which is extremely quad-intensive.
The current goal is a double bw back squat, which would currently be an even 500. With the growing strength and confidence box squatting is affording me, I’ve no doubt that I’ll be hitting it within the next year.
Quads and hamstrings. That was the answer.