The Squat and You - A Breakdown of Basic Mechanics
The barbell back squat is often touted as the king of strength exercises, the most manly movement the human body is capable of, the cure of cancer, etc. As such, it would be a shame to not understand the mechanics of such an exercise. I hope that I might be able to shed some light on the subject for newer lifters. This is by no means a comprehensive guide to the squat, merely a brief overview of some aspects of it that may help people understand various form considerations.
High Bar Squat vs Low Bar Squat
The main thing I've noticed on these forums is that people don't seem to understand the role of bar position in the squat. To help you out, I have drawn a diagram in MS paint.
In order to remain balanced during a squat, the bar needs to be over the centre of gravity of the body, which can be estimated by drawing an imaginary line through the middle of the foot (obviously people have different sized feet, so this is a rough guide, though it will still be accurate to within about an inch).
As such, the bar placement on the back determines a few things. It determines back angle and knee position. These are the two things that change to keep the bar over midfoot. As shown in the diagram, a higher bar position leads to a more upright back and knees further out over the toes.
As such, there are going to be differences in muscle recruitment between these different styles of squat.
The more acute the hip angle, the more work for the hip extensors (posterior chain - glutes, hamstrings). The more acute the knee angle, the more work for the knee extensors (quadriceps). That is to say, the lower the bar position, the less emphasis on the quads and more on the glutes and hamstrings.
Stance width and toe angle
Stance width and toe angle ultimately determine how wide your knees will be at the bottom of the squat. Correct toe angle will be determined by the external/internal rotation of your hips, which is partially structural and partially determined by the flexibility of the hip musculature - abductors, adductors, glutes, hip flexors, etc. Stance width will also play a role in determining knee width in the bottom position of the squat. Knee width in the bottom of the squat affects adductor (the groin musculature) contribution - wider = more contribution. This is because the adductors lengthen more the wider the knees are, allowing them to shorten more on the way up to contribute to the movement. Note that if you do not keep your knees actively "shoved out" on the way up, the adductors will shorten without contributing anything to the lifting of the weight, therefore not performing their job.
So how do I know what style of squat is right for me?
To be perfectly honest, the differences in development will not be immense, though they will probably be somewhat noticeable. Olympic weightlifters use high bar squats because the back angle allows them to mimic the recovery position of the Clean. Powerlifters typically use lower bar positions, as the glutes are the largest and strongest muscle group in the human body, and therefore allow them to lift the most weight.
Most athletes will benefit more from a lower bar position, as the posterior chain plays a very important role in almost all sports. There are, however, anthropometrical reasons for using different types of squats. I'll talk about my own squat because I know more about it than anyone else's. I have long femurs, which means that my centre of gravity is thrown backwards in the squat because my hips are further behind my feet. There are a few ways that I can compensate for this:
The first picture is what would happen if I tried to squat with a low bar position, no knee drift, and knees not shoved out. Hip angle is far too acute and I would essentially be doing a "good morning" with the weight, which is very inefficient.
The second picture is what would happen if I tried to compensate by letting my knees drift far over my toes (which I can't actually do due to poor ankle mobility). The hip angle is much more obtuse, meaning less contribution from the glutes, and a lot more stress on the knees which may (though not always) cause injury in the long- or even short-term.
The third picture (very poorly drawn, my bad...) is what would happen if I shoved my knees out to almost 180 degrees (not possible, a dramatisation to emphasise my point. I'd get a lot less glute AND quad contribution, putting most of the work on the adductors. The adductors are a very strong muscle group... but not quite THAT strong.
The fourth one is what I actually do - please ignore the scream in this video, ha ha.
- a happy medium between the second and third pictures. My toe angle is wide and my knees are shoved out over the line of my toes. My knees go forward slightly over my toes. This means that my hips are further forward, which means a slightly more obtuse back angle, and a more even squat overall.
Shoes
A heeled weightlifting or powerlifting shoe may be beneficial to those with long femurs, poor ankle mobility, poor general flexibility, or those who are performing high bar squats and front squats. Raising the heel means that the ankle is slightly extended when standing upright, which means the foot is less dorsiflexed at the bottom of a squat. This will allow your knees to drift further over your toes to accomodate your own anthropometry.
You'll need to apply the information given here to work out how to make your squat work for you - hopefully I've explained it well enough, but if there is anything else I can help with, or you can think of something I should add, feel free to PM me or post in this thread. Hope this helps.
Last edited by pierrespies; 11-05-2009 at 06:21 PM.
Nice break down. I'm tinkering with my form right now. I find I'm getting more power out of a narrower stance, your article leads me to believe I most have weak hip adductors. I also have shite hip mobility.
Most athletes will benefit more from a lower bar position, as the posterior chain plays a very important role in almost all sports.
Ive always felt like the high bar/oly squat was the more athletic like lift. It may be because oly lifters walk around like they have springs for muscles and powerlifters seem like they have trouble getting out of a chair.
" -likkuid
