However, individual differences in strength and body structure such as our individual femur-to-torso ratio determines how we squat, ranging from general mechanics to depth.
There's No "One Size Fits All" Approach To Squatting
We squat when we sit in our chairs, use the bathroom, get in our cars and even when we sit at the dinner table. It’s such a fundamental movement that most athletes, regardless of sport, incorporate the use of squats into their training programs.
Athletics aside, squatting can help improve an individual’s strength, which can directly transfer to improving balance and coordination; a very important yet often overlooked benefit of working out.
In mainstream media, people often paint a picture of a perfect squat. However, the existence of an “ideal” squatting position is debatable and should likely vary from person to person based on individual differences like range of motion, flexibility, and the often overlooked femur-to-torso ratio.
Factors That Influence Squat Depth
In order to squat without falling over, you need to maintain your body’s center of mass over your base of support, (your feet). The body will take whatever steps are necessary to keep you upright, especially under load.
Limited ankle range of motion, for example, can have a huge impact on squatting deep by preventing your knees from pushing forwards towards the toes, and often causes excessive forward lean in a squat. That’s because in order to keep your center of mass over your feet, your body adjusts to keep half the weight in front of your ankle and about half of the weight behind it.
Limited ankle mobility (and a bad femur:torso ratio) often manifests in what is often called a “Good Morning Squat, somewhere in between an actual good morning and a squat (like the squatter on the left, above). If the ankles can’t flex, this results in a change in how the knees and subsequently, hips flex, resulting in much more forward lean.
Some people will argue that tight hip flexors or hamstrings will cause an anterior pelvic tilt and make squatting past parallel impossible or unsafe by putting extra stress on the lumbar spine.
Additionally, even people who regularly work on improving their range of motion can have trouble getting past parallel. Often to the extent that even using heel platforms or lifting shoes won’t rectify the issue.
Femur:Torso Ratio Determines Depth
I dug through the anthropometric research, and one thesis on the topic found the ratio of femur length:torso length has a relatively wide range (0.7-1.25).
As it turns out, if you have a femur:torso ratio of 1:1 (equal femur:torso ratio) or higher, you will likely have trouble squatting to parallel or below. If you approach a ratio of 1.2:2 (or have a longer femur than torso), it’s almost impossible to squat to or below parallel.
Meanwhile, if you’re on the lower end and have a ratio of 0.8 or less (meaning a long torso and short femurs), it’s likely that you’ll have no problems whatsoever going ass-to-grass, (or full range of motion).
The reason it may be helpful to know your ratio is simple: If you have a higher ratio, then all the foam rolling, yoga, and heel lifts in the world may not help you get to parallel or below.
But if your ratio is lower and you still have trouble, you may simply be dealing with limited soft tissue range of motion, which may be improved with some dedicated range of motion work.
Based on these measurements, you should be able to fairly accurately determine if you should be able to squat to parallel or below.
As you can see above, in order to maintain the bar's center of mass inline with your own, your body needs to hinge accordingly, based on the length of your torso and femur ratio. If you have a long femur and short torso, you can almost guarantee that you'll have much more forward lean with your torso than that of someone with short femurs and a long torso.
Alternative Exercise To The Squat
If by some stroke of bad luck you have long femurs and a short torso, all hope is not lost.
As Tom Purvis points out, we can ‘functionally’ shorten the femur by taking a wide stance and angling the feet outwards. This allows people to maintain their center of mass over their base of support, and keep their chests more upright as they approach (and blow past) parallel. We can also elevate the heels as a way to ‘functionally’ lengthen the tibia and accomplish the same thing.
If it turns out that you’ve been dealt a bad hand, you should consider why you are doing squats in the first place. Everyone is different and there is potential that doing a traditional back squat is not optimal.
If this describes you, consider the following alternatives:
The Final Word
The squat is a fundamental exercise that uses the largest muscle groups in the legs and can help you accomplish many goals ranging from general function, to hypertrophy and strength.
However, based on many variables including your femur-to-torso ratio, squats may not be optimal or will require modification to fit your individual biomechanics (how your body moves according to your structure).
If your mobility is ample, and you’re having difficulty performing a full range squat or remaining erect throughout, consider measuring your femur-to-torso ratio to determine if long femurs are the primary issue or if there is something else to blame (and fix).
If you had a bad luck of the draw and happen to have relatively long femurs, consider adjusting your squat form by increasing the width of your stance and rotating your toes outward to maintain the bar’s center of gravity inline with your own.
If the aforementioned options aren’t suited for you, rest assured that there are many other exercises you can perform in place of the squat to receive a similar benefit
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