[Riley Edmonds from St. Bonaventure University in 2016 with a bachelor’s degree in Exercise Science and is currently in the Coaching Mentorship Program at Athletic Lab.]
Squatting is one of the most natural movements we do, and arguably one of the most important exercises we can use in training. The odds are everyone that has ever done any bit of exercise has probably been taught how to squat in one form or another. But what if I told you that what you were taught or are teaching is wrong? Okay, well maybe not totally wrong but certainly, the information currently in circulation by many coaches is a little outdated. Specifically, the idea that the knees should never pass the toes in a barbell back squat is wrong and should no longer be a common cue used by coaches.
Imagine if you will two people, one fairly tall person and one fairly short person. In general, taller people have a relatively short torso but long legs, while shorter people have a relatively long torso but short legs. Now, when these two individuals perform a restricted squat, that is, a squat in which the knees are not supposed to pass the toes, the end result will be two very different looking squats. What you will probably see is the shorter individual will be able to squat just fine, keeping good posture and balance. (1) However, what you will typically see for a taller individual is a very hunched-over looking squat, with very poor posture and less balance. The simplest reason being that as the length of the leg, specifically the femur, increases relative to the torso, the center of mass will shift further backward, away from the center of the foot at the bottom of the squat. Meaning that when taller people squat down to parallel or even deeper they must then counter that shift in their center of mass by leaning forward more to balance the load and shift their center of mass forward. This excessive forward lean will not only affect their ability to squat heavier weights, but it will also compromise their form, therefore increasing the risk of injury. (1,2) Lowering this risk of injury should be number one on the priority list of any coach.
Taller people may not be the only ones that could benefit from an unrestricted squat; in fact, most lifters might as well. This is because during unrestricted squats there is significantly less torque at the hips than at the knees. In fact, it was found that during an unrestricted squat there was 10 times less torque placed on the hips than the knees as compared to a restricted squat. In addition, it was also found that there was decreased shear forces in the lumbar spine as well as decreased forward lean during unrestricted squats. (3) Likewise, it has been shown that during unrestricted squats there is a smaller range of motion (ROM) in the spine and hips than in a restricted squat. The reason for this being that during a restricted squat one must lean forward to compensate for the shift in their center of mass as well as arch their back more in order to try and maintain proper posture. (4) And it stands to reason that with longer femurs one would see even more torque being placed on the hips and a larger ROM in the back during the restricted squat as a lifter would have an even further forward lean. All this being said, it seems like a no-brainer that unrestricted squats are far better not only for taller people but for everyone, right?
Well no, not exactly. Since safety is a priority for any coach, it is important to have all the facts before jumping to conclusions. While unrestricted squats do have a lot of advantages they also have some drawbacks. For instance, in the study that measured torque, it was found that despite the lowered hip torque during the unrestricted squat there was actually slightly more torque placed on the knees than compared to the restricted squat. Not quite 10 times the amount of torque, but still a statistically significant amount. (3) Likewise, in the study examining ROM it was found that during the unrestricted squat there was also a significant increase in the ROM of the knee, despite the lowered ROM of the back as compared to the restricted squat. (4) So clearly there is a bit of a trade-off when it comes to the balance of stress at the hips, knees, and back during a back squat. Furthermore, it is also very important to remember that when it comes to handling torque and stresses, the hips are bigger and more equipped to do so than the knees, but most know any type of prolonged excessive forces can lead to injury.
So that is why as a coach I feel that it is more important to allow the lifter to find that comfortable, happy medium between restricted and unrestricted squats, so there is no sense in ever coaching it anyway. Not to mention one of the biggest determining factors in someone’s ability to squat is their mobility, not just at the knees and hips but everywhere. (1) And in fact, people may be self-restricting because they don’t have the adequate mobility at a certain joint to allow them to be fully unrestricted. And lastly, as any good coach will tell you, less is more when it comes to instructions, so why waste your time trying to fix something that actually is not an issue at all and instead focus on a lifters safety, comfort, and proficiency. Because at the end of the day as long as the lifter is able to squat without their knees caving in or bowing out, heels coming off the ground, or compromising a neutral spine, then don’t nitpick too much because everyone squats differently.
1) Myer GD, Kushner AM, Brent JL, et al. The back squat: a proposed assessment of functional deficits and technical factors that limit performance. Strength Cond J 2014;36:4–27. doi:10.1519/SSC.0000000000000103
2) Contreras, B (2016, March 5) How Femur Length Affects Squat Mechanics [Blog post]. Retrieved from https://bretcontreras.com/how-femur-length-effects-squat-mechanics/
3) Fry AC, Smith JC, Schilling BK. Effect of knee position on hip and knee torques during the barbell squat. J Strength Cond Res. 2003;17:629–633.
4) List R, Gulay T, Stoop M, Lorenzetti S. Kinematics of the Trunk and the Lower Extremities During Restricted and Unrestricted Squats. J Strength Cond Res. 2012