By: Barbell Logic Team
The concept of progressive overload makes consistent squat depth an important consideration. If you squat to a particular depth one day, then you squat high or excessively deep the next day, you have changed not only the weight on the bar but also the distance part of the work calculation. This doesn’t mean that the training stress was unproductive, but a change in depth represents inconsistency in your training. When we are concerned with as little as 2.5 lb. changes in the weight on the bar, inconsistently executed form is a problem that undermines the predictability of your adaptation to training.
Squat Depth – Definable and Repeatable Range of Motion
The squat has a specific range of motion (ROM). Or, at least, the model for the squat that we teach includes a threshold ROM, a minimum depth defined by the crease of your hip dropping below the top of your knee; and there is such a thing as “too deep” for each lifter. When we coach the squat, one of our goals is to help maintain the lifter’s ROM within the prescripts of this model, efficiency and the use of the lifter’s muscle mass determine what is excessive depth. There are many reasons why we teach the squat this way: Knee safety, the training effect of the squat, lifting competition rules, and others. On both sides of parallel, you can find arguments for and against squatting to different depths. One often overlooked issue is the need for a definable, repeatable ROM.
The most useful exercises for overall strength development are the big, multi-joint lifts that cause a lot of training stress with relatively few sets and reps. They Use the most muscles mass, over the longest effective range of motion, and are performed in ways that allow the lifter to lift the most weight. These are the exercise selection criteria outlined in Starting Strength Basic Barbell Training that describe the aspects of a lift that contribute to overall strength. Note that the criteria do not mention specific muscle groups. The effect of maximizing these criteria is to generate systemic stress, because our bodies respond to stress as whole organisms, not just a collection of fibers, muscle groups, and degrees of motion around a joint.
Squats and Work
Two of the three exercise criteria contain elements of the work performed in each lift. Work is a measure of energy transfer when a force causes movement. Measured in Joules (J), work is the product of force times distance. In barbell training, gravity gives definition to the weight on the bar. A 300 lb. squat only has meaning in the context of the earth’s gravitational pull. We take that for granted, but the important part of that is that gravity only pulls straight down. (Also, “In space, no one can [see you squat.]”) If we care about the weight on the bar—and we do—we are concerned with work against gravity or the vertical displacement of the bar through the lift’s ROM. This is the distance portion fo the work calculation.
The weight itself determines the amount of force in the work calculation. When you complete a repetition, we know that you applied at least the minimum amount of force needed to move the barbell vertically against gravity. If you add weight, the minimum force necessary to accomplish the work goes up over time; it takes more force to move 305 lb. than it does to move 300 lb. Work, then, is the way that we try to measure force, since in normal gym circumstances we cannot know exactly how much force you used to move the barbell, only that it exceeded the amount of force that would have normalized the gravitational pull on the bar. It takes more force to move 300 lb. than it does to move 295 lb.
The longest effective ROM and the ability to use the most weight both speak to the amount of work performed in the lifts. The more work, the more stress, the stronger we get. There are other ways to generate productive training stress, but the main lifts all involve movement and work against gravity. Coordinated action is part of displaying strength in generally applicable ways, and work against gravity helps us measure and increase the amount of stress over time.
Progressive Overload and Squat Depth
Progressive overload has been a part of strength training since Milo of Croton, and is one of the crucial factors for building strength. The concept is often thought of as merely increasing the weight on the bar. The load on the bar, however, is one of several factors that make up training stress. Progressive overload means increasing the training stress over time, encompassing several variables such as the frequency of training, exercise selection, the number of productive sets and reps, and the intensity of the lift.
When we train novices, however, the only variable we change is the weight on the bar, the smallest and most direct variable affecting the lifter’s strength. The novice lifter starts with a standard organization of training stress: the four lifts that best meet the exercise selection criteria, performed for sets of five at a volume sufficient to induce training stress for an extended period of time, requiring no changes in these variables during the first weeks of training. From session to session, the lifter will change only the weight on the bar. The idea is that the lifter adjusts the stress by lifting a little bit more weight, linearly increasing the stress, causing their body to adapt to the stress continually, making them stronger.
Controlled, stepwise overload is where squat depth becomes important. If you squat to a particular depth one day then high or excessively deep the next day, you have changed not only the minimum force needed to perform the work but also the distance part of the work equation. While the work changed, it did not change in the manner anticipated by your programming and reflected in your training log. One of the advantages of good, consistent lifting form is that it leads to predictable training responses. If the squat is much lower, the amount of work might have increased significantly. This doesn’t mean that the training stress was unproductive—not necessarily—but a change in depth represents inconsistency in your training. When we are concerned with as little as 2.5 lb. changes in the weight on the bar, inconsistently executed form is a problem that undermines the predictability of your adaptation to training.
The need for consistent ranges of motion makes visual depth markers preferable to depth by feel or by some internally-defined criteria. Setting the target as the crease of your hip dropping below the top of your patella, makes depth something that you can see in your videos, something your coach can address, and something most powerlifting judges can judge accurately. If instead, you defined your range of motion by feel, you will have trouble calibrating your depth from session to session, set to set, and squat to squat. Anyone who has ever been under a crushing weight with doubt in their mind knows that your normal depth can feel about a foot lower than it used to be. Correct depth is not just an anatomical or mechanical benefit. A defined visual range of motion is verifiable and repeatable, giving you the ability to stay consistent and adjust the stress of training predictably. When you squat to depth, and that depth is just below parallel, your squat is a squat today, tomorrow, and for every PR.
 “Milo’s strength was legendary, and even though he lived in the 6th Century BC, records of his career survive and speak to a man whose strength and skill at wrestling were as close to mythological as anyone in history has been. There are many stories about him, but the most famous is that he began lifting a calf every day from the time it was very young until it was a full grown, 4-year-old bull. As the animal grew, Milo adapted to lift it, and his strength grew in tandem—perhaps the most gradual and most protracted linear progression in history.” (from Early Barbells and the Physical Culture Movement)
 “The truth is that the Novice Program is individualized. It’s just that the changes that we make to accommodate individual variability are not to the overall structure of the program, at least not at first. The exercise selection, set and rep schemes, and frequency don’t change whenever someone is first starting out. The reason is that having a standard place to start gives us good data that we can easily interpret. Your responses to training then inform the changes to the program, but those changes are big overhauls to the program: they are small, measured changes that preserve the ability to test, observe, and analyze your response to the changing variables.” (from Novice Linear Progression: An Individualized Program)