Parallel Squats vs ATG Squats, Which do Athletes need? Which is more effective?

If you work out in any strength training gym or big box gym, you have most likely heard the term ATG (Ass To Grass) term to describe squat depth. The argument has been going on for years on whether ATG, parallel, or 90-degree squats are the most beneficial and which is right. Well, we are here to continue the discussion, we would hate to break that cycle, ha.  

Many lifters argue that ATG squats are superior to parallel or 90-degree squats because they are more difficult, intense, and strenuous on the body, but the reality is, the exact opposite.

Although, that may stand true, if shallow squats are sometimes superior in terms of strengthening specific leg muscles, then those same squats have the potential for better size development of those same muscles.

Of course, using a full range of motion is pretty much the first rule of thumb in the bodybuilder's playbook. Muscular growth, however, is not solely determined by ROM. It’s a result of gradually doing more and more work.

Work is technically defined as the displacement of a mass over a specific distance. As a result, you may end up doing the same amount of work (or even more total work) by moving a heavier weight for a shorter distance than you could by moving a lighter weight for a longer distance.

Parallel or 90-degree squats require markedly greater activation, muscular tension, concentration, mental fortitude, intensity and overall strength. Fun fact: ATG squats are the polar opposite of this, requiring less muscle activation and more neuromuscular relaxation.

When we look at neuromuscular physiology, biomechanics, muscle physiology, osteokinematics, and functional anatomy principles, we find strong support for the idea that the squat should look almost identical from person to person. This requires 90-degree joint angles at the knee and hip joints, as well as a relatively straight foot position.

Athletes who support ATG squats frequently argue that the increased load the lifter can handle on parallel squats is simply a form of cheating because it makes the exercise easier. Once again, incorrect. This idea couldn't be more flawed. True, when performing ATG squats, the lifter will not be able to handle as much weight, but this is due to the decreased motor unit recruitment and muscle activation required to achieve such a collapsed position. As a result, the lifter suffers from reduced contraction strength and force-producing capabilities.

The sensation of the lighter load feeling heavier is simply a byproduct of faulty mechanics giving the lifter the illusion that he or she is doing more work.  They’re doing less work as they’re reinforcing neuromuscular inefficiency making the movement feel unnecessarily taxing and physiologically exhausting. 

A proper 90-degree squat, on the other hand, rewards the lifter with greater force-producing capabilities because every muscle fiber is firing maximally, transforming the muscles into coiled springs. As there can be no weak links or energy leaks, this requires the highest levels of concentration and focus, as well as mental and physical intensity. This effectively increases load, power, speed, motor unit recruitment, intramuscular tension, and hypertrophy, all of which are compromised during ATG squats.

In conclusion, unless you’re a competitive weightlifter or powerlifter there’s no reason to perform heavy loaded squats deeper than 90 degree. If your goal is hypertrophy, strength, power, athletic performance, muscle function, & joint health, 90 degrees is optimal. ATG squats were implemented in Olympic lifting as a standard guide reference for competitors, this theory has just taken it’s place in the fitness industry as a rule.

If proper mechanics are not used and sloppy form is used, then excessive depth will be required to achieve any semblance of adequate muscle activation. A crisp and perfectly dialed in 90-degree squat, on the other hand, produces maximum recruitment while sparing the joints. Findings that suggest otherwise, contradicting foundational elements of human physiology and biomechanics, are most likely the result of insufficient subject coaching and cueing – a common problem in kinesiology studies.

We will never find the answer if we try to determine optimal squat depth based on specific squat studies because there is literature supporting all sides. Instead, we must examine all foundational elements of kinesiology, including neurophysiology, biomechanics, structural physiology, and functional anatomy, using logical reasoning and deduction. Once we've done that, it's clear that 90 degrees is ideal for most movements, not just squats.

In essence, with 90-degree squats, the lifter controls the load, whereas with ATG squats, the load controls the lifter. Now, we aren’t suggesting you go to the gym today and find a place for this discussion, but at least you have a firm ground to stand on next time you get in the squat rack.