What Are ATG Squats? Form, Depth, and Knee Safety

Maximum-depth squats push the hip crease well below the kneecap, bringing the hamstring into contact with the calf at the bottom of each rep. “ATG” stands for “ass to grass,” a phrase that describes the full-range position many strength athletes pursue for stronger quadriceps, healthier knees, and better carryover to sport. The term spread online through Ben Patrick, the “Knees Over Toes Guy,” whose ATG program paired this deep squat with reverse nordics and belt squats to rebuild knees that doctors had written off.

This guide covers the mechanics, mobility requirements, and ongoing knee-safety debate surrounding ATG squats so you can decide whether maximum-depth squatting fits your training goals.

Defining ATG and Why Maximum Depth Matters in Strength Training

The acronym stands for “Ass to Grass,” and in practice it means squatting to the lowest position your body can reach without rounding the lower back or losing tension. The benchmark is straightforward: the crease of the hip must travel below the top of the kneecap, often called the femur parallel line. Below that line, you’re in deep squat territory; above it, you’re working in a parallel or partial range.

How the Term Spread Across Strength Communities

Olympic weightlifters have always trained this deep because full-range catches demand it. Outside federations, functional fitness gyms made the term mainstream by prescribing it as the default depth for air squats and thrusters.

Ben Patrick built on that base with the ATG (Athletic Truth Group) brand, training thousands of clients through a system that treats deep squatting as knee rehab, not knee punishment. His “Knees Over Toes” philosophy, popularized on YouTube and through online courses, reframed what coaches like Mark Rippetoe once considered risky. ATG now sits at the intersection of strength sports, physical therapy, and viral fitness culture.

• ▸Olympic lifting: Full depth is non-negotiable because catches from a clean or snatch require the hip crease below the knee.
• ▸Powerlifting (IPF, USA Powerlifting): Only parallel is required for a “white light,” though many lifters train below in the gym for stronger drives out of the hole.
• ▸Functional fitness: Coaches default to ATG for air squats because full range develops better body awareness and durability.
• ▸Rehab and longevity: Programs built around the knees-over-toes philosophy use deep squatting to load the patellar tendon gradually.

The Anatomy Behind a Full Depth Squat

At the bottom of an ATG rep, three joints share the load in roughly equal measure. The ankle dorsiflexes past 30 degrees in most lifters, the knee flexes past 120 degrees, and the hip flexes deep enough that the femur approaches the belly. This trifecta is what makes the movement feel foreign to anyone who has spent years stopping at parallel.

Joint Positions at the Bottom

Ankle dorsiflexion drives the shins forward over the toes. Knee flexion past 120 degrees loads the meniscus and the patellofemoral joint in a way partial squats never do. Hip flexion combined with a posteriorly tilted pelvis protects the lumbar spine from the rounding that often plagues lifters chasing depth.

Why the Quadriceps Take Over Below Parallel

The last 20 degrees of knee flexion are where the vastus medialis oblique (VMO) earns its keep. This inner quad teardrop fires hardest in the stretched position, which is why deep squats build the kneecap-tracking strength that protects the joint long-term. Above parallel, the glutes and hamstrings dominate; below parallel, the quads become the limiting muscle, which is the entire point of training this range.

Stabilizers around the knee and hip also ramp up. The rotator cuff of the hip, often called the hip stabilizers, has to control the femur as it tracks inside the acetabulum. Adductors fire to keep the knees from caving. Practicing this bottom position under load teaches those smaller muscles to cooperate under pressure.

Mobility and Preparation Needed Before Squatting Below Parallel

Most lifters who try to drop straight to ATG depth fail for the same three reasons: tight ankles, locked-up hips, or a weak VMO that can’t stabilize the kneecap in the deepest position. Mobility work before loading is not optional for this lift.

Ankle Dorsiflexion and Hip Rotation Requirements

Ankle dorsiflexion of around 35 degrees or more is the typical threshold for ATG without the heels lifting. A quick test: kneel with one foot in front, toes about four inches from a wall, and try to touch the wall with your knee without the heel rising. If your heel pops, dorsiflexion is the limiter.

Hip internal rotation and flexion need to be generous as well. Tight hip flexors pull the pelvis into anterior tilt, which blocks the posterior pelvic tilt required for clean depth. Spending time in a 90/90 stretch or a couch stretch each day can open that range within weeks for most lifters.

A Practical Pre-Squat Warm-Up Checklist

• ▸Goblet squats with a pause: 2 sets of 8 with a three-second hold at the bottom prime the joints without heavy spinal compression.
• ▸Box squats below parallel: Sit to a low box or pad to teach yourself the bottom position without fear of getting stuck.
• ▸Ankle rocks: 10 per side against a wall, driving the knee forward while keeping the heel planted.
• ▸90/90 hip switches: 8 to 10 slow reps per side to grease internal and external hip rotation.
• ▸Reverse nordic curl setup: 1 set of 6 light reps to wake up the VMO and the patellar tendon.

Skip the deep squat on any day the warm-up feels gritty. If a goblet squat to depth pinches in the front of the knee, you’ve earned the right to stop. Forcing through pinching usually turns a recoverable ache into a longer setback.

Executing the Movement With Sound Technique

Setup matters more than load. A barbell resting on your back can force your torso forward and rob you of depth; a goblet or front-rack position usually lets lifters sit back further with a more upright chest. Pick the equipment that fits your hip anatomy, not the equipment you saw someone else use.

Step-by-Step Setup and Descent

1. 1Stance: Set feet roughly shoulder-width apart with toes turned out 15 to 30 degrees, matching wherever your hips sit naturally.
2. 2Brace: Take a deep breath into the belly, brace the abs as if about to take a punch, and set the chest tall.
3. 3Descent tempo: Drop at a controlled 2-second pace for early practice; speed up only after the bottom position feels automatic.
4. 4Bottom control: Pause for a one-count with the chest up, the elbows tracking inside the knees, and the weight spread across the whole foot.
5. 5Drive out: Push the floor away, exhale past the sticking point, and stand without dumping the hips forward at the top.

How Bar Position Affects Depth

High-bar back squats keep the torso upright, which makes ATG depth easier for most lifters because the hips can sit back without the chest folding forward. Front squats demand even more upright posture and tend to force the deepest positions because the load pulls the trunk vertical. Low-bar back squats, favored by powerlifters, shift the load over the hips and make deep squatting harder because the chest has to travel further forward.

For dedicated ATG practice, a goblet squat, a belt squat, or a leg extension is often the most forgiving choice. Ben Patrick’s programming leans heavily on belt squats and sissy squats because they load the knees without compressing the spine, allowing higher training volume without the recovery cost of heavy barbell work.

Benefits, Risks, and the Knee Safety Debate

Deep squatting has been chased, feared, and debated for decades. The modern view, supported by coaches like Dr. Aaron Horschig of Squat University, is that the knees are far more adaptable than old gym lore suggested, but they still need to be loaded gradually.

What Consistent Deep Squat Practice Can Do

• ▸Build patellar tendon resilience: Tendons adapt to slow, heavy, stretched-position loading, which is exactly what deep squats provide.
• ▸Strengthen the VMO: The inner quad, often called the “teardrop,” fires hardest in deep flexion and helps track the kneecap.
• ▸Improve ankle and hip mobility: Practicing depth under load is one of the best mobility drills you can do, far more effective than passive stretching alone.
• ▸Increase athletic carryover: Sports that demand deep catches (Olympic lifts, wrestling, gymnastics) transfer directly from full-range strength.

The Cartilage Question

Coaches at Westside Barbell and elsewhere have trained heavy deep squats for years without widespread reports of cartilage damage. Studies in lifters who routinely squat below parallel have not shown higher rates of knee osteoarthritis than the general population. The myth that deep squats shred cartilage is mostly a holdover from the 1970s and 1980s, when barbell technique was less refined and lifters often bounced out of the bottom with no control.

“A sharp, pinpoint pain under the kneecap during deep flexion, or a buckling sensation in the joint, means stop the set. Pinching and grinding are signals that the technique has broken down, not signs that the knees are weak.

ATG Versus Parallel and Quarter Squats for Different Goals

Depth choice should match the goal, not the trend. A powerlifter chasing a competition total needs different depth than a 50-year-old rebuilding knees after surgery. Picking the right range for the job saves time and reduces joint frustration.

How the Three Depths Compare

Matching Depth to Training Goals

Hypertrophy work for the legs almost always rewards full range, because muscle growth happens through stretch and time under tension. Rehab protocols for patellar tendinopathy also default to deep, slow eccentrics to remodel the tendon. Athletic power, on the other hand, often peaks around parallel because the bottom position is too slow to generate force quickly.

Start where your mobility allows, not where the internet says you should be. A beginner with stiff ankles and tight hips is better off doing paused parallel squats with extra mobility work for several weeks before chasing depth. Progressing through belt squats and sissy squats can bridge the gap without the spinal load of heavy barbell work. As range opens and the bottom position feels owned, slowly add depth until the hip crease consistently drops below the knee.

Bottom Line

Full-depth squats drive the hip crease well below the kneecap, with controlled posture maintained even at the bottom of the movement. They build quad strength, joint resilience, and mobility in ways partial squats cannot, but they demand real ankle and hip range to do safely. Train the mobility, respect the warning signs, and let depth grow as a skill over months rather than forcing it on day one.

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