The acronym “ATG” in the fitness world stands for “Ass To Grass,” describing an exercise, most commonly the squat, performed with maximum possible depth. This depth is characterized by descending until the hips are positioned as low as they can go, often resulting in the glutes nearly touching the floor or the heels. The concept emphasizes utilizing the body’s full range of motion, which maximizes muscle engagement and physical adaptation. The pursuit of ATG depth measures both strength and mobility, indicating a commitment to training through the entire movement pattern.
The Definition of Ass To Grass
“Ass To Grass” defines a technical standard in lower body exercises, particularly the barbell back squat, where the hip crease descends definitively below the top of the kneecap. This depth is significantly deeper than a parallel squat, the standard required in most powerlifting competitions. Achieving this maximal depth ensures the muscles surrounding the hip and knee joints are taken through their complete length-tension curve.
The mechanical goal of ATG depth is to maximize the recruitment of the posterior chain musculature, specifically the gluteal muscles and hamstrings. At the bottom of a deep squat, the glutes and hamstrings are placed under a greater stretch, which prepares them for a powerful concentric contraction upon ascent. Training with this full range of motion helps build strength at the most mechanically disadvantaged position, which translates to better overall control and stability.
Conversely, partial range of motion movements, such as quarter or half squats, limit muscle fiber recruitment and adaptation. While partial movements can be useful for overloading specific strength ranges, they do not provide the same comprehensive stimulus across the entire joint structure. Consistently training to the ATG standard develops strength and flexibility concurrently, which helps mitigate strength imbalances arising from limited movement patterns. This full depth approach is also applied to other lower body movements like lunges and split squats, where the goal remains maximal, controlled descent.
Essential Mobility for Achieving Full Depth
The ability to safely reach an ATG position depends on specific physical prerequisites beyond mere muscular strength. Three areas require sufficient range of motion: the ankles, hips, and thoracic spine. Restrictions in any of these areas can prevent proper depth or introduce compensation patterns that increase the risk of injury.
Ankle dorsiflexion, the ability of the shin to move forward over the foot, is a major limiting factor for many individuals attempting a deep squat. If the ankle joint cannot flex enough, the heels will lift off the floor or the torso will lean excessively forward to maintain balance. This restriction shifts the load away from the hips and onto the lower back and knees, compromising the lift’s biomechanics.
The hip joint requires substantial mobility to allow the femur to travel deeply into the socket without causing a posterior pelvic tilt, often called “butt wink.” This occurs when the lower back rounds at the bottom of the squat, placing undue stress on the lumbar spine. Improving hip internal and external rotation, as well as general hip flexion, is necessary to maintain a neutral spine position throughout the descent.
Maintaining an upright posture in the deep squat necessitates adequate thoracic spine extension, allowing the upper back to remain straight and preventing the shoulders from rounding forward. A stiff upper back forces a forward lean of the torso, which places the load in a less advantageous position. Addressing mobility across these three joints concurrently is necessary for achieving a safe and stable ATG position.
The ATG Training Methodology
While “Ass To Grass” historically refers to squat depth, “ATG” has also become synonymous with a specific training methodology popularized by Ben Patrick, the “Knees Over Toes Guy.” This system, formalized as the Athletics Truth Group (ATG), goes beyond deep squatting to focus on strengthening the body through its full range of motion. The philosophy centers on proactively conditioning joints and connective tissues for long-term, pain-free athletic performance.
A core principle of the ATG methodology is “reverse engineering” movements to build resilience, particularly around the knees. Instead of avoiding movements like letting the knees travel over the toes, the program systematically strengthens the muscles and tendons in these positions. Specific exercises, such as the Patrick Step, the ATG Split Squat, and the Tibialis Raise, strengthen the body’s protective structures.
The ATG Split Squat is performed with the knee of the front leg extending far past the toes while the back knee touches the ground, forcing a deep range of motion and strengthening the quadriceps through their full length. Another signature exercise is the reverse sled pull, which trains the quadriceps and ankles eccentrically with minimal joint impact. By combining movements that strengthen both the front and back of the joints, the methodology aims to create a body capable of handling the forces of athletic movement and daily life.