The ATG Split Squat is a demanding, unilateral lower body exercise popularized for its extreme emphasis on full range of motion. This movement is a deviation from traditional split squats because it deliberately encourages the front knee to travel far past the toes, a technique long avoided in conventional training. The goal is to achieve maximum flexion at the knee and hip joints under load, promoting strength gains throughout the entire length of the muscle. By challenging the body in this deep, stretched position, the exercise aims to build muscle resilience and joint stability.
Primary and Secondary Muscles Activated
The primary drivers of the ATG Split Squat are located in the anterior compartment of the thigh, making the quadriceps the most heavily stimulated muscle group. Specifically, the vastus medialis obliquus (VMO) receives a high degree of activation, particularly as the knee reaches its deepest point of flexion. This concentrated activation is highly beneficial for supporting the correct tracking of the kneecap.
The gluteal complex also plays a significant role during the movement. These muscles are responsible for powerful hip extension on the ascent and are constantly engaged to maintain a stable, upright posture throughout the entire repetition. The glutes work in tandem with the quadriceps to control the deep eccentric (lowering) phase and drive the concentric (lifting) phase.
Stabilizing Muscles
While the hamstrings are not the prime movers for this exercise, they act as important stabilizers, assisting the glutes in balancing the pelvis. The adductor muscles, located on the inner thigh, are also recruited heavily to prevent the working knee from collapsing inward during the deep descent.
Core Engagement
The core musculature, including the rectus abdominis and obliques, must engage intensely to maintain the required upright torso position, which prevents excessive leaning forward or backward.
The Unique Benefits of Full Depth Training
The signature feature of the ATG Split Squat is its full range of motion, which delivers distinct physiological benefits beyond simple muscle hypertrophy. This deep, loaded stretch is particularly effective for enhancing joint mobility across three major areas of the lower body.
The first benefit is a significant increase in ankle dorsiflexion, the ability of the shin to move forward over the foot. By intentionally driving the front knee far past the toes while keeping the heel planted, the movement forces the ankle joint to stretch and adapt to extreme angles under load. This improved range of motion is crucial for achieving better positions in other movements, like a full-depth conventional squat.
Lengthening of the hip flexors on the trailing leg is another benefit. Because the back leg remains relatively straight and the torso stays upright, the hip flexors are stretched aggressively while the muscle is simultaneously under tension. This loaded stretch can help counteract the tightness often associated with prolonged sitting, which improves hip extension and potentially reduces strain on the lower back.
The deep range of motion also fosters improved tendon resilience. By consistently loading the patellar and quadriceps tendons through a full, deep stretch, the exercise encourages the tissues to adapt and strengthen in their most vulnerable, lengthened positions. This process increases the capacity of the tendons to handle stress, which is a key factor in injury prevention for athletes who perform explosive movements.
Deep knee flexion stimulates the knee joint. Moving the knee through its maximum range of motion promotes the circulation and production of synovial fluid, a substance that nourishes the cartilage and joint structures. The combined effect of strengthened tendons and a better-nourished joint environment leads to a more robust and stable knee over time.
Proper Technique and Progression
To execute the ATG Split Squat effectively, the setup is fundamental, beginning with a slightly wider stance than a traditional lunge to facilitate the forward knee travel. The torso must remain as vertical as possible throughout the movement, requiring constant core engagement to prevent the body from pitching forward.
The primary movement cue is to consciously drive the front knee forward over the toes, aiming to eventually touch the hamstring to the calf at the bottom of the repetition. This forward drive is essential for achieving the desired depth and VMO activation. It is equally important to maintain balance and ensure the front knee tracks directly in line with the foot, avoiding any inward collapse.
Progression in this exercise involves modifying the front foot position. Many individuals start by elevating the front heel on a small wedge or weight plate, which immediately allows the knee to travel farther forward without being limited by ankle mobility. As strength and mobility improve, the elevation can be gradually lowered until the exercise can be performed with the front foot flat on the ground.
For those new to the movement, a regression involves using a stable object, such as a post or rack, for light hand support to assist with balance. Once bodyweight repetitions can be completed with excellent form, progression continues by adding external load, typically holding dumbbells in each hand. This systematic scaling allows the trainee to continually challenge the muscles and joints across a deep range of motion safely.