The sissy squat is a specialized bodyweight movement designed to isolate the quadriceps muscles, particularly emphasizing the vastus medialis (teardrop muscle). It differs from traditional squats by intentionally minimizing hip flexion, placing the workload primarily on the knee joint extensors. Although controversial due to the extreme forward knee travel, when performed with correct form and careful progression, the sissy squat is a powerful tool for building quad strength, stability, and knee tendon resilience.
Step-by-Step Execution
Begin by standing tall with your feet approximately hip-width apart. Immediately elevate your heels off the floor, transferring your body weight entirely onto the balls of your feet. For stability, especially when learning the movement, hold onto a vertical support, such as a squat rack or pole, with one hand.
The movement is initiated by simultaneously bending the knees and leaning the entire torso backward. Push the hips forward, maintaining a rigid, straight line from your shoulders down through your hips and knees. This plank position prevents the hips from flexing, keeping tension focused on the quadriceps and preventing glute assistance.
As you descend, allow your knees to track far forward past your toes, which is a necessary characteristic of this exercise. Continue the controlled lowering until your knees are close to the ground or you reach your maximum comfortable depth. The descent should be slow and deliberate to maximize muscle time under tension.
To ascend, forcefully contract your quadriceps to reverse the motion, driving your body back up along the same fixed line. The upward movement is pure knee extension; focus on pushing through the balls of your feet while maintaining the backward lean. Ensure your quadriceps are completely contracted before initiating the next repetition.
Safety and Avoiding Common Errors
A frequent concern with the sissy squat is the movement of the knees past the toes. While often cited as dangerous in other exercises, in this specific movement, the forward knee travel is essential for quad isolation. Proper alignment is paramount to safety: ensure the knees track directly over the feet and do not collapse inward, a movement known as knee valgus, which indicates weakness in the kinetic chain.
A common error is allowing the hips to flex, resembling a traditional squat. This shifts the focus away from the quads and onto the hip extensors, defeating the isolation purpose. To prevent this, actively squeeze your glutes and engage your core throughout the movement to maintain a neutral spine and the straight body line.
Performing the descent too quickly compromises form and joint protection. A controlled, slow eccentric phase is necessary to build the required tendon strength and muscle resilience. If you lack the strength for a controlled ascent, focus only on the lowering phase (eccentric) and use your hands to assist the return to the starting position.
Adequate ankle mobility is a prerequisite for comfortable execution, as the exercise requires you to remain on the balls of your feet. If you experience sharp pain or significant knee discomfort, your current quad strength or connective tissue conditioning may not be prepared for the full range of motion. Build a base of strength before attempting the full depth of this highly stressful movement.
Scaling the Exercise
For those new to the movement, the most effective modification is using a sturdy vertical object for support. Holding onto a rack or wall eliminates the balance requirement, allowing focus on muscle activation and the movement pattern. Beginners should also limit the range of motion, performing partial repetitions where the knees travel only a short distance forward before reversing.
Once stability is established, the next progression is to reduce reliance on the hand support, moving from two fingers to one, and eventually attempting the unassisted sissy squat. This intermediate variation requires significantly greater core and ankle stability to maintain the fixed body line. Another option is the kneeling sissy squat (reverse Nordic curl), which strengthens the quads and conditions knee tendons with a reduced load.
To increase the challenge for advanced athletes, external resistance can be introduced by holding a weight plate or dumbbell against the chest. This weighted variation forces the quadriceps to overcome a greater load during the ascent. A further modification involves elevating the toes on a small block or plate while keeping the heels off the ground. This change in foot positioning increases the demand on ankle flexion and allows for a deeper knee bend, maximizing the stretch and contraction of the quadriceps.