Meaning: This rule addresses a common concern in squatting technique.
Mechanics: While traditionally it was taught to keep the knees behind the toes, modern biomechanics suggests that allowing the knees to track slightly over the toes during a squat is often natural and necessary for maintaining an upright torso and proper depth, especially for individuals with certain anthropometrics (e.g., shorter tibia, longer torso). The key is to ensure the movement is controlled and doesn't cause pain, and that the weight remains balanced on the midfoot. Pushing the hips back excessively can compromise depth and activate the posterior chain less effectively.