The idea that knees shouldn’t go past toes during squats is a common piece of fitness advice. This belief likely stems from a 1972 study that linked forward knee movement with increased shear force on the knee joint. However, this study has been criticized for methodological flaws, particularly for not controlling squat depth. More recent research suggests a more nuanced approach.
While excessive shear force on the knee can indeed lead to pain or injury, restricting knee movement during squats may not be the best solution. Consider everyday movements like descending stairs. Our knees naturally travel forward, and this rarely causes pain in healthy individuals. Similarly, Olympic weightlifters often squat with significant knee flexion, showcasing that forward knee movement isn’t inherently problematic.
Focusing solely on knee forces ignores the biomechanics of other involved joints, like the hips and lower back. A 2003 study by Fry and colleagues compared knee and hip torques in squats with and without restricted knee movement. They found that restricting knee movement significantly increased hip torque, potentially leading to greater stress on the lower back. This suggests that allowing some forward knee travel may actually protect the lower back during squats.
The key is to balance forces across all involved joints. Restricting forward knee movement can shift the load excessively to the hips and lower back. This can be a dangerous trade-off, potentially increasing the risk of lower back injuries. Lists and colleagues further supported this concept, demonstrating reduced lower back stress during unrestricted squats.
Effective squat technique involves several key principles: keeping heels planted firmly on the ground, maintaining weight centered over the mid-foot, and ensuring knees track in line with toes. A moderate amount of forward knee travel is acceptable, as long as weight remains balanced.
Individual anatomy, particularly femur length relative to tibia length, significantly influences squat form. Those with longer femurs naturally lean forward more during squats. Squat depth should also be individualized. While achieving parallel depth is a good general guideline, the most important factor is squatting as deep as comfortably possible.
Forcing a universal “knees behind toes” rule isn’t ideal. It overlooks individual anatomical differences and may lead to compensatory movements that stress other joints. A balanced approach, considering the interplay of all involved joints, is crucial for safe and effective squatting. Remember, these guidelines apply to healthy individuals. Those experiencing knee pain should seek guidance from a qualified healthcare professional.
