365. Why you should stop cueing knee alignment

Everyone "knows" that knees going inwards in a squat is bad, right?

It means the glutes are weak or underactive, and it's not good for the knee.

But is it REALLY?

This episode is a deep dive into the biomechanical, epidemiological, and prospective research on knee alignment during squatting, jumping, running and hopping. Our goal is to answer 2 questions:

1. Does the knee going inwards indicate weak glutes?
2. Is the knee going inwards dangerous?

Links:

• Knees going in during a squat shifts load toward the glute max here
• Knee extensor effort rises with squat depth, hip extensor effort rises with load here
• Same depth-versus-load split found again in a separate study here
• In elite powerlifters, heavier loads shift the work from knee to hip here
• Elite powerlifters hit ~23x bodyweight at the knee joint at 90% of max here
• Weightlifters share load between hip and knee; powerlifters are hip-dominant here
• Sideways knee load in a barbell squat is a consequence of stance width, not a fault here
• Elite weightlifters produce MORE frontal plane hip moment than lower-level lifters, not less here
• Elite powerlifters vary widely in how they load their joints, so there is no one ideal form here
• Lifters who fail a squat above their max show reduced extension and lower muscle activity here
• The knee falls into valgus in ~77% of ACL injuries on video here
• But knee valgus does not predict who goes on to tear an ACL here
• And the drop jump test cannot predict ACL injury in elite players here