Knee caved in during a cut or landing? Here’s what actually happens inside your joint: The femur violently rotates in and collapses over the tibia and then BOOM—ACL tears from the torque. The femur slams down on the meniscus → crushes it, shear force rips through the MCL. That’s the unhappy triad—ACL meniscus MCL. And guess what? 👉 70% of these injuries are NON-CONTACT. Which means they’re preventable. Collapse happens when your body’s out of alignment—when your knees cave in, feet flatten, and