What really leads to things like crow hopping and drag foot collapse? The most common cause of these big time mechanical issues is improper use or improper timing of the hips when you push off the rubber When you first push off the rubber, it’s the HIPS and the stride leg knee that go first Not the head, not the upper body, and not the chest. We also doing push straight up and immediately lock out the leg on the rubber. And we definitely do not immediately turn sideways and pull everything open