Lower body mech:
The leg action should occur under the body with no emphasis on reaching to achieve greater stride length. Foot plant must be as close to under the hip as possible not in front as a breaking force to overcome. As your leg recovers after push off, your ankle should be dorisflexed and your heel comes to your buttocks violently as this shortens the leg lever and eliminates the residual time of the leg behind the body. AS you thigh reaches to parallel to the ground unfolding occurs at the knee and extension begins at the hip. Extension is due to transfer of momentum not reaching or quads contraction. When leg claws the ground under the hip violently extend the ankle joint in the springboard action. Elastic force production is essential and the shorter the ground contact time the more efficient is the force application.
I took out a bunch of words above, now it’s good :). People use too many damn words. It’s sprinting, not time travel. I think talking about clawing the ground and violently extending the ankle is what turns 10.40 potential kids into 10.90 potential kids.
If you heard that you should try to step over the opposite ankle then I’m thinking that whoever said it was talking about during the drive phase when you try to stay low. You have to step over the knee when at max v.