Spring Shoes FTW wrote:
Bad Wigins wrote:
Springy shoes is NOT a secret to running success, and it can't be, any more than bouncy tires on a bike. It's just not how the mechanics of running work.
Yes it is actually. When you run most of your energy is spent re-gaining the kinetic energy lost every stride. Therefore if you reduce the kinetic energy loss you can maintain a higher kinetic energy at the same effort level.
Setting aside that this is a meaningless generalization, a foot accelerated upward by a spring mechanism doesn't gain free kinetic energy. The body above it has to exert extra force to counteract the acceleration, otherwise the foot merely goes up relative to the body.
It is misleading to reduce runners to point physics in any case. The heel is lifted off the ground nearly immediately on its own, after which all weight is borne on the forefoot. Adding a bouncy heel to this process is like attaching a slingshot to a bow. Acceleration both forward and upward is achieved by the body itself accelerating forward from the planted foot. Motion of the foot itself has nothing to do with it.
This cat will demonstrate.
https://www.youtube.com/watch?v=M6A31tfVybE