The carbon fiber and foam behave just like springs- they return almost all of the compressive force applied to them. They are indeed springs, just not made of steel as one typically thinks of one.[/quote]
[quote]CO= hr x sv wrote:There are no "springs" in the shoe...
so are asphalt and concrete, the difference is they bounce back up a lot quicker.
Try this simple experiment, land on your "spring-loaded" shoes and observe whether you bounce back into the air.
The result shows what use that has in running. The body accelerates at the forefoot point of contact on toe-off. The toe stays in contact with the ground while the body pushes itself forward in front of it. The shoe itself is not accelerating the toe forward, but even if it were, that forward acceleration would require the body to exert extra force to gain the same boost, otherwise only the toe would be affected.