Have you ever been on a Segway? Or better yet do you know what a Segway is? You typically see them in larger centres, specifically being ridden by mall security. The rider stands on a platform with a handle in front and two wheels at the base. To initiate movement the rider leans their body forward which is detected by a gyroscope within the unit and results in forward motion. Motions other than leaning the until forward by shifting body-weight won't help in moving the Segway. In the same way the Segway can be stopped by returning the unit to a vertical position, and I am assuming, come to sudden stop if the unit is tilted backwards. We can think about running in  the same way. To generate the forward momentum to propel us we need to have our centre of mass in front of the point of ground contact. Some describe running as 'controlled falling'. The body is falling forward and we catch ourselves with each stride just enough to not fall flat on our face but not so much that we can to a complete stop. This forward lean of our bodies needs to be from the ground however. Many hear this concept of having a forward lean and simply bend over at the waist rather than leaning from the ground. By bending forward at the waist a number of bad things happen. 1. Less Stability We don't maintain the tallest spine possible. And a tall spine is a more stable spine. So when we are shorter and we shorten the lengthen of the spine we won't be as stable. A lack of stability means that every time a foot contacts the ground some energy will be lost as it leaked out through point in the kinetic chain where...