Auto Support Structures

To run effectively, the foot needs to achieve 3 main objectives. It must act as a shock absorber at heel strike and it must be able to adapt to any unevenness in the terrain. These first 2 objectives mean that for the first part of the gait cycle, the foot must remain supple and mobile. But the third function is for the foot to convert from a mobile, adaptive structure, to a rigid lever, capable of propelling the entire body weight forward against the forces of gravity. For this to occur arch stability is very important. The foot must maintain its arched structure in order to act as an efficient lever for forward propulsion. To achieve this, the autosupport structures work together in a coordinated fashion.

The autosupport structures are literally those structures that contribute to the stability of the foot, and it’s ability to maintain an arched shape - these include the tendons and ligaments, the muscles that act on the bones, the capsules that hold the joints in place, and the shape or architecture of the bones themselves. All these structures have a specific purpose and interact to play a very important role in stabilizing the foot.

The foot has autosupport structures, the most important is called the plantar fascia, - a long, very strong band of fibrous tissue running the length of the arch. The plantar fascia acts like the tension band– it is an elastic structure that can develop and store elastic energy as the foot accepts the load of the body’s weight, and flattening of the arch occurs. The plantar fascia resists this flattening.