Foot motion - pronation and supination

There is a lot of confusion surrounding the terms pronation and supination. These words are thrown around with impunity by the sport shops and other medical professionals, but there still seems to be a lack of understanding about what they really mean.

Pronation and supination describe normal movements of the foot that are essential for foot function.

Everybody pronates and supinates, it is a matter of how much, dictated by the inherited structural mal-alignments and acquired muscle imbalances. It is when these motions become excessive that the potential for problems arises.

The foot ideally should at one point of the walking cycle be a loose adaptor, adapting to uneven surfaces and absorbing shock and at another point, a rigid lever for propulsion.

The foot strikes the ground a little laterally, or supinated, then the foot moves into pronation and becomes a loose adaptor and shock absorber. The tibia at this point is rotating internally. Just after this phase has finished and the foot has absorbed shock, the tibia starts to de-rotate as the foot re-supinates, creating a higher arch and a rigid lever for propulsion, heel lift off and toe off. There is a timing involved in the foot that when it works, the foot functions with very little effort at all, and the muscles of the foot have no need to overwork at all.

Should this timing not be achieved, for whatever reason ie: muscle-imbalances, structural mal-alignment, the potential for a large range of problems exists in growth and development, sport and other activities. Should one be wearing incorrect footwear on top of that, or be overweight and stand a lot, you then have the recipe for long term foot problems.

The foot however does not exist in isolation and it is influenced by problems that may exist elswhere in the body. Scoliosis, leg length discrepancies for example may influence foot function.