The Basic Mechanics of the Foot and the Horseshoe
© James Rooney, D.V.M.

The purpose of this paper is to discuss the basic mechanics of the horse’s foot and the horseshoe. A single, major principle will be developed: The effect of the horseshoe on the movement or stance of the horse is completely determined at the moment of impact of the foot (and shoe) with the surface and at the moment of lift-off of the foot from the surface. When the foot is not moving relative to the surface, the horseshoe has no effect.

I shall not explicitly discuss various shoeing systems such as four point, Burgey’s, Duckett’s dot, etc. While these may be worthy of discussion, they do not directly relate to the present analysis. Some of these shoeing systems are said to be derived from study of the natural wearing of the unshod hoof. The nature of such wearing has been addressed by Rooney (1999).

In order to discuss the mechanics of the foot in definite, clear-cut terms we must define the forces which are acting on the foot. In mechanics there are two such forces to be defined: linear forces and moments. In what follows, a simplified and two-dimensional analysis is used. The real system is more complex and three dimensional, but for practical purposes this analysis suffices.

I realize from long experience that neither farriers nor veterinarians, on average, care to concern themselves with “mathematical stuff.” In order to have a clear understanding of how the foot works, however, that mathematical “stuff” is necessary. What follows is couched in mathematical terms but with immediate relationship to the physical situation. It is not difficult if the reader is willing to overcome fear and loathing and reread as necessary in order to understand.

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