American Farriers Journal
American Farriers Journal is the “hands-on” magazine for professional farriers, equine veterinarians and horse care product and service buyers.
Hardly any other motion event is of greater interest in the daily shoeing routine as breakover. Various shoe modifications have been developed to ease breakover for athletic performance and the treatment of orthopedic patients. But what does “ease of breakover” mean? How do trimming or a shoe’s toe design influence biomechanics and the function of the equine distal limb
The effect of trimming and shoeing is a frequent topic of professional discussions and scientific examinations. This article shall give an overview of the practical relevance of influencing this motion event and the research findings about the influence of farriery on the quality of breakover.
Breakover is defined as the period of rotation of the heels around the toe in the terminal part of the stance phase. However, detailed descriptions are related to different aspects of equine biomechanics.
Visualization of the ratio between the amount of the supporting area of the hoof (blue) and the dorsal moment arm (red).
Geometric aspect. Breakover is the length of the dorsal leverage in relation to the distal phalanx or the center of rotation of the distal interphalangeal joint (DIPJ) (Figure 1).
This pressure image is an average of seven strides of the left hoof, with the black and white box (circled in red) showing the location of the last hoof-ground contact during breakover.
Spatial aspect. Breakover is the location of the point of last hoof-ground contact at the dorsal aspect of the distal margin of the hoof (Figure 2).