In evaluating the impact on forelimb kinetics during the swing phase of the trot, Hilary Clayton and other Michigan State University researchers found no significant differences between flat and egg bar shoes of the same weight. But there were significant differences in limb kinetics due to changes in the inertial parameters of the hoof when these shoes were compared with an unshod horse.
Clayton, the head of the Mary Anne McPhail Equine Performance Center in East Lansing, Mich., determined that the flexor muscles had to generate more energy in the early swing to overcome the additional inertia created by the extra shoe weight. The elbow extensors also had to generate more energy in the late swing to overcome the extra momentum due to the weight of the shoe.
Since many researchers believe limb injures are related to poor hoof conformation or poor shoeing, corrective shoeing is an essential part of treating lameness problems in athletic horses. However, the exact impact of various shoes is unclear and much of the current information is conflicting, says Susan Stover, an equine researcher at the University of California in Davis, Calif. She’s found that a short shoe or a shoe with a toe grab provides slightly higher suspensory ligament strains. Softer track surfaces also enhanced the effects of shoe changes on suspensory ligament strains.
A couple of years ago, Ray Miller ran a newspaper…