Researchers used a pressure plate to test the effects of placing a 2-inch layer of soft sand with synthetic fibers and a rubber mat over a pressure plate compared to just using the hard rubber mat on top of the plate. Five clinically normal unshod ponies were used in the study and measurements were obtained at a walk and trot over the pressure plate.
Peak vertical force, vertical impulse, peak vertical pressure and stance duration were all lower with the sand surface. Load distribution was more even between the toe and heel regions at impact on the sand surface with more load distributed to the toe region at mid-stance. There also was a more even load distribution between the medial and lateral sides of the hoof at impact on the soft surface at the walk, but this effect was not seen at the trot. On the hard surface, the loads were distributed peripherally around the wall, while the loads on the soft surface were distributed more broadly across the sole in the area of the toe with a larger contact area.
The authors suggest the more even distribution of loading between the toe and heels at impact may have a protective effect on the heels. While further analysis using force plates will be needed to confirm and better define the effects of the cushioned surface, using a more realistic ground surface could have an important influence on these types of studies.
— Oosterlinck M et al.…