Impact and shear resistance of turf grass racing surfaces for Thoroughbreds
Zebarth, B.J.; Sheard, R.W.
American Journal of Veterinary Research 46(4): 778-784
1985
ISSN/ISBN: 0002-9645 PMID: 4014827 Document Number: 244421
The 2 dominant processes involved in the horse hoof-to-racing surface interaction are the shock loading of the horse's leg upon impact with the racing surface and rotation of the horse's hoof into the racing surface. These processes were measured as impact resistance (ie, the peak deceleration of a moving body upon impact with the test surface) and as resistance to shear. The objective of the present study was to measure physically (under a variety of conditions) those soil and turf factors related to the 2 processes. It was concluded that thatch accumulation and mowing height of the turf did not have a significant (P less than 0.05) effect on racing surface hardness (therefore, turf management should optimize turf growth and recovery), that turf roots were responsible for an increase in impact resistance and in resistance to shear, that control over soil moisture through irrigation and drainage allowed modification of racing surface hardness, and that soil materials tend to have lower impact resistance (ie, lower shock loading of the horse's leg) and higher resistance to shear (ie, greater resistance to hoof rotation) than do sand materials.