Fat-free Mass is Related to One-Mile Race Performance in Elite Standardbred Horses

Abstract

This study examined whether body composition was predictive of competitive success in elite standardbreds (STB). Rump fat and muscle thickness (MTH) (vastus lateralis/intermedius [VL], extensor carpi radialis [ECR]) were measured in vivo in male n=6; female n=8 by B-mode ultrasound. Percentage body fat (%fat) was calculated from rump fat. There were no gender differences for age, body mass (males 432±11kg; females 443±13kg), fat-free mass (FFM) (males 400±12kg; females 400±11kg), ECR MTH (males 61±2cm; females 60±2cm) or race time (RT) (males 113±3s; females 114±2s). Males had less (P<0.05) fat mass (males 32+4kg; females 44±3kg) and %fat (males 7.4±0.9%; females 9.9±0.5%) and larger (P<0.05) VL MTH (males 88±7cm; females 81±3cm). RT was correlated to %fat and fat mass in males (r=0.89; r=0.82, P<0.05) not females (r=0.51;r =0.14). FFM tended to relate to RT in males (r=−0.76, P=0.07) and females (r=−0.59, P=0.12). Combined %fat and FFM data were correlated to RT (%fatr =0.70, P<0.01; FFM r=−0.65, P<0.01). RT was not correlated to MTH (VL r=−0.28; ECR r=−0.31). In conclusion, FFM was related to RT in elite STB with %fat negatively related to RT in males.