Fat-free mass is related to one-mile race performance in elite standardbred horses.
Authors: Kearns C F, McKeever K H, Kumagai K, Abe T
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary Competitive success in standardbred racehorses depends significantly on body composition, yet quantifying which physical characteristics drive performance has remained unclear. Kearns and colleagues measured fat-free mass (FFM), body fat percentage, and muscle thickness in the vastus lateralis and extensor carpi radialis of 14 elite standardbreds (6 males, 8 females) via ultrasound, then correlated these variables to one-mile race times. Fat-free mass emerged as the strongest predictor of race performance across both sexes (r = −0.65, P < 0.01), with higher FFM associated with faster times, whilst body fat percentage showed a negative correlation with performance, particularly in males (r = 0.89, P < 0.05); notably, muscle thickness alone did not predict race times, suggesting that total lean mass matters more than localised muscle development. For practitioners involved in conditioning and nutrition, this work underscores the importance of maximising fat-free mass whilst maintaining lean body composition—a metric that ultrasound assessment can objectively quantify—rather than focusing purely on muscle hypertrophy in specific muscle groups. The findings support individualised body composition management as part of a systematic approach to optimising standardbred racing performance.
Read the full abstract on PubMed
Practical Takeaways
- •Maximizing fat-free mass while minimizing excess body fat is associated with better racing performance in standardbreds; conditioning programs should prioritize muscle development over weight reduction
- •Body composition assessment via ultrasound can help identify performance-limiting excess fat, particularly in male horses where fat mass shows stronger correlation with slower race times
- •Muscle thickness alone does not predict race performance; overall body composition and lean mass are more important than localized muscle measurements
Key Findings
- •Fat-free mass was significantly correlated with one-mile race time in both male and female elite standardbreds (combined %fat r=0.70, P<0.01; FFM r=-0.65, P<0.01)
- •Percentage body fat negatively correlated with race time in males (r=0.89, P<0.05) but not females (r=0.51)
- •Males had significantly lower fat mass (32±4 kg vs 44±3 kg) and body fat percentage (7.4±0.9% vs 9.9±0.5%) compared to females with no gender difference in fat-free mass (~400 kg)
- •Muscle thickness measurements of vastus lateralis and extensor carpi radialis were not correlated with race performance