Effects of training on maximum oxygen consumption of ponies

Abstract

Objectives - To establish maximum oxygen consumption (V•O2max) in ponies of different body weights, characterize the effects of training of short duration on V•O2max, and compare these effects to those of similarly trained Thoroughbreds. Animals - 5 small ponies, 4 mid-sized ponies, and 6 Thoroughbreds. Procedure - All horses were trained for 4 weeks. Horses were trained every other day for 10 minutes on a 10% incline at a combination of speeds equated with 40, 60, 80, and 100% of V•O2max. At the beginning and end of the training program, each horse performed a standard incremental exercise test in which V•O2max was determined. Cardiac output (Q•), stroke volume (SV), and arteriovenous oxygen content difference (C [a-v] O2) were measured in the 2 groups of ponies but not in the Thoroughbreds. Results - Prior to training, mean V•O2max for each group was 82.6 ± 2.9, 97.4 ± 13.2, and 130.6 ± 10.4 ml/kg/min, respectively. Following training, mean V•O2max increased to 92.3 ± 6.0, 107.8 ± 12.8, and 142.9 ± 10.7 ml/kg/min. Improvement in V•O2max was significant in all 3 groups. For the 2 groups of ponies, this improvement was mediated by an increase in Q• this variable was not measured in the Thoroughbreds. Body weight decreased significantly in the Thoroughbreds but not in the ponies. Conclusions and Clinical Relevance - Ponies have a lower V•O2max than Thoroughbreds, and larger ponies have a greater V•O2max than smaller ponies. Although mass-specif V•O2max changed similarly in all groups, response to training may have differed between Thoroughbreds and ponies, because there were different effects on body weight.