Effects of two field continuous incremental tests on cardiorespiratory responses in Standardbred trotters.
Authors: Fortier J, Goachet A G, Julliand V, Deley G
Journal: Journal of animal physiology and animal nutrition
Summary
# Editorial Summary Measuring oxygen consumption (VO2) in field conditions has long challenged equine exercise physiologists, yet this data is crucial for evaluating performance capacity and training responses in working horses. Fortier and colleagues compared two continuous incremental trotting protocols in Standardbred trotters, with T1 beginning at 4.2 m/s with 1.4 m/s speed increases every three minutes, and T2 starting at 6.4 m/s with smaller 0.8 m/s increments every two minutes, both continuing until horses broke to gallop. Horses achieved significantly higher peak oxygen consumption during T1 (116.6 ml/min/kg versus 88.9 ml/min/kg) and peak heart rate (217 bpm versus 209 bpm), whilst the longer test duration of T1 (17.5 minutes versus 12.9 minutes) and more complete speed increments improved the reliability of heart rate–VO2 relationships. For practitioners assessing aerobic fitness or monitoring training adaptations, T1's extended timeline and steeper increments appear to provoke greater physiological demand and yield more robust data; the stronger HR-VO2 correlation also makes it a more practical field tool for estimating energy expenditure without portable gas analysis equipment.
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Practical Takeaways
- •The T1 field incremental test protocol is more practical for equine practitioners to implement and provides more reliable cardiorespiratory data for assessing aerobic fitness in trotting horses
- •Starting incremental tests at lower speeds (4.2 m/s) with longer increment intervals yields better physiological measurements than rapid, high-speed increments
- •Field-based testing using the T1 protocol can estimate aerobic energy expenditure and training responses without requiring laboratory VO2 measurement equipment
Key Findings
- •T1 protocol (starting at 4.2 m/s with 1.4 m/s increments every 3 min) produced significantly higher VO2peak (116.6 ± 11.5 ml/min/kg) compared to T2 protocol (88.9 ± 10.2 ml/min/kg)
- •T1 achieved higher HRpeak (217 ± 5 bpm) than T2 (209 ± 3 bpm) in Standardbred trotters
- •T1 protocol was significantly longer in duration (17.5 ± 1.9 min vs 12.9 ± 1.6 min) and showed better HR-VO2 correlation for assessing cardiorespiratory adaptations
- •Both protocols reached similar peak velocities (approximately 10.6-10.7 m/s) when horses transitioned from trotting to galloping