Blood lactate responses to submaximal field exercise tests in thoroughbred horses.
Authors: Davie A L, Evans D J
Journal: Veterinary journal (London, England : 1997)
Summary
# Blood lactate responses to submaximal field exercise tests in Thoroughbred horses Davie & Evans investigated how accurately blood lactate concentrations could predict exercise performance in Thoroughbreds, testing 21 horses on sand and 25 on grass tracks during standardised 800-m runs at speeds between 12.8–16.6 m/s. On sand, an exponential model best described the lactate-velocity relationship (r² = 0.58), whilst on grass a second-order polynomial equation performed better (r² = 0.57), suggesting that track surface influences the metabolic response to submaximal exercise. Repeatability of the predicted versus measured lactate difference was excellent, with mean discrepancies of only 1.9 mmol/L on sand and 1.8 mmol/L on grass, and no significant relationship between running speed consistency and lactate variability. For practitioners using field fitness testing, these track-specific regression equations offer a practical framework for identifying performance changes and metabolic adaptations without requiring laboratory conditions, though the moderate r² values indicate that individual variation remains substantial and lactate response should be interpreted alongside other fitness indicators. This approach may prove particularly valuable for trainers and veterinarians monitoring Thoroughbred conditioning programmes, particularly when repeated testing on the same track surface provides the most meaningful comparison data.
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Practical Takeaways
- •Use track-specific regression equations when interpreting blood lactate responses in standardized exercise tests, as sand and grass surfaces produce different lactate-velocity relationships
- •The repeatability of lactate differences (±1.8-1.9 mmol/L) indicates this field test is reliable for monitoring fitness changes in individual horses over time
- •Velocity variability during the 800-m test does not confound lactate measurements, so this test can be used consistently even with minor variations in pacing
Key Findings
- •Blood lactate response to submaximal exercise (800 m at 12.8-16.6 m/s) in Thoroughbreds follows an exponential relationship on sand tracks (r² = 0.58) and a second-order polynomial relationship on grass tracks (r² = 0.57)
- •Measured versus predicted blood lactate concentrations showed good repeatability with mean differences of 1.9 ± 1.8 mmol/L on sand and 1.8 ± 1.7 mmol/L on grass tracks
- •No significant association exists between exercise velocity and variability in performance within the 800-m test on either track surface
- •Track-specific predictive equations for lactate response have potential application in field-based fitness monitoring of Thoroughbred racehorses