Global Positioning System-Determined and Stopwatch-Determined Running Speeds of Horses Differ.
Authors: Lindner Arno, Brand Anna
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: GPS Speed Measurement Accuracy in Horses Determining exercise intensity during standardised fitness testing relies heavily on accurate speed data, yet the validity of popular GPS devices in equine settings remained largely unexamined until this 2020 investigation. Lindner and Brand compared speeds recorded by the Polar M400 Equine heart rate monitor's integrated GPS against traditional stopwatch timing in eleven and eight horses respectively, running repeated laps of 130 m and 250 m across indoor and outdoor arenas at five progressively increasing intensities. The GPS measurements consistently underestimated speed across all intervals and both environments (P between 0.01 and 0.001), with the discrepancy widening substantially as speeds increased—a finding that directly contradicts manufacturers' accuracy claims and fundamentally undermines reliability for prescription and monitoring of exercise protocols. For practitioners designing conditioning programmes, interpreting heart rate data tied to GPS-derived speed metrics, or benchmarking performance, these results suggest that GPS-determined speeds from the Polar M400 cannot be treated as absolute measures and may necessitate manual verification or recalibration against stopwatch timings, particularly when precision in exercise intensity is clinically important.
Read the full abstract on PubMed
Practical Takeaways
- •Do not rely solely on Polar M400 GPS measurements for accurate horse speed determination; consider cross-referencing with manual timing methods
- •GPS underestimation of speed increases at higher velocities, so caution is warranted when using GPS data for high-speed exercise assessment or training prescription
- •Manual stopwatch timing over measured distances remains a more reliable method for determining running speed in horses during standardized exercise tests
Key Findings
- •GPS-determined speeds from Polar M400 were significantly lower than stopwatch-determined speeds across all intervals (P between 0.01 and 0.001)
- •The difference between GPS and stopwatch measurements increased with increasing speed
- •Accuracy of GPS speed determination in horses is questionable under the conditions tested (standardized exercise tests in sandy riding arenas)