1. Measuring movement asymmetry: A first step in accurately quantifying lameness?
The movement of Thoroughbred racehorses in training can be accurately quantified using an inertial sensor-based system
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2. School of Veterinary Medicine, University of Glasgow
Validation of an inertial-sensor method of gait analysis in the Thoroughbred racehorse
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Dr John Marshall
Dr Lance Voute
Dr Tim Parkin
School of Veterinary Medicine, University of Glasgow

3. Reasons for the study
Lameness is a major reason for lost days racing and training and has a massive impact on welfare
Traditional subjective lameness examination is subject to the effects of observer experience and bias
Poor agreement between veterinary surgeons on lameness exam findings

4. Project aims and objectives
To validate inertial sensor kinematic gait analysis for objective assessment of movement in the Thoroughbred racehorse
Our objectives were:
Perform kinematic lameness examinations of racehorses in training
Analyse data to determine reference values for movement asymmetry in the Thoroughbred

5. Summary
Subjective (traditional visual) and objective inertial sensor examination of a group of 105 Thoroughbred racehorses in training was performed
Data on age, sex, recent training and medical history was collected

6. Main results Horses often displayed asymmetric head movement
Associated with forelimb lameness
Median vector sum 9.7mm (IQR mm)
Horses often displayed asymmetric pelvic movement
Associated with hindlimb lameness
Median PDMax 4.5mm (IQR mm)
Median PDMin 4.3mm (IQR mm)
Majority of horses (96.5%) exhibited movement asymmetry greater than existing ‘sound’ reference values

7. Conclusions
Head (forelimb) movement asymmetry was similar to previously published ‘sound’ values (≤8.5mm)
Pelvic (hindlimb) movement asymmetry was greater than previously published ‘sound’ values (≤3mm)
Objective evidence of lameness was common in racehorses in training

8. Impact on the Thoroughbred
Movement of racehorses in training can be quantified using non-invasive, portable inertial sensor based devices
The clinically significant amount of movement asymmetry may be greater than existing reference values

9. Potential next steps
Future studies to elucidate the relationship between movement asymmetry, lameness, injury and racing performance are warranted.