Equine locomotor analysis on vet-gates in endurance events

Abstract

Reasons for performing the study: Fatigue during endurance rides might induce changes in gait pattern that could be difficult to distinguish from subtle lameness.

Objectives: To assess changes in gait pattern en route, in fore(FL) and hindlimbs (HL) and establish differences between excellent (EP) and good performers (GP).

Methods: Seventy-five sound and fit horses that completed endurance rides of 80 km were filmed at trot in the vet-gates (VGs) prior to competitions (VGO), and at 29 km (VG1), 59 km (VG2) and 80 km (VG3). Mean gait velocity (V), stride length (SL), duration (SD) and frequency (SF) were measured. Also, stance (StD), swing (SwD), braking (BrD) and propulsion (PrD) durations were determined in the 4 limbs and expressed as % of SD.

Results: Horses trotted with a significant lower V at VG3 in comparison to VG0 (mean +/- s.d. 2.3 +/- 0.6 m/sec, 3.3 +/- 0.6 m/sec) and showed a shorter SL (1.5 +/- 0.4 m and 2.2 +/- 0.3 m in VG0 and VG3). Regression analysis confirmed that the reduced SL at VG3 was due to the lower V. Horses in VG3 presented longer FL-StD (46.2 +/- 4.7%, 38.1 +/- 4.6%), BrD (22.0 +/- 2.5%, 16.9 +/- 2.5%) and PrD (24.1 +/- 21%, 21.5 +/- 2.47%) compared to VG0. In VG0, HL-PrD (23.0 +/- 3.0%) and HL-BrD (18.7 +/- 1.8%) were longer than FL-PrD (21.5 +/- 2.47%) and FL-BrD (16.9 +/- 2.5%). EP showed fastest V and longer SL at VG0, and VG3 than GP (P<0.05).

Conclusions: Sound endurance horses undergo changes in gait pattern during competition, mainly due to reduction of V. Some differences exist between FL and HL, and EP show higher V and SL in the VGs.

Potential relevance: Understanding of the locomotor effect of fatigue will provide an objective basis for the assessment of soundness during endurance events.