Back kinematics at take-off in elite showjumping horses over an upright and parallel-spread fence forming part of a three-fence combination

The objective of this study was to evaluate head, neck and back kinematics during take-off in elite level horses jumping, and to compare these over an upright and parallel spread fence. Ten mixed-breed elite-level showjumping horses were opportunistically evaluated jumping the same 15-fence course (1.35 m) during a British Equestrian Federation World Class Performance three-day training session. Two fences were evaluated using high-speed motion-capture (250 Hz). Head, neck and back kinematics of the horse were determined at take-off, at vertical orientation of leading and trailing third metacarpus/tarsus and as the trailing hindlimb left the floor. Very consistent patterns between all horses over both upright and spread fences were observed in neck-trunk (NT) angle, lumbosacral (LS) angle, the angle of the thoracolumbar (TL) to horizontal and of LS to horizontal. Head-neck (HN), TL angle and distance to fence showed moderate variation between horses. There were no significant differences between fence-type in HN, NT, TL, LS angle or distance to the fence, but TL to the horizontal angle was greater over the spread for all stride phases. LS to the horizontal angle was greater over the upright when the leading forelimb was vertical at take-off and when the trailing hindlimb was vertical at take-off. These findings suggest that elite horses may use some similar strategies to achieve a successful jump. Further understanding regions which are most influenced by velocity, rider, and horse stability could enable us to modify jumping patterns for the performance and welfare of jumping horses.