Kinematic characteristics of hoof landing in jumping horses at elite level

Abstract

Biomechanical events of the distal limb during the landing phase of a jump have been proposed to be risk factors for injury, indicating need for further characterisation of the landing and the hoof-surface interaction. This is essential also for valid testing of arena surfaces when simulating actual conditions. To investigate the hoof landing characteristics for different limbs of elite showjumping horses during the landing phase when jumping 1.30-1.50 m competition fences on 2 different arena surfaces. A single, fixed high speed camera (1000 frames/s) was aimed at landing spots after different fences during 2 competitions. A total of 64 hoof landings were recorded on one sand and one turf surface (using studs on the turf). Hoof movements were tracked from calibrated video sequences. Landing velocities, landing angles, maximal vertical and horizontal deceleration and timing of maximal deceleration peaks were calculated and compared between leading/trailing fore-/hindlimbs. All outcomes were analysed for limb, using generalised linear models and controlling for effects of surface and obstacle. Landing speed differed among limbs (P < 0.02 for all speeds and models). The leading hoof approached the ground more acutely angled to the horizontal plane than the trailing comparing fore- (P < 0.001) and hindlimbs (0.05 ≥ P > 0.01), respectively. Differences in landing and braking kinematics were also found between surfaces and obstacles; however, these effects were hard to separate because of the nonexperimental design. The landing and braking characteristics of the hooves varied substantially between hind-, fore-, trailing and leading limbs. Developing mechanical testing devices for arena surfaces, this fairly wide range of biomechanical events must be considered, in order to simulate the horse-surface interaction.