Meeting Abstract

69.2  Tuesday, Jan. 6  Turning Performance of Horses TAN, Huiling*; WILSON, Alan M.; The Royal Veterinary College, U.K.; The Royal Veterinary College, U.K. htan@rvc.ac.uk

Sprinting around a bend increases effective body weight as body mass experience both gravity and centripetal acceleration equal to v²/r. Human maximum running speed has been shown to be limited by the ground reaction force legs can withstand and the maximum speed of human sprinters is lower on a bend with a speed reduction that is concomitant with a leg force limit. Recent studies show that greyhounds and mice do not have to run slower on a curve partly due to the decoupling between muscles for weight support and propulsion in quadrupeds. Here we explore the limits of turning performance in horses trained to perform maximum rate turns. We collected horizontal speed and heading from polo horses undertaking maximum rate turns under field conditions during training (Number of horses: 5; Number of turns: 5) and during a real competitive polo game at a range of speeds (Number of horses: 16; Number of turns: 200) using mobile data collection techniques based on GPS and inertial sensors. All the horses did decelerate prior to and during turning to achieve higher angular velocity. The maximum angular velocity observed was 5 rad/s achieved at a horizontal speed below 2 ms^-1. The data fitted a model of a limiting centripetal acceleration, which was 8 ms^-2 during the training for sharp turns on sand surface and 5.5 ms^-2 during the polo game on grass surface. This may represent a safe grip limit in generating horizontal force or mechanical factors involving limb interference.