Relationship between experience and head kinematics in race riding jockeys.

Thoroughbred race-riding requires jockeys to attenuate horse movement and maintain postural stability whilst galloping at high speeds. This study aimed to investigate the head movement of jockeys in relation to race-riding experience. Accelerometer and heart rate data were collected from twelve apprentice and two senior jockeys during 85 exercise rides and 82 trial rides. Mean head displacements were determined for each jockey by double integrating the filtered acceleration data. A mixed effect multivariable linear regression model was used to investigate the relationship between jockey experience, physiological variables and head kinematics. The median (IQR) head displacement was higher for exercise riding (0.12 m, 0.09-0.14 m) than trial riding (0.06 m, 0.05-0.09 m). Jockey head displacement decreased with increasing speed of the horse (p < 0.001) and greater jockey experience (p = 0.007). Higher exercise load had a greater effect on head displacement with less experienced jockey's (p = 0.02). The effect of speed was lower for trial riding than exercise riding (p < 0.001). More experienced jockeys had a greater ability to attenuate horse oscillation than inexperienced jockeys. This ability became more pronounced at higher exercise loads, reflecting a higher level of physical fitness and riding skill level. Measurement of jockey head displacement may provide a simple measure of assessing jockey race-riding ability or fitness.