Rein tension during canter

Riders generally use reins as a means for communication with the horse. At present, the signalling pattern is poorly understood. The aim of this study was to illustrate and analyse the rein tension patterns in a number of rider/horse combinations across a variety of exercises in the canter gait. Our hypothesis was that some riders will follow the movement of the horse more closely than others. Data were collected from eight professional riders riding each three (in one case two) horses that were familiar to them in canter. Horses were instrumented with rein tension meters logged by inertial measurement unit technique (IMU). Inside and outside rein tension data were synchronised with the gait using the vertical acceleration IMU-signal at the poll. Stride-split data (0-100 percentages) were analysed using mixed models technique to elucidate the inside/outside and stride percentage interaction, taking into account the exercises performed. In general, tension was maximal just before the beginning of vertical stance, as defined by the maximal acceleration of the head, with the release closer to the suspension phase. The release was significantly more marked on the outside rein, but between riders and horses the pattern varied substantially. In total 26% of the variation was represented by riders and 21% by the horses. On average there were significant inside/outside rein differences, but at the same time in some horse/rider combinations these differences did not exist.