Kinematics of saddle and rider in high-level dressage horses performing collected walk on a treadmill

P>Reasons for performing the study: The kinematics of the saddle and rider have not been thoroughly described at the walk. Objective: To describe saddle and rider movements during collected walk in a group of high-level dressage horses and riders. Methods: Seven high-level dressage horses and riders were subjected to kinematic measurements while performing collected walk on a treadmill. Movements of the saddle and rider's pelvis, upper body and head were analysed in a rigid body model. Projection angles were determined for the rider's arms and legs, and the neck and trunk of the horse. Distances between selected markers were used to describe rider position in relation to the horse and saddle. Results: During the first half of each hindlimb stance the saddle rotated cranially around the transverse axis, i.e. the front part was lowered in relation to the hind part and the rider's pelvis rotated caudally, i.e. in the opposite direction. The rider's seat moved forwards while the rider's neck and feet moved backwards. During the second half of hindlimb stance these movements were reversed. Conclusion: The saddles and riders of high-level dressage horses follow a common movement pattern at collected walk. The movements of the saddle and rider are clearly related to the movements of the horse, both within and outside the sagittal plane. Potential relevance: The literature suggests that the rider's influence on the movement pattern of the horse is the strongest at walk. For assessment of the horse-rider interaction in dressage horses presented for unsatisfactory performance, evaluations at walk may therefore be the most rewarding. Basic knowledge about rider and saddle movements in well-performing horses is likely to be supportive to this task.