The CavaleTIC project, funded by IFCE, aims at developping new monitoring technology to assist trainers in elite horse riders. In collaboration with UBS (Universite Bretagne Sud), the first step of the project consists in designing the specifications of such a technologica support. To this end, we carried-out in September experiments with elite riders of the Cadre Noir de Saumur, and with first year trainees to become professionnal coaches. A 10x10m square large motion capture are has been used to capture various dressage exercises with this population. Based on the motion capture data, we aim at identifying the relevant biomechanical variables that would help the trainer to evaluate and coach the trainees. We also aim at designing relevant real-time and off-line feedback that would help both trainees and coaches during their practice, for example using multisensory feedback.