With the growth of connected and smart sport devices to improve performance, this kind of object is developed for equestrian sports. An accelerometer and a gyroscope are put on horse withers. It collects data from the 3 space directions (x, y, z) and it allows calculation of parameters that characterize motion like cranio-caudal, medio-lateral and dorsoventral energies or gallop frequency. The objective is to predict the speed of the horse per second with an exactness of 0,6 m/s in order to have a new parameter characteristic of the horse motion.