The system (1) has a speed sensor (13) to measure a usual walking speed (VA) of a user, and a data memory (12) storing the usual speed and rapid walking speed (VC). A generation unit (14) generates a visual/sound signal. A program memory (11) has a program (11.1) to calculate a motivation difference (D1) between the speeds and determine a motivation state of the user based on a comparison between the difference and a reference motivation difference (D1ref) and/or value of the motivation difference of the user. A program (11.4) controls the transmission of a signal corresponding to the state. An independent claim is also included for a method for transmitting a signal relative to the motivation state of a user.