The concept and use of the YO-YO system in the sporting context, takes origin from the classic children’s game. Yo-Yo is a toy consisting of two disks connected by a central axle and a string looped around the axle itself. By holding the yo-yo by the string and letting the discs unwind downwards, due to gravity the yo-yo accumulates rotational energy translating into kenetic energy. When the string is completely unwound, this rotational energy allows the yo-yo to wind itself back up towards the individual’s hand. Compensating for the lost energy with a hand motion, the yo-yo can completely wind itself back to one’s hand. There are several types of yo-yo: classic – the string is fixed to the axle; Modern – the string is not fixed to the axle, it allows the yoyo to sit at the bottom of the string to exploit the energy accumulated from the first launch without returning to the hand (sleeper). The modern yo-yo differs in two types: auto clutch – this uses centrifugal force to return to the yo-yo without any effort; ball bearing – a small buffer allows countless evolutions (trick) thanks to long sleeper. Applying this to sports, it uses this principle for the accumulation of kinetic energy of a flywheel with the following explanation: The resistance allows the exploitation of kinetic energy produced by the rotating body (flywheel) in the form of the traction rope tension in response to the power expressed in periodic regime by the pull exerted by the user. The user applies a starting voltage to the rope (wound on a drive shaft), this unrolls the flywheel system; this kinetic energy of initial rotation is stored in the flywheel which, by inertia, continues to rotate around the axis of rotation of the system itself, by wrapping the rope again around the tree of transmission. This process is much more efficient because it is a respected periodic regime and the correct operating distances.