A roller skate includes a sole, a beam, a fastening unit, supporting elements and connecting units. The sole includes bores around an aperture. The beam includes an orifice between two recesses and stepped holes in communication with the recesses. The fastening unit includes a nut engaged with a threaded bolt inserted in the orifice and the aperture. Each of the supporting elements includes an arched portion for supporting a roller and a positioning portion formed on the arched portion and insertable in a selected one of the recesses. Each of the connecting units includes a detent and a spring. The detent is movable in a corresponding one of the stepped holes. The spring is compressed between the detent and a shoulder of one of the stepped holes so that the spring tends to push the detent in one of the bores.

Various powered mobility systems for users are described. The powered mobility system can include at least one powered skate. The powered skate can include a platform, a plurality of wheels, and a motor assembly. The motor assembly can include a motor. The motor can be powered by a power supply. A motor control can be implemented to determine when power is supplied to the motor from the power supply.