A pedal assembly for electromechanical exercise or rehabilitation of a user is disclosed and can include pedals to engage appendages of a user. A spindle supports each pedal and has a spindle axis. A pedal arm assembly is located between the spindle and a rotational axle of the equipment. The pedal arm assembly is radially offset from the spindle axis to define a range of radial adjustability for the pedal relative to the rotational axle. The pedal arm assembly can include an electrically-actuated coupling assembly to adjust the radial position of the pedal in response to a control signal, and regulate motion of the user engaged with the pedals.