Before revision:  We assume that the motion of the motor is directly affected by the entropic barrier due to confinement when it is in the passive, unbound state, but not in the active, bound state . Confinement can further modulate the motor's binding kinetics.
After revision:  We assume that the motion of the motor is directly affected by the entropic barrier due to confinement when it is in the passive, unbound state, but not in the active, bound state where it moves with a constant bound velocity.