You could use it either to power a crank connected to the axle of the front bar (which is how Biohazard and Griffon did it, both using two actuators) or just have the actuator act on the front bar (a la Flick, Suren Balendran's pneumatic 4 bar flipper thing from a while ago). You could probably use both of those on the rear bar too but more torque would be needed I think?