As Eckhard says its to do with fitting the gear in the bay. A330 uses a shortening mechanism in the leg to also aid the gear fitting in the bay; a pitch trimming actuator ensures the rear wheels touch the runway first as well as giving a greater angle during aircraft rotation angle for take off.
Other aircraft use truck tilt actuators to tilt the truck aft when the weight of the aircraft is off the ensure rear tires make contact first.
As for impact damage, I cannot say. However I do not believe the any steering actuators would be damaged as they are in the nose gear.