An exemplary assembly includes a cylinder, a piston, and a lock. The lock is transitionable between an unlocked position that permits extension and retraction of the piston relative to the cylinder, and a locked position that limits retraction of the piston relative to the cylinder. The lock is blocked from transitioning from the locked to the unlocked position when a load supported by the piston exceeds a threshold load. An exemplary method includes transitioning a lock from an unlocked to a locked position. The lock in the unlocked position permits extension and retraction of a piston relative to a cylinder. The lock in the locked position limits retraction of the piston relative to the cylinder. The method further includes holding the lock in the locked position using a load supported by the piston that exceeds a threshold load.