spin is created with very little force through the action of the helical fletching moving through the air. There is not a lot of inertia there. All of the impact energy comes from the forward motion of the arrow.

one could probably argue that adding helical fletching to an arrow would actually diminish the impact energy because to create the spin, the energy is being drawn from the forward motion of the arrow - similar to drag. The loss is likely insignificant and the gain in flight stability would outweigh the small energy loss.