Full context:   The innovative aspect of the invention of the bow and arrow was the amount of power delivered to an extremely small area by the arrow. The huge ratio of length vs. cross sectional area, coupled with velocity, made the arrow more powerful than any other hand held weapon until firearms were invented. Arrows can spread or concentrate force, depending on the application. Practice arrows, for instance, have a blunt tip that spreads the force over a wider area to reduce the risk of injury or limit penetration. Arrows designed to pierce armor in the Middle Ages used a very narrow and sharp tip ("bodkinhead") to concentrate the force. Arrows used for hunting used a narrow tip ("broadhead") that widens further, to facilitate both penetration and a large wound.