The duo tested their hypothesis in a series of experiments in which men pounded punching bags, squeezed pressure sensors or performed one-handed push-ups on top of pressure sensors. From this, the scientists learned that force meted out by the hand is about the same when a bag is punched by a fist versus slapped, but nearly twice as great when you consider that the fist delivers its force to a smaller surface area. The study also found that the knuckle joint of the index finger is rendered stiffer and more stable -- transfering force more effectively and protecting the hand -- when a tight fist is made.
In other words, the fist is a dandy fighting tool.
Maybe we should have to register them or have concealed carry permits if we walk around with them in our pockets.