Fist or Open Hand?

It's 4.30am and I've given up attempts at sleep. Editing my kansetsu waza chapter, I had occasion to reread the article arguing that the human hand evolved for punching in addition to dexterity. This article formed the basis of a post I wrote on one particular aspect of the study.

One of the things studied in that study was the difference between striking with a fist or an open hand.

The force and force impulse of both forward and overhead strikes were not different when the subjects struck with a fist or an open palm.

Although the forcefulness of a strike can be important to the outcome of a fight (e.g. accelerating the body, knocking an opponent off their feet; or accelerating the head, causing unconsciousness or a concussion), local tissue damage, such as bone fracture and contusion, is produced not by force but by stress (force per area)

The striking surface area of a fist is less than one-third the area of the whole hand and ~60% of the area of the palm. This means that if the total force applied in a strike is the same, then the stress in the targeted tissue will be 1.7 to 3.0 times greater in a fist strike than in a palm strike. Thus, although striking with a fist appears not to result in more forceful strikes, fists increase the peak stresses that are imposed on the target and, therefore, the potential for injury.

One thing that is not lacking in the martial arts is opinions. One thing that is lacking is authoritative facts. Studies like this, and hopefully my work, goes towards increasing the martial arts body of knowledge with facts rather than more opinions.