A group of researchers from the University of Utah have published a study focusing on the human hand. During the study, the researchers used instruments to measure the forces and acceleration when martial artists hit a punching bag. The study found that the structure of the fist provide support and increases the ability of the knuckles to transmit punching force when a blow is delivered.
The researchers believe that fighting may have helped shaped the evolution of the human hand. The scientists say that during the study they asked if you could strike harder with a fist than an open palm. During the study, they discovered that fist strikes had no additional force when compared to palm strikes. However, the surface that strikes the target with a fist blow is smaller, creating more stress on the target.
With increased force over a smaller area, more localized tissue damages is caused. Those were rather ancillary findings from this study with the main intent being to determine whether the proportions of the human hand allow buttressing or support. The team says that during the investigation they discovered that a clenched fist did indeed provide protective buttressing of the delicate bones of the hand.
According to the team, creating a fist increases the stiffness of the second meta-carpo-phalangeal (MCP) joint, which are the knuckles visible when you make a clenched fist, by a factor of four. Clenching the fists also doubles the ability of the proximal phalanges to transmit punching power. The scientists believe the human hand evolved from the need to both provide manual dexterity and the ability to be used as a club for striking an enemy.