Injuries may be classified in various ways. The origin of over-loading from the mechanical point of view must be considered if the prevention of injury is to be attempted. There are 4 main causes of injury; the most common and dangerous resulting from shock loads in the brain, specifically in the cases of moped- and motor cycle riders.
The principal object of the investigation was comparison of the shock-absorbing qualities of present day helmets to those of natural materials e.g. the coca-nut rind.