In
martial arts, hand
conditioning is the
process of
toughening and reshaping the
striking surfaces of the hands by repeated,
long term punching and
striking of hard, heavy objects. These may be padded boards, unpadded tiles, rolled ropes, buckets of
sand, or the hands of a
sparring partner. Over time, the
knuckles flatten, the longer bones compress, tendons and ligaments thicken and solidify.
Basically, the trainee deforms his hands over a period of years into a pair of "weaponless swords" that are much tougher than the relatively fragile assortment of bones and ligaments that make up a normal human hand, better able to withstand the higher stresses of advanced techniques, and able to deliver more force to the target.
Because this practice results in much less dexterity and sensitivity in what are ordinarily a person's principal physical instruments, the degree of hand conditioning undertaken is seen as a sign of the devotee's committment and dedication to their art.