Perhaps this could be considered prior to matches, and take effect on both Tori and Uke.
Such as, a 'power' percentage which you could scale down or up depending on what you were wishing for; ranging from 0% to 200%~
Power, could affect the dismemberment threshold, fracture threshold, the speed at which all the joints move, or the potential energy behind a movement (e.g. a punch).
This could later be altered to only affect certain joints, by using a map or diagram of the joints, and selecting specific ones.