Early whiplash tests involved monkeys and even recently, cadavers have been used to understand the mechanics of the injury. Accident reconstruction experts measure the injurious forces generated in a car accident with arrays of accelerometers attached to a crash test volunteer. Occupant G forces are compared to vehicle velocity or more specifically the change in velocity of the impact vehicle, or Delta V. Recent studies at Chalmers University of Technology in Sweden suggest that rapid changes in the spinal column pressure cause damage to the nerves. Rapid change in the spinal fluid result in pressure damage to nerve fibers because the forces that occur during a rear impact happen too fast to allow normal fluid exchange. This research indicates that the speed at which the motion occurs is more critical compared to the extent of the neck motion.
Some studies show that the range of motion is equally important.
Head angular acceleration and resultant linear head acceleration are considered key injury predictors. Reducing either or both of these factors would result in reducing the severity and duration of whiplash injuries. Independent crash tests showed remarkable reductions of both forces when using the Add On Head Rest. National Highway Traffic Safety Administration Head restraints designed properly can prevent whiplash injury. When vehicle occupants involved in rear crashes had their heads against the head restraint during impact no injury occurred.