The authors considered this disparity in acceleration to be fundamental
to the whiplash mechanism as the disparity has to be
accommodated by the components of the neck. The results are
shown graphically in Figs. 1 and 2.
The research by Henderson, published in 2006, supported an
injury threshold of 5 mph but perhaps more importantly, that work
went further using the results of simulated rear impacts to propose
a second threshold of 3 mph. Simulated rear impacts with
speed changes in the order of 2.5–3 mph indicated that at that range
there was no positive disparity on average. That led to the theory
of three brackets when considering the possibility of whiplashrelated
injury in the target vehicle, those being as follows: