Effect of head rotation in whiplash-type rear impacts

Direction of impact is a factor in determining the muscle response to whiplash, but head rotation at the time of impact is also important in this regard. More specifically, when a rear impact is left posterolateral, it results in increased EMG generation mainly in the contralateral sternocleidomastoid, as expected, but head rotation at the same time in this type of impact reduces the EMG response of the cervical muscles. Muscle injury seems less likely under these conditions in low-velocity impacts.