On Monday, August 19, 2019 at 4:42:44 AM UTC-4, wrote:
Hmmm .... every case of whiplash I treated over the years followed a
vehicle rear end impact where the recipient occupant's head went
back then whiplashed forward....

Right, injury would be more common in a car from a rear-end hit,
in a glider the headrest is to prevent injury on the rebound.
Or so it was explained to me...