I've actually been involved in the commissioning of an FMVSS 202a headrest strength tester.
A lot of science and work goes into the construction of those headrests - if it was less firm, you'd get a concussion from the rotational forces in the whiplash or just break your neck, more firm and you'll get a concussion from the linear impact. It's not at all arbitrary, there's a reason they are exactly as firm as they are.
A lot of science and work goes into the construction of those headrests - if it was less firm, you'd get a concussion from the rotational forces in the whiplash or just break your neck, more firm and you'll get a concussion from the linear impact. It's not at all arbitrary, there's a reason they are exactly as firm as they are.