Padding and Injury
Does the amount of padding in a football helmet reduce impact
for head on collisions?
A guess. Probably yes, but the design of helmets and other protective
sports equipment is a complicated engineering problem, so the simple
answer is probably only partially true, and does not take into account
many other factors (e.g. volume, damping (to minimize whiplash), motion
upon impact). The list is long, and the problem difficult.
Yes, more and thicker padding will help reduce impact to the head. But
the type of padding is very important. If it is too soft, the head will just
squash it in an impact and bash into the inside if the helmet's hard
shell. If it is too hard, then it will not cushion the impact enough.
In general, yes, the padding in a football helmet reduces "impact." The
goal of any helmet is twofold. 1) A helmet is a hard shell that prevents
the collision with a sharp object from injuring or penetrating the head
and, 2) reduce the intensity of the impact, which can harm the brain, by
spreading it over a longer time period by having the cushioning material
deflect on impact. The idea is that it is more comfortable to fall onto an
air mattress that is laying on the floor than to fall on the hard floor
The nature of the padding influences how well a helmet reduces the forces
experienced by a player's head. The padding is often crushable and so
directly absorbs some of the energy of impact which might go to the head.
The stiffness of the padding is important. If the padding is too soft then
the padding easily crushes and is squeezed on impact and doesn't help much -
the player's head hits the inside of the hard helmet shell and gets a large
impact. If the padding is too hard then the padding does not deflect or absorb
any energy at all, and the player's head also gets a large impact. The best
stiffness is that which crushes the optimal amount for the kind of collision
that is experienced. Motorcycle helmets have very stiff padding because the
goal is to reduce impact for very severe accidents.
The thickness of padding is important - if the padding is very thin then it is
like it is not there at all, and the player receives an impact as if they were
wearing only the hard shell itself. Very thick would be better but then the
helmet size would be huge.
Robert A. Erck
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Update: June 2012