D
David Martin
Guest
BARRY wrote:
> All a cycle helmet can give you is additional protection to your
> head.....
Not true. A cycle helmet can also give you additional risk of serious
head injury through two clear mechanisms and additional risk of neck injury.
Head injury mechanism 1: helmets increase the effective size of the
head, turning near misses into glancing blows at the peripherary of the
skull.
HI mech 2: blows tangentical to the head (rather than in line with the
centre of motion) will cause rotational acceleration. You need 50 times
less rotational acceleration to get a permanent brain injury than from a
direct linear blow. Helmets can increase the rotational component of an
impact, increasing the likelyhood of HI, and are only designed to cope
with linear blows.
Neck injury: The increased size and weight of the head with a helmet on
increases the risk of neck injury (whiplash type).
So helmets do protect against minor linear blows and against scratches
and bruises, but the payoff is that they may kill you as well. You
really don't know which is more likely without looking at full
population studies. I'd suggest you do so.
...d
> All a cycle helmet can give you is additional protection to your
> head.....
Not true. A cycle helmet can also give you additional risk of serious
head injury through two clear mechanisms and additional risk of neck injury.
Head injury mechanism 1: helmets increase the effective size of the
head, turning near misses into glancing blows at the peripherary of the
skull.
HI mech 2: blows tangentical to the head (rather than in line with the
centre of motion) will cause rotational acceleration. You need 50 times
less rotational acceleration to get a permanent brain injury than from a
direct linear blow. Helmets can increase the rotational component of an
impact, increasing the likelyhood of HI, and are only designed to cope
with linear blows.
Neck injury: The increased size and weight of the head with a helmet on
increases the risk of neck injury (whiplash type).
So helmets do protect against minor linear blows and against scratches
and bruises, but the payoff is that they may kill you as well. You
really don't know which is more likely without looking at full
population studies. I'd suggest you do so.
...d