A few contributors to this thread have suggested that,
"If you are
scared...," then something's wrong. First of all, anyone who does high
risk work knows that when you're not scared is precisely when you're
most likely to get hurt. It's that controlled fear which keeps one
alert for danger. With rollerskis, one of those dangers is rocks. Yes,
depending on the ski wheel size, speed, angle of contact and use of a
fender, a rock can definitely bring one down. So can a small twig,
as small as about 1/4" x 1" long. To the extent that rollerskiing is
not just exercise but also an attempt to improve one's form (technique,
balance, speed), then progressively challenging those fears is
essential for improvement.

rm

I really think that if you roller ski when frightened you are likely to not
replicate effective efficient snow technique. Tentativeness is not a good
quality for skiers to have. Obviously there is a learning curve. Of late
I've been humbled as I re-enter the world of roller skiing. It will take a
while to develop the reckless abandon indicative of powerful and relaxed
technique. But I agree that even if practiced with technique that does not
duplicate your snow skiing, or with technique that is "unacceptable", there
are still benefits to be enjoyed.

As to the helmet/no helmet and protection issue. Jeeeze, I'd much rather
have on protective gear when I crash,. But really, in a serious crash impact
with a car, a helmet probably won't help much.
You know that in populations studied in which it became law to wear a helmet
when cycling the incidence of head injuries went up. Why? Decreased risk
aversion maybe? Anyway I think it is foolish to not wear a helmet when doing
so doesn't much interfere with enjoyment. However I wouldn't hesitate to
roller ski or ride in most circumstances if a helmet wasn't available.My
greatest fear of a head injury is when standing stationary on roller skis
with out a helmet on. The thought of a fall backwards onto an unprotected
head brings to mind the image of the outcome of dropping a melon onto the
asphalt from 5.5 feet. I put my helmet on before I put my roller skis on.

I've just researched a rare cancer that my dear friend has in his skull. I
expected that it might have had something to do with a motorcycle accident
and head injury 25 years ago. Indeed, there seems to be a relationship
between trauma of the skull and latter development of this vascular cancer
of the bone.

Gary Jacobson
Rosendale, NY