ASTM Roller Skating Helmet Standard
BROCKMANN,UWE
Speedskating Times (305-782-5928). It will be published in this
month's issue which is supposed to reach 80% of subscribers by
1/21/93. My involvement was prompted by Les Earnest's posting to this
newsgroup. Please comment.
The ASTM Roller Skating Helmet Standard
---------------------------------------
The American Society for Testing and Materials (ASTM) will soon release
a new bicycle helmet standard. A roller skating helmet standard is also
in preparation. The ASTM Sports Equipment Committee (F-8) has formed a
task group to determine whether a standard different from the bicycle
helmet standard, possibly calling for more rear head protection, is
needed for roller skating. I represent the IISA Competition Committee on
this task group.
In addition to performance tests similar to those specified in ANSI
Z90.4 and Snell B90 the ASTM bicycle helmet standard will soon
incorporate a roll-off test and a vertical vision impairment test.
I believe that the standards for cycling and skating helmets should be
the same. Unfortunately, no accident statistics are available. Therefore
my belief is based only on personal experience, observation, stories
related to me by other skaters, and analytical thought.
Please contact me at the address given at the end of this article with
helmet and head injury experiences, arguments for or against separate
standards, and questions about the ASTM standard.
Bicycle helmets provide little rear head coverage to allow for
sufficient clearance between helmet and back in the bent-forward cycling
position. Due to the recent rapid growth of inline skating most skaters
are beginners. As they gain experience they will move to the more
efficient bent-forward skating position already used by experienced
skaters. Thus skaters will need the same amount of clearance between
helmet and back as cyclists.
Skaters tend to fall forwards when their skates get blocked by an
obstacle. A helmet with more rear head coverage would provide no more
protection in this type of accident than regular bicycle helmets.
Facial and jaw protection for skaters is desirable but no feasible
designs have been proposed.
Skating, unlike walking on ice, does not rely on traction in the forward
or backward direction. Sudden loss of traction in these directions and
resulting hard falls cannot occur.
Skaters may fall backwards at low speeds when their skates are
accelerated forward unexpectedly but gently by a decline such as a
lowered driveway on a sidewalk. In this case they fall slowly, slow the
fall with posterior or hip impact, and slow it further with their arms.
If the head hits the ground at all it will do so at low speed. A bicycle
helmet suffices for spreading the load even though it can spread it only
over a limited head area.
Racers may need additional side and rear head protection against skates
from following skaters after falling during a race. However, this need
is not clearly established and does not apply to the larger group of
recreational skaters who do not skate in tight packs under accident-
promoting competitive conditions.
Falls while skating backwards at high speed can lead to hard rear head
impact. However, this is not a typical use of skates. The same is true
for skating down stairs forwards. I recommend that all ASTM-approved
bicycling/roller skating helmets be labelled as not designed for high-
speed backwards skating, forwards skating down stairs, and other
unspecified "radical" maneuvers.
Inline racing appears to be less dangerous than expected. In 1992 IISA
CC sanctioned more outdoor races than any other roller skating
organization in the U.S. Only minor injuries occured in sanctioned
events. Due to low claims experience, IISA CC will offer twice the
medical coverage for less than half the insurance premiums to race
organizers in 1993.
Skaters can achieve higher speeds than cyclists on downhills due to
lower wind resistance. They are likely to suffer the same amount of
injury as cyclists when hitting fixed objects at the same speeds. A
skating helmet standard should therefore be no less demanding than a
cycling helmet standard.
Skating head injuries can be reduced by increasing helmet use,
especially among beginners who are least likely to wear helmets.
A skating-specific helmet standard would lead to higher helmet cost,
lower helmet availability, delayed consumer helmet purchase decisions,
and reduction of helmet use. Owners of cycling helmets would be
discouraged from using their helmets for skating and encouraged to
skate without helmets.
A skating helmet with additional rear head coverage would not be
accepted by the growing percentage of experienced skaters if it
interfered with the bent-forward skating position. IISA CC would not
mandate the use of such a helmet in its events.
The ASTM F-8 committee should adopt the same standard for roller skating
and bicycle helmets. The standard should require prominent marking of
compliant helmets as dual-purpose bicycling/roller skating helmets to
help educate consumers that cycling helmets provide good head protection
for skating.
Uwe Brockmann
58 6th St., N.E.
Atlanta, GA 30308-1140
phone: 404-892-4872
fax: (Uwe Brockmann c/o Henry Zuver) 404-634-9032
Internet: u...@cc.gatech.edu
[(Mr.) Uwe (pronounced "oova") Brockmann, (404)892-4872, u...@cc.gatech.edu]
Lynd Wieman
I agree with you basic conclusions but there are a couple of minors points
I have questions about.
> Falls while skating backwards at high speed can lead to hard rear head
> impact. However, this is not a typical use of skates.
I've only been skating about 6 months but my worst falls have been going
backwards. True, I haven't been going very fast and didn't hit my head.
But I believe skating backwards is pretty common. However, I don't think
this justifies having a different standard than bicycle helmets.
> Skaters can achieve higher speeds than cyclists on downhills due to
> lower wind resistance.
Really? Wow! I get up to 50 mph every now and then on my bicycle and I have
gone 60 mph in a bike race. I can't imagine going this fast on skates.
> They are likely to suffer the same amount of
> injury as cyclists when hitting fixed objects at the same speeds.
No kidding. At 60 mph into a fixed object, the helmet standard is not real
important. :-)
Lynd
BROCKMANN,UWE
>> lower wind resistance.
>
>Really? Wow! I get up to 50 mph every now and then on my bicycle and I have
>gone 60 mph in a bike race. I can't imagine going this fast on skates.
Skaters can draft each other more closely than cyclists. They can touch
each other and form a "train" when going downhills. This allows them to
go faster than cyclists.
In the Athens-to-Atlanta race I observed the lead pack of skaters
routinely outrunning all support bicycle riders on the major downhills.
A skater who does not stay with the pack on downhills loses a lot of
ground that is hard to make up afterwards. This forces skaters to
stay in the pack and achieve high speeds. I estimate that groups of
skaters exceed 50 mph in this race whereas individual skaters can only
go about 40 mph on the same downhills.
Skaters are less stable than cyclists at high speeds and they cannot
brake as well. Therefore they tend to avoid high speeds for safety
reasons. However, in some races they cannot avoid high speeds if they
want to be competitive.
John Svensson of the Ultra Wheels race team claims that he went 72 mph
on one downhill in California. His friend drove a pick-up truck next
to him and read the speed off the speedometer.
BROCKMANN,UWE
>> lower wind resistance.
>
>Really? Wow! I get up to 50 mph every now and then on my bicycle and I have
>gone 60 mph in a bike race. I can't imagine going this fast on skates.
Skaters can draft each other more closely than cyclists. They can touch
each other and form a "train" when going downhills. This allows them to
go faster than cyclists.
In the Athens-to-Atlanta race I observed the lead pack of skaters
routinely outrunning all support bicycle riders on the major downhills.
A skater who does not stay with the pack on downhills loses a lot of
ground that is hard to make up afterwards. This forces skaters to
stay in the pack and achieve high speeds. I estimate that groups of
skaters exceed 50 mph in this race whereas individual skaters can only
go about 40 mph on the same downhills.
Skaters are less stable than cyclists at high speeds and they cannot
brake as well. Therefore they tend to avoid high speeds for safety
reasons. However, in some races they cannot avoid high speeds if they
want to be competitive.
John Svensson of the Ultra Wheels race team claims that he went 72 mph
on one downhill in California. His friend drove a pick-up truck next
to him and read the speed off the speedometer.
[(Mr.) Uwe (pronounced "oova") Brockmann, (404)892-4872, u...@cc.gatech.edu]
Uwe Brockmann
>> impact. However, this is not a typical use of skates.
>
>I've only been skating about 6 months but my worst falls have been going
>backwards. True, I haven't been going very fast and didn't hit my head.
>But I believe skating backwards is pretty common. However, I don't think
>this justifies having a different standard than bicycle helmets.
I believe that beginning skaters experiment to find out what they can
do on skates. They try skating backwards, turning around, slaloming,
stopping with different methods, jumping, skating on grass, etc. In the
long run skaters either stop skating regularily or become more focused
on skating forwards for aerobic exercise with little experimentation.
They develop a regular schedule that fits their lifestyle and work
schedule. They then tend to skate regular routes at regular times with
other regular skaters. At least this is what I have observed in myself
and other skaters around me.
Due to the recent fast growth of inline skating there is an unusually
large proportion of beginners. Therefore skating backwards appears to be
more common than it will be in the long run.
Skating backwards fast requires going downhills or training specifically
for it. Racers only train for skating forwards fast. Few people skate
downhills backwards.
I have been skating outdoors regularily, mostly on conventional skates,
for over ten years and I have done long-distance races for over six
years.
Uwe Brockmann
wearing helmets? Reports of such cases might invalidate my belief that
bicycle helmets are sufficiently protective for skaters.
Examples of (avoided) head injuries follow. The examples suggest that
wearing a bicycle helmet is a good idea even though some head injuries
cannot be prevented by helmets (but can be prevented by common sense
safety precautions).
I have heard of two cases of permanent brain damage. Both involved
inline skaters who achieved speeds beyond their control unintentionally
on downhills. One case involved a beginner who probably had not yet
learned how to use her rearbrake effectively. The other case involved an
"experienced" skater who had been skating for several years. However, he
did not use a rearbrake. Neither skater wore a helmet.
One Atlanta skater scratched the side of her head on the bumper of a
parked car in a forward-fall accident on a downhill. She bleeded
profusely from her head and required 40 stitches. She did not suffer any
permanent injury other than a scar. The accident scared her so much that
she quit skating afterwards. She used conventional skates. She usually
wore a helmet but, unfortunately, not at the time of the accident.
I believe that the injuries in the three cases cited so far could have
been prevented by any ANSI- or SNELL-approved bicycle helmet. These
cases only suggest that wearing a bicycle helmet is a good idea. They
do not help determine whether cycling helmets provide sufficient
protection for skaters.
Several years ago a Mexican skater lost one eye in a skitching accident
on conventional skates ("Skitching: Skate-hitching. Grabbing on to a
moving vehicle and a big DO NOT!" according to "The Complete Blader" by
Joel Rappelfeld.) He let go off a car on a descent from one of the
surrounding hills into Mexico City at high speed. He could not
adequately control his speed or direction afterwards and ran into some
kind of lantern or telephone pole. I do not know whether he wore a
helmet but I believe that it is not possible to design a helmet that
could protect against this type of accident. This case suggests that
hanging on to a car while skating is not a good idea. This should be
common sense.
One Atlanta skater fell over a cat while skating downhills backwards
at high speed. He claims that he was going 40 mph. I believe that his
speed was closer to 30 mph. He broke both wrists despite wearing wrist
guards. He probably did not wear a helmet but he did not injure his
head.
I once broke my jaw in a chin-first forward-fall accident. One of my
conventional skates was blocked by a small pebble/piece of rock. No
hills, vehicles, or other skaters were involved. My speed was about
17 mph. I wore a bicycle helmet but it never touched the ground.
I believe that this accident was caused in combination by harder wheels
than normally, smaller diameter wheels than normally, and plates that
were mounted further backwards relative to the boots than normally.
I had just replaced my Riedell 195 boots with Riedell 395 boots and
was skating with the new boots for the first time. Both styles of boots
use the same sole but in the 395's the foot tends to be further forward
relative to the sole than in the 195's. I hadn't known this and had
mounted the soles in the same position relative to the skates as
before.
After the accident I switched to larger diameter, softer wheels and
moved the boots backwards on the plates. Inline skates use softer,
larger diameter wheels on average. Their front wheels, esp. on 5-wheel
frames, are mounted further forward than the front wheels on
conventional skates. These factors combined with narrower wheels make
forward-fall accidents less likely on inline skates than on conventional
skates. I believe that there is no way to design an acceptable helmet
that protects against jaw injury.
A friend of mine slipped with one foot in an indoor-speedskating
session. This caused him to spin around 180 degrees. While still going
about 20 mph he fell backwards and hit the rear of his head hard. He
lost consciousness for two minutes. His head continued to hurt for some
time afterwards but he did not suffer any permanent injury. His Giro Air
Attack bicycle helmet was crushed. If he had not worn a helmet he would
probably have sustained serious head injury. I believe that his bicycle
helmet provided adequate rear head protection.
He now wears an Australian-made Headway brand bicycle helmet which he
claims provides more rear head protection. He believes that SOME bicycle
helmets, notably the Specialized Sub-6, do not provide adequate rear
head protection for skaters. He believes that skaters may fall backwards
and slide forwards (i.e. with their feet in the front) after a fall
caused by a collision with other skaters in a race. Cutting-edge
lightweigth helmet technology results in bicycle helmets with minimal
rear head protection such as the Specialized Sub-6 that still manage to
pass ANSI and SNELL performance tests.
Conceivably such helmets could roll off the head in a backward-fall
forward-slide accident. This may be especially true for foam-only
helmets which stick to the road surface more than hardshell helmets.
I believe that this type of accident is too unlikely to suggest that
any bicycle helmets do not provide adequate protection for skaters.
I might change my mind if I heard of actual head injuries in which
cycling helmets did not provide sufficient protection for skaters.
Please let me know of such accidents if you know any.
Melanie Humphrey
>>> Falls while skating backwards at high speed can lead to hard rear head
>>> impact. However, this is not a typical use of skates.
>>
>>I've only been skating about 6 months but my worst falls have been going
>>backwards. True, I haven't been going very fast and didn't hit my head.
>>But I believe skating backwards is pretty common. However, I don't think
>>this justifies having a different standard than bicycle helmets.
>
>I believe that beginning skaters experiment to find out what they can
>do on skates. They try skating backwards, turning around, slaloming,
>stopping with different methods, jumping, skating on grass, etc. In the
>long run skaters either stop skating regularily or become more focused
>on skating forwards for aerobic exercise with little experimentation.
>They develop a regular schedule that fits their lifestyle and work
>schedule. They then tend to skate regular routes at regular times with
>other regular skaters. At least this is what I have observed in myself
>and other skaters around me.
well, as a fellow experienced skater, i just can't agree with your
assesment.
the above statement seems to me to say 'if you survive the first six
months, you won't need back-of-the head protection because you'll either
quit, or outgrow the urge to be creative.'
the use you describe characterizes a certain class of bladers --
that portion of blading enthusiasts that use their blades as speed
skates. this is fine. more power to anyone who's found a sport they
want to stick with! people that skate forwards exclusively probably don't
need side and rear protection. however, basing an helmet standard for
the entire industry on a single specific application may not be
prudent.
there is at least one other class of bladers out there, people like
myself who think that going fast in a straight line is about as
exciting as watching paint dry. we're the ones havent outgrown going
up and down stairs, jumping over things, doing stunts, practicing our
stem christies (does that date me?) and playing hockey.
a bicycle type helmet is poor protection at best for this type of
blading. there's scant lower-back-of-head protection, no side of head
protection, you can't add a shield or cage, and worst of all (from a
financial standpoint) you can only hit your helmet once -- then you
have to throw the damn thing out -- nearly all bike helmets are
single-impact (read that little sticker on the inside of your bike
helmet sometime). ka-CHING!
not to mention that bike helmets make almost everyone look like some
sort of lycra-encased egg-headed alien from deep space 9.
but, as a survior of a non-trivial head injury (yes, i was wearing an
'approved' helmet at the time), i know exactly how important wearing
head protection is. so i got a jofa hockey helmet. lightweight,
excellent protection, more secure fit than the 'lid' type bike
helmets, multi-impact, and i can add a shield when i play
hockey. plus it doesn't involve any lycra.
so i guess you could say i don't give a hoot about the standard because
a bike-style helmet doesn't meet meet my protection needs and i
wouldn't wear one even if it were 'approved' in some way. but i do
care because novice skaters could be buying something that is
'approved' but potentially of little or no use in certain types of
relatively common falls or impacts.
seems to me there needs to be at least two types of helmets, one for
'general-purpose and radical' skating and one for 'speed' skating. else
the 'speed' people end up with something they don't like and 'radical'
skaters end up with a helmet that may not protect them properly.
>Due to the recent fast growth of inline skating there is an unusually
>large proportion of beginners.
>Therefore skating backwards appears to be
>more common than it will be in the long run.
ahem. make this statment to any experienced defenseman and he or she
will raise an eyebrow at least. we need to be able to go as fast
backwards as we can go forwards, not to mention being able to turn as
fast backwards, and stop as fast backwards. this requires a lot of
skating backwards at relatively high speeds while training. not to
mention while playing.
[...]
>
>I have been skating outdoors regularily, mostly on conventional skates,
>for over ten years and I have done long-distance races for over six
>years.
>
but when was the last time you did a cartwheel with your blades on?
>[(Mr.) Uwe (pronounced "oova") Brockmann, (404)892-4872, u...@cc.gatech.edu]
--
-------------------------------------------------------------------------------
Melanie Humphrey | Systems Services | BISS --
m...@uiuc.edu | Beckman Institute | If we can't fix it, it
217-244-1079 | University of Illinois | ain't broke.
-------------------------------------------------------------------------------
George Robbins
> >> Skaters can achieve higher speeds than cyclists on downhills due to
> >> lower wind resistance.
> >
> >Really? Wow! I get up to 50 mph every now and then on my bicycle and I have
> >gone 60 mph in a bike race. I can't imagine going this fast on skates.
>
> Skaters can draft each other more closely than cyclists. They can touch
> each other and form a "train" when going downhills. This allows them to
> go faster than cyclists.
Bicylists to this in race situations.
> In the Athens-to-Atlanta race I observed the lead pack of skaters
> routinely outrunning all support bicycle riders on the major downhills.
I would wonder if this says more about the condition of the cycists
relative to the skaters than the efficiency of the skates vs. cycles.
What kind of average speed can good skaters maintain over several
miles or tens of miles?
> A skater who does not stay with the pack on downhills loses a lot of
> ground that is hard to make up afterwards. This forces skaters to
> stay in the pack and achieve high speeds. I estimate that groups of
> skaters exceed 50 mph in this race whereas individual skaters can only
> go about 40 mph on the same downhills.
Very much the bicycle case too.
--
George Robbins - now working for, work: to be avoided at all costs...
but no way officially representing: uucp: {uunet|pyramid|rutgers}!cbmvax!grr
Commodore, Engineering Department domain: g...@cbmvax.commodore.com
George Robbins
> Does anybody know of head injuries sustained by skaters despite their
> wearing helmets? Reports of such cases might invalidate my belief that
> bicycle helmets are sufficiently protective for skaters.
>
> Examples of (avoided) head injuries follow. The examples suggest that
> wearing a bicycle helmet is a good idea even though some head injuries
> cannot be prevented by helmets (but can be prevented by common sense
> safety precautions).
Reviewing your examples, it sounds reasonable to me. From my personal
point of view the bicycle helmet is adequate and the broad availability
and low price of such helmets is probalby more important than any
marginal inprovement in protection offered by a specialized helmet.
Statistically, there's far more benefit to wearing *any* helmet than
the one or two exception accidents that a different design *might*
protect against.
As far as the difference between cycling and skating accidents, the
main thing I see is that many cycing accidents are of the type where
you "fly" over the handlebars and land rolling or backwards, where
many skating accidents are more "frontal" where you simply run into
something or your feet get caught and you emulate a falling tree.
In such cases, I would wonder if more face/chin protection would be
the key, rather than worrying about the rear of the head.
Andy Hill
> In article <1993Jan20....@cc.gatech.edu> u...@cc.gatech.edu (BROCKMANN,UWE) writes:
> > Skaters can draft each other more closely than cyclists. They can touch
> > each other and form a "train" when going downhills. This allows them to
> > go faster than cyclists.
>
>
Huh? I've done a lot of drafting in bike races, but I don't remember ever
hanging onto the guy ahead of me (I'd need arms down to my feet). I believe
the point is that drafting skaters can more closely approximate the ideal
of a single person taking the wind, and everyone else in the slipstream
(there's a lot more more garbage hanging off a bike, and, since they're
quite a bit longer than a crouched skater, they don't pack as tightly).
Uwe Brockmann
>well, as a fellow experienced skater, i just can't agree with your
>assesment.
>
>the above statement seems to me to say 'if you survive the first six
>months, you won't need back-of-the head protection because you'll either
>quit, or outgrow the urge to be creative.
I skate with a local club, the Atlanta Peachtree Roadrollers. We have
regular skates with many participants on Monday and Wednesday nights
and less popular and less regular skates on some other days. The Monday
night skate is designed specifically for beginners. Faster skaters
stop and wait for the slowest skaters at several points.
Some people "play around" creatively during such stops and at the
meeting place before and after the skate, but for the most part people
only skate the regular route forwards. Local skaters, myself included,
prefer skating with others over skating alone. "Being creative" doesn't
seem to work as well in a group as skating forwards. Maybe that is bad
in some sense, but skating with others seems to be a good thing to me.
Due to a lack of other skaters I skated by myself for several years in
my home country, Germany, before moving to Atlanta. After I joined the
local group my skating improved rapidly beyond anything that I could
have achieved by myself. At first I just benefited from the experience
of others. By now I have progressed so much that I can make a
contribution to the local collective level of experience.
I see a distinct difference in the level of experience between people
who have only skated by themselves and those who have joined a group
of experienced skaters and shared experiences. Level of experience seems
to be more closely related to whom you skate with than to how long you
have been skating.
Few people can stick with any sport unless they participate in it
together with others. As people start to skate with others, experimental
skating seems to take a back seat to forward skating at least from what
I have seen.
> the use you describe characterizes a certain class of bladers --
> that portion of blading enthusiasts that use their blades as speed
> skates. this is fine. more power to anyone who's found a sport they
> want to stick with! people that skate forwards exclusively probably don't
> need side and rear protection. however, basing an helmet standard for
> the entire industry on a single specific application may not be
> prudent.
There seems to be a greater variety of equipment use among skaters than
among cyclists. I believe that the best approach is to approve bicycle
helmets for forward recreational skating and speed skating and to
include a warning that these helmets are not intended for use in other
types of skating.
> there is at least one other class of bladers out there, people like
> myself who think that going fast in a straight line is about as
> exciting as watching paint dry. we're the ones havent outgrown going
> up and down stairs, jumping over things, doing stunts, practicing our
> stem christies (does that date me?) and playing hockey.
I wish there were more skaters like you around here. That would allow me
to tap into a different source of experience. There is, however, a good-
sized roller hockey community in the Atlanta area with some crossover
to the general skating community.
> a bicycle type helmet is poor protection at best for this type of
> blading. there's scant lower-back-of-head protection, no side of head
> protection, you can't add a shield or cage, and worst of all (from a
> financial standpoint) you can only hit your helmet once -- then you
> have to throw the damn thing out -- nearly all bike helmets are
> single-impact (read that little sticker on the inside of your bike
> helmet sometime). ka-CHING!
The ASTM Roller Skating Helmet Standard is not intended to
address the needs of hockey players. In my original posting (the article
for Speedskating Times), I suggested that roller skating helmets be
required to bear a label warning against their use in fast backwards
skating, skating down stairs forwards, and other types of radical
skating. Your comments have caused me to believe that the label should
also mention roller hockey specifically.
The ASTM standard will consist of specific standards for several helmet
applications based on a generic standard applicable to all types of helmets.
Among others, there will be specific standards for bicycle, roller
skating, skateboarding, and multiple activity. As currently drafted,
the standards specify essentially the same performance tests for bicycle
and multiple-activity helmets, i.e. same drop height onto similar
anvils. Both are single-impact. The skateboarding helmet is multi-impact
but the performance test is more relaxed (drop height of 1 meter vs.
drop height of 2 m for bicycle and multiple-activity helmets).
Acceleration measured inside the helmet at time of impact must be less
than 300 g (peak) for all three standards and must not exceed 200 g for
more than 3 ms or 150 g for more than 6 ms.
The multiple-activity standard requires more rear head protection than
the bicycle helmet standard. The current issue is whether the roller
skating standard should be identical to the bicycle helmet standard
or the multiple-activity standard. Other possibilities include making
all three standards the same or developing a separate standard for
roller skating helmets only.
Bicycle helmets are single-impact because multiple-impact materials
cannot reduce peak acceleration as much as single-impact materials.
> not to mention that bike helmets make almost everyone look like some
> sort of lycra-encased egg-headed alien from deep space 9.
I think that bicycle helmets make skaters look responsible and safety-
conscious.
> but, as a survior of a non-trivial head injury (yes, i was wearing an
> 'approved' helmet at the time), i know exactly how important wearing
> head protection is. so i got a jofa hockey helmet. lightweight,
> excellent protection, more secure fit than the 'lid' type bike
> helmets, multi-impact, and i can add a shield when i play
> hockey. plus it doesn't involve any lycra.
Please, please tell me more about your head injury. What brand and model
of helmet did you wear? What caused you to fall? How did you hit the
ground? What injury did you sustain? Why didn't the helmet provide
sufficient protection?
So far, all serious head-injuries that I am aware of were sustained by
skaters who did not wear any helmet or could not have been prevented
by a helmet with more rear or side protection. A single credible report
of a head injury sustained while wearing an ANSI/Snell-approved bicycle
helmet that could have been prevented by a more protective helmet, may
influence my opinions and the roller skating helmet standard.
I agree that the helmet you are using now is better for the type of
skating that you do than bicycle helmets.
> so i guess you could say i don't give a hoot about the standard because
> a bike-style helmet doesn't meet meet my protection needs and i
> wouldn't wear one even if it were 'approved' in some way. but i do
> care because novice skaters could be buying something that is
> 'approved' but potentially of little or no use in certain types of
> relatively common falls or impacts.
My main concern is that novice skaters don't wear helmets at all.
Different helmet standards for skating and cycling would make skaters
less likely to wear helmets (due to higher cost and lower availability
of skating-specific helmets combined with a discouraging effect on use
of already-owned bicycle helmets for skating).
> seems to me there needs to be at least two types of helmets, one for
> 'general-purpose and radical' skating and one for 'speed' skating. else
> the 'speed' people end up with something they don't like and 'radical'
> skaters end up with a helmet that may not protect them properly.
I agree. Maybe the warning label on dual-purpose cycling/skating helmets
should also steer "radical" skaters to helmets meeting the multiple-
activity and skateboarding standards?
>> Due to the recent fast growth of inline skating there is an unusually
>> large proportion of beginners.
>> Therefore skating backwards appears to be
>> more common than it will be in the long run.
>
> ahem. make this statment to any experienced defenseman and he or she
> will raise an eyebrow at least. we need to be able to go as fast
> backwards as we can go forwards, not to mention being able to turn as
> fast backwards, and stop as fast backwards. this requires a lot of
> skating backwards at relatively high speeds while training. not to
> mention while playing.
My statement does not apply to roller hockey.
>> I have been skating outdoors regularily, mostly on conventional skates,
>> for over ten years and I have done long-distance races for over six
>> years.
>
> but when was the last time you did a cartwheel with your blades on?
I have never tried it. No skater's experience can cover all modes of
skating. That's why I am soliciting input from others. I appreciate
your reply very much. At first I was afraid that nobody would respond.
Kimon Papahadjopulos
Obviously skates are not faster than bikes on the flats, but Uwe may have
a case for the downhills since a skilled pack of skaters will have a more
efficient draft than bikers, and a lower profile. Also, when skaters touch
each other in a draft they can push togther as one unit, which bikers cannot
do.
>> Skaters can draft each other more closely than cyclists. They can touch
>> each other and form a "train" when going downhills. This allows them to
>> go faster than cyclists.
>Bicylists to this in race situations.
Do what? Get as close as skaters? Or touch? They can't do either because of
the wheels.
>> In the Athens-to-Atlanta race I observed the lead pack of skaters
>> routinely outrunning all support bicycle riders on the major downhills.
>I would wonder if this says more about the condition of the cycists
>relative to the skaters than the efficiency of the skates vs. cycles.
Uwe may have been talking about the Dutch team that raced in Athens to
Atlanta in 1991. The number I heard was 65mph down the three diamond
hill-- the steepest hill in the race which graciously has no sharp turn or
stop at the bottom.
>What kind of average speed can good skaters maintain over several
>miles or tens of miles?
22-24mph on the flats.
Kimon
ki...@holonet.net
--
Sig test
George Robbins
I'm sorry, I didn't mean to say that they grab ahold of each other,
but drafting, forming pace lines and such are very important parts
of bicycle racing.
I'm quite a bit skeptical about your assertions that skaters are
"faster" than cyclists, but lacking any direct observations to
the point, I'll leave it.
Phil?
Uwe Brockmann
>In article <1993Jan20....@cc.gatech.edu> u...@cc.gatech.edu (BROCKMANN,UWE) writes:
>> Skaters can draft each other more closely than cyclists. They can touch
>> each other and form a "train" when going downhills. This allows them to
>> go faster than cyclists.
>
>Bicylists to this in race situations.
I did not know that bicycle racers touch each other on downhills.
I assume that a cyclist who pushes another cyclist on a downhill has
to be slighly to the side of the cyclist whom he is pushing. This
increases frontal area. Skaters can be directly behind each other with
almost no gap between them.
If cyclists could form two parallel pacelines offset by half a bicycle
length in the direction of travel and if each cyclist could push the
cyclist of the other paceline who is half a bicycle length ahead of him
than they would form a "zig-zag train" and would be able to go very
fast. Can cyclists do this? If this should not be possible due to the
protruding wheels than they would be stuck with an "offset-train" in
which each additional cyclist adds to the frontal area.
The ASCII drawings below show cylists in a "zig-zag train" (1), cyclists
in a less efficient "offset-train" (2), and skaters in a train (3).
(1) (2) (3)
| I |
| | |
| | |
| | |
| | |
| | |
The drawings make it look as if cyclists were separated by a full
bicycle length. The separation should really be only half a bicycle
length. I just don't know how to make a better ASCII drawing.
I don't believe that cyclists would be able to go as fast as skaters on
steep downhills even if they could form "zig-zag trains". In my
experience I can go about 40 mph (clocked by cycle computers) on the
steepest downhills that I have skated with cyclists. This is without
drafting cyclists or other skaters and without pushing off (i.e. just
coasting). Cyclists can go about the same speed when coasting down the
same hills without drafting other cyclists. When coasting at 40 mph they
can still add a little bit of speed by pedalling hard.
I believe that my frontal area and my wind resistance are smaller than
theirs. Their equal speed must therefore be caused by lower
rolling resistance. On steeper downhills and at higher speeds their
higher wind resistance should be more of a disadvantage for them and
my higher rolling resistance should be less of a disadvantage for me.
Thus I should be able to go faster than them. I cannot try this because
hills aren't sufficiently steep around here. I also don't want to try
it because I already start feeling uncomfortable at 40 mph.
Even if cyclists could form zig-zag trains, a number of skaters in a
train should still be faster than the same number of cyclists because
each additional skater in the train only adds a small portion of the
wind resistance of a single skater to the train whereas each cyclist
adds a large portion of the wind resistance of a single cyclist to the
train. That's because skaters can draft each other more closely with
less wind resistance-increasing gaps between them.
Cylists have another disadvantage on steep downhills. Their large wheels
cut into the wind at up to twice the speed of the cyclists. This adds
significantly to wind resistance. For skaters with their small wheels
this is not a concern.
>> In the Athens-to-Atlanta race I observed the lead pack of skaters
>> routinely outrunning all support bicycle riders on the major downhills.
>
>I would wonder if this says more about the condition of the cycists
>relative to the skaters than the efficiency of the skates vs. cycles.
On steep downhills coasting on skates is faster than skating (pushing
off) on skates. Therefore the conditioning of skaters has no effect on
their downhill speed. I assume that hard pedalling will usually increase
the speed of cyclists even on steep downhills. However, at higher speeds
the effect of pedalling is reduced. One cyclist told me that he believes
that sitting on the top tube does more to increase speed on steep
downhills than pedalling and that hanging behind the seat is faster yet.
Is this true? On sufficiently steep downhills the conditioning of
cyclists has very little effect on their speed.
>What kind of average speed can good skaters maintain over several
>miles or tens of miles?
Haico Bouma of Holland won the 1991 Athens-to-Atlanta race in a record
time of 4:28 (hours:minutes). His average speed was about 19 mph. He
skated the last 100 km by himself because nobody else could keep up.
In Holland with no hills and more fast skaters average speed is higher.
Cyclists can of course go much faster on average.
Lynd Wieman
|>
|> I did not know that bicycle racers touch each other on downhills.
|> I assume that a cyclist who pushes another cyclist on a downhill has
|> to be slighly to the side of the cyclist whom he is pushing.
(stuff deleted about possible drafting patterns)
In my experience, at 50+ mph on a bicycle in a pack, I am not looking for
ways to get closer to other riders. The distances between riders generally
opens up a bit. (I am only speaking from my experience. Top racers are
probably a lot more willing to take risks then I am.)
I'm sure skaters can get a more stream-lined profile than bicyclists and,
at these speeds on a bike, it is more effective to tuck as tightly as possible
then to try peddling. I suppose you could have special gears that would be
usable at these speeds but most bikes aren't equipped with them.
I believe the fastest position for coasting on a bike is sliding back so
your stomach is on the seat and your arms straight forward holding the bars
in the middle. In this position the rider probably doesn't have much
more wind resistance then a skater but the bike adds a fair amount.
One thing that cyclists do is take turns at the front so that a cyclist in
the back can use the slipstream of the leader to go faster than him. After
he passes, the previous leader tucks in behind until he overtakes and passes.
This allows the entire pack to go faster than an individual without touching.
Evidently skaters get the same effect, perhaps more efficiently, by pushing
each other.
|> Thus I should be able to go faster than them. I cannot try this because
|> hills aren't sufficiently steep around here. I also don't want to try
|> it because I already start feeling uncomfortable at 40 mph.
Ah, there's the rub! I think bikes are more stable at these speeds and
having brakes that allow fine control of speed without shifting my weight increases my confidence.
Wind resistance and rolling resistance be damned! You'll never see me
doing 50 on skates. :-)
My top speed of 60 mph in a pack was clocked with a cycle computer, as was
my individual speed of 50. I still have a question I haven't seen an answer
to: Have skaters been measured going this fast? ("they looked really fast!
It must have been 60 mph!" doesn't count :-) )
Lynd
George Robbins
> In article <melanie....@ph-meter.beckman.uiuc.edu> m...@uiuc.edu writes:
>
> >well, as a fellow experienced skater, i just can't agree with your
> >assesment.
> >
> >the above statement seems to me to say 'if you survive the first six
> >months, you won't need back-of-the head protection because you'll either
> >quit, or outgrow the urge to be creative.
>
> I skate with a local club, the Atlanta Peachtree Roadrollers. We have
> regular skates with many participants on Monday and Wednesday nights
> and less popular and less regular skates on some other days. The Monday
> night skate is designed specifically for beginners. Faster skaters
> stop and wait for the slowest skaters at several points.
>
> Some people "play around" creatively during such stops and at the
> meeting place before and after the skate, but for the most part people
> only skate the regular route forwards. Local skaters, myself included,
> prefer skating with others over skating alone. "Being creative" doesn't
> seem to work as well in a group as skating forwards. Maybe that is bad
> in some sense, but skating with others seems to be a good thing to me.
It sounds like some sort of selection is in effect here. You have a
touring club and the folks that stay with the club settle down and
concentrate on touring don't fool around much.
The people who find other forms of skating more intesting may drop out
of your activities or lurk on street corners, playgrounds or skateboard
terrain.
I skate mostly indoors, but after a few years, the last thing I like
to do is just stroke around efficiently with the pack. After a lap or
two, I'll start doing cross-steps, turns or zooming edges.
At the moment, I'm not too comfortable with my in-line skates, and don't
risk anything except forward skating and an occasional crossover, but as
I put in some more time and try to go more than a mile, I wonder what
will happen.
Phil Earnhardt
>"faster" than cyclists, but lacking any direct observations to
>the point, I'll leave it.
>
>Phil?
I don't really know. Road Rash Rod could tell us for sure.
The thing I've heard about the close-quarters downhills is that the rearmost
person pushes on the person in front of him, who pushes on the person in front
of him, who pushes [...]. The person at the front of the line can literally
have hundreds of pounds of pressure on his hips adding to his acceleration
going down the hill.
Of course, there's absolutely no way for the poor guy in the front to bail if
the speeds exceed his tolerance for pain (I had a ski instructor once who
appropriately labeled this subjective speed "point death.") And if he crashes
and burns, everyone behind him probably will, too.
In short, I don't know if skaters are faster than cyclists. But the amount of
faith they must have in the skills of their fellow atheletes is pretty darn
similar.
--phil
Kevin Matocha
> person pushes on the person in front of him, who pushes on the person in front
> of him, who pushes [...]. The person at the front of the line can literally
> have hundreds of pounds of pressure on his hips adding to his acceleration
> going down the hill.
This is the old idea that a cannonball falls faster than the feather.
The line of skaters should only be able to gain greater acceleration through
the minimization of air drag. Another way, as often practiced in roller
derby, is to transfer the momentum from one skater to another, an impossible
feat if they are all in a line holding each other by the hips.
I hope this clears a few things up.
Regards,
Kevin
Matt Hicks
>> person pushes on the person in front of him, who pushes on the person in front
>> of him, who pushes [...]. The person at the front of the line can literally
>> have hundreds of pounds of pressure on his hips adding to his acceleration
>> going down the hill.
>This is the old idea that a cannonball falls faster than the feather.
>The line of skaters should only be able to gain greater acceleration through
>the minimization of air drag.
Right. Nobody's pushing on anybody. It's the same idea as in auto racing.
It shouldn't actually make much difference on a descent, but when the racers
are on a flat, you end up with two skaters working against the resistance
of one (+ a little). The lead skater still has to contend with the resistance
of their frontal surface area, but loses the drag produced by the trailing
turbulence; the reverse is true for the trailing skater. Note that this
doesn't equate to twice the power versus the same resistance; rather, each
skater is dealing with some fraction (probably 70-90%) of the original
resistance and they are thus able to go X miles an hour faster. The reason
it doesn't matter much on a descent is that the skaters aren't working
against air resistance--gravity is doing the work, which remains constant
assuming constant pitch--and it doesn't matter how the resistance is divided
up if the total resistance remains the same. Note, too, that adding more
skaters between the two should have a minimal impact on skating speed--the
lead skater gains no more advantage from two or more skaters behind him
(or her) than s/he does from one. And it is the lead skater who dictates
the speed of the line. Of course, all the skaters behind the leader get
to skate without frontal resistance and will stay fresh longer than the
leader or a lone skater (assuming proper conditioning, of course).
_________________________________________________ /\_/\ _________________
Matthew B. Hicks | Unidata Program Center | ((ovo)) The spotted owl:
ma...@unidata.ucar.edu | UCAR, PO Box 3000 | ():::() the other "other
303/497-8676 | Boulder, CO 80307-3000 | VVV white meat."
--
_________________________________________________ /\_/\ _________________
Matthew B. Hicks | Unidata Program Center | ((ovo)) The spotted owl:
ma...@unidata.ucar.edu | UCAR, PO Box 3000 | ():::() the other "other
303/497-8676 | Boulder, CO 80307-3000 | VVV white meat."
Kimon Papahadjopulos
>>>The thing I've heard about the close-quarters downhills is that the rearmost
>>>person pushes on the person in front of him who pushes on the person in front
>>>of him, who pushes [...]. The person at the front of the line can literally
>>>have hundreds of pounds of pressure on his hips adding to his acceleration
>>>going down the hill.
>mat...@engr.latech.edu (Kevin Matocha) writes:
>>This is the old idea that a cannonball falls faster than the feather.
>>The line of skaters should only be able to gain greater acceleration through
>>the minimization of air drag.
ma...@unidata.ucar.edu (Matt Hicks) writes:
>Right. Nobody's pushing on anybody. It's the same idea as in auto racing.
No...there is a big difference and pushing the skater in front of you is the
key.
When you are drafting somebody properly it is very easy to keep with them
even though they may be working very hard-- you find yourself easily gliding
behind them (if you are at least as quick a skater as they are, that is).
Often times you think...Dang... this guy is going too slow! So you pull out
and try to pass him. Then you realize how much work he was doing for you,
and you pull back behind.
So if you don't touch him, you just save energy, but can't go any faster than
he would be going on his own.
Then a lightbulb lights up... Say! I could go faster, but he is in front of
me... How about I help push him and we will both go faster!
Ah, now you've got something-- You are using the excess power that you
have because he is cutting the wind for you to help both of you go faster.
As more and more skaters pile on behind pushing together, you begin to
approach the speed that you could maintain if there were no wind resistance.
This is because as you get farther and father back in the skating line, wind
resistance is less and less significant.
Which is the original premise of which we were pondering: can skaters in a
pack might go faster than bikes-- especially on hills since they can
reduce the effects of wind resistance more effectively than bikers because
they can touch one another.
>It shouldn't actually make much difference on a descent
Oh, man it does! If you've ever been in one of these skating columns or
been passed up by one, you would not bother trying to disprove it with
physics!
Kimon Papahadjopoulos
ki...@holonet.net
Matt Hicks
>> The thing I've heard about the close-quarters downhills is that the rearmost
>> person pushes on the person in front of him, who pushes on the person in front
>> of him, who pushes [...]. The person at the front of the line can literally
>> have hundreds of pounds of pressure on his hips adding to his acceleration
>> going down the hill.
>This is the old idea that a cannonball falls faster than the feather.
>The line of skaters should only be able to gain greater acceleration through
>the minimization of air drag.
Right. Nobody's pushing on anybody. It's the same idea as in auto racing.
It shouldn't actually make much difference on a descent, but when the racers
are on a flat, you end up with two skaters working against the resistance
of one (+ a little). The lead skater still has to contend with the resistance
of their frontal surface area, but loses the drag produced by the trailing
turbulence; the reverse is true for the trailing skater. Note that this
doesn't equate to twice the power versus the same resistance; rather, each
skater is dealing with some fraction (probably 70-90%) of the original
resistance and they are thus able to go X miles an hour faster. The reason
it doesn't matter much on a descent is that the skaters aren't working
against air resistance--gravity is doing the work, which remains constant
assuming constant pitch--and it doesn't matter how the resistance is divided
up if the total resistance remains the same. Note, too, that adding more
skaters between the two should have a minimal impact on skating speed--the
lead skater gains no more advantage from two or more skaters behind him
(or her) than s/he does from one. And it is the lead skater who dictates
the speed of the line. Of course, all the skaters behind the leader get
to skate without frontal resistance and will stay fresh longer than the
leader or a lone skater (assuming proper conditioning, of course).
--
Jim Aites
small of my back...*I'm* going to go faster with less effort.
If whoever is behind me can keep up AND keep pushing...and there is someone
behind them. (ad infinity) Then we *all* should be able to reach warp 1 in
about 5 minutes...right? Of course, heaven help the guy at the end...hanging
on for dear life
Thanks for the explanation. ;')
Phil Earnhardt
>mat...@engr.latech.edu (Kevin Matocha) writes:
>
>>> The thing I've heard about the close-quarters downhills is that the rearmost
>>> person pushes on the person in front of him, who pushes on the person in front
>>> of him, who pushes [...]. The person at the front of the line can literally
>>> have hundreds of pounds of pressure on his hips adding to his acceleration
>>> going down the hill.
>
>>This is the old idea that a cannonball falls faster than the feather.
>>The line of skaters should only be able to gain greater acceleration through
>>the minimization of air drag.
>
>Right. Nobody's pushing on anybody. It's the same idea as in auto racing.
I'm fairly amazed how folks who have never been in one of these skating chains
can tell us so much about them. I would prefer to not come to conclusions
until we hear from Rod Murillo or another world-class racer.
--phil
George Robbins
>
> I'm fairly amazed how folks who have never been in one of these skating chains
> can tell us so much about them. I would prefer to not come to conclusions
> until we hear from Rod Murillo or another world-class racer.
>
> --phil
Uh Phil, your description of pushing from the rear guy up to the front
guy resulting in several hundred pounnds of push on the front guy was
kind of intersting in it's own right. Was that experience speaking?
Phil Earnhardt
>>I'm fairly amazed how folks who have never been in one of these skating
>>chains can tell us so much about them. I would prefer to not come to
>>conclusions until we hear from Rod Murillo or another world-class racer.
>
>Uh Phil, your description of pushing from the rear guy up to the front
>guy resulting in several hundred pounnds of push on the front guy was
>kind of intersting in it's own right. Was that experience speaking?
No. It was not.
It was tales from someone who was in A->A a year or two ago. I probably
misquoted him.
That was my point: since we do have net.readers who have been in such
chains, let's hear from them before we come to conclusions.
The "race car" analogy does not hold: people from the rear can indeed push on
people in front of them. And the "Warp speed: falling off the end" analogy
doesn't work: the person at the front of the chain will have more air
resistance than anyone else.
>George Robbins
--phil