W-skate videos -- Double-push

xcskier09 wrote:
The only time you are gliding on your ski is when it is
gliding in the opposite direction of your body. In fact
you want your body gliding over your ski as this is when
your skis will be flat and the fastest.

Well you're right that "W skate" is _not_ about gliding on a flat ski.
And there is some additional frictional loss from edging the ski. The
question is whether the additional power from pushing that way is more
than the additional frictional loss. In "V1 skate" up a hill there is
little or no gliding on a flat ski, and yet elite racers still use V1,
so I guess sometimes the additional power is worth it.

As for the body moving away from the gliding the ski, that's what
Newton's Third Law says is required to happen if you're applying
effective _pushing_ force thru the ski.

As you leap off of the ground you are essentially
throwing your body in the opposite direction of your ski.

The main point of double-push is to _increase_ that opposition of
forces in the sideways direction between the body mass and the ski
gliding on the snow surface. That "sideways opposition" component is a
key difference between W-skate (or "half W") and other jump-skate
techniques.

I think when you are watching the races you are seeing the
male skiers throwing their body's forward over their skis

Not knowing which video segment you're referring to, I'll say that when
a ski skating technique includes double pole push, then it definitely
helps to get the shoulders forward just before the poles are planted,
because then the upper adominal muscles are better "aimed" for pushing
partly backwards on the poles. (If the shoulders were more vertically
above the hips at the moment of the pole-plant, the upper abdominal
muscles would tend to push the poles forward, which hurts rather than
helps propulsive work.) Jumping up and landing on the poles also helps
add propulsive work to the pole-push. Like in the second half of the
third video on this page: http://roberts-1.com/t/806/wp

But that's all for poling. For legs in skating, it's definitely
advantageous to move the opposite hip forward. But I think it's pretty
tricky to derive overall net positive advantage for the skating _leg_
push by moving other body parts forward -- because pretty soon you just
have to move them back again to get in position for the next stroke.

The physics of skating makes it simpler to gain some net advantage in
propulsive power by moving body weight sideways, sorta like
"throwing" it from one side and "catching" it on the other, then
throwing it back again. And that's the big theme of W-skate.

Ken

When I was double-pushing my Crosskates, it *felt* like I was shifting my
weight around like a swinging hour glass, with my hips as the virtual pivot
point. I'd spend most time with my weight quite a bit away laterally from my
tires, and because of DP those were all four close together. I also felt
extremely efficient, although I centainly did not reach higher than
"cruising" speeds.

"Ken Roberts" schreef in bericht
oups.com...
xcskier09 wrote:
The only time you are gliding on your ski is when it is
gliding in the opposite direction of your body. In fact
you want your body gliding over your ski as this is when
your skis will be flat and the fastest.

Well you're right that "W skate" is _not_ about gliding on a flat ski.
And there is some additional frictional loss from edging the ski. The
question is whether the additional power from pushing that way is more
than the additional frictional loss. In "V1 skate" up a hill there is
little or no gliding on a flat ski, and yet elite racers still use V1,
so I guess sometimes the additional power is worth it.

As for the body moving away from the gliding the ski, that's what
Newton's Third Law says is required to happen if you're applying
effective _pushing_ force thru the ski.

As you leap off of the ground you are essentially
throwing your body in the opposite direction of your ski.

The main point of double-push is to _increase_ that opposition of
forces in the sideways direction between the body mass and the ski
gliding on the snow surface. That "sideways opposition" component is a
key difference between W-skate (or "half W") and other jump-skate
techniques.

I think when you are watching the races you are seeing the
male skiers throwing their body's forward over their skis

Not knowing which video segment you're referring to, I'll say that when
a ski skating technique includes double pole push, then it definitely
helps to get the shoulders forward just before the poles are planted,
because then the upper adominal muscles are better "aimed" for pushing
partly backwards on the poles. (If the shoulders were more vertically
above the hips at the moment of the pole-plant, the upper abdominal
muscles would tend to push the poles forward, which hurts rather than
helps propulsive work.) Jumping up and landing on the poles also helps
add propulsive work to the pole-push. Like in the second half of the
third video on this page: http://roberts-1.com/t/806/wp

But that's all for poling. For legs in skating, it's definitely
advantageous to move the opposite hip forward. But I think it's pretty
tricky to derive overall net positive advantage for the skating _leg_
push by moving other body parts forward -- because pretty soon you just
have to move them back again to get in position for the next stroke.

The physics of skating makes it simpler to gain some net advantage in
propulsive power by moving body weight sideways, sorta like
"throwing" it from one side and "catching" it on the other, then
throwing it back again. And that's the big theme of W-skate.

Ken

Jan Gerrit Klok wrote:
When I was double-pushing my Crosskates, it *felt* like I was shifting my
weight around like a swinging hour glass, with my hips as the virtual pivot
point. I'd spend most time with my weight quite a bit away laterally from my
tires, and because of DP those were all four close together. I also felt
extremely efficient, although I centainly did not reach higher than
"cruising" speeds.

If you're a newby to skiing, I advise you to not think of this W skate
stuff, it is nothing like proper, effective skate ski technique. I put
it in the category of novelty - sort of like doing daffy's and back
scratchers off a bump on XC skis - interesting, mabye fun to do, but
absolutely nothing to do with skiing down the trail.

Also cross skates will have little if anythign to do with skate skiing.
It's hard enough to translate from good roller skis to snow skis.
Inlines and cross skates are nothing like it. I'm not saying don't
cross skate - by all means do it and enjoy it. But you'll be getting
fit, not learning to ski and are wasting yur time discussing things
like "W Skate", double push, or cross skate techniuqe in terms of snow
skiing.

JMHO but I know what I can see 8-)

On Sat, 20 Jan 2007 19:28:39 +0100, "Jan Gerrit Klok"
wrote:

When I was double-pushing my Crosskates, it *felt* like I was shifting my
weight around like a swinging hour glass, with my hips as the virtual pivot
point. I'd spend most time with my weight quite a bit away laterally from my
tires, and because of DP those were all four close together. I also felt
extremely efficient, although I centainly did not reach higher than
"cruising" speeds.

I find it bizarre that you have not been on snow, and are ostensibly
using crossskates for ski training, and are doing techniques that
almost no one does on snow.
--
JT
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*almost* no one? Has Jan Gerrit Klok used up the 500 free posts people
who haven't skied yet get on rsn?

rm

John Forrest Tomlinson wrote:

On Sat, 20 Jan 2007 19:28:39 +0100, "Jan Gerrit Klok"
wrote:

When I was double-pushing my Crosskates, it *felt* like I was
shifting my weight around like a swinging hour glass, with my hips
as the virtual pivot point. I'd spend most time with my weight quite
a bit away laterally from my tires, and because of DP those were all
four close together. I also felt extremely efficient, although I
centainly did not reach higher than "cruising" speeds.

I find it bizarre that you have not been on snow, and are ostensibly
using crossskates for ski training, and are doing techniques that
almost no one does on snow.

"John Forrest Tomlinson" schreef in bericht
...
I find it bizarre that you have not been on snow, and are ostensibly
using crossskates for ski training, and are doing techniques that
almost no one does on snow.
Give me a break please?

Why should everyone do everything just the same as all the others that came
before?
What did you say when someone started making skating moves in XC races?

We're talking about the winning technique in the biggest skate-sport on
earth. In the end it's all about having single-directionally gliding/rolling
foot attachments being pushed sideways to net forward propulsion. It's been
done on inlines with poles, rollerski's with poles, so surely it's nonsense
for ski's with poles?

FYI I'm actually not on the Crosskates anymore (too easy too fast), trying
to get to grips with "proper" rollerskis which isn't exactly easy. You won't
see me doing W-skate or DP on those any year soon, trust me.

Call me arrogant (and stand in line), but in bikes I'm an innovator "too",
and not even just self-proclaimed. I reach decent results with an out of
shape body because my bike I built is faster and I ride it differently from
others at my physical level. Been there done that on bikes, skis are next.

This thread is about Ken's accomplishments, adding a totally new skate
technique to a very short list of possible variaties. Give him some credits
and help him find the most useful way to go about W-skate. Fun excersize?
Race winning? Useless leg breaker? At less discuss the technique and what
you expect from it, NOT what you expect from someone in a snowless country
who dares look past the horizon. Acting elitist and talking down on newbies
on a discussion forum is just about as charming as in person. Glad I never
did that on bike forums. Call me stupid 3 years from now when I'm still
rambling about this despite having failed to make DP on skis work, ok? Go
out and ski in the snow, and know you're lucky. I'll join later on.

Now back to Ken's W-skate vids and how to optimize this technique please?

On Sun, 21 Jan 2007 10:37:23 +0100, "Jan Gerrit Klok"
wrote:


"John Forrest Tomlinson" schreef in bericht
.. .
I find it bizarre that you have not been on snow, and are ostensibly
using crossskates for ski training, and are doing techniques that
almost no one does on snow.
Give me a break please?

Why should everyone do everything just the same as all the others that came
before?
What did you say when someone started making skating moves in XC races?

You can't get anywhere unless you know where you've been.
Acting elitist and talking down on newbies
on a discussion forum is just about as charming as in person.

It's not elitist to tell you to go skiing, to take some proper lessons
and to approacht the sport practically.

This forum is about skiing. It's not about pretending you're
interested in skiing and taking about other stuff. Until you actually
go skiing, I frankly don't believe you really care about skiing. If
that sounds obnoxious, perhaps it is. But it's not because you're a
newbie. It's because you keep talking about silly stuff that is
pointless until you go skiing and understand skiing.

Go skiing.



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JT
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I will go skiing when snow actually falls in Europe and I get away from
work.
You know I only found one single weblink for a skating skischool, and in a
snowless part of Germany? I guess this summer it's to Sweden or Finland for
a ski tunnel camp.

If I weren't totally passionate about skiing I'd have much better things to
spend my time on than to be bullied on a web forum. On my own forums I am
the expert, can't recall having treated newbies with weird ideas like this.
Maybe it's a skiing thing.

Enjoy your skiing, I'll join you soon.

J

On Sun, 21 Jan 2007 19:20:28 +0100, "Jan Gerrit Klok"
wrote:

If I weren't totally passionate about skiing

LOL

--
JT
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Jan Gerrit Klok wrote:
I will go skiing when snow actually falls in Europe and I get away from
work.
You know I only found one single weblink for a skating skischool, and in a
snowless part of Germany? I guess this summer it's to Sweden or Finland for
a ski tunnel camp.

If I weren't totally passionate about skiing I'd have much better things to
spend my time on than to be bullied on a web forum. On my own forums I am
the expert, can't recall having treated newbies with weird ideas like this.
Maybe it's a skiing thing.

Enjoy your skiing, I'll join you soon.

J

Jan, I truely don't believe you're being bullied. I do think you are
being advised - by people who have skied a lot and who probably are
knowledgable in good ski technique - that the stuff being discussed
here has very little if any bearing on real skiing. I really hope you
get to ski soon and I really urge you to spend the time before and
after that great day talking and learning about real skiing not this
novelty or roller skating stuff. It really is not skiing. I'm not
meaning to be bullying, just trying freiendly advice. I would love to
be with you the first time you ski! I will bet money that you will
learn quickly and become quite good - mostly because of your fitness.