suggestions for my technique on video

Darlene, This is a good example of where scientific methodology training
counts. The sentence you find so objectionable is not a scientific
finding, but part of a theoretical conjecture on the part of the
author, Gerald Smith (an American in Scandinavia, no less). It is
a discussion of the relation between abdominal muscles and back
extensors in double poling. He raises a good question: We coaches tell
people about "the importance of abdominal muscles to effective force
generation" in double poling, but is that really the way it works
biomechanically? His main points are that it's the back extensors not
the abs that are key to allowing gravity to flex the trunk during
poling, and that straight double poling is not any different from any
other technique in this regard. He sees trunk flexion's most important
role in double poling as "putting the arms into an advantageous
position for generating propulsive force during poling."

Now, tho some of this seems pretty obvious to me, I really don't know
to what extent he's right or wrong overall, and I'll bet you don't
either. Same thing for torso rotation and ski angles. Gerald Smith
doesn't (or didn't) know for sure about abs and back extensors either.
He'd have to hook up some skiers on a ski lab treadmill to find out.
Sports science is like that, theoretical discussion based on limited
studies, basic knowledge and some field experience, posing questions
for further study. It's really fascinating stuff, as you recognize. But
the trap is that it does take training and experience in scientific
methodology - sytematic thinking - to even begin to separate the good
stuff from the poorly done studies, fads, marketing, and well-meant but
superficial thinking. And that's before getting into anatomy,
physiology, kinesiology, etc.

rm


wrote:

The text which I referenced is the same quoted in a couple of places
the xczone films:

Handbook of Sports Medicine and Science Cross Country Skiing - An IOC
Medial Commission Publication, Blackwell Publishing, edied by Heikki
Rusko, ISBN 0-632-05571-5

The handbook is a must read for serious skiers. My only criticism is
that the studies are very much 3rd person observations and sometimes
miss the essence of skiing. The quote that we a bit odd was found on
teh bottom of page 43 "...it is not clear that the abdominal group is
more important in double poling than it is in other techniques."

As a skier, it would seem rather obvious how much the abs are worked
if you do a double poling workout. This lead me to believe that
these scientists did not ski at the same level as the subjects that
they we testing.

Thanks again for the idea of getting the hips lower ("leg compression") for
climbing hills, rm. It contradicted my old theory, but I checked the elite
racer videos, and saw how they were able to grab the positive while avoiding
the negative, and seems to help me.

rm wrote
On uphills in V2 and V1, some people will set up
for the next skate by first turning their hips in the new direction.

The nomenclature of rotating hips + pelvis can be kinda tricky, so I'm not
completely sure what's meant here. In response to my previous videos posted
a couple of years ago, some smart people suggested that while I'm pushing
with my Left leg, I should be advancing my Right hip forward. Some people
call this "forward hip rotation" -- though (since hip rotation has another
meaning in formal kinesiology) I sometimes prefer to call it "pelvis
rotation": like rotating pelvis the about a roughly vertical axis, or about
the axis of the spine.

The physics of this seems very clear to me: Moving the Right hip forward
also moves it further away from the Left ski, which by Newton's Third Law
adds Force to my current pushing thru my Left ski. It also sets up my hips
and pelvis into position for a maximum "pelvis rotation" or "forward hip
rotation" move to add force to my next leg push on the opposite side. So it
is simultaneously a direct propulsive move and a recovery move. The physics
and biomechanics do not much better than that: a self-recovering move. It
also works to add propulsive power for Classic striding on skis and to
dryland running and walking.

But to me it seems like this move of my Right hip forward while my Left leg
is still pushing is tending to turn my hips in the "old" direction, _away_
from the next push, which feels sorta unnatural for skating. But it's the
way to take advantage of the physics -- so I've practiced it pretty
faithfully for two years.

What feels more "natural" for skating is to move the Right hip _backward_
while the Left leg is pushing. That's the natural way to move the hips when
practicing KNT / NKT / Nose - Knees - Toes alignment while preparing for and
starting the next push thru the Right leg. Assuming that the shoulders are
supposed to rotate "naturally" with the Nose, this backward rotational move
sorta makes the pelvis align with least tension relative to the Knee and
relative to the shoulders and Nose.

This "natural" pelvis or hip rotation backwards is the _worst_ thing about
using the mental image of KNT / NKT / Nose - Knees - Toes alignment. That's
my analysis of the physics: this "natural" backward pelvis (or hip)
rotation _absorbs_ propulsive force + work, because it accelerates mass
toward the direction of the intended push. Newton's Third Law says that when
you do that, you reduce the desired leg-push force. My view is that the
rejection of this "natural" rotation of the pelvis was one of the big things
the New Skate (original 2000 version) got right.

some people will set up for the next skate by first
turning their hips in the new direction.

OK, "some people" do that.
But I don't think any successful World Cup racers do it. In all the
controversy between Borowski and Vordenberg about shoulder rotation and
whether the head of an elite racer made a "big loop" or a "little loop", I
don't remember anybody claiming they ever found an instance of an elite
racer making a backward rotation of their hips or pelvis.

Ken

Rotate inside of pelvis. When I first learned it, it was to turn the
crease on the inside of the leg-pelvis connection. The idea is to help
oneself get around ski to ski by aligning the pelvis early in the new
direction. Just a little cue that can help maintain momentum in the
face of uphills and fatigue.

rm

"Ken Roberts" wrote:

rm wrote
On uphills in V2 and V1, some people will set up
for the next skate by first turning their hips in the new direction.

The nomenclature of rotating hips + pelvis can be kinda tricky, so I'm
not completely sure what's meant here. In response to my previous

DH wrote
The xczone products do not market themselves as scientic studies

Huh?
Then why do they say at least one DVD is in "the Science of Nordic Skiing
series"?
(quoted from the first sentence on the back cover of box of the "Nordic
Skiing Technique" DVD I'm holding in my hand right now)

As I said about another author a month ago: If you don't want to be held
accountable by the standards of science, then just don't call it "the
Science". Instead call it "lotsa helpful tips from some experienced
coaches."

Ken

I'm just starting to think that which way to rotate the pelvis or hips is
like a selection of which gear on a bicycle. Perhaps especially when
climbing up a hill, "forward" rotation is like a higher gear, and "backward"
rotation is like selecting a lower gear.

I had written
some smart people suggested that while I'm pushing with my Left leg, I
should be advancing my Right hip forward. Some people call this "forward
hip rotation"

And I've been practicing and practicing that "forward" direction of
pelvis/hip rotation for two years since then.

But now I'm wondering if for lots of us skating up a very steep hill,
rotating the pelvis or hips in the "backward" direction might instead be
more helpful: "backward" is like while I'm pushing with my Left Leg, I
allow my Right hip to drop behind -- so my navel tends to turn toward the
next pushing leg. (This tends to be obvious result of practicing NKT
Nose-Knee-Toe alignment).

This "backward" direction of pelvis rotation results in less propulsive
power output (in Watts) from my leg push, because it moves some of my body
mass connected to my Right hip toward the direction of the current leg-push,
which tends to reduce the force of the push.

In itself that's bad, but when I'm climbing a steep hill it has another
important effect: It means that my next step does not go as far up the
hill -- so my vertical distance per step is smaller. If I keep my turnover
frequency the same, then my vertical rate of climbing is slower. Which means
it requires less power (in Watts) to keep me moving up the hill without
stalling. That's how it's like selecting a lower gear on a bicycle.

For elite ski racers that would normally make no sense, but for lots of the
rest of us skating up a steep hill the big problem is that we're climbing
_too_ fast, and our leg muscles get burned out. For lots of us the big
problem with skating is how to find a lower "gear" that allows us to survive
the hill with our leg muscles still in shape to enjoy another hour or two of
skiing.

So if the "backward" direction of pelvis or hip rotation reduces the rate of
power output of my skating leg-push by 15 Watts, but it also reduces the
power rate required for climbing the hill by 35 Watts, then my muscles and
cardio-vascular have gained 20 Watts of "slack" -- so there's a better
chance I can stay below my Lactate-related Threshold while skating up a hill

That idea would fit some of the discussion that followed the proclamation of
the original old "new skate" in USA -- which said that the hips or pelvis
should "aim" straight in the direction of skier's overall forward motion --
with no rotation toward the next ski (as typically went with the
NKT-alignment concept). It seemed to help some national-level racers, but
lots of citizen mid-packers said it didn't work for them. Maybe both were
right -- for their own capabilities.

Ken

On Mar 5, 10:34 pm, "Ken Roberts"
wrote:

......
But now I'm wondering if for lots of us skating up a very steep hill,
rotating the pelvis or hips in the "backward" direction might instead be
more helpful: "backward" is like while I'm pushing with my Left Leg, I
allow my Right hip to drop behind -- so my navel tends to turn toward the
next pushing leg. (This tends to be obvious result of practicing NKT
Nose-Knee-Toe alignment).

This "backward" direction of pelvis rotation results in less propulsive
power output (in Watts) from my leg push, because it moves some of my body
mass connected to my Right hip toward the direction of the current leg-push,
which tends to reduce the force of the push.

In itself that's bad, but when I'm climbing a steep hill it has another
important effect: It means that my next step does not go as far up the
hill -- so my vertical distance per step is smaller. If I keep my turnover
frequency the same, then my vertical rate of climbing is slower. Which means
it requires less power (in Watts) to keep me moving up the hill without
stalling. That's how it's like selecting a lower gear on a bicycle.
......


Rather than screw around with two or more versions of your
offset, wouldn't it be simpler, when the hill gets too steep,
just to revert from offset (V1) to diagonal skate?

(Said partly in jest): If this lengthy thread goes on long
enough, and we go back-and-forth often enough
from hips (pelvis) rotate forward, to hips rotate backwards,
to, well, hips rotate forward but a bit less, to, no,
backward but only a little, to ..... ,
in the end we can take the average and say, as I
gather many do these days, keep hips as square
to the direction of motion as possible, without destroying
natural athletic movement!

You seemed to do very well at Lake Placid loppet, Ken,
presumably with your last two years' theory (but personally
I think mainly because you do have a much higher natural
talent as an `aerobic' athllete than you yourself credit your
mum with giving you), so it will be interesting next year
to see how the backwards rotation does for you. (That
sample of 1 is seriously flawed as science---but what
else is new in the almost oxymoronic ``sports science"?)
Though I have been unable to get down for that, I have skiied
the ``women's 5 km loop" or whatever it's called a few times
in the past, so I do have 1st-hand experience of the claim
that the LP loppet has very steep climbs, presumably
just the sort your post refers to.


Best, Peter

Peter H wrote
Rather than screw around with two or more versions of your
offset, wouldn't it be simpler, when the hill gets too steep,
just to revert from offset (V1) to diagonal skate?

The same "gear selection" choices for pelvis/hip rotation are available no
matter what poling motion you're using: V1/offset,
single-poling/herringbone/diagonal -- or no poling at all. You still get a
"higher gear" by advancing your non-pushing hip further up the hill, and you
still get a "lower gear" by lagging your non-pushing hip behind and below
the currently pushing hip.

in the end we can take the average and say, as I
gather many do these days, keep hips as square
to the direction of motion as possible ...

Indeed, that is yet another choice for hill-climbing: the "mid-range" gear.

Maybe there's lots of _talk_ about square hips these days. What's the
evidence that people are doing it? As far as I know the winning racers are
doing what they've always done: smiling at the coach and saying "Yes sir"
and demonstrating it while the coach is watching. When it comes time to race
to win, they do what they and their unconscious neuro-muscular controller
"knows" to really be faster in most race situations: advancing the
non-pushing hip forward. (Not square.)

You seemed to do very well at Lake Placid loppet, Ken.

Thanks for saying so, Peter. But actually I was kinda disappointed. It was
the worst "positive split" I've had doing the Lake Placid Loppet: My time
for the second 25km was 7 minutes slower than for the first 25km lap - (two
laps of the same course). Several skiers passed me in the last half hour --
where usually it's been me who is coming on stronger at the end. Felt good
on the flats in the last hour, but every time I hit any hill, it was painful
survival.

I'm convinced that this was because I did not go slow enough up the steep
hills. I think the snow conditions were slow this year because it had fallen
cold and stayed cold and soft for a long time. I do think I would have done
better if I had known how to find a "lower gear" that day.

Ken

P.S. I'm not the doing the 50K again at Lake Placid. The course is really
better as a 25K race. If you carefully look at all the results this year you
can see that almost all the local New York racers had already figured that
out. I think it would be a better event if they just killed the 50K
sections, so that the 25K races would have larger participation. (Then once
they get off the need to make the course distance hit some special number,
maybe they could eliminate that sharp turn on the biathlon side -- or add a
couple more good hills on the Porter side)

Peter H. wrote
... keep hips as square to the direction of
motion as possible, without destroying
natural athletic movement!

(twisting Peter's words a little spurs me on ... )

** Theory versus Natural "elite" learning rotation from Classic:
There's nothing "naturally athletic" about keeping pelvis/hips square to the
overall direction of forward motion. Otherwise why would it be necessary to
send racers to special "New Skate" camps to learn it properly.

Rotation of the pelvis/hips is a no-brainer for Classic striding on
gentle-to-moderate terrain. No racer who kept their hips "square" would have
a chance in high-level competition. Advancing the non-kicking hip ahead is
the obvious "athletic" thing to do to get more power (in Watts) out of each
Classic leg-push, for the goal of going faster. Also works to go faster in
walking and running on dry land (flat or gentle). The only reason not to do
it is because it hadn't occurred to you to try it - (or because some
authoritative coach or book or DVD told you loudly and confidently to stop
it.)

So it doesn't take some theoretical analysis to get a national-level racer
to try "forward pelvis/hip rotation" -- The only reasoning needed is, "If it
works for Running and for Classic, let's try it for Skating." More likely no
conscious reasoning at all: Their unconscious neuro-muscular controller
already "feels" how the pelvis/hip rotation move helps go faster in Classic
and Running, and its "natural athletic" mode easily transfers that "feel" to
Skating.

** Classic versus Skating: different physics + execution:
Different Physics for how pelvis/hip rotation increases speed for Skating
versus Classic -- which can changes how the move is performed.
For Classic the move works by moving more mass connected to the non-pushing
hip _forward_ -- because the Classic leg-push force is straight backward, so
accelerating more mass forward quicker increases the push-force. And the
bigger the move forward is made, the more force is added.
But for Skating the pelvis/hip rotation move works by moving mass connected
the the non-pushing hip diagonally _sideways_ -- because the Skating
leg-push force is diagonally sideways. So making the _forward_ move bigger
does _not_ keep adding more Skate-push force.

It's just a geometric coincidence that _part_ of the "circular" rotational
move includes both a forward component favorable for Classic and a
sideways-diagonal component favorable for Skating. As the "forward rotation"
goes farther it the sideways-diagonal component becomes smaller, and if too
far it would go _negative_: start accelerating mass _toward_ the skate push
force -- which would reduce its propulsive benefit.

Therefore it might make sense to exaggerate the Forward pelvis/rotation move
in Classic: more is more (though of course there's trade-offs) -- but it
does not make sense to exaggerate the Forward move for Skating: a little
goes a long way.

** low gear for Classic
"backward" pelvis/hip rotation works to reduce the Power requirement for
climbing a steep hill using Classic: whether doing Herringbone or normal
diagonal Striding. Another way to make the climbing easier -- by going up
the hill slower: less vertical in each step. Though Classic has more other
ways to go slower up a steep hill, so it's not clear to me how often this
one gets used -- maybe just avoiding the forward hip move is a more helpful
strategy?

** Theory versus Natural learning by "mid-packers"
I don't think I'm not proposing some new move for us "mid-packer" skaters to
survive hills. Rather I'm explaining how the "natural" tendency of the
unconscious neuro-muscular controller - (to rotate pelvis/hips to aim the
navel away from the current leg-push and more toward the next one) - was
correct in Physics for how to _survive_ a steep hill without burning out.
I'm saying that Skating is really complicated, and here's another case where
lots of skiers did better to rely on their unconscious than to follow the
simplistic coaching theories of "hips always square, never rotate" -- or my
recent theoretical attempt: "always rotate hips forward, never backward".

Ken

On Mar 6, 9:51 am, "Ken Roberts"
wrote:
Peter H wrote

Rather than screw around with two or more versions of your
offset, wouldn't it be simpler, when the hill gets too steep,
just to revert from offset (V1) to diagonal skate?

The same "gear selection" choices for pelvis/hip rotation are available no
matter what poling motion you're using: V1/offset,
single-poling/herringbone/diagonal -- or no poling at all. You still get a
"higher gear" by advancing your non-pushing hip further up the hill, and you
still get a "lower gear" by lagging your non-pushing hip behind and below
the currently pushing hip.

So it looks like you're trying to produce a triple chain ring (hips
forward,
square, retarded) to go with the gears (on the back wheel?) we've
already got via different techniques of skating.
I'm wondering whether that amount of complication is
at all practical. On a bike you don't have much variation, other than
cadence, pushing those pedals. But wouldn't, for example,
diagonal skate with square or forward hips be the same gear
as offset (V1) with retarded hips in your theory? All this
complication
for the brain could of course be advantageous in my feeble attempt
at humour quite awhile back here related to burning off lactic acid by
excessive brain activity during a race.

Anyway (correct me if I'm wrong JFT or other bike afficianados), the
excessive gears on bikes are only there to have a handy system
which produces a very low lowest gear and very high highest.
Many of the gears are so close as to be superfluous in principal,
only needed for convenient shifting.

I'm inclined to think that a 4- or 5-speed is all you need for
ski racing, even up that final hill in the Tour de Ski.
Looking at videos of that might give you
some evidence about how those top skiers
tried to cope when they finally got stuck with something way
steeper/longer than usual.

Best, Peter

Peter H. wrote
So it looks like you're trying to produce a triple chain ring
(hips forward, square, retarded) to go with the gears
(on the back wheel?) we've already got via different techniques of
skating.

Thanks for the creative analogy.

the excessive gears on bikes are only there to have a handy
system which produces a very low lowest gear and very high highest.

Using the pelvis/hip rotation option could help for that: Like if you think
single-poling / Diagonal / Herringbone skate is your slowest motion, then
combine that with the backward / lagging of the non-pushing hip. If you
think Open Field Skate / V2A / 2-skate is your high-speed technique, then
could combine that the "forward" rotation of the non-pushing hip.

I'm wondering whether that amount of complication
is at all practical.

Good point. I doubt that consciously trying to keep track of those
combinations in a performance situation is a useful strategy.

My guess is that a more helpful strategy is to try out the different range
of pelvis/hip-rotation options in practice situations on different terrain
(flat, moderate hill, steep hill) -- maybe try some different
goal-situations (e.g. max speed versus LSD; "conquering" the hill versus
"surviving" it with minimum fatigue) and just see how each one _feels_.
Expose your unconscious neuro-muscular control super-computer to different
possibilities.

If some combinations feel like they help, then practice those some more to
let your neuro-muscular controller "refine" its control of them, maybe
elevate those in its "priority activation" list. But during actual
performance, just leave it to your unconscious super-computer module to
select the best style of pelvis/hip rotation for each situation.

I think my problem was that was that first like three years ago I had no
idea that pelvis/hip rotation made sense as an option -- I just assumed that
any deviation from "square straight" was wasted motion (and would look
"wierd"). Then somebody told me about forward pelvis/hip rotation for my
ski-skating. So I practiced it lots, also added it to my walking + running +
backcountry Classic striding. I decided in rational theory that it must be
the optimal "right" way to skate. So I was consciously forcing it in
situations where it wasn't helpful -- like some steep hills in the Lake
Placid Loppet.

My guess is that lots of skiers are already (unconsciously) varying their
pelvis/hip rotation in a helpful way for various situations. They should
just keep skiing happily. There's other skiers whose unconscious control
module _would_ use rotation beneficially, if they would release it from some
simplistic rule -- perhaps figuring out (or arguing against) my more
complicated theory will keep their conscious mind busy enough so it will
just leave their unconscious super-computer some slack to operate better.

I'm inclined to think that a 4- or 5-speed is all you
need for ski racing, even up that final hill in the Tour de Ski.
Looking at videos of that might give you some evidence
about how those top skiers tried to cope when they finally
got stuck with something way steeper/longer than usual.

The fact that the Giro d'Italia pro bicycle-race winners can climb some
ridiculous hill with only 2 chainrings does not mean that lots of the _rest_
of us will not benefit from having a 3rd smaller "granny" chainring.

Ken