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Turn Initiation

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john petersen

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or anything that requires anticipatory balancing movements, a few c-forces and some uneven or pitched terrain.....

sure makes those first runs more enjoyable.

JP
 

PTskier

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Does this discussion deserve to get back on track?
This year’s breakthrough was (1) the realization that my COM wasn’t crossing over along with transitioning to the new edge leaving me perpetually in the back seat as the terrain got steeper and faster. In the past I’ve worked to improve my transition to the new edge always concentrating on (2) “skiing from the feet up” which I found an appealing touchstone, but seemingly (3) did little to get me out of the backseat. So, here’s my question, (4) why not initiate the new turn by moving my COM (top of hip bones) down fall line instead of my feet, or boots or knees or whatever is lower on the kinetic chain?
Numbers mine.
(1) Is that actually what gets one into the back seat? (Heels ahead of hips.) I don't think so.
(2) Well...the feet are relatively light, easy to move, and we have big muscle groups to provide some of this movement. The trunk is heavy and slow to move.
(3) Maybe the concept was correct and the execution wrong.
(4) How?

--What if...good skiing does indeed start with the feet. Body movements amplify what the feet are doing.
--If the feet & skis are making curves under the upper body, and the upper body movements are balancing and amplifying what the feet are doing, things go very well.
--Pull both feet strongly back to get the skis' sweet spots under the body's center of mass. (The sweet spot is somewhere forward of the toe bindings. Some skis have a smaller sweet spot and require more precision here--others have a big sweet spot and are easier to ski well.) We have strong hamstring muscles that pull the skis back. We have little to push the body forward.
--Roll your skis on edge so they ski away from the body into the turn you want to make. We paid a lot for the edges and sidecut and flex pattern--use them.
--Make your upper body movements of angulation and counter to balance and amplify the action the feet are taking.
----That's kind'a it. A pole tap to the side (not a big arm swing and heavy pole plant) is helpful. There's lots more details, but those come after the fundamentals get into line.
 

Don Duran

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Not looking to argue the point but basic biomechanics tells us that moving the feet is done with multiple muscle groups. None of which are actually in the feet. Even flexing the ankles (dorsi and plantar) uses the muscles of the lower leg. Making the claim that the body only "amplifies" what the feet do completely false.
As far as the sweet spot being ahead of the bindings an aft mount might produce that but most manufacturers don't prescribe that mounting spot. Twin tips feature a center mount making the sweet spot and stance well aft of what you suggest.
Pulling the feet back is a function of trying to get the body over the feet because we allowed it to lag behind. Or the feet to get too far ahead. As a corrective adjustment it makes sense but as a habitual strategic move it demonstrates a lack of skill coordinating simultaneous upper and lower body actions. Usually something corrected around U12-16. Watch World Cuppers and you will see a variety of transition where the feet and body play leap frog down the hill. But the feet and body moving on their seperate paths is the reason. Barnes' infinity move is based on exactly this idea. Not slowing down the feet so the body can catch up.
Angulation is another often misunderstood act. It is a counter balancing thing that projects the CoM (a mental construct BTW) laterally out to the side the body. If dropping the hip too far inside the turn is why you adopt an angulated stance again it is a corrective move not good technique. Adding it to allow higher edge angles (to tighten a turn) is a more legitimate use. Typically done through the second half of the turn it begins the migration of the upper body away from the inside of current turn. That outward momentum helps carry the body over the feet through the transition and it hardly originates in the feet. An important detail overlooked in the release the feet first mantra.
So while the body and feet move in complimentary ways the feet cannot change location relative to the body, or snow, or in the air for that matter without the rest of the body actually moving them. Another inconvenient fact for those who take the feet first mantra too literally.
Ultimately it comes back to the simple phrase, the entire body participating in our balancing efforts.
 
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Zentune

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Thought these videos might be interesting (warning: geek factor)...we can see that the articulation of the feet in both open and closed chain scenarios has a direct influence and implications upstream (internal/external leg rotation, dorsi/plantar flexion, inversion eversion). If the foot cannot, or *is not allowed to* function in this manner, then the movements of the legs (and therefore the rest of the body) will have to be initiated by "grosser" muscles and joints higher up in the chain (think hips, pelvis, upper body) and balance is compromised.

Note that both scenarios ("foot first" vs "top down") are actually simulataneous whole body activities.




zenny
 

razie

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Pulling the feet back is a function of trying to get the body over the feet because we allowed it to lag behind. Or the feet to get too far ahead. As a corrective adjustment it makes sense but as a habitual strategic move it demonstrates a lack of skill coordinating simultaneous upper and lower body actions. Usually something corrected around U12-16. Watch World Cuppers and you will see a variety of transition where the feet and body play leap frog down the hill.

hmm... pulling the feet back is a big function of needing dorsiflexion.

I wouldn't say that focusing on placing the feet for fore/aft is demonstrating a lack of skill, especially in a racing environment, but quite the contrary... in fact here's one of my favorite quotes:

Good racers frequently adjust leverage and pressure distribution by sliding their skis forward or backward under the center of mass. How the Racers Ski, Warren Witherell, 1972​

In terms of modern WC racing... I really enjoyed this guy last year and looking at his upper body, I see "quiet" and "disciplined"... no leap frogging or any such other...


cheers.
 

Don Duran

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So you don't see the cross overs? Raz you disappoint me. It's down the hill not fore / aft Raz and I know you know that.
 

razie

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Oh- they do, they cross over and over, but what I see is a very disciplined upper body, moving down the hill at an almost constant speed and the feet moving all over the place: up, down, left, right, forward, back and I'm sure there's some more dimensions I'm missing ;)

...and yes, this simple trajectory difference is responsible to some extent for getting forward, but placing the feet where they need to be is what creates the diverging trajectories and it sure looks more important than trying to "place" the upper body...

... for those into sailing, it sure looks like he's tacking down the hill? Or is that gybing ?
 

markojp

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... depends on which way the wind blows... Could be reaching as well. :roflmao:
 

john petersen

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... depends on which way the wind blows... Could be reaching as well. :roflmao:

and which side of the sailfish he is sitting on.....

I like the whole body aspect to the last few posts here....and can imagine with experience, the right tutors and good equipment, many can achieve efficiency and good flow.
I was thinking about this on my way to work oddly enough, the whole body aspect and in particular, that the feet themselves are not the initiators, but do help with micro and some macro adjustments in all planes of adjustments. Receptors getting initial input from the terrain are down there so they are key in providing information......I was just approaching the thought of the lower leg doing a great deal of work with the strength of the quads and core allowing the feet and ankles to do some micro adjusting...
then got distracted as I opened my office door!.........

Don, can you clarify....
Making the claim that the body only "amplifies" what the feet do completely false.

Is it the word "amplify" that can be replaced? perhaps with the word "receiver" like stereo equipment. "the body is the receiver of what the feet are doing" or could it be the other way around?......the feet only amplify what the body can do?....not sure. the more I think about this the more it does not make sense at all....


Pulling the feet back is a function of trying to get the body over the feet because we allowed it to lag behind. Or the feet to get too far ahead. As a corrective adjustment it makes sense but as a habitual strategic move it demonstrates a lack of skill coordinating simultaneous upper and lower body actions. Usually something corrected around U12-16

What about the progressive nature of the same movements in the infinity move? As a tactic or or corrective adjustment, okay....but isnt it good strategically "on the way" to enlightenment? in the sense that one can be guided to evolve that coordinated skill set? (yes, I am hopeful!)

ski placement either in anticipation or reaction modes with a stable upper body working in harmony with one another is certainly ideal....experience, intent and application are other blends that certainly play their part. Experience....or skill, whether emergent or a long way off, is probably subjective to the level of skillful MA by the viewer. So is my own use of "emergent" for that matter. ;) I guess more experience and refined skill allow deeper values sometimes.

As far as correcting disharmony in upper and lower body movements by U12 or so.....well, if contemplating the over and under on that one... I guess Im in the OVERS category! Though I have been enjoying the infinity move quite a bit...so I guess Im emergent.....;)

ahh well...

JP
 

karlo

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why not initiate the new turn by moving my COM

Try this on a gentle slope. Just wiggle your hip left and right. Keep your upper body still and feel yourself centered on top of your feet, even though they will be on one side of you or the other. Now try this on progressively steeper terrain, resulting in your hip getting lower, and the angle at the hip greater. Keep it simple by doing this while going down the fall line, no matter how shallow or steep.
 

dj61

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This year’s breakthrough was the realization that my COM wasn’t crossing over along with transitioning to the new edge leaving me perpetually in the back seat as the terrain got steeper and faster. In the past I’ve worked to improve my transition to the new edge always concentrating on “skiing from the feet up” which I found an appealing touchstone, but seemingly did little to get me out of the backseat. So, here’s my question, why not initiate the new turn by moving my COM (top of hip bones) down fall line instead of my feet, or boots or knees or whatever is lower on the kinetic chain?

Focus on your feet, or focus on you COM; it is exactly the same thing. It is as with any form of instruction: good trainers look for the pointers that help their students to make the click. When I do Pilates my trainer gives me all kind of 'formal' instruction like 'use your powerhouse' (= abdominal muscles), but if that does not help me to do the routine the way it should be done, she says thinks like 'nose first'. That often helps me more. Apparently, the feet thing did not work for you. But things like 'pulling your feet back' (which seems to me the new mantra) is exactly the same as 'bring you center of mass forward' (old school). Same muscles, same result. And only the results count.
 

Rod9301

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Focus on your feet, or focus on you COM; it is exactly the same thing. It is as with any form of instruction: good trainers look for the pointers that help their students to make the click. When I do Pilates my trainer gives me all kind of 'formal' instruction like 'use your powerhouse' (= abdominal muscles), but if that does not help me to do the routine the way it should be done, she says thinks like 'nose first'. That often helps me more. Apparently, the feet thing did not work for you. But things like 'pulling your feet back' (which seems to me the new mantra) is exactly the same as 'bring you center of mass forward' (old school). Same muscles, same result. And only the results count.
Wrong!
Not the same muscles at all.
Feet back- hamstrings.

Center of mass forward- other muscles.
 

François Pugh

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Wrong!
Not the same muscles at all.
Feet back- hamstrings.

Center of mass forward- other muscles.
Apparently some folk do use hamstrings to move their CoM forward (e.g. dj61), but many don't. Hence the need for a GOOD instructor who can see what their student is doing in response to their instruction and adjust accordingly.
 

Don Duran

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A while back a study out of two prominent Austrian universities investigated muscle use in two different types of ski turns. Carved and skidded. The data suggested for each turn type we use our muscles differently. No real surprises in that conclusion IMO.
I only mention it to suggest we avoid claiming too much about what muscle groups are used and how they are used without providing hard data like they did. We also need to provide context like they did about what type of turns we are talking about rather than claim any universal muscle use patterns for all turns.
 

Rod9301

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Apparently some folk do use hamstrings to move their CoM forward (e.g. dj61), but many don't. Hence the need for a GOOD instructor who can see what their student is doing in response to their instruction and adjust accordingly.
Can't see how you could use the hamstrings to move the com forward.

Hamstrings are used to move the heels towards the butt, similar in function to biceps.
 

Zentune

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Well, technically the hamstrings will fire in either scenario. To pull your feet back they will concentrically contract (shorten) while the quads will eccentrically contract (lengthen, to decelerate the knee flexion), and to move the com forward via extension it is the opposite--the hamstrings eccentrically contract (to decelerate the knee extension) and the quads will concentrically contract.

zenny
 

Zentune

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So a big difference between the 2 extremes lies in regards to outcome because, pronation (dorsiflexing, everting, internal leg rotation) ie rolling towards the big toe, typically involves leg and hip flexion, not extension....and the opposite is true, generally. This is why when you extend, it typically takes longer to create angles, because you have moved to the supination phase of the outside foot pretty much from the get-go, a movement that ultimately rolls the foot towards its little toe side and presents with external leg rotation, so you have to wait for the mass to "come back down" inside the new turn to create your angles.

zenny
 

dj61

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Can't see how you could use the hamstrings to move the com forward.

Hamstrings are used to move the heels towards the butt, similar in function to biceps.
That is one movement that involves your hamstrings. Now try this and focus!
Stand on both feet. Now pull your feet backwards. To be able to do this in full control you will need your hamstrings (and glutes and lower abdominals). You see: no flexing, no heels that will move towards your butt. But the hamstrings are working.
But at the same time you upper body will move forward. One and the same movement. Some people realize what to do if you tell them to 'pull their feet back'. They will be able to make this movement. Others respond better to 'move your CoM forward'. Not everyone has enough body awareness to actually feel which muscles they use when they move parts of their body. But after 15 years of intense Pilates training, you will know.
 

Rod9301

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Well, technically the hamstrings will fire in either scenario. To pull your feet back they will concentrically contract (shorten) while the quads will eccentrically contract (lengthen, to decelerate the knee flexion), and to move the com forward via extension it is the opposite--the hamstrings eccentrically contract (to decelerate the knee extension) and the quads will concentrically contract.

zenny
That is one movement that involves your hamstrings. Now try this and focus!
Stand on both feet. Now pull your feet backwards. To be able to do this in full control you will need your hamstrings (and glutes and lower abdominals). You see: no flexing, no heels that will move towards your butt. But the hamstrings are working.
But at the same time you upper body will move forward. One and the same movement. Some people realize what to do if you tell them to 'pull their feet back'. They will be able to make this movement. Others respond better to 'move your CoM forward'. Not everyone has enough body awareness to actually feel which muscles they use when they move parts of their body. But after 15 years of intense Pilates training, you will know.
Yeah, that's because there is friction between your feet and the floor.
On the snow, without friction, your feet move back.
 

Zentune

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Yeah, that's because there is friction between your feet and the floor.
On the snow, without friction, your feet move back.

Yes your feet will move back in either scenario, although MUCH less in the case of extension.

zenny
 
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