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Discussion request regarding terminology. Leverage

post #1 of 21
Thread Starter 

More L3 studying going on here.

 

Is leverage a form of pressure control?

How does it relate to our skiing?

Too much forward leverage leads to ?

Too much aft leverage leads to ?

 

References?

post #2 of 21
Thread Starter 

Just looking for more opinions or information. I am relatively sure I know the answer but again trying to argue both sides of this question as well.

 

DC
 

post #3 of 21

Have you seen this article? The Complete Encyclopedia of Skiing—EpicSki Skiing Glossary

 

There's a bit about leverage...and a lot of other great information!

post #4 of 21
Thread Starter 
Quote:
Originally Posted by nolo View Post

Have you seen this article? The Complete Encyclopedia of Skiing—EpicSki Skiing Glossary

 

There's a bit about leverage...and a lot of other great information!


I have. I also own 2 copies of the third edition, one which is signed by Bob..

 

the only thing in the glossary is :

-----------------------------------------------

Leverage
controlling pressure fore and aft on the skis; part of the skill group of Pressure Control

 

----------------------------------------------

 

And the only thing in the PSIA Alpine Technical manual is a picture showing a person standing on some skis with force arrows depending on if the person is leaning forward or backwards..

 

I understand all that. I'm just trying to generate some "debate/dialog" to bring out more examples so we as instructors that are studying for exams, can get a clearer understanding in our minds.

 

What are some of the affects of us using leverage?

 

For instance, I do know from experience that overleveraging the front of the skis can often exhibit in our skiing like we are pushing out our heels. The actual reason for this behavior in my case was not so much a technique problem but a ramp/delta angle, combined with my physical dimensions (leg length/structure) that put my weight further. I was simply overpowering the front of the ski, thus causing an inability to get the rear half of the skis edge to engage properly. 

 

 

DC

post #5 of 21
Moment of inertia, torque, and leverage are all interesting subjects but the act of levering fore / aft might help you make more sense out of the term. Especially when it is used in combination with tipping and steering a ski.
post #6 of 21

  This is an interesting thread: http://www.epicski.com/t/99527/reconciling-foot-squirt-with-foragonal-movements

 

     zenny

post #7 of 21
Thread Starter 
Quote:
Originally Posted by justanotherskipro View Post

Moment of inertia, torque, and leverage are all interesting subjects but the act of levering fore / aft might help you make more sense out of the term. Especially when it is used in combination with tipping and steering a ski.


Thanks JASP..

 

I think I have a good grasp of levering fore/aft. I'm again looking for ways to argue/debate if leverage is really a "good way" to do pressure management. What are the symptoms of over leverage both fore and aft?

 

When might leverage be a help, or when is it a detriment to our skiing (as in my example above)

 

DC

post #8 of 21

DC, go play outside and discover what occurs when you use excessive levering.

post #9 of 21

   Situationally, too much fore movement would be perhaps not a good thing in soft snow (powder). Excessive tip pressure would not be indicated in such a scenario. I wouldn't recommend you try it, but.....

Conversely, unless prepared and well versed in skiing, carved turns at speed, on hard snow, would preclude grossly excessive pressure aft when exiting the turn--as one doesn't want to get shot into the air! I saw a fellow fore-running a slalom 6 feet in the air...upside down even. I was close enough to feel him land. 

 

   If I show up to my local mtn having foolishly left my all mtns. at home when it's soft-ish, and all I have is my racetigers, I change tactics. Certainly going to back off the tips/front of the ski just a tad, as I don't want to go to China the hard way. 

 

   I don't suppose there's too much to debate regarding your OP, DC, like Jasp suggests--go out and play (be carefulwink.gif).

 

    P.s. there are other threads regarding fore/aft: http://www.epicski.com/t/115364/reasons-for-finishing-aft/60#post_1512737

     

     zenny

post #10 of 21
Quote:
Originally Posted by dchan View Post

More L3 studying going on here.

 

Is leverage a form of pressure control?

How does it relate to our skiing?

Too much forward leverage leads to ?

Too much aft leverage leads to ?

 

References?

 

Caveat emptor - I just make this stuff up as I go. This is talking in the bar stuff....

Too much forward leverage (depending on timing, but in general) can be caused by either too much hip flex or too much ankle "flex". Too much hip flex (that is not offset by less ankle flex which would eliminate the too much forward leverage) causes falling. Too much ankle flex (and too little hip flex) leads to the spine losing it's parallel relationship to the lower leg/tibia. Knee flex in this position causes weight to shift backward. Forward movement of the ski pulls the upper body instead of pushes the upper body. Ability to absorb terrain variations, to control upper body positioning and engage the edge in the first half of the turn becomes compromised.

 

Too much aft leverage leads to ... Wayne Wong impersonations!

 

references? Pirates of the Caribbean - "the proper application of leverage"

post #11 of 21

Aft stances that pressure the tail have been known to lock the ski on edge. Done in excess (a parameter mentioned by DC), the consequence is the knee is very vulnerable. ACL injuries are quite common from extreme aft stances that include pressuring the tail. For that reason I am against ever offering advice to lever on tails that much. I know some here would point out that the foot squirt maneuver and even retraction turns end with an aft stance but neither maneuver includes the excessive aft pressure that makes releasing the tail so difficult.

 

As far as excessive forward levering , the tails wash due to lack of pressure and again releasing the edge (this time at the tip) is more difficult. Some classic signs of this are windsheild wiper skidded turns, sequential edge release / re-engagement, rotary push off moves, abstems and even poor absorbing skills can be traced back to excessive tip pressure.

 

So DC, the short version here is the lack of balance imposes limitations on our ability to use all of the skills at will. That doesn't mean small amounts of levering is not present in good ski turns. It also doesn't mean levering is always a product of flexing and extending movements. For example, steering a tipped ski changes pressure along the engaged edge and even tipping a ski onto edge requires us to use lateral "leverage". That is why I mentioned and suggest once more that we avoid using a single word like leverage to describe specific movements like fore /aft levering movements. I understand the E ed staff may use it but as a coach going through certification, understanding specifically what they are talking about, (and more importantly what they are not talking about) requires you to seek further clarification and that usually requires more details than it would have taken if they didn't abbreviate the term in the first place. It also is quite common here and IMO is usually the reason for all the circular definition debates.

I hope that advice helps you, I know it helped me when I realized acronyms and abbreviated terms can be more confusing than helpful.

JASP

post #12 of 21
Thread Starter 
Thanks JASP

This is exactly the kind of dialog I was aiming for.

Going out and playing! Yes done a lot of that.. As TheRusty mentioned this is bar room debate stuff. Learning and hearing others take on these terms helps me (and others I hope) get a better handle on what I think I understand. You probably know how that goes.. As soon as you think you got it, someone smarter than you, or playing devils advocate, challenges your observation and you have to rethink or defend your conclusion.
post #13 of 21
i would agree with jasp, in that, "foot squirt" (having done some reading, i am inclined to think of it as having an illusory quality...it may be a misnomer) is not going to produce excessive aft-ness on its own, unless other factors, either intentional or circumstantial are present(ed). same would hold true for properly performed retraction (in a sl course however, things "happen"--like unseen cross ruts;))

and certainly, one shouldnt experiment with reckless abandon, risking knees in the process.

zenny
post #14 of 21

 

There is no illusion about an aft stance while flexing through the transition, but during a floating (some would call this unweighted) phase the tail doesn't get hung up since there is not much pressure on the tails. The feet shuffle (squirt forward) and the stance is momentarily quite aft. Although by the time we extend to maintain contact with the snow and eventually create more pressure on the skis, our stance will return to a more centered place. It's a function of the femur moving into a mostly horizontal position and then returning to a more vertical position. It's also worth noting that a reaching turn with a retraction finish represents only one type of turn and all of this needs to be seen through that very specific filter. Change turn types and all of this stuff changes as well.

Bode is performing just this sort of retraction transition in this montage.

1000

 

Ted on the other hand is using more of a vaulting cross over move that doesn't feature the deep flexing of the legs through the transition.

liget-bc-2006-gs-2.jpg

post #15 of 21
i meant foot squirt as a concept is misleading...because the feet (outside) are always moving faster than the CoM (inside), so naturally, at the moment of transition (whichever type it may be), when the feet come from "behind" and pass the body, it can be (mis)interpreted that the skis were loaded on the tail (or heavy duty rebound was obtained from stored energy in the ski (vb), and jetted, or squirted, ahead...when this is not the case.

i mentioned those threads to raise this (and other points) for the OP, but im sure he is aware of these...

zenny
post #16 of 21

Bob can certainly offer clarification about why he coined the term "foot squirt" but I would offer the idea that it addresses the feeling of the feet passing the body and preceeding it throught the edge change / transition. Often in the ski teaching world we talk about movements through the lens of a result that is in reality not exactly what is occuring. For example; Knee angulation (it's actually medial rotation of the femur), Rolling the ankles (inversion / eversion of the foot), or even keeping the shoulders and chest facing downhill (overdone it requires the spine to rotate instead of the femurs to turn in the hip sockets) all are examples of this sort of terminology. They express an outcome and how it feels but taken too literally the terms are a bit inaccurate. What is most important is the accuracy of the demos and activities used to teach / learn the correct movements. Since most skiers are not anatomy and bio-mechanics experts that slight inaccuracy in terminology is common. I don't get too hung up on that stuff as long as the writer / teacher expresses the intent and shows an accurate demo / leads accurate practice. 

post #17 of 21
i get ya Jasp! thats what i enjoy about epic. incidentally, we were just discussing on the slopes the other day about rotational foot steerings relationship with the femurs rotation. interesting how things tie together anatomically...while at the same time being a possible source if confusion;)

i was under the impression that "foot squirt" wasnt bob's... i musta been wrong on that.

zenny
post #18 of 21

"Foot squirt" belongs to Epic (the person, not the site), not Bob Barnes.

post #19 of 21

Can you really own a term that's used by multiple people in multiple disciplines? My inline skate coach who's also a course conductor for CSIA has been working with "foot squirt" for a long time despite never meeting Epic. And then on the other side of the country (i.e. in Ontario) early this season I was told to eliminate my foot squirt. eek.gif So it's tough to say that any one person coined this wonderful phrase. Kudos to Epic for introducing it to the folks on epicski though!

post #20 of 21

Epic, where are you?

post #21 of 21
Gotcha! smile.gif

zenny
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