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Balance - Page 10

post #271 of 318
Actually, the latest numbers indicate that our return rate at Level I is 37.5%, which I believe is partly attributable to better record-keeping after the resorts learned that the beginner retention nationwide was around 15% in 1999-2000.

In my considered opinion, having done a fair bit of research, the proverbial hole in the bucket comes after the honeymoon period during the intermediate phase of development.

Not meaning to hijack the thread, just to correct this particular misperception. It's not the introduction, it's the middle period that offers too little reinforcement to keep the players in the casino.
post #272 of 318
Ok Ott, we're all in this together. Hell I didn't know the muscles either. But I knew that was more to this than I was getting elswhere, and all these gut feelings, isolated observations and intuitions needed clarifcation. I'm further down the road to the simple side of complexity than I was a couple of weeks ago. Thanks DM for helping me fit the pieces in the puzzle!
post #273 of 318
There are 2 separate formulas, one without the shaft of the boot and one with it. The idea (was?) to make it easy to understand that as the cuff resistance increased the muscle contribution to the equation would eventually reach zero. In other words either soleus can equal the external force or the external force of the cuff shaft can equal the external force or there will be a mixture of the 2. Hope this clarifies the issue. If anyone would like to put this issue into clearer terms please do. If it can't be easily understood there is not point in trying to communicate it.

I have no reason to enter into a prolonged battle with you. I would rather spend my time more productively. However I am getting very weary of hearing ski instructors say the equivalent of "I want to be a brain surgeon but I don't want to take the time to learn about the brain. I just want to cut".

And I am even more tired of hearing safety experts posture that knee injuries are the greatest mystery ever to face mankind. The current epidemic of knee injuries has been raging for over 20 years. Either the industry is incredibly stupid or they aren't looking very hard. Neither option bodes well for skiers. Guessing is not an option when it comes to assessing the impact of equipment. Yet this appears to be precisely what is going on.

The point here is that the human system is the most ingenious thing I have ever come to study. I believe that most people don't even begin to use realize a fraction of its potential. In my humble opinion this is a crying shame.

I agree that the Atomic boot has too much forward lean.

You are hopefully right re the stats. I got the 1-1.5 skier retention from Intrawest people a few years back. Interestly enough when the big boys started buying up the ski hills they started studying where the skiers were coming from and who was leaving. You may be more current than I but there are figures in my head about it costing way more money to bring in a new skier than retain an established. Neither was pocket change.

I will add a few more issues re: foward lean and flex when I get a bit of time. Please let me know if anything I say can not be understood. I have to presume if your interested in the subject you will have a bit of knowledge in anatomy. [img]smile.gif[/img]
post #274 of 318
Originally posted by Ric B:
Ok Ott, we're all in this together. Hell I didn't know the muscles either. But I knew that was more to this than I was getting elswhere, and all these gut feelings, isolated observations and intuitions needed clarifcation. I'm further down the road to the simple side of complexity than I was a couple of weeks ago. Thanks DM for helping me fit the pieces in the puzzle!
OK - just a quick suggestion - if some of the main players here didn't know the anatomy stuff then it isn't just my blind spot...

Can someone post a quick lower leg anatomy picture as a guide for the rest of us?

post #275 of 318
Hi dsski. I have loads of great drawings but so far as I know I can not import them into this forum.

Can someone please enlighten me here? LM seems to know how to access the drawings on the forum file. I don't know where to find them.

I agree that pictures at the right time are worth 1000 words. is there anything else I can do to make it easier for you dsski? I appreciate your input to date. [img]smile.gif[/img]
post #276 of 318
The cost difference between recruitment and maintenance is huge, David. That's what puzzles me about it. The economic argument is too compelling to ignore.

As far as the stats go, there is some dissent on the 37.5% figure, but I believe there is significant skew in the numbers because now we are more focused on counting. The Kottke Report divvies lessons into Level 1 and Level 2+, and approximately 33% of lessons are Level 1 to 67% Level 2+. Why don't they break down the Level 2+ lessons by level?

I think you know the answer.
post #277 of 318

Scroll down, there are a few charts of the lower leg. Even though I do not see any copyright info, we better cover our a$$es and just put up the link. Besides, there are way too many pictures. A suggestion: If you want to refer to a specific picture, copy and paste the url of that picture. That way we will be scrolling less.

Apropos to what nolo said about losing the intermediates from "the casino', once again, we may be coming full circle back to balance.
In levels 1-3 there can be some skills that can possibly be faked. Once you get into carving or more challenging terrain, any of the unresolved issues, either in your body or in your equipment, will cause you to either stagnate or get injured. The more an instructor understands about what a given student's roadbacks to progressing are, the more valuable they will be as a teacher.
Refer back to Nettie's thread "Treating root Causes instead of symptoms".
post #278 of 318
Thanks LM - I was pretty sure you'd know where to find it...

We just were not taught gross anatomy. I could draw a single nerve cell structure better than name parts of the body. (I do know most major bits - but through dealing with patients & nurses& doctors - not from learning)

The only GROSS anatomy I was good at - CANE TOADs - we used to chop out their spinal cords & nerves to gastrocnemius to do drug tests on muscle contraction....

[ November 24, 2002, 05:11 PM: Message edited by: disski ]
post #279 of 318
>>>However I am getting very weary of hearing ski instructors say the equivalent of "I want to be a brain surgeon but I don't want to take the time to learn about the brain. I just want to cut".<<<

What is the equivalent of that quote? " I want to be a ski instructor but I don't want to take the time to learn about skiing, I just want to instruct".

You really have heard many instructors say that?

That is very condescending, and very lame.

post #280 of 318
Ott - I think it would be closer to

I don't want to learn to teach - I just want to ski
post #281 of 318
disski, I don't know any ski instructors, either PSIA or CSIA who didn't get training in teaching methodology, much less get hired.

The implication was that INSTRUCTORS he talked to weren't interested to learn the craft they were instructing.

I think I'll go and have another manhatten to calm me down. [img]smile.gif[/img]

post #282 of 318
I'd like to continue with the discussion about forward lean and flex. I am learning a great deal from this, but I completely understand that others may not be. Learning in public makes us vulnerable to criticism (referring to the comments about how instructors might be perceived or perceive themselves) but that is why we are here at this site, because of the opportunity to learn. The size of the opportunity is proportional to the quality of the information given and the willingness of the participants to put some skin in the game.

Just a thought.
post #283 of 318
Given the size of this thread, should someone start a branch off thread on the topic of lean and flex. Makes no difference to me since I have been pretty much following all along, but in case someone comes in new and does not feel like weaving through over 200 posts...
post #284 of 318
Originally posted by Ott Gangl:
disski, I don't know any ski instructors, either PSIA or CSIA who didn't get training in teaching methodology, much less get hired.

The implication was that INSTRUCTORS he talked to weren't interested to learn the craft they were instructing.

I think I'll go and have another manhatten to calm me down. [img]smile.gif[/img]

Ott - I know of a bunch of Oz kids who have had NO training in ski instructing at all & are all headed to the states this season to teach skiing. The sole criteria - they are full time students & UNTRAINED - so they can get a J1(I think it is) visa.

Of these ONE wants to TEACH skiing(she shadowed an instructor I knew as part of her uni training this season here -she REALLY wants to TEACH skiing)

The rest are doing it to get a CHEAP skiing trip overseas
post #285 of 318
Ok - a suggestion

Can someone summarise the ankle/boot stuff out of this & start a new thread.
This one has grown tooo huge it seems for wading through...

Tried to get instructor to have a look - but there was too much junk to wade through....

His comment - at a quick look was that he thought there was a technique to flexing a boot - which hadn't been mentioned... Nolo? RicB?
post #286 of 318
If someone wants to start a new thread it is fine with me. So long as we keep the perspective that all the segments relate to balance.

More boot flex/forward lean issues

There is one more interesting effect related to boot flex. When COG is supported on the base of support at your feet the weight is carried under the heel and the balls of the feet (COP is the center of the pressure or weight). In terms of balance the base of support under your feet is what your balance system uses to help determine which way is up.

As explained in my last post when the soleus is relaxed and the shin begins to bend the cuff the pressure under the forefoot decreases until it is only under the heel bone. As this happens the plane of reference for the balance system switches from being the plane defined by the heel and the balls of the feet to a plane defined by the heel and the center of pressure (force) of the shin on the cuff. (You connect the 2 points with a line to find the plane of reference). To the balance system it is as if the ground suddenly tilted up from level to 45 degrees.

If you have too much forward lean in your boots and you hit a bump or mogul and your shin suddenly loads the cuff will this panic the balance system? Of course. Will you pitch forward wildly at the waist in response? Probably. Any females out there with moderate to large calves? Do you have too much forward lean in your boots? Odds are that you do. Did you recognize the sensation I just described. Yes? OK, it wasn’t you. It was your boots.

So, why do ski boots have the forward lean angle they do? The first reason is because they have to look good. And boots don’t look nearly as good if the cuffs are straighter. The second reason is that someone has decided that you need this lean angle to put pressure on the front of the ski. So, we have that, what do they call it…….., oh yes that “aggressive forward lean”. We’ve already sunk that theory.

What determines individual forward lean requirements? First and foremost is the critical angle at which your ankle joint switches to isometric contraction. This angle should be shaft angle or lean of the boot where your calf rests against the rear cuff. You need some free space to flex forward from here. We will get into this later.

What determines the lean angle of the shaft of the boot? Manufacturing considerations. Remember that the boot maker has to have an economical way to make a boot. No matter what angle he choses the boot maker has to fix the cuff to the lower shell so the two components act as one. At this point the boot is a bent plastic tube with a seam up the middle starting at the toe so you can bend the flaps open to get in.

But, doesn’t that big rivet on the side of the cuff allow it to hinge? I think not. The resulting plastic structure would not be stable enough. Here’s a bit of trivia. The stiffest plastic you can make a boot out of that won’t break like glass in the cold is about 1/20th as stiff as steel. Plastic boots generally rely on wrapping tightly around your foot for their stability.

There has been some inference in posts by others that I believe boots should be soft. I never said that. Did I say that? No. If a boot is set up right I believe they need to be very stiff on the sides of the leg but not to apply leverage to the ski edge. This is one of those external force on the wrong side of the balance equation issues. The shaft of the boot has to be stiff to provide a stable vertical reference to help you align internal forces through your foot. It is like training wheels for your balance system.

The process by which the boot maker establishes and fixes forward lean is at best arbitrary. It can be all over the map from one boot to another.

The big problem for the skier is that the forward lean of the boot is decided behind your leg where the calf muscle is. The forward lean angle you require for skiing is determined by the angle your shin is at when the soleus switches from eccentric to isometric contraction – i.e. the critical angle. However the ski boot typically over rules your body because the rear cuff will push your shin forward based on what? Based on the size of your calf muscle where the boot cuff wraps around it.

What does this all mean? Well if you have a large calf muscle you are in big trouble. If standing up for more than 5 minutes is exhausting do you think there is any hope you can ski? Not likely. Even if you have a small calf you may still be in trouble if you have small feet. Why? Because although boot makers allow for some variation as they shrink shell sizes down they still use the same forward lean angle on the cuff. Why? Looks, looks. The boot has to look good. Looks aside the other reason is “because that’s what we do”. In other words, “don’t ask us”.

Is forward lean easy to change. Sometimes. More often than not it can be a nightmare. The reason for this is that the molded interfaces can make it very difficult to put the cuff at an angle that is much different than the boot maker designed it to be at. In many instances I have not been able to straighten the shaft enough. A brand new pair of boots I bought for my wife 2 years ago went into the garbage because I could not make them upright enough for her calf.

One more issue. Assuming you can successfully align the cuff the next nightmare is the liner. Remember, it was formed to the shape of the shell the way it came from the factory. Am I saying forward lean can be a tough problem to correct. Absolutely.

This pretty much wraps up the boot flex issue. Please post any questions you have on this issue before I move on. Thanks
post #287 of 318
Ok david

I am slowly copying all the boot & ankle bits into a new thread

What about my instructors comment that flexing a ski boot requires technique to achieve on snow boot flex???
post #288 of 318
G' day disski. Good on you for starting a new thread.

So far as your ski instructor bloke first thing is to get your stance right. This is coming soon.

Then make sure there is what I call some 'free play' in front of the shin within the boot shaft before the shin starts to press into the tongue in flexion. In skiing you have to keep your ankle resistive. By that I mean you retain the feeling you get just as your calf draws tight when COG passes over your ankle joint. In skiing the ankle should flex very little.

There is an article called 'Get Wired' in November 2002 Skiing that features Joanne Younker doing pressure analysis on a writer, Susan Schiener. JO focussed on getting Susan to keep her ankle resistive. The before and after photos show the dramatic results.

One thing to keep in mind with forward lean. It depends on the calf size of the person. The critical angle of the ankle joint in dorsiflexion does not appear to be much different from person to person. Boot shafts often have to be made almost vertical as seen at the rear cuff for some whereas in others one has to put the modified boot next to an unmodified one to see the difference. You should not base your requirements on what works for some one else. I always look at each case individually.

Nolo has found a way for me to put up drawings. I will try and do this soon.
post #289 of 318
David - back to my earlier qusetion - do you happen to know Roger Systad

And another - are you the distinguished looking gentleman that helped me out with some shimming stuff last March down at Creekside?
post #290 of 318
ok - job done - all the ankle & boot stuff re balance is now

post #291 of 318
disski. amazing, how did you get the patience to do that! If you are just starting this thread now, and want to get through the gist of it without having to go through all the editorials as to whether this is a "valid' thread or not, check out disski's summation.

Question, just so we can keep everything cohesive and comprehensible, do you want me to start a specific thread as to how postural alignmenet and postural distortion effects balance? I usually put that sort of stuff in fitness, but very few peoeple read it!
If there is an interest, I will do it. Would be fun to do, since I'll be doing a bit of this at the Academy.
post #292 of 318
LM, I would be very interested in this topic.

Fifth attempt to post this this morning.

Disski, It's not that I knew nothing, but my knowledge was basic, and I didn't know the names of the lower leg muscles off the top of my head starting this thread. Truth is, I was more familiar with the foot and the leg from the knee up to and including the hips. The connection between these two area was something I felt, but couldn't put a technical face on it. I didn't know enough to connect the dots. And really, in the big picture you could say I really didn't know much. I felt and intuitively knew, but the science behind it was somewhere I hadn't gone, but certainly wanted and needed to. Our istructor training certainly doesn't take in this direction, and if we do go in this direction, it's doesn't seem to be recognized as valuable by those who do the recognizing. : So be it. For me, I will continue, because that's how I'm made.

DM, did you as a result of your experimental testing come up with a way to determine that point the soleus goes into eccentric contraction, or that angle of the ankle for an individual? How do we figure this?

I have thought of balancing off the boot before, but never thought of it as changing the plain of the reference for balance.

I was curious how you would get to the soft boot thing, because as you said way back, you didn't like soft boots, yet this info seems to point to soft in some areas, or maybe as I said, movement with contact. That Lateral stiffness should channel or direct the force to our feet and hence the edges, works for me. You do say you need room in front of the shin for some unobstructed movement of the shin for ankle dorsiflexion. I'm reading that this amount of space for movement should corespond to the amount the ankle needs to dosiflex to put the soleus into eccentric contraction and the foot to find full connection to establish a base of support as the foot goes into plantarflexion and thus establish our balance in a natural way. How can this be achieved and still keep that lateral contact that is so nessasary for directing our force to the feet at the same time? I gonna assume there will be a compromise somewhere. Did your experiments show where this compromise would have the least impact?

As an aside, the bulk of my calf is out of the boot. Yet I've always felt that every boot I've owned in some ways inhibited fully getting the leg close to straight and still stay centered over a flat foot. One can force the issue but you soon find yourself rising up on your toes, lifting the heel, which changes the plain of your balance to the ball of the foot to the top of the back of the boot, totaly opposite from flexed position and just as unproductive for our balance I would think. My best skiing always happens when I'm flat footed, rooted in my boot to the snow, making that connection, reading the forces and responding naturaly to them. I can feel this. But it doesn't always happen. Truly understanding why is key to makng any changes in a persons skiing. More please [img]graemlins/thumbsup.gif[/img]
post #293 of 318

I would rather see THIS thread in the Health and fitness heading.

The additions from your field of expertise should be found there as well.

I will go there to read them. I promise!

post #294 of 318
Will answer your questions later. Meantime I have jumped to the other thread re my experiments. I will repond to your questions there.
post #295 of 318

Very informative, a little condesending at times but what's one more big ego among friends.

Here is a question for you. I ski with a four centimeter+ tall heel lift in my boot (its a big wooden wedge). How does this affect what you are talking about?

post #296 of 318

My friend Horst Abraham has said (profoundly): the teacher's job is to eliminate the barriers to learning. This suggests that first the teacher has to recognize a barrier when s/he sees it. Only then can s/he work to eliminate it.

This insight affirms for me that this thread does indeed belong in the technique and instruction forum.
post #297 of 318
What I find interesting about this thread is that it could have been in a few sections of the forum, instruction, fitness, gear or general. David is the first person I have ever spoken to involved in the boot world that acknowledges the fact that alignment and core activation are also necessary as well as instructional tecnhiques that reinforce balance.

Its all about an integrated approach. This, BTW is one of the major philosophies of the Epicski Academy!
post #298 of 318
Originally posted by Lisamarie:
disski. amazing, how did you get the patience to do that! .
As I've pointed out before - I am VERY stubborn....

Just a quick note - my instructors comment re the BALANCE part - "of course balance can be taught - JUST LOOK AT YOU"...

anyone who has seen my skiing change over the last 6 years KNOWS balance can be taught
post #299 of 318
ooops [img]redface.gif[/img]

[ November 25, 2002, 12:13 AM: Message edited by: disski ]
post #300 of 318
Page 8 arrrgggghhh....
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