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# "NEW School" v "OLD School"??? - Page 4

Thanks MA.

I picked 45 degrees because I thought that in the manner I've always understood and explained balance it would make things easier. If balance exists with the CM on a 45 degree rise line from the ski base it means that magnitude of the horizontal force of momentum (centrifugal force) acting on our CM is equal to the magnitude of the vertical force of gravity. When such a state of equal vertical and horizontal forces exist, the resultant force vector acts on the CM at a 45 degree angle.

By making it 45 degrees I assumed all I'd have to do would be determine what radius turn at 30 mph would produce a centrifugal force equal to 32fps2.

Thanks for the formula for centripetal acceleration. That may be the formula I was missing for calculating the centrifugal force levels. I assume it works for the opposite side of the force picture relationship (centripetal/centrifugal) as both exist in a state of harmonic opposition.

I'm still sure something is wrong here. I wonder if reducing the Gravity component to 22 because of the pivoted tip may have something to do with it. Here's my thinking. The force of gravity always carries the pure potential of 32fps2. The resultant acceleration will only be diminished if a resistant force opposes it, in this case the ground. But,,, if we are in a state of balance there is no tipping/acceleration occurring, only the potential exists and acts on the CM. 32 pushing down from gravity, 32 pushing laterally from momentum, and we have a resultant state of force equilibrium in which the resultant force pushes directly into the snow under the ski, and the snow pushes directly back.

What do you think? Under that scenario we would have velocity2 (1936 fps)/r = 32 fps2. Result would be a 60.5 ft radius, a little under 20 meters.

Hmmmm,,, still seems off to me. That's like putting a FIS legal GS ski on a 1 degree edge angle and running the arc that it would produce with the CM inclined at 45 degrees. Man, talk about reverse angulation! Sompin aint right here. We need some professional help.

Oh, and I caught a small mistake. About your time to complete a 180 degree, 85 ft radius turn, at 30mph. Distance covered would be 85(pi) at 44 fps, so actually it would be around 6 seconds.

I'm sure everyone is just captivated by this conversation.
Good,,, glad you found a glitch.
OK, minor problem with ‘falling direction’ in my original calculation …

Lem'me try again... 30 mph is actually 158,400 feet per hour, or 44 f/s. I also assume our skier is perfectly inclined (stance/CM is straight up from the ski - no angulation) at 45-degrees from the specified Outside-Ski's Inside Edge, and is traversing flat terrain for the moment.

When an out-of-balance object is 'falling over' from such a pivot point as the "Outside-Ski's Inside Edge" its rate of acceleration (falling over) depends on the degree of tilt the CM is away from 'vertical' (WRT Gravity) over that pivot point.

[12/07/05 EDIT] - See post #123 for corrections to this post. It's not the horizontal-component that is needed as the paragraph below suggests, it's the horizontal-compensation that is needed. Most of the ideas and math here is basically correct but the 16.075 s/b 32.15 at 45-degrees.

The

correct result ends up exactly half of the Radius that the errant thinking below will find. Oh well, it was fun figuring it out anyway. Now back to our regularly scheduled posting... .ma [End of 12/07/05 EDIT] I earlier used 22.733 f/s² (in error) as my ‘rate of falling over’ when tipped to a 45-degree angle. This is true when measured in the direction of the fall (at 45-degrees) - but I should have been using 16.075 f/s² since I need only the horizontal component of the ‘falling rate’ (because the Centripetal Acceleration of our ski is -horizontal- to our flat terrain). All my skiing-related spreadsheets deal with acceleration along the slope itself. The only one to show the horizontal rate was … well, not looked at. Bummer.

So, moving on… our skier’s horizontal rate of fall-over is at 16.075 f/s² so we need a turn radius made at 30-mph that will deliver this rate. Nope, it wasn’t 85 feet.

The centripetal acceleration of a ski making a turn should be obtainable with V²/r or (Velocity²/radius).
Since we want it to equal 16.075 (the rate our skier is falling over) I’m thinking we need

(44 f/s)² / (unknown-radius in feet) = (16.075 f/s²)
(1936 f²/s²) / (unknown-radius in feet) = (16.075 f/s²)
(1936 f²/s²) = (16.075 f/s²) x (unknown-radius in feet)
(1936 f²/s²) / (16.075 f/s²) = (unknown-radius in feet)

(1936 f²/s²) / (16.075 f/s²) = (120.4355 feet) Bummer, even worse than I thought originally.

Anyway, our -ski- is being 'pushed' horizontally to the inside of our 120.4355-foot radius turn at the rate of 16.075 f/s² by Centripetal Acceleration (when at 30-mph). Since we’re leaning in at 45-degrees, our CM is also ‘falling’ to the inside of our turn at that same rate (at least horizontally).

So long as the push-to-the-inside by the ski is the same rate as we’re falling to the inside, we never quite 'fall' any lower - we’re in balance.

---
Yes, it's still possible I've blown it. Only PhysicsMan knows for sure... and maybe Ghost. (I'd like to get a confirmation on my thinking from someone in-the-know if possible)

Seems off to me also but consider this... the rate of 'falling over' that's important is not that of our -head- (where we mostly perceive such things), it's our -CM- that matters. Also, at 30mph a 120-foot radius turn wouldn't seem all that big. Remember, we're moving at 44 fps - that means we'd complete a full 180-degree skiing turn in 8.5 seconds. Also remember it's the CM at 45-degrees from the Outside-Ski's edge - the one we often reach way out there.

As to the ability of a modern ski to 'carve' an 120 foot radius turn... If you'll recall, I sidestepped any input on the ski's precise physical attributes. Still, I will suggest that a stiff ski with the appropriate sidecut should be able to do it if my math above is correct.

Anyway,

Thoughts? Gripes? Aspirin? ...say, what was this thread about again? Aw damn, lookit the time. Oh well, wouldn't have slept anyway knowing something was out of whack.

.ma

PS: just noticed - you must have caught my errant post. Knew I should'a checked that old spreadsheet first. Dang.
Quote:
 Originally Posted by Rick I'm sure everyone is just captivated by this conversation.
Hey, not much else can keep me up this late... oh, wait.... Everything does.

I also fixed the 'perception' issue before re-posting. I think we don't really notice it on the slope but our CM really isn't in our head. The CM is way down there where.. where the center of the human male's universe is anyway.

We detect the 'faster' rate of fall-over at our head and perceive were falling over much faster (overall) than we really are. Effectively, our head is moving twice as fast as our CM when falling to the side.

At a 45-degree toppling angle, the CM 'falls' over at 22.733 f/s² since there's no real friction to hinder it. But with our Inside-Foot helping to prop us up, the 'real' angle to our Average-Point-of-Pivot is actually less than 45-degrees. And we're all even sneakier than that. Figuring all this stuff out gets even harder when you consider the 'counterbalancing' weight that materializes in the form of our outside leg & gear when we partially pivot over the Inside-Ski... Ahhhh, the infinitesimal. Don't leave home without it.

.ma
Quote:
 Originally Posted by michaelA The centripetal acceleration of a ski making a turn should be obtainable with V²/r or (Velocity²/radius). Since we want it to equal 16.075 (the rate our skier is falling over) I’m thinking we need ... (44 f/s)² / (unknown-radius in feet) = (16.075 f/s²) | (1936 f²/s²) / (unknown-radius in feet) = (16.075 f/s²) | (1936 f²/s²) = (16.075 f/s²) x (unknown-radius in feet) | (1936 f²/s²) / (16.075 f/s²) = (unknown-radius in feet) | (1936 f²/s²) / (16.075 f/s²) = (120.4355 feet) Bummer, even worse than I thought originally. ... Anyway, our -ski- is being 'pushed' horizontally to the inside of our 120.4355-foot radius turn at the rate of 16.075 f/s² by Centripetal Acceleration (when at 30-mph). Since we’re leaning in at 45-degrees, our CM is also ‘falling’ to the inside of our turn at that same rate (at least horizontally). Dang.
OK, I'm up early today... and in no mood to grab out my space/time calculator to start on this... I did understand the last word though!

Also, it is becoming quite clear to me... that without a MIT doctorate of physics, it must be quite impossible to ski!!! Who the heck could figure this stuff out "on the fly" headed down the hill to make sure we don't go tipping over??? :

Tim
Dynastars. I told 'em to go with Atomics.
Isn't he still on Nordica?
That guy looks good even when he's crashing.
Going back to the original "issue" about the 50-50 weight distribution that timvwcom presented ...

If somebody already mentioned this, my apologies, I sped through many posts.

I prefer to look at this a little differently. I like to think in terms of 50-50 effort. In other words, the downhill leg may have more pressure and more weight distribution, but the effort to achieve that pressure is similar to the effort my uphill leg makes to carve and guide the turn.

At times that "effort" is mostly mental. Meaning that even if 80% of the weight is on the downhill leg, I focus just as much on the uphill leg to keep it clean and engaged. To me 50-50 skiing is not about pressure or weight distribution, but about the level of engagement from each leg/ski.
That's a good call. Helluvaskier and I were having a private converation about that (I am gonna get back to ya). A lot of times when trying to teach something, we teach what will get a result, but not necessarily what is going on. It seems to me that the 50/50 is an example of that. I am still working on that one.
timvwcom, the skier in your post above is clearly not concerned with centripetal force in that shot... he's probably much more interesed in ballistics at that moment.

Reviewing your initial post I found this...
Quote:
 Originally Posted by timvwcon This "new school" advice of "carving" with BOTH feet doesn't seem to match the physics I experience here on planet earth? People think they are carving with equal (or very nearly equal) weight on both feet? They look down on using a ski pole to help trigger a weight shift and turn? Any physical movement you make that would be "too quick" seems to be defined as "aggressive" and "bad technique"??? I'd argue the ski edges don't really care how you get them "locked in", carving is carving... your upper body could be flailing to and fro (not that we want it to be), but if those edges are set and arcing purely around their radius... it is "carving"!
Here, you seem to be decrying the 'physics' of new stuff. Reviewing what's physically happening using calculation seems a good way to overcome purely perceived experiences in figuring out what's really going on. Examining the actual turning forces based on one-footed edging vs. two-footed edging seems a good way to compare old-school and new-school weighting ideas.

While Rick's initial question might have been humor, it's a pretty good question in light of your early comment that, "...if those edges are set and arcing purely around their radius... it is "carving"" - delivered without enough context to decide if this was a reasonable statement or not.

How can the Inside-Ski Edge possibly be 'carving' if it has no weight on it? It takes a certain amount of weight to press it into the snow doesn't it? Centripetal force could bend it alone, but you'd still need enough weight on it to keep it engaged for that to happen. Or do you suggest in Old-School the inside ski is skidded instead?

Not trying to be Evil here, just pointing out there's more than one way to skin a ski... and once skinned, you can actually walk uphill with it.

.ma
Quote:
 Originally Posted by TomB Going back to the original "issue" about the 50-50 weight distribution that timvwcom presented ... If somebody already mentioned this, my apologies, I sped through many posts. I prefer to look at this a little differently. I like to think in terms of 50-50 effort. In other words, the downhill leg may have more pressure and more weight distribution, but the effort to achieve that pressure is similar to the effort my uphill leg makes to carve and guide the turn. At times that "effort" is mostly mental. Meaning that even if 80% of the weight is on the downhill leg, I focus just as much on the uphill leg to keep it clean and engaged. To me 50-50 skiing is not about pressure or weight distribution, but about the level of engagement from each leg/ski.
Absolutes and maintaining a percentage (whatever you determine that should be) is only an exercise. If you can demonstrate 50/50 it only means you are versatile enough to do an exercise. Is it an absolute ski everywhere this way task? Hardly.
Somewhere in another thread an interview with Bode was presented. In that article he was quoted as saying "I try not to use the same turn twice in a row." To put that comment in context, he was talking about a skidding maneuver he uses to set up for a specific gate placement. When he shared this with another teammate, that teammate promptly went out and did every turn in that day's race using that maneuver. He came in dead last and asked Bode what he did wrong.
The percentage of weight on a ski changes throughout a turn. Then it changes again during the next turn. How you adjust and how you resist the forces in play is the key. The only constant is that there are no constants. Adding one for a specific maneuver is just a means, a contrived isolation for an experiential learning segment.
Quote:
 Originally Posted by Rick Now Tim, here's another one for you. At a speed of 30 mph, and an edge angle of 45 degrees, at what sidecut radius threshold will a skier begin needing to employ reverse angulation to remain balanced on his outside ski? Have fun.
Edge angle of 45 degrees imples a=g: V^2/Rturn = 32 ft/s/s,
or working in metres, V^2/Rturn = a = g= 9.8 m/s/s
and Rturn=Rsidecut* sin(45).
A sidecut radius of about 26 m (or turn radius of about 18.4 m) ought to do it, given 30mph = 44ft/s = 13.4 m/s
Hi Michael... thanks for the comments, I've been busy for several days... My father has parkinsons and I needed to have him hospitalized again... obviously its times like this that remind us all of TWO things. There are things that are more important than talking about skiing (or maybe even skiing itself?)... BUT, we all have only so many days of our lives to try to get our turns in, so don't waste too many chances, either!!!

Quote:
 Originally Posted by michaelA Reviewing your initial post I found this... Here, you seem to be decrying the 'physics' of new stuff. Reviewing what's physically happening using calculation seems a good way to overcome purely perceived experiences in figuring out what's really going on. Examining the actual turning forces based on one-footed edging vs. two-footed edging seems a good way to compare old-school and new-school weighting ideas.
I think if you read my initial post fully, you'll see I was commenting more on the perception that I read often here that skiers think they are ACTUALLY putting equal 50/50 weight on their skis. My quote there was "People think they are carving with equal (or very nearly equal) weight on both feet?" I've seen several comments since then, here on this thread, that do admit saying "50/50" is probably only a way to try to teach "MORE" weight on the inside ski... and that those most knowledgeable admit it's NOT anywhere near 50/50 in reality even if you are trying to do that. That's a clarification I can believe in...

Quote:
 Originally Posted by michaelA How can the Inside-Ski Edge possibly be 'carving' if it has no weight on it? It takes a certain amount of weight to press it into the snow doesn't it? Centripetal force could bend it alone, but you'd still need enough weight on it to keep it engaged for that to happen. Or do you suggest in Old-School the inside ski is skidded instead?
Good point, I didn't precisely say what does happen with the inside ski... But one clarification first; your comment here above seems to imply I advocated ALWAYS putting ALL the weight on the outside ski? This is how I actually commented on it on that post "Why not TRY to shift as much weight as possible to the inside edge of the downhill ski on a turn? Basically all your body weight gets shifted there anyway, even if you claim to be weighting your skis equally, I think physics proves it's not." You can see the last sentence(s) tie in with the point earlier here.

I think we'd all admit that on a "tips straight down the hill" part of a run, weight is and should be equal 50/50 on both feet. I think the distribution of weight is progressive based on the tightness/agressiveness of the turn. A mild little slow turn one way or the other involves only a cooresponding "little" shift in weight. (Now I'm not arguing that at this point any real carving is always happening, but it could be IF your speed matches with the radius of the ski you are on; slower for a smaller turning radius-faster as the turning radius gets longer) As your turns get more and more agressive, which may also indicate a similar shaped turn but at higher speeds, I would argue the weight shift becomes greater and greater... but to really answer the specific question you had... I DO think the inside ski can/is carving, but just with lessening and lessening weight on it. And perhaps at some point in a hard turn when most of the weight is on the outside ski, may be "grounded", but is more "tracing" a similar arc to the downhill ski??? Does that help clarify at all??? Again, as I've said many times - and really do believe - "but who cares what I think!"

Tim

"Ski on dude!"
ps. I like the "ballistic" comment!
Tim & Michael,
While it is encouraging to see you trying to understand skiing from a mathematical point of view, I must tell you that you are missing the point. Skiing is not a left brain activity. So describing it with math is like finding an equation for crying. Shift your focus to your right brain and let feeling and bio-feedback be your guide. You will progress so much faster.
BTW I can maintain a 50/50 weight distribution on demand. So can dozens of other skiers I know. It really is not that difficult. So when you come up with an equation to prove something is impossible maybe you should investigate things a little further.
jasp... I agree with the "bio-feedback"! Maybe I'd call it "feel' though?

Quote:
 Originally Posted by justanotherskipro Tim & Michael, While it is encouraging to see you trying to understand skiing from a mathematical point of view, I must tell you that you are missing the point.
I blame "others" for MOST the math. And I WILL NOT say who... I may have "started it" though?

Quote:
 Originally Posted by justanotherskipro BTW I can maintain a 50/50 weight distribution on demand. So can dozens of other skiers I know. It really is not that difficult. So when you come up with an equation to prove something is impossible maybe you should investigate things a little further.
Interesting point since how can YOU even "prove" you have a 50/50 distribution? Because it "feels" like it is? Try the chair and scale thing... I'll cut and paste the basic parts of it again below here; curious how your answer compares to the others who did it without TRYING to put MOST their weight on bent leg???

--------------------------------
Get out your home scale and a simple kitchen type chair and pick a flat level surface (not carpet). First weigh yourself with both feet on the scale. Now place the scale on the floor next to the chair, put one foot on the scale, the other on the chair seat (about 10 to 12" higher than the top of the scale). Looking forward try and get an "even" stance, a stance that is comfortable (edit: one that "feels" balanced, but do it WITHOUT looking, that's cheating)... maybe hold it for 15 seconds (edit: maybe try a couple minutes to minimize any attempt to intentionally weight the bent leg, we are aiming for this to "feel" even), now check how much of your full weight is actually on the scale and on the longer leg. I tried it last night, and had 80/20 one way, and 83/17 when reversing the legs. I had my youngest son try it, he was 84/16. Again, even at rest without someone pushing me from the other side of the chair to try and simulate the turn "g's", I get 80%+ of my weight on the extended leg. I would argue our bodies are designed so we shift weight off the more bent leg. I'm not an ergonomic's expert though, maybe if one is reading they can help out? I guess the point here is that even if it "feels" like you are weighting your skis equally, that's not what's really happening...
--------------------------------

Thanks for the feedback and great conversation jasp!!!

Tim
Another nice demonstration not to be attempted if you've had knee surgery or have weak knees, shown to me years ago by my uncle. Stand on one foot and stick your other foot out in front of you. Now bend down while standing on one leg until your buttock(s?) is touching the heel of your supporting leg, and stand up. You are amazingly heavy. It seemed like a pretty good leg-press exercise until I learned that it's not good to weight your knee when it's bent more than 90 degrees.
Tim, The whole chair exercise is flawed for many reasons.
Taking half of your weight off of one foot in a static pose is not all that hard. Maintaining it is only a matter of strength and conditioning. The racers who use these high edge angles have the strength to do this quite easily. Don't you do one legged squats in you training regimine? We do them using a picnic table. The straight leg cannot even touch the ground. So only bearing half of your weight is just not that hard. It is just a static strength drill.
Secondly, skiing is a dynamic activity not a static one. Parking in one position (especially such a contrived one) should not happen. There are more forces involved and they keep changing as you move through a turn. None of this happens on the chair.
Finally, I would suggest you try your exercise using a stair and I bet it is easier and closer to the angles you create on skis. Yes world cupper get that inclined but not for long, the braking it would create is counter productive.
Jasp,
I think the point of the chair-scale exercise is to be surprised at how little of your wieght is actually on the chair when you think it is divided 50-50%. Yeah, most skiers can probably support their weight on a bent leg, but can they accurately judge 50%, and if they can't do it with a stable exercise, how accurate will they be on the hill?
Yes I know, but a static drill at such a large leg length discrepency is unrealistic. Especially with the qualification that you cannot conciously focus on shifting your weight to the bent leg. I concentrate on this all the time on skis. So does most of our staff, it is part of our required training. When you spend enough time doing this stuff you get a better feel for it. Try railroad track turns next time you go out skiing. If you can maintain it during these simple turns move on to medium radius carvers. When you can do so under the scrutiny of demo team level clinicians, move on to slalom turns. There are levels of coaches and clinicians who can tell you exactly what weight distribution you are using at any point in a turn. If Tim wants to doubt that level of expertise exist because of his kitchen chair exercise, I am here to say he is wrong. He lacks the qualifications to make such a statement.
Quote:
 Originally Posted by timvwcom I blame "others" for MOST the math. And I WILL NOT say who
Oh come on, spit it out. Who's was the it? Tell us and we'll get a rope! :

On the 50-50 thing. Of course you can distribute weight 50-50, or any other ratio for that matter. Can you know for sure to the percentage point? I doubt it. But you for sure can do 100 percent on either leg, and a multitude of variations in between, simply by moving the CM laterally. This is not a hard thing for skiers who've refined their balance skills.

Tim, what your chair exercise best demonstrates is the indisputable concept that the more flexed a leg becomes, the more physically taxing it becomes to support G forces on that leg. As edge angles increase, so does the flexion of the inside leg. This weakens the inside legs ability to bear load at a time when bigger edge angles are causing force magnitudes to increase. That makes for a bad combination. Your demo represents that high edge angle state.

Check out these images I've borrowed from Ron Lemaster's site. They're the best he had of current images for clearly illustrating lateral pressure distribution. I hope everyone can see the dominant outside ski pressure in these shots, it's very apparent (look at the amount of bend in each ski). These guys may not have studied physics, or done the math, but they know instinctively that trying to resist the mega forces acting on them predominantly with their bent inside leg just won't fly.

http://ronlemaster.com/images/latest-images/slides/maier.html

http://ronlemaster.com/images/2003-2004/slides/maier-pc-gs-2003-1-stance-width-A.html

http://ronlemaster.com/images/latest-images/slides/spencer-bc-2004-gs-1.html

http://ronlemaster.com/images/latest-images/slides/maier-bc-2004-gs-1.html

Tim, try your scale exercise standing on a phone book or two. This is a better representation of recreational skiing edge angles, and it's here, with lesser inside leg flexion and turn forces, that more dominant inside leg pressure becomes a more feasible option.
Just a couple quick comments... (like I'm ever brief? Sorry!)

Quote:
 Originally Posted by justanotherskipro Yes I know, but a static drill at such a large leg length discrepency is unrealistic. Especially with the qualification that you cannot conciously focus on shifting your weight to the bent leg.
Would you argue that with a larger force, say holding a 50 lb or 100 lb weight... that the discrepency would be smaller??? I'd argue it's more likely to be LARGER??? Also, of course this experiment is dependent on how tall the chair is, and since you stand on the scale, it too. I haven't measured that difference on my set up, but estimate it at 12" +/-. Since my comments here HAVE stated that I believe the weight shift is progressive: the largest differential is experienced in the most extreme/agressive turns... I don't think a foot +/- would be out of the range of normal for that type of turn?

Quote:
 Originally Posted by justanotherskipro There are levels of coaches and clinicians who can tell you exactly what weight distribution you are using at any point in a turn. If Tim wants to doubt that level of expertise exist because of his kitchen chair exercise, I am here to say he is wrong. He lacks the qualifications to make such a statement.
Hey, at least when I try and make my point... I use an exercise that any reader can re-create and verify for themselves. I don't and would never disparage anyone who believes they are able to "tell you exactly what weight distribution you are using at any point in a turn"... but I guess until I see someone "prove" it... say with a pressure pad inserted under each foot that can measure the "forces"... I'd say they were closer to guessing??? But hey, I don't have any pressure pads... so I'm guessing too!

And lastly, how do you know I'm not certified as an expert in "using normal household stuff to try and convince people" by the "Institute of Using Normal Household Stuff to Try and Convince People"??? Huh???

Like I've said earlier... I CAN claim EOIETTOSO (Every One Is Entitled To Their Own Stupid Opinon) applies expecially to ME! Thanks for the discussion.

Tim

I agree 100% with your comments. The "50-50" distribution is little more than an exercise and in normal skiing I am only vaguely aware of the level of engagement of the inside leg.

timvwcon,

The kitchen exercise is too radical to give you a good sense of the 50-50 distribution. Far better is to try to do some RR tracks on easy blue terrain and you will see how easy is to move 100% of the weight from the outside to the inside leg.
Or suddenly find that branch/rock in front of your downhill/outside ski in the spring slush.... amazing how much weight you can get on the other ski then!!
Tim it is not my intent to put you down for an opinion I disagree with, only to call you on the errors in the details you used to support that opinion. Psuedo-science verses real science. You will learn that here at Epic I am not alone in the belief that mis-information needs to be challenged. A tough room at times but hopefully the honest feedback will help you grow as a skier.
The pressure pad thing has been done and you can find the results in the archives of American Ski Coaches or just about any national team coaches periodical. It is pretty dry reading but if that stuff is what will help you understand this subject better, have fun. Frankly, the whole subject is not that complex. Just pay attention to how the skis are bowing under load to determine how much load each ski is under.
Here's something else to think about...
Like Rick said, since your bent leg cannot exploit the bones for weight bearing you use more muscle activity to support your body. Take this one step further, This difference in tension skews your perception of how much pressure you have on each foot. Basically because the Plantar Fascia is kept in tension by the calf muscles of the bent leg. The weight/force is not spread evenly across the bottom of that foot and the high pressure spots fool you.
Perhaps it's all the still pictures used to demonstrate and explain a split second in a turn. Static positions produce really bad skiing. Even movies cannot catch everything that is happening because it is a two dimensional media. First hand experience is the only way you can learn to ski.
I'll apologize AHEAD of time on this one, I'm afraid I might end up sounding like a "prick" with my responses??? NOT intended! I also hope readers can see I really believe what I've posted here... and have tried to keep it light and fun, adding some humor to get it from being too confrontational. Take this all in that spirit then... thanks!

Quote:
 Originally Posted by justanotherskipro Tim it is not my intent to put you down for an opinion I disagree with, only to call you on the errors in the details you used to support that opinion. Psuedo-science verses real science. You will learn that here at Epic I am not alone in the belief that mis-information needs to be challenged. A tough room at times but hopefully the honest feedback will help you grow as a skier.
To be honest... I'm thinking there may be no way to convert the "50/50 believers", science be dammed. The only hope I may have, how ever slim, is that the same types teaching this "new" 50/50 stuff, were teaching the feet stuck together fanny waiving of 20 or 25 years ago... maybe in another 20 or 25 years they'll move on again???

Quote:
 Originally Posted by justanotherskipro The pressure pad thing has been done and you can find the results in the archives of American Ski Coaches or just about any national team coaches periodical. It is pretty dry reading but if that stuff is what will help you understand this subject better, have fun.
Wow, sounds like great info... do you have a link or can you post some of the data??? I'd especially love to see data from the race teams!!! I don't know how much data from another teaching "exercise" would help me???

Quote:
 Originally Posted by justanotherskipro Frankly, the whole subject is not that complex. Just pay attention to how the skis are bowing under load to determine how much load each ski is under.
Good idea... let me see if I can do something on this one...

Quote:
 Originally Posted by justanotherskipro Here's something else to think about... Like Rick said, since your bent leg cannot exploit the bones for weight bearing you use more muscle activity to support your body. Take this one step further, This difference in tension skews your perception of how much pressure you have on each foot. Basically because the Plantar Fascia is kept in tension by the calf muscles of the bent leg. The weight/force is not spread evenly across the bottom of that foot and the high pressure spots fool you.
Boy, that "plantar fascia" must be REALLY tricky, since it not only fools my "perception", it also fools my scale???

Quote:
 Originally Posted by justanotherskipro Perhaps it's all the still pictures used to demonstrate and explain a split second in a turn. Static positions produce really bad skiing. Even movies cannot catch everything that is happening because it is a two dimensional media. First hand experience is the only way you can learn to ski.
I don't want to put words into your mouth, but I'd swear you just basically said... don't trust pictures and video... believe how you "feel"??? Is that what you meant???

Again, jasp... I know this will sound more "cocky" than I intend it... SORRY!

Tim

"That's what I think, but who cares what I think!"
"pseudo-science"... geez.

OK, back on track... I've grabbed some images that Rick was nice enough to link to, and added some comments here. It's late, maybe I slapped these together too quickly... but I think they make some of my points??? These stop-motion capture images are GREAT, thanks go out to Ron LeMaster... you is "the master"!!!

Tim

Tim,

Are you saying these montages represent the turn you described in the ski's crossing thread? I don't think they do. I don't see what you do (see questions/comments below) but I'm not qualified to do MA on these guys, so I'll leave that to the pro's.

Quote:
 Originally Posted by timvwcom "pseudo-science"... geez. OK, back on track... I've grabbed some images that Rick was nice enough to link to, and added some comments here. It's late, maybe I slapped these together too quickly... but I think they make some of my points??? These stop-motion capture images are GREAT, thanks go out to Ron LeMaster... you is "the master"!!! Tim
Did the skier above intentionally unweight? ...or are they "trying" to keep the skis on the snow?

Quote:
 Originally Posted by timvwcom
So you're saying that in the second to last frame, this skier conciously picks up the inside ski and pulls the tail towards the outside ski.

My take is that the skier came through transition light (yeah, likely off the ground) from the rebound out of the prior turn and is now guiding the inside tip down and into the turn.

Quote:
 Originally Posted by timvwcom
Tim,
I'm not sure what you do for a living but it is not teaching skiing. Good thing because you would starve. Most of the comments you added to the pictures are way off base. For example, look closer at #22's first photo. The outside ski is cambered from not being weighted, while the inside ski is bent. The transition clearly shows parallel tibias which means from the previous frame the new inside leg has tipped more than the new outside leg. Which is the point of the little toe drill, an active inside leg. While I know this continues through the next frame, at engagement (somewhere between picture 4 and picture 5) you cannot even see the legs or the skis, so drawing a conclusion from the pictures is difficult. (One of the problems with a two dimentional stop action medium.)
Inso far as the Aspen sequence, notice all of the red coated instructors watching it live. None of us who were there share your observations BTW. Tanya's inside ski is on the snow in picture one (the tail), the tip gets launched by a terrain variation but is back on the snow by the next frame. Notice that it is still the inside ski. By the next frame the edge change has happened and the tip of the new inside ski is on the snow. Additionally, it is tipped enough so that we can see the top of the ski, so she is doing a little toe move. Nowhere in this does she match her skis by pulling in the tail. The skis stay parallel from the second to last frame to the last frame. Also, she is very two footed even though the terrain makes that difficult. (look at the third and the last photos)
Again the limitations of stop action photos is that we cannot even see the edge change.

So while you seem to think you are using science to prove your point, the pictures prove you wrong again and again. Depth perception and missing part of the action are just some of the problems we encounter when we try to capture live three dimensional action on a two dimensional media. The same problem exist in your kitchen drill. Just because you lack the experience to know when you have acheived 50/50 and what it feel like, does not mean other lack that experience. Then armed with very little understanding of the subject, you choose to argue with experts in this field. That is not cocky Tim, it is foolish. Continuing to do so just makes you a bigger fool.
I've tried being kind but you just don't seem to respond to courtesy. You have a lot to learn but you refuse to see beyond your limited perceptions. Does that mean I think I am always right? Hardly, Like the old saying goes...
The more you know, the more you realize how much more there is to learn.
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