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Those turns...illustrated

post #1 of 141
Thread Starter 

Hi all--

Here are 3 illustrations that I'm working on for the upcoming (eventually) 4th Edition of my book, relevant to several of the current threads. I submit them for discussion and feedback....

They show the "perfect turn" that we've discussed represented at three typical levels of skier development. If you look closely, you will see that the fundamentals are identical for all three. The only differences are due to speed, steepness of the hill, and as a result, intensity and range of movements and forces involved. The movements are less dramatic at the lower levels for two reasons--the reduced forces and speeds don't require as much motion, and the skills and movements of the skier at that level are, naturally, less advanced.

(MODERATOR NOTE 12/31/2008: The following diagrams are new and updated. They may not exactly relate to the discussions that follow in the thread.)

There is a lot to see here--look closely! A few things to note, in all three illustrations:

1. The skis (and legs) rotate in the hip sockets beneath the pelvis, analogous to the steering of a car's wheels beneath the chassis. As a result, there is a subtle lead of the inside ski tip throughout the turn, passing through square or "neutral" in the transitions (frames 4, 12, and 20). The rest of the body parallels that inside tip lead--a line across the hands or shoulders would be parallel to the line across the tips. There is no rotation or counter-rotation of the upper body, and there is no blocking pole plant.

2. The skier steers the INSIDE ski tip INTO the turn, throughout the turn. While there is some skidding, especially noticeable in the lower Wedge and Basic Parallel levels, there is no PUSHING of the tails--no INTENTIONAL skidding. The skidding happens because the turns are tighter than the skis could turn purely by bending into an arc and carving, especially again at the lower levels, where neither the skills nor the forces involved are sufficient to tip and bend a ski into a tight, pure-carved arc. With greater forces and edge angles, the Dynamic Parallel turns show more carving, less skidding--because they can!

3. Both skis tip smoothly into the turn, progressively, from the start to the point of maximum edging (approximately frame 17). Then the edge angles begin to roll smoothly the other way, first reducing the angles to end the one turn, then RELEASING in the transition (frames 4, 12, and 20), and continuing to roll smoothly into the next turn. (Note that the ski does not need to be completely flat on the snow to release. It releases the moment its angle becomes less than the "critical" edge angle that we have discussed. Therefore, even the wedge turns, where the skis never become completely flat, initiate with an edge release.)

4. The skier's body (center of mass, indicated by the red dotted line) flows smoothly throughout the sequence, taking a shorter path than the skis, with the "crossover" in the transitions (frames 4, 12, and 20). The solid blue line indicates the path of the "balance point" or "center of pressure," the point on the snow where the skier's balance is focused regardless of stance width or ski length.

5. Related to #4, there is no active movement TOWARD the new outside ski (uphill) to create a weight transfer at the turn initiation. There is a weight transfer, though, as there is in a car, resulting from the forces of the turn (gravity and centrifugal force) pulling the skier progressively toward the outside ski as the turn develops. With the higher speeds (and of course, more accurate, skillful movements), the Dynamic Parallel turns show a complete weight transfer from quite early in the turn. The weight transfer is less complete in the lower speed turns, and develops more gradually. Regardless, all the turns flow through a moment of "neutral" where the pressure is equal on both skis. While I've illustrated this point in the transition frames (4, 12, and 20), in reality it often occurs later, especially at lower speeds, or on steeper slopes. Indeed, the timing and completeness of the weight transfer is hugely variable, at all levels. The weight transfers I've illustrated are typical, but not obligatory! Remember that, in these turns, weight transfer is an outcome of specific appropriate movements affected by many other variables. It is not a requirement, or an end in itself.

6. In short, these illustrations clearly show the "positive movements" that we've discussed--the signature of the "perfect turn"--as they appear at various skill levels with typical speeds, turn shapes, and condtions. They represent typical turns, not dogma! The movements, and their outcomes, will vary according to changing conditions, speeds, needs, intents, and whims of the skiers.

Have fun with these! I'd love to hear any comments or suggestions on how I could improve them.

Best regards,
Bob Barnes

PS--the skiers in these illustrations include Hermann Maier, Regine Cavagnoud, Jerry Berg, Gates Lloyd, Stephanie Sugars, Jennifer Metz, and myself.


[EDIT 3/4/2012--frame numbers in descriptions have been updated to correlate to the new illustrations added in 2008. In particular, "turn neutral" is represented now in frames 4, 12, and 20, not frames 5 and 18 as in the previous illustrations. --Bob]

post #2 of 141
May I offer my services as an independent literary critic to proof read your 4th edition. I won't charge you for this service.

post #3 of 141
Hey Bob,

Outstanding and obviously very detailed work. I really like it.

Are the basic parallel turns showing a bit more angle development than would really show in that level turn? They seem to be fringing into the dynamic realm.

Just a question, are you planning any illustrations on independant leg steering such as using our turntables or "barstools" to really lock in the concept? I think it's pretty obvious to a "trained" eye in the pictures but perhaps others may need a bit of help.

Back to my "goof" game; that's how I'm playing right now. But the boss is working with me tomorrow so maybe we can get back on track. :
post #4 of 141

Great work. Look forward to the book.

post #5 of 141
These are going to really jazz up the book, not to mention the conversations on EpicSki.com.

I agree with Snow&Golf, the basic parallel photos look pretty advanced to me and don't match up with the drawings. In the drawings, it appears that the outside ski in both wedge and basic parallel sequences is in are identical relationship to the blue line. I would have expected to see less skidding of the outside ski in a basic parallel turn than in a gliding wedge turn.

Question: Wedge christy is gone for good?

[ June 28, 2002, 07:00 PM: Message edited by: nolo ]
post #6 of 141
Awesome explanation and photo montaige Bob!! I can't wait to use it in clinics and take all the bows.

Check your email or give me a call.
post #7 of 141
Wow, your illustrations are chock full of info. Love the birds-eye-view. Very nice job.

1. It took me a minute to figure out what you were trying to convey with the "path of center of mass" line and the "path of balance point" line. Perhaps "base of the neck" or, more simple but less accurate, "head" could replace "path of center of mass." Similarly, "hips" may be able to replace "path of balance point."

2. Tiny legs or ski boots drawn on the skis in the "angle to the slope" illustrations would clarify the orientation. Just in the first snapshot of the sequence.

[ June 28, 2002, 04:52 PM: Message edited by: WhosThatGirl ]
post #8 of 141
Well, since you asked...

I think its pretty cool and informative, but I think its upside down. To me it would make more sense for the diagram to read from the top of the page to the bottom since that is the way the skier is going, and also the way that we normally read. Also, the skis at the bottom took a little extra to understand. At first it looked like it might represent lower legs and not skis. Maybe you could draw some litle ski boots on them to make that more clear.

Content-wise, I think Im a little under-qualified to comment (but I will anyway). On the racer isnt the transition (18) a little late? Or is that where a modern racer would go over. We are trying to show a so-called perfect turn here. Of course, who knows where the gate is? He might be right on time... Also, are the edging angles and weighting really that extreme? The skis are tipped almost 90 deg. to the slope and the skier has 100% of the weight on one ski.

Anyway, I think your sequences are trés cool. Also, I realize that this is just one page of a whole book, so some poetic license may be used to make your point.

BTW: Is this a revision of an existing book, or a whole new one.
post #9 of 141
Thread Starter 
Thanks for the comments, everyone. I will play with your ideas some more, although I have actually tried several of the suggestions en route to creating the illustrations that I posted. Here's my thinking on why these seemed to be the best version, so far.

Yes, the "Basic Parallel turn" illustration shows a fairly dynamic turn, not necessarily a first-day entry-level turn. But it is clearly far LESS dynamic than the "Dynamic Parallel" sequence, and somewhat more dynamic than the "Wedge Turn" sequence. Indeed, ALL the illustrations show perhaps slightly exaggerated angles.

I found it had to be this way for clarity. When I tried "actual" angles, you had to use a microscope to see the progressiveness, or even the movements at all, especially at the lower levels. Remember that the slope upon which entry level turns actually happen is VERY flat--maybe 4-5 degrees. Distributed through the frames of the drawing, that would mean a change of 1/2 degree or so from frame to frame--not even visible! So, like a relief map of the world, I had to exaggerate a little to show the movements. That is why I used the word "relative" on the drawings, but your comments show that it needs further explanation.

On the other hand, the angles shown are not far, if at all, beyond the realm of what really does happen in skiing. Those "nearly 90 degree" edge angles of the racer (Hermann Maier) actually do happen--check out some of Ron's pictures at ronlemaster.com, including the one of Maier that welcomes you to his home page. "Basic Parallel" encompasses a pretty wide range of skill levels and speeds, too, and I don't think the turns I illustrated are outside that range.

Nolo--I don't see a need for, or observe a reality of, more skidding in a wedge turn than in a basic parallel turn, necessarily. That outside ski can run the gamut from pure-carving to pure sideways braking, regardless of what the inside ski does, can it not? In fact, in the "wedge christie" (begins with a wedge, ends parallel), don't you find most instructors skidding MORE in the parallel phase, after they match? (Not that they should....) A point I've wanted to make strongly here is that none of these turns has ANY intentional skidding. While edge angles of wedge turns MAY be less than those of parallel turns, so usually are the speeds and pitch that produce the forces that those edges must resist. In either case, the skis are steered and tipped just enough to create the desired turn shape. No more, and no less!

Perhaps this last point is the jist of the "wedge vs. parallel" battle. While many instructors STILL teach wedge turns by steering only the OUTSIDE ski, pushing it into a skid, these are exactly the "dead end movements" that more enlightened instructors rightly criticize. This is where Harald Harb and I are in complete agreement.

A couple of you have suggested little legs or boots on the ski angle indicators, so I'll play with that some more. What I've found, though, is that anything additional on this diagram clutters and confuses it even more. I've tried a lot of different things to illustrate this relationship of the changing ski angle to the changing slope angle, and not been entirely satisfied with any of them. I'll keep working on it.

Like I said, these diagrams do not lend themselves to just a casual glance--there's far too much information. Unfortunately, at the small size of the posted illustrations, it is hard to see the varying shades of gray of the skis that indicates the relative amounts of pressure on them, too.

WTG--your suggestions for lines indicating the path of the head and the path of the hips, to replace the lines shown, would be easier to draw. But they would not represent the very important relationship that "path of the cm" and "path of the balance point" indicate. The center of mass, unlike the head, shoulders, or hips, is NOT part of the body. Its location varies with changing body position. What I've tried to illustrate from the "bird's eye view" is a point that is between the head and the feet, although closer (laterally) to the head, near the hips. This is roughly accurate, and actual turns and real skiers have enough variation to make much nit-picking here irrelevant.

In any case, the relationship between the balance point--the point upon which you are balanced--and the center of mass--somewhere near the hips but variable--is the critical relationship. It is what indicates the degree of "inclination" of the skier--the angle he/she leans in for balance. The line connecting these two points at any given moment is the "line of action"--the line that indicates the direction of the total forces acting on the skier. The distance between the two lines in the drawing indicates the intensity of the turn--how "dynamic" it is. Note that the lines are farthest apart in the "dynamic parallel" sequence and closest together in the "wedge turn" sequence.

If the skier is balanced on one foot, the "balance point" will be directly under that ski--see the "dynamic parallel" sequence frames 8-16. If the skier has some weight on each foot, the balance point will be somewhere between the skis, as all the diagrams clearly indicate (but you have to look closely!).

Epic--You are not the first to suggest inverting the diagrams. (Yes, this book is a revision of THE COMPLETE ENCYCLOPEDIA OF SKIING, 3rd EDITION, which is now out of print. These illustrations are refinements of similar illustrations from the previous edition.) I've tried the diagrams oriented both ways. They both have their uses. If you print them out and turn the print "upside down" the way you suggest, you will see different things! But oriented as they are, it is easier to visualize making the turns yourself. The skier is moving forward, the direction you (presumably) usually ski, and if you practice, you can "enter" the illustration and "be" the skier! At least, that's the plan....

Thanks again, everyone. I really appreciate the comments and suggestions, and will consider them all and continue to tinker. Meanwhile, keep looking and playing with ideas. If analyzing these diagrams helps create a deeper understanding of skiing, well, that's what they're there for!

Best regards,
Bob Barnes

[ June 28, 2002, 11:32 PM: Message edited by: Bob Barnes/Colorado ]
post #10 of 141
Thread Starter 

Oh--one more thing, Nolo--no, I do not mean to imply that the "Wedge Christie" is dead! In the typical skier development, there is still a "wedge christie" phase where turns begin with a slight wedge and finish parallel, as a result of the exact same movement patterns illustrated in these three diagrams. But a), I haven't updated the wedge christie illustration yet, and b), I'm not sure that giving it full status as a "milepost" of skill development doesn't just confuse the issue somewhat. Again, the important issue is not the "wedgeness vs. parallelness" of the skis, but the fundamental movements that take place regardless of the stance.

Nevertheless, here is the old Wedge Christie illustration from the 3rd Edition, for comparison:

Best regards,
Bob Barnes


[Edit 3/4/2012--Well, the original Wedge Christie illustration was hosted on a now-defunct site, so it's gone. But I did insert the updated Wedge Christie illustration into the first post with the others in 2008.]

post #11 of 141
Hmm. The other photos match up with the diagrams, but while the basic parallel diagram matches my understanding, the photos look like Level III dynamic parallel turns.

(Scratch my comments about the outside ski--I wasn't looking closely enough at the inside ski. Note to self: need glasses.)

It's an outstanding way to present a great deal of information. This alone is worth the price of the book. Bravo!

(Are you going to take Fox up on his offer? I would recommend it!)
post #12 of 141
Thread Starter 
You are right, Nolo--there is a bit of a discrepancy between the illustration and the photographs of the "Basic Parallel" skiers, especially the sequence of me (bottom, in the orange and black). I will try to find an example of slightly more subdued skiing.

That's the problem with summer! I wish I could just go out with a camera and shoot exactly what I need, but I've got to work with what I already have. Still, I know I have some appropriate footage in the many hours of video I've accumulated. It's a question of finding it, then creating the photo sequence (very time consuming!).

Thanks again!

Best regards,
Bob Barnes

[ June 29, 2002, 02:50 PM: Message edited by: Bob Barnes/Colorado ]
post #13 of 141
Thread Starter 
And WTFH--YES! Thanks for the offer. As the rewrite progresses, I'll get in touch with you. Do you think you could edit in a bit of a brogue? Ski instructors with foreign accents do so much better here in the US....

Best regards,
Bob Barnes
post #14 of 141
Thanks Bob - hope you don't mind me printing it out [img]smile.gif[/img] Please tell us when the book is finished - I would like a copy
post #15 of 141
While I know full well the advantages of my accent in a foreign land , I need to point out that I'm not an instructor. I would be reading the book as a layman, and a vox pop for the target audience.

post #16 of 141

Glad to see you've got time to work on your book this summer. I really like the addition of the photos to the great illustrations. The photo of you doing basic parallel is way cool, even though everyone thinks it's too dynamic at this level.

One comment on your explanations: You say that there is no active movement to the new outside ski, and that the weight transfer is not active, but results from the turn forces. I would suggest that an offensively minded skier whose objective is to get down the hill will actively pressure his uphill (new outside) ski, in order to get downhill faster. I agree that we don't want negative movement back up the hill, but active pressure up the hill will get us going down the hill faster. After all, track and field sprinters, even if they were on a sloped track, would probably always want to use starting blocks, and with each stride, the harder they push backwards, the faster they go. Where am I wrong?

Hope to see you around the county this summer.

Take care,

post #17 of 141
Barnes I can't even believe that you're embellishing wedge turns like you are.

That has to be a step backwards.

Barnes, you're trying to drink an ugly girl pretty.
post #18 of 141
Nice job Bob
I would like to use your illustrations to stop beating around the bush though.

In the parallel and dynamic parallel sequences you will notice in the edge angles of 6 & 18 in the parallel and 6 & 19 in the dynamic parallel that the edge change is clearly inside foot first and SEQUENTIAL.

Sequential, there ain't no other way to put it so lets call it what it is and say its more efficient.

To hell with this simultaneous edge change stuff. The sport has evolved past that. The quicker we admit that its squential the quicker our students will get it.

[ June 29, 2002, 08:52 AM: Message edited by: Pierre eh! ]
post #19 of 141
Hi Bob, nice illustrations. At least now the powers-to-be can't infer that you used THEIR illustrations of which they wrongly accused you in the 3rd edition. Maybe this time they will actually read the book :

As before, my assistance is always available, should you need or want it.

post #20 of 141
Hey look kids, it's Juan Pierre.

Folks, please excuse Juan Pierre. He's been sulking, ever since he got pounded by yours truly. [img]tongue.gif[/img]

Hey Juan Pierre.
Have you found any trousers that fit you yet? [img]tongue.gif[/img]

Hey Juan Pierre. What the hell do you know? You're just some putz from Ohio with lousy turns and who can't find a decent meal. [img]tongue.gif[/img]

Tell Lonnie the Magnificent I said hello.
post #21 of 141
Hey SCSA, please cool it. You didn't like it when I commented on your intermediate skiing, so Pierre isn't going to like it when you comment on his skiing, whatever it is. OK?

post #22 of 141
Bob, the diagrams are pretty cool, because when I first looked at them, I was able to put myself into those turns.
They show medium radius turns on moderate slopes at moderate speeds (i.e. "ski school turns"). How about a diagram of a "perfect fall line short turn", and a "perfect bump turn" on steep slopes?
Also the diagrams illustrate what I don't like about the wedge. Notice how in the wedge turns, the center of mass NEVER moves inside of the inside ski. Even in the basic parallel, it dips inside, if only for a split second. Basically the wedge is too much like a car and not like the motorcycle ride of a modern parallel turn. You would know better than I if this is a problem, but it seems that if the wedge skier gets on steeper slopes, he will make a wider wedge for the express purpose of keeping his CM between the skis. To avoid comitting to the turn. Again, you would know better than I, but it seems to me that what the beginner would most remember from a wedge introduction is that you can completely avoid that scary part of the turn. Is this true?

[ June 29, 2002, 10:39 AM: Message edited by: milesb ]
post #23 of 141
Ott, c'mon.

If we're embellishing wedge turns I think it's a step backwards.

But that's ALL I have to say - thank god, right

Well, ya know. History never repeats itself.

Back to our regularly scheduled programming....
post #24 of 141
Ott between SCSA, me and the trees we know what the skiing outcome was.
I think SCSA is simply trying to goad me into visiting more often. I am still very busy with my house project. [img]tongue.gif[/img]
post #25 of 141
Bob, you are right about the center of mass being variable and being lower than, say, the head. I am just wondering out loud whether a reader would be able to process the term "center of mass" correctly. A reader may stumble over it, having last heard the term defined in a foggy high school physics class. Just a thought.

[ June 29, 2002, 12:24 PM: Message edited by: WhosThatGirl ]
post #26 of 141
way cool Bob.

I'll inspect more later when I have a block of time. Like Pierre, lots of summer projects keeping me busy.
post #27 of 141
Thread Starter 
You're absolutely right, WTG--many people do not know what the center of mass is. But to understand skiing, you HAVE to understand center of mass, at least intuitively! They should have paid attention in that high school physics class--many mysteries would have been solved! Movements of the center of mass are not the same as movements of any body part. Move your hips...not the same. Move your head/shoulders...not the same! It may work both ways too--understanding CM will help you comprehend the illustration, and trying to comprehend the illustration may help develop an understanding of center of mass. If not, they can look it up, currently on page 51!

This is exactly what Einstein meant with his famous line:

Everything should be made as simple as possible, but not simpler!"

"Simplifying" the drawing to describe movements of, say, the shoulders, would be "simpler than possible." It would not be accurate and ultimately, it would create more confusion than it eliminates. Balance in a turn requires that the CM move inside the balance point. It does NOT require that the head, shoulders, or any other particular piece of the body move to the inside!

So I repeat--if someone doesn't understand CM, he won't understand the illustration, no matter HOW I draw it! And learning to understand the diagram will come with a bonus--the "eureka" of suddenly understanding the concept of center of mass!


BINGO, MilesB! Great points, but look at it from another angle. The reason the Wedge Turn skier's CM never moves inside the inside ski is not BECAUSE of the wedge. It is the other way around! The wedge is a RESULT of, and a compensation for, the fact that at this low speed, the skier's center of mass never moves very far to the inside. The moment the speeds increase, and the natural balancing movement causes the CM to move a little farther in, that inside ski will flatten and roll to its other edge. Voila--the wedge is gone, and the wedge turn becomes a wedge christie, becomes a parallel turn!

What you have pointed out is the foundation of the entire model! At very low speeds, you CANNOT move far to the inside, without losing your balance. Like I said from the beginning, the only REAL difference between the three diagrams lies in the increasing speeds and dynamics. The low speed, and resulting very slight movement of the CM, CAUSES the wedge turn. The wedge does not cause the low speed--it's a consequence of it! When the speed increases (comfortably), the wedge will vanish.

I've demonstrated this many times, with top instructors and trainers, racers, and even "direct parallel" gurus. I've asked them to make PARALLEL turns, at a very low speed, with no "tail-pushing," focusing on my mantra of "left tip left to go left" or "right tip right to go right." This description, you might think, should cause the tips to diverge, if anything. But that is not what happens. Without fail, the result (if they go slowly enough) is WEDGE CHRISTIES. You should have seen the face of a PMTS-certified instructor I did this with in a clinic last winter at Winter Park. Despite his previous denouncement of the wedge and the wedge christie, and despite my clear instruction to make PARALLEL turns, he couldn't NOT make a wedge! Talk about light bulbs coming on....

While Ant might not approve of my treachery with this Guided Discovery tactic, there was a lot of learning that took place at that moment. THIS is why we recognize the wedge, and the wedge christie--because they HAPPEN! Not because they are goals in themselves, or even steps in a progression, but because they are the nearly inevitable outcomes of the same exact fundamental movements and tactics that, at higher speeds and skill levels, will produce dynamic parallel turns. If a highly skilled and trained, well-equipped, knowledgeable, athletic, PMTS instructor trying not to make a wedge makes one, it would be ostrich-like to pretend that the wedge isn't significant for beginners!

These three diagrams, plus the Wedge Christie, represent in many ways "typical" milestones of progress, typical images of skiers as they develop in skill and confidence from beginner through advanced. They are NOT goals or steps--I've said this so many times. Any given skier may spend a little, or a lot, of time at any representative level. Some may skip through entirely--hockey players are famous for that. Today's new very short and deeply sidecut skis make parallel turns more easily at ever lower speeds. Accurate, active tipping movements originating in the ankles and feet, too, help flatten that inside ski and hasten the onset of parallel turns. With these tools, the wedge and wedge christie stages may well become so abbreviated that they ALMOST don't exist.

"Direct parallel," if we really understand it, and aren't too picky or dogmatic, is a reasonable description of teaching skiing these days. We CAN, and we SHOULD, teach the movements of great parallel turns from the start.

But they just might look like Wedge turns!

Best regards,
Bob Barnes
post #28 of 141
Originally posted by Bob Barnes/Colorado:
...They should have paid attention in that high school physics class--many mysteries would have been solved! ...
I read that and broke into this huge s*** eating grin.

To most students, we rank well behind lawyers and dentists in popularity.

Tom / PM

[ June 29, 2002, 06:46 PM: Message edited by: PhysicsMan ]
post #29 of 141
I totally agree!
I started to read "The Skier's Edge" yesterday, and the first thing that struck me was how studying Physics to 'A' Level (age 18) and then studying Mechanical Engineering at university, was actually useful and important to my skiing.
Now all I can hope is that I remember those classes!

post #30 of 141
Hey - at least you 2 are guys - it's even worse when you are female & like Physics! [img]redface.gif[/img]
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