Parallel shins, and equal edge angles.

A snowHead

Are they really so important? Tell us what you think.

I'm celebrating Thanksgiving, but will be back to jump in in a couple days. I suspect this one might prove controversial.

A snowHead

For what? Must be more important for the most efficient skiing than for fastest possible skiing anyway...

Well, the person's real but it's just a made up name, see?

My feeling is not that important more nice to have. I don't find that my turns are functionally very different whether I focus on this or not.

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Hmmm good topic.

this gets a lot of discussion with the racers cause it seems popular topic with the really top skiers. Good to aspire to but in a similar way as looking at developing lots of counter can produce worse results if skiers who dont have the skills, dynamicism or athletic ability try to ski with parallel shins and equal edge angles end up getting too much on the inside leg and diverging or splitting and makes matters worse...

You gotta be pretty darn good to do this well.. Here is a shot of someone trying to get parallel shins and not doing it very well.

Anyway, snowHeads is much more fun if you do.

skimottaret, Laughing

I wouldn't mind being able to do it that badly.

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pam w, lots of banking going on, inside leg really isnt parallel and the outside leg has some knee angulation to compensate, reasonable counter but inside leg is too long and more angulation is needed through letting the hip drop into the turn and leveling the shoulders. now if the patient was more focused on dominating the outside ski and creating bigger edge angles he would probably ski stronger.

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a better illustration of what FastMan, is talking about

After all it is free

skimottaret, well he'll just have to try harder, won't he? Should he be driving the outside hip forward and down into the turn?
?

or a more extreme example

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Ted Ligety - nuff said. They're not parallel but we'll let him off given the angles he's got there.

Great video of Ligety's angulation here:

http://youtube.com/v/yW4r27teE9E

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The only WC racers that I see with parallel shins are Felix Neureuther and Marcel Hirscher.

Just watching the Downhill from the USA (?). Not having parallel shins doesn't seem to be harming them too much.

You know it makes sense.

I think looking at this from a racer perspective is pretty pointless, though - a more relevant angle is how it affects the recreational skier.

Otherwise you'll just go on seeing the one name:

H versus A in other words.?

Obviously the prevailing dogma is that it is A Good Thing. And I am sure it is a good mental image.

Trouble is some of the people teaching it best look mechanical and joyless, including some people (not Fastman) who produce well received instructional videos.

A snowHead

If shins aren't parallel because there is too much weight on the inside leg and the skier is standing on too flat a ski I'd say it's a problem.

If the shins aren't parallel because the skier is rotating the outside leg's femur slightly to increase the edge angle a little to shape the turn I'd say that's skilful skiing.

A snowHead

I suppose at some point toward the exit of the turn you will be shifting your weight across both skis, if one is being pickly i guess at this point you would want both skis equally angled to give you maximum grip, like in that picture skimottaret, you would push the inside knee in to engage the inside edge before putting weight on it.

But do you need equi-distant knees throughout the turn, i honestly doubt it, i tend to vary the edge angle of my ski depending on the weight on it or what im planning to do with it.

Well, the person's real but it's just a made up name, see?

It must be important because I think this is what we were working towards with rob@rar, on Monday.

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Anyway, snowHeads is much more fun if you do.

rob@rar, Noted Smile

and 'working towards' was very intentionally added Very Happy

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Were we? I wasn't. Confused

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Where's Fastman? it must be one hell of a Thanksgiving party.

After all it is free

Surely parrallel shins means equal edge angle, so the skis will be forced round in the same arc, which is impossible to do with the skis still parallel. The inside ski has to take a tighter radius, so naturally will have the slightly greater edge angle than the outside.

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29 pages later.... Toofy Grin

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OK, finally back to this.

You guys have this topic pretty much nailed. Well done, everyone! Parallel shins equates to similar edge angles. The more equal the edge angle of the inside and outside ski, the more the skis tend to turn in harmony. The amount they bend is similar, and so is the turn shape they produce. The is why the suggestion to strive for similar edge angles is useful. It allows the skis to not work against each other. It also encourages the inside leg to tip into the turn, which removes a common barrier to high edge angles, where the upright inside leg actually blocks the bodies ability to tip into the turn.

So, as a learning prompt, striving for parallel shins can be helpful. However, as an absolute model for what actually happens in high level carving, the concept has a few holes. Understand, that the outside ski is generally the ski that dictates the nature and shape of the turn. The majority of a skiers weight is usually located there, for good reason, and it's therefor the ski we use to manage our turns. It's for that reason that in racing circles a right turn is referred to as a left footed turn, and a left turn is referred to as a right footed turn. The inside ski is basically just going along for the ride, making its way around the turn shape the outside ski is dictating, the best it can.

Tipping the inside ski up to an edge angle similar to the outside ski can help it track the turning path of the outside ski more easily, but remember, it will always have to follow a path that's a smaller radius than that of the outside ski, so it will always be at a disadvantage. Something will have to be done to compensate. Increasing the edge angle of the inside ski, to produce the necessary smaller radius turn is impractical. The reason it's impractical is that it requires contorted body positions difficult to assume. At high edge angles, even parallel shins can require contrived body contortions that attempting to achieve can degrade overall skiing performance. This is why you so often see A framed stances in world cup race photos. Trying to make the inside ski track the turning of the outside ski via edge angle is inefficient, so they don't worry about pure parallel shins, and seek another method. What follows is how they often do it.

Divergence. I've talked about this technique before, but never have had the source to the appropriate images I needed to explain it well. Now I do. Divergence refers to the skis pointing different directions. Specifically, the tips spaced more widely apart than the tails are. Skiers use this technique to get the inside ski through the turn on a smaller radius than the outside ski. By diverging the inside ski at the start of a turn, it essentially has less of a turn it has to make once engaged. It can carve cleanly, yet at a larger radius, and still end up parallel with the outside ski at the end of the turn. It's a pretty cleaver and useful tactic. Here's a picture of the currently best GS racer in the world doing it a couple weeks ago at the Beaver Creek World Cup.

Notice too in that picture, the A-Framed stance. Ted is not concerned about having to contort his body to assume equal edge angles. He doesn't need to be concerned about it, he's using divergence to get his subservient inside ski to follow his dictatorial outside ski through the turn properly and cleanly.

The other option would be to utilize functional tension in his inside leg, such that the inside ski would be forced into an auto steer as it proceeded through the turn. With that strategy, the skis remain parallel, and the inside ski produces a very slight skid as it turns. Both options work, and both are used at the highest level of skiing.

Though almost impossible to measure, my suspicion would be that divergence would provide a slight speed advantage over functional tension, simply because of the lesser amount of skid that takes place. The difference would be minimal though, and both methods are used pervasively on the World Cup. In the end, line and cleanness of carve on the outside ski are the factors that determine the winners from the also rans.

Credit: the above photo is from Your Ski Coach, at www.YourSkiCoach.com

FastMan, fascinating, really enjoyed reading that, and a great example photo.

You know it makes sense.

FastMan, great stuff, very clearly explained.
One more thing: the early divergence usually leads to convergence towards the end of the turn, due to the greater loading and edge angle on the outside ski.
It's clearly visible in this video, especially at 0:35:

Svindal GS highspeed cam from aksel svindal

http://vimeo.com/14430888

Otherwise you'll just go on seeing the one name:

FastMan, just watched Lindsay Vonn at Val d' spending most of her run on her inside ski wink

stunning recoveries Shocked

But I think you have to issue a caveat to your post. The situation and example you've used is a talented skier at the extreme of a racing carve. It's hardly applicable to the level that the majority of us reading this can achieve. I certainly don't disagree with you (as we've talked in the past) but we need to be able to finesse a carve at much less acute insertion angles and with more equal weighting and that requires more than just bouncing an unweighted ski tip at a high divergence angle.

I can't shake the feeling I'm squatting naked, over a smouldering bottle rocket wink

A snowHead

Thanks, guys, glad to hear it came across clearly.

Martin, spot on. It most definitely does go from divergence to convergence. I'll search my shots and see if I can find a good one showing it. It would be a good one to add to the gallery. If I find one, I'll post it up here, to supplement and support the video you've presented.

Masque, very true. The bigger the edge angles employed, the more it tends to become an issue. Still, even in the lower angle carving done by the average recreational skier, the outside ski is still the strongest mechanism for support, and where the bulk of a skiers weight should generally be. Therefore, the tactics I've described here can still be used in that environment, when needed. Thanks for jumping in, Masque, it's always fun to explore ideas with you, as we have done in the past. Pull your pants up my friend. snowHead

A snowHead

Careful FastMan, the last time anyone talked about divergence/convergence it got to 27-odd pages Smile

Seriously though, fantastic post and a great photo.

Well, the person's real but it's just a made up name, see?

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moffatross, he's clearly not that good a skier either, look at how short and narrow his skis are without even a hint of tip rocker, let alone full reverse camber. No wonder he's not managing the sought-after skurf turn, totally last millennium skiing wink

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Sideshow_Bob,

And where are the baggie pants around his ar_e Puzzled

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rob@rar, You stand a bit downhill and I'll demonstrate for you . . . a nice spring slush day and my board will be perfik Twisted Evil

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Parallel shins, and equal edge angles.

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