 Poster: A snowHead
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| Spyderman wrote: |
Great thread guys. Good to throw some ideas about, without an ego trip.  |
Can I just echo these comments - thanks everyone for keeping it civilised!
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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| Wear The Fox Hat wrote: |
| GrahamN wrote: |
... The last thing that gets into the new turn is actually the ski. Discuss  . |
Question on this: What brings the new ski into the turn? Are they brought into it by the rest of the body, or is it the feet getting the edges going? |
Sorry, forgot to reply to that earlier. This is how I see it.
The ski comes into the new turn by being put onto its edge, i.e. its angle has to change. The boot is attached rigidly to the ski so that can only happen by the boot changing angle, and hence it has to be changed by the lower leg moving. So far so good, but the question then turns on how you move the knees wrt the skis. We had a bit of a discussion some time ago as to whether the turn was physicially initiated from the ankles or not. Yes it can be, depending on how tight your boots fit around your lower leg, but the major movement is of the shin and how much of the ankle stuff is psychological and how much is physical is open to argument (but I think ankle involvement is equally important whichever the truth turns out to be). ISTM you can move into the turn either by moving the knees over under the body or by moving the whole body. There is of course the danger with too much angulation at the knee that you blow ligaments, so you can only go so far. In more cruisy skiing it's probably perfectly OK to move everything pretty much together. But the purpose of a turn is to get the whole body (which can be localised to the CoM) moving in a different direction, so if you're trying a high performance transition you can use the flexibility in your legs to get the upper body moving into that new direction while still finishing the previous turn - the body starts moving in the direction of the new turn with the pole plant while the skis are still moving in the direction of the old turn. Henceo you then get the CoM further in the direction of the new turn right at its start and the angle is there for a high performance turn much earlier and requires less angulation at the knee once the forces start building up in the new turn.
Actually you probably do something like this on a very small scale when trying to start a turn from a straight run. You need to get the body on the inside of the turn for the forces generated by the skis to push the CoM in the right direction - as otherwise you'll end up with the skis moving into the turn and leaving the CoM behind, and you fall over to the outside. Actually this may well be what is happening whe we get " stuck in the old turn" - we've tried to turn our skis into the new turn before transferring our mass to the new inside and so we're fighting to keep the CoM from falling outside the outside ski. This is most easily done by making a very small counter-turn right at the beginning, so taking the skis to the outside of the body at the start of the turn - i.e. your body is turning in the direction you want to go, but you've artificially constructed a "previous" turn for your skis to finish at the same time. There is a very similar situation when making a turn on a pushbike - if you concentrate hard on turning the handlebars only in the direction you want to turn you'll probably fail to make any turn at all - or fall off towards the outside.
There is of course a major difference between skiing and riding a bike, in that you have two skis and only one wheel (laterally that is). So if you have a wide stance you can get the CoM towards the inside of the turn just by shortening the inside leg and letting gravity do the rest. I guess this is why the counter-turn is of less significance now than it used to be, but it's still of use if you need to get into a turn quickly. It's also quite significant when skiing in deeper and softer snow where you want a more even weighting between the two skis - there's a significant disadvantage to just getting gravity to get that lateral dispacement, so you need to do something additional to get it to happen - either a small counter-turn, a stem or maybe a small jump to place the skis on their edges. As I write this I remember that this stuff is actually covered in Phil Smith's second DVD - although there he's talking about it just as a means of changing edges, and doesn't make any explicit point about achieving a lateral separation of CoM and BoS.
It's obviously a dynamic situation as you're deliberately putting your body out of balance in the process but it's something we do all the time, and different situations require different solutions.
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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GrahamN, thanks for the detailled reply - I'm going to have to read it a few times to get everything you've said in it!
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