 Poster: A snowHead
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Partially related to the Galapagos thread, specifically:
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Any motion sickness is caused by the brain receiving conflicting signals from the two systems we use for balance - the vestibular (inner ear) system and our vision.
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We get our 'sea legs' because after a time you brain is able to make the adjustments and realise that it is getting conflicting signals, you aren't hallucinating, there aren't any neurotoxins in your system that it needs to get rid off, and so there is no need to induce vomiting. |
So why wouldn't closing my eyes work? Puzzled |
| BGA wrote: |
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So why wouldn't closing my eyes work?
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It should do to an extent, however when your eyes are shut your brain is still receiving signals from your inner ear telling it that you are moving, and as there is no visual confirmation of this then we are back to the conflict situation again which = barf. The best way to reduce it (without using scopolamine or other drugs) is to look out at an area which gives you visual confirmation that you are in fact moving, so look out towards the horizon and gradually bring your focus back to just in front of you, then back out to the horizon again. |
Now, consider that in a true carve that spends a considerable amount of time in between intersections of a fall line, the eyes are probably tracking the center of the turn, which does not really move very much. Would this not create conflicting signals between the two balance systems? Would there not be a temptation to resolve the conflict through either
a) looking towards the outside with all the motion cues that involves, including leaving the turn unfinished
b) triggering a braking cue
long before reverse peristalsis sets in?
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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| comprex wrote: |
Partially related to the Galapagos thread, specifically:
Now, consider that in a true carve that spends a considerable amount of time in between intersections of a fall line, the eyes are probably tracking the center of the turn, which does not really move very much. Would this not create conflicting signals between the two balance systems? Would there not be a temptation to resolve the conflict through either
a) looking towards the outside with all the motion cues that involves, including leaving the turn unfinished
b) triggering a braking cue
long before reverse peristalsis sets in? |
I don't look to the centre of my current turn, but rather ahead a turn or two.... in fact when racing I was taught to be watching for the next gate only until I reach the aiming point, and then be looking for the next aiming point to be hit... so I'm looking 1-2 aiming points ahead(spotting two ahead and watching for the next to be reached)
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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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comprex, in that situation there are other signals that the brain is receiving to confirm motion. As I said above motion sickness is caused by confusion between the vestibular and visual systems, the brain gets confused, resulting in vomit stimulus to remove the toxins that the brain thinks is causing the perceived hallucination. When skiing our peripheral vision and proprioception will confirm that we are moving, and also we are consciously causing the movement so there is no confusion, and so no barf.
The only time I feel sick when carving is watching it on video afterwards..
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You need to Login to know who's really who.
You need to Login to know who's really who.
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comprex, oh but I may be an outlier statistically because I have walked off a boat that was last off an island in a storm (and just ahead of the last flight) and been one of TWO passengers that had not succumbed to sea sickness, and most of them had partaken of travel sickness tablets for the trip....
I don't seem to get travel sick very easily... although I did have one queasy episode when confined to and area near the diesel of an old ferry.... as soon as they let me into the area near an open window I was fine again...
Last edited by You need to Login to know who's really who. on Thu 2-08-07 23:32; edited 1 time in total
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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| BGA wrote: |
| When skiing our peripheral vision and proprioception will confirm that we are moving, |
Agreed, but there remains the element of -trust- in one's peripheral vision, possibly a learned response in snow environments and possibly physically limited by goggles/glasses/sunnies.
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and also we are consciously causing the movement so there is no confusion,
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Well, not so sure about that, particularly when both edges are released in transition. In fact that is the import of this thread, the need? to consciously cause the movement and how that might influence style development and adoption.
not that we would allow it to get there, I expect I'm more concerned with the preceeding unease even at low levels and whether there might be subconscious correction therefor.
little tiger, yes certainly, outside the norm because you have been trained. I don't get motion sick either so I'm curious.
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You'll need to Register first of course.
You'll need to Register first of course.
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comprex, I'd say if you don't actually cause your edges to be released and reengaged you are skiing strangely.... you may not think of the specific body movements once your have trained them well... but rather "go there" and perhaps "this transition" or "this route" but your body is translating that into the specific movements and so knows what to expect to occur.... this is why vertigo happens in white outs - you can no longer rely on the visuals to let youdo the "go there" part.... and instead must rely more on feet and feel ....
I seem to get little effect from vertigo due to white out either - I'm already very dependant on feet and feel.....
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maggi, classic vertigo. No visual confirmation of the vestibular system input to the brain so feeling of nausea ensues. Add to that anxiety and everything goes wrong. There is a very good comparison with learning to fly small aeroplanes in cloud, once you enter a cloud and have no external visual references, you have to rely on flying on instruments inside the cockpit. When you first start it is very easy to become disorientated because you used to relying on external references to keep straight and level flight, whereas in cloud the only reliable source of information is the instruments in front of you. If you take your eyes off the instruments, to read a map or reset the radios or something then your inner ear becomes the only input to tell you which way is up and unfortunately this is insufficient. You get disorientated, look back at the instruments, your brain doesn't then let you believe what they are telling you because the inner ear input is stronger, resulting in a spiral dive and death  But as your training continues you can train yourself to ignore what your inner ear is telling you and rely solely on the visual input from the instruments resulting in straight and level flight  I would say that as a skier as you get more experienced and your muscle control and proprioception improves you are able to override the inner ear input and rely on other trained inputs to your brain in order to keep you upright - esentially what little tiger is saying above
comprex, I think it's difficult to say movements we do consciously in response to visual, proprioceptive or vestibular stimuli and what we do as a result as a trained response because the last time we received 'x' stimuli we did 'y' and it worked out OK so we'll automatically do it again. Tricky one.
My brain hurts now
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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BGA,
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My brain hurts now
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Sorry! But thanks for the explanation. And it's a good thing I never wanted to be a pilot  .
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maggi, has anyone shown you how to use the ski poles as 'feeler antennae'? Fun and useful exercise even in sunlight.
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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comprex, No. Tell me more .... (please  )
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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| little tiger wrote: |
| comprex, I'd say if you don't actually cause your edges to be released and reengaged you are skiing strangely.... |
There is that moment of float in between that is -so- counterintuitive because it is, in fact, well-directed but not necessarily by the action immediately prior to release.
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maggi, simple enough, the idea is to leave not 2 but four continuous tracks in the snow, one from each ski and one from each pole tip.
It is pretty easy to keep uniform pressure on the uphill pole tip and drag it through the snow, but the downhill one is tricky because you can't afford to allow a fearful pulling away from downslope. That pulling away also leads to less effective edging, so you're actually improving edge hold. If you're pretty good at the short leg/long leg exercise, the 4-points of contact are even more effective to teach angulation.
Once good at that the poles can become feelers. The trick is to pick a turn spot with the downhill pole and allow the upper body to move towards that hand.
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You know it makes sense.
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But as your training continues you can train yourself to ignore what your inner ear is telling you and rely solely on the visual input from the instruments resulting in straight and level flight
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Does the same happen at sea then? Is that why people say you actually "get your sea legs", that you eventually get better at NOT getting sea sicked?
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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abc, in a way. Getting your sea legs is learned behaviour - after a few days at sea your brain learns that the conflicting signals it is getting are not as a result of illness/hallucination/malfunction and there is not need to throw up to get rid of (non-existent) toxins, therefore it stops sending out the signals to induce vomiting. It's slighty different with the flying analogy because you are consciously overriding the vestibular input (at least initally) and telling yourself to believe the instruments despite what your body is telling you. So one is a conscious decision you are able to reach through training and experience and the other is an unconscious behaviour that is learned (essentially Pavlovian)
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Poster: A snowHead
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comprex, Thanks .
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FAQ
. Or it may just be sheer terror as to whether I am ever going to make it back to the valley 
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