 Poster: A snowHead
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| little tiger wrote: |
| rob - actually every foot should pronate and supinate with every step |
I understand that. There's a full description of gait analysis, including the role played by normal pronation / supination here.
I would have thought it was common sense that the normal operation of pronation / supination was rendered useless by clamping your foot and lower leg into the hard shell of a ski boot? Or are you saying that pronation / supination continues as normal, and that exercising some control over pronation / supination can provide extra control over the angle that your ski edge makes with the snow?
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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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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rob - when i asked a race coach he insists that normal foot function occurs depending on how you ski.... eg hip position can stop weight transfer fore/aft along foot occurring ( or you could stay always in back seat and never get pressure over the arch/ball of foot)... The race guys I know have no problem with pronation needing to occur in ski boots and I am told the old footbeds that prevented all pronation are old hat and it is now recognised that feet need to be able to perform foot functions to allow better use of other muscles for other jobs....
In fact I have been TOLD to get grip on ice with pronation... and then slowly/gently add and subtract edge with other mechanisms... the pronation will not overpower the ski/snow interface like other moves may.... Most instructors do not use the word - but then they don't tell me to increase lower leg angulation or hip angulation or stop banking either - they tell me what they want... and seem surprised I know the tech words... but i had little choice skiing with a collection of instructors from different lands and needing constant feedback we needed a common language.... no point one saying xxxxx and the other yyyyy for the same thing.... so they settled on the more tech terms to use with me (very few students take 50 or so private lessons a season hence this is RARE)
I am also told it is why I get to ski with my buckles undone (all undone) ... so i learn to edge with feet movements not by throwing me around against the boots (try that with boots undone and you come to grief fast)
Ditto the austrian fast edgeroll exercise - I'm told it is to teach me to be fast with the pronation/supination moves for initiation.... they seem very into it! I hate it having not much natural fast twitch reaction naturally.... so I STRUGGLE with it... although I'm told I'm improving...
lastly but most importantly my podiatrist - who is a high level skier himself and works as podiatrist to many australian sportspeople - tells me I MUST wear my orthotics skiing as my bad foot needs to be able to pronate to be able to ski well.... (it really does not do so causing me many problems including headaches from shock transmission during walking)
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| little tiger wrote: |
| rob - when i asked a race coach he insists that normal foot function occurs depending on how you ski.... |
Well, I'm not going to argue because it's well outside my scant technical knowlegde of skiing, but I still find it hard to believe that a foot can move laterally with respect to the lower leg when trapped inside a ski boot. I suspect that the techniques that you're talking about are a bit above most recreational skiers like me, although if the mental imagery works for anyone, that's a good thing...
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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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It is NOT a simple lateral movement... it involves a 3d movement pattern.... foot flattens and "twists" almost around a point in the middle of ankle with femur sort of following the rotation... it is not a HUGE movement.... quite small... but on a slalom ski with 0.5 or 1 degree base bevel quite enough to engage an edge...
see this [url] http://www.gla.ac.uk/ibls/fab/tutorial/anatomy/hindt.html#CONTENTS[/url]
especially note the second last para
| Quote: |
| The main point to note is that the foot has to be maximally pronated at these joints during the period of full support of the body on the foot. i.e. at the midpoint of mid stance. At this point the foot is locked and stable giving a rigid lever for propulsion of body weight over the foot. If the two joints are fully or partially supinated the foot is unlocked and therefore unstable and hypermobile. The foot at this point can be a mobile adaptor. |
my bolding
(I had not had it explained quite this way but it matches with the race coach guys stuff about where you are weight bearing over the foot.... must go find that stuff and reread now)
Try simply changing from a foot with no wieght to putting weight on a foot as though you will stand on it... (I have done with lines all over it in the podiatrists... fun... also my physio plays with feet as mine are stuffed!) If you are sitting with hand on thigh you can feel femur rotate a tad - also with finger touching arch you can feel it flatten....
I can feel the foot do this in my boots and I either have a footbed or a full on (9/10 correction and rigid) orthotic in that boot (still playing to try to fix dodgy ankles/feet)....[/b]
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You'll need to Register first of course.
You'll need to Register first of course.
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rob - it is why everyone talks about "rolling to big toe" etc etc etc... they are trying to get people to pronate.... just you can roll an ankle sideways and weight on heel and foot does not pronate (at least that is how i understood it)....
So when i was taught how to use my ankles (remember I have no idea even how to flex them and had to be taught) I was taught how it felt to "pronate" and "supinate" my feet.... I stood around drinking coffee with one foot in each position (other side while coffee was ordered and made).... It is a weird look when an instructor rips off a students boots and plays with their feet and then orders them to stand still.... Now there was little point in him telling me what I had been learning was "roll to big/little toe side" .... and he was always going to have me PRONATED/supinated not inverted/everted as he wanted me to learn to weight the inside edge and stabilise the foot to balance over it... As I use the feel to drive my skiing i only think "pronate" for that sensation
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If I skied barefoot I can see that that page would be helpful, but as I ski with my feet encased in ski boots it's still a mystery to me! Perhaps we have a different understanding of pronate / supinate?
My understanding of being told to roll onto my big toe is either (a) increase my leg angulation by crossing over my skies with my hips, or (b) dropping my knee further into the turn by rotating my femur in the hip socket. I don't think that it has anything to do with changing the lateral angle of my foot relative to my tibia/fibia.
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this from a race coach.....
Rick
EpicSki Supporter
Join Date: Dec 2002
Location: COLORADO
Posts: 2,356
Quote:
Originally Posted by Rusty Guy
I talked to an orthopedic surgeon/skier who contends, unlike runners, skiers don't pronate or supinate because there is no heel-toe strike. Runners who pronate strike the heel and as the forefoot is coming down there is pronounced lateral rotation according to the Doc.
Skiers do the same thing, he claims, merely with the footed fully planted.
Rusty,
I for the most part agree with your doc. The foot of the skier does much the same thing as the runners foot, minus the toe/heal lift and more pronounced dorsi/plantar flexions. Depending on the fore/aft balance point movement pattern, the skiers outside foot can, and should, move into a state of pronation. But as your doc says, it happens within the parameters of a somewhat planted foot.
At the end of a turn a skiers balance point is commonly toward the heal of the foot. If pressure is transferred onto the old inside/new outside ski prior to the pelvis returning to rotational neutral, (as during inside leg extension transitions) one has in essence made a step forward onto the heal of the new stance foot just like a runner does, minus the toe lift, and is in a state of supination.
As pelvis rotation goes to neutral, and then onto countered again, and weight is simultaneously moved forward on the foot, the foot rolls laterally from a state of supination to a state of pronation. This is exactly what we want because it directs pressure to the inside edge of the outside ski, providing us with an optimal point of balance/pressure.
If, on the other hand, pressure is not transferred to the new outside ski until after the pelvis rotated back to the opposite side of neutral, and the CM has returned to a fore position, (as during retraction transitions)then the supination phase is eliminated and the skier applies pressure directly to a pronated foot.
FASTMAN
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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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and there was some biomechanics dude running around canada (I think) who had a ski boot wired for testing what WC racers did with feet when they skied.....
I believe he was responsible for the change in atomics boot shape (they have a wider toe area to allow for the foot to function more like a foot... it can't do this with toes all crammed in together).... also the toes in atomics are (??offset a bit??) not in same line as other boot companies... Easyski - do you know what I mean?? I remember him talking about how the design would change and it did.... but not exactly what it all means....
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little tiger, thanks, that's an interesting description. Does the author (Fastman or Rick? I couldn't work out which one) contend that the amount of pronation / supination is controllable by the skier, or is it simply a response to the pressures put on the foot during the turn? The post talks about the skiers outside foot "moving into a state of pronation" when loaded during a turn, and then back to supination when the pressure is removed at the end of the turn. That doesn't sound like the skier is varying the pronation / supination to control the ski's edges, more like the pressure from the ski is changing the shape of the foot/ankle.
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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Rick is fastman... forum meltdown meant we all lost our nicks... some never got put back... he has 2 names now....
in other threads we talked about how it is hard to put a lot of weight on inside ski and maintain foot in supination.... hence why the majority of weight should be on the outside foot that can sustain the large weight....
I have asked I am sure and he has said yes to pronation/supination as initiation move... (just not how you usually describe to people)....
It is hard to see - and once I was in your camp..." there is no dynamic strike why would I pronate" then i changed my mind....
If you can find it the canadian guy is David McPhail I think.... did lots of research on biomechanics of ski feet....
I know a bootfitter (many years) in Oz that did podiatry because he wanted to know more... and then studied ski podiatry as part of his course.... I have an agreement to go play feet with him when i have time in the right city.... might be able to find out more.... but again we talked about how feet NEED to pronate in skiing... all the stopping pronation footbeds do NOT help... (excessive pronation is another matter)
Rick and I have had the talk on ILE a few times.... in an ILE initiation the foot definitely is DRIVEN into pronation by the turn forces.... you only have to work on the supinating foot.... it is this turn I described initially (or tried to) .... it has a VERY engaged feel - quite secure.... somewhere here I have a lemaster sequence with a rick description of the whole ILE part.... I'll look on the weekend...
You can't pronate past fully.... but the speed of pronation can be and the amount until then (but why only part way as not stable?).... the supination I personally find easier to control... while pronation I only control to DO it... It is one reason I think that "roll" works badly... - I do something OTHER than pronate as i think that is what it is that is wanted....
Note - one thing that changed my mind re pronation was discovering that i could NOT pronate my worst foot... with my orthotic though i CAN.... and then the ski movement felt different! (also lots of physio on the ankle to loosen it up to allow for the movements needed)
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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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the contention among some is we invert/evert as opposed to supinate/pronate. why? as dredged up from an old epic post no heel strike is involved.
i don't think it is needed for us to wordsmith. what we do with our foot is not nearly as powerful as what we do with our femur.
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little tiger, It doesn't seem to be the Atomic boot that's offset, but the toe bit that goes under the binding. Thus (I have a pair) when you put your ski on it looks as if your boot isn't properly in the binding - very disconcerting to start with! It's supposed to give you extra and easier edge. It does seem to work (up to a point). The shape inside the boot has been described to me as a wedge (wider in the forefoot), whereas I understand the Salomon (for example) is basically rectangular.
The big toe thing is just something that most people find easy to do - they can feel their big toe pressing into the corner of the boot, and they can feel which part of their toe is doing it - it's also a good image, easy to retain. If you tell the majority of people to press on their big toe they probably don't do it 100%, but get the weight forward onto the inside of the ball/toe area of their foot - that's enough to initiate the turn and hopefully eliminate the initial foot rotation that so many people seem to suffer from.
Rusty Guy, 
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You know it makes sense.
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little tiger, your concept concerning mobility of the foot in a ski boot is one the basis (sp?) for "posted" vs "non-posted" footbeds. it is certainly a controversial topic among bootfitters and one i doubt we will resolve here. i think it all comes down to a matter of personal preference.
i was told by a good source that for a time bodie miller skiied sans orthotic. he was quoted as saying he wanted chaos in his boot. whether that is true or whether bodie went this route i don't know. btw.....i ski in a non posted footbed which allows a little movement of my foot in the base of the boot.
one particularly interesting point for me to remember is something my bootfitter once pointed out to me and that is the fact that foot movement is "tri-planer". in other words movement typically involves rotation (laterally or medially), flexing (dorsi or plantar), and inverion or eversion.
merely food for thought
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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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| Rusty Guy wrote: |
little tiger, your concept concerning mobility of the foot in a ski boot is one the basis (sp?) for "posted" vs "non-posted" footbeds. it is certainly a controversial topic among bootfitters and one i doubt we will resolve here. i think it all comes down to a matter of personal preference.
....
one particularly interesting point for me to remember is something my bootfitter once pointed out to me and that is the fact that foot movement is "tri-planer". in other words movement typically involves rotation (laterally or medially), flexing (dorsi or plantar), and inverion or eversion.
merely food for thought |
para 1) yes exactly.... but as i said I have asked TWO podiatrists... one a high level skier and the other also a bootfitter who studied podiatry to improve his knowledge... and included ski biomechanics in his study because of this... BOTH state that feet do need to pronate - ie pretty much they agree with Rick... it depends on what you are doing but the need is there... they dislike many footbeds because of this...(Check out ant's story re her mangled ankles from bootfitters efforts - she is now back in high heels-sometimes- after using her orthotics in her ski boots and ditching all footbeds - she could barely walk before - we shaer a podiatrist)....
at this point in time I'm going with them.... so if my foot can't pronate in a ski boot (arrrgggh very tight boot/or heavy posted footbed) I will be upset...
My preference is to use my orthotics - they are very hard - but do actually HELP my bad foot to pronate(it does not naturally do so)...
para 2) YES... that is exactly why pronate works for me and "tip foot" does not so well..... pronation is 3 dimensional - tip is only side to side... so I find (having been taught what pronate is) that pronate works for me better than tip does (OK maybe I'm weird)
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