 Poster: A snowHead
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Even if you're a lightweight midget?
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Yep! you can have a 90 underfoot ski that is still quite soft and therfore easy to flex
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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Fattes13, goody. I shall definitely stop worrying.  (My skis aren't very stiff.)
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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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feef, I'd say you're absolutely right. The instant your 'vertical load', a term relating to the resultant force direction in reference to a moving skier (NOT a vertical load like Trees have to resist), goes outside of your supporting foot features i.e ball, through arch, upto heel ( say, using 100% loading on downhill ski only), this creates a turning / bending moment which has to be equalized by an opposite turning / bending moment somehow. NO MATTER how good you get at balancing on this edge, if it's outside of the support foot laterally ( skiing one or 2 feet it doesn't matter), then the moment force in the Frontal plane has to be countered by an opposite moment force produced (probably) by a subtle body position change or muscular action. However it's countered... nonetheless there remains this moment force going up the leg into the body. Ankle is supported in high sturdy rigid boot, so YES i can see the Knee 'seeing' / 'resisting' frontal plane rotation forces.
One reason why skiers report less knee irritation with wide skis on the piste could be a), The longer turn radius resulting in lower 'vertical' G forces and hence, lower frontal plane, force moment on the knee. b), wider skis are LESS rigid laterally and as the ski edge is further away from the foot also, the ski might absorb/ smooth the' hard surface' vibrations being transmitted into the body.
Not sure i have contributed anything new here.
We have seen world cup racers going back to 30m turn radius for GS skis due to unacceptable 'Knee' injuries thought caused by 'Carving Skis' AND high octane dynamic skiing. If evidence begins to surface that 'Fat' skis are also not ideal in the extreme widths, wouldn't that be interesting. Unfortunately there is no 'international authoritative body' looking after the interests of ordinary skiers - and for sure if manufacturers put 'health warning labels' on ski's, we'd all laugh! Skiing has caused me so many injuries over the years - i've never stopped recommending it to anyone apart from the cost!
Getting yourself up on edge and staying there might not be that difficult in benign / steady / predictable conditions, but if you suddenly have to alter course / or hit / avoid something massively fast ( usual stuff on the hill), then that's the injury scenario. Older age = easier injuries that take longer to heal if ever properly.
Last edited by Well, the person's real but it's just a made up name, see? on Thu 14-11-13 19:14; edited 2 times in total
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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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| Tim Heeney wrote: |
Not sure i have contributed anything new here.
We have seen world cup racers going back to 30m turn radius for GS skis due to unacceptable 'Knee' injuries thought caused by 'Carving Skis' AND high octane dynamic skiing. If evidence begins to surface that 'Fat' skis are also not ideal in the extreme widths, wouldn't that be interesting. |
Doesnt need to be 'new'. Confirmation is enough to encourage me that i'm on the right track and not completely wrong.
An interesting thought regarding racers.. The forces they are subject to are SO much greater than what we experience that maybe even a slight increase in width could result in a significant increase in the forces, even without going as far as a 'fat' ski.
If it DOES turn out that fat skis contribute to the forces in this way, you know where you saw it first 
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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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feef,
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f it DOES turn out that fat skis contribute to the forces in this way, you know where you saw it first NehNeh
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i'll not forget -promise 
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You'll need to Register first of course.
You'll need to Register first of course.
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| Quote: |
We have seen world cup racers going back to 30m turn radius for GS skis due to unacceptable 'Knee' injuries thought caused by 'Carving Skis' AND high octane dynamic skiing
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Tim Heeney, Its 35M for men and 30m for women and "Unacceptable Knee Injury" is a big crock of bull! One small research project done in Austria bye FIS no info published and the great quote from Anje Person, her and Svindal stood up at a meeting of athletes and she said "You have done extensive research and testing and the solution you have come up with is the same for me as it is for him, do you not see the flaw?"
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feef, Just wanna add, Im also reading 'Ultimate skiing' by Ron LeMaster along with. I think it's a brilliant book bought for 10 or 12 pounds which is the best money i've ever spent on skiing. If you've 'into' understanding the physical principles, this is a must have book. A couple of years ago i was on a moguls course along with 7 others. Missed first day through sickness, skied days 2 and 3, falling / injuring on 4th, then retired. Course was taught by BASI 4 trainer, i wasn't very good - all the 'personal advice' to practice was, 'go find medium sized moguls and traverse them attempting to get your knees and chest as close as possible at the mogul top and stretch out in the valley in between'. I considered at the money i was paying ( even in a 8 group), surely that wasn't all what a BASI 4 trainer could come up with? Well, back to the book. I now exactly now what i need to do and what to practice and where i'm very weak on.
If i could afford personal, consistent high level training i would take it. Some of the content in this book has never been said to me and it's all so obvious now! ARGH!!!!!
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Fattes13, Yes at the time i remember the controversy and i remember what AP / ALS was reported to have said. However, although the physical difference between them 'appears' more extreme than 35m men / 30m women, i would not be prepared to dispute FIS and it's medical body in their decision. They are there to protect the athletes and promote the sport and NOT to sell straighter skis. I cant see any other interest, other than, less injuries cutting short skier careers. Sorry, i just can't!
Aren't the athletes 'accepting the new skis' 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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Tim Heeney, 4 High profile Knee injuries in GS since the new regs came in!
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i would not be prepared to dispute FIS and it's medical body in their decision. They are there to protect the athletes and promote the sport and NOT to sell straighter skis. I cant see any other interest, other than, less injuries cutting short skier careers. Sorry, i just can't!
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The research was rushed very secretive and not fully published and done by an Austrian university, which if it was as clear cut as FIS say it appears odd. What we know is the Research was only carried out on Male subjects, FIS collaborated with the University of Salzburg, which in turn interviewed 63 World Cup experts many Austrian based, such as coaches, athletes, officials, and organizers. Together they decided that equipment changes were the best way to minimize risk.
The really interesting aspect was the ration of injures Downhill 9, GS 16 and Slalom 11, now take into account that most DH race GS as do most SL skiers, the ratio becomes less worrying as more people compete in GS at WC level than do at the other disciplines. It would probably have made more sense to change the SL skies. The reality is it is not about selling more skis the change favours a particular type of skiing that a nation who are dominant in the administration of FIS actively encourage and want.
Having skied on teh new skis I feel less safe as in any condiiotns other than bullet proof Ice they are horrible and not all FIS Races have the type of piste preperation the WC guys enjo!
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Fattes13, Thanks for further information and your thoughts.
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the change favours a particular type of skiing that a nation who are dominant in the administration of FIS actively encourage and want.
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IF that can be surmised by you, and i hasten to add 'others in the know', i have no 'insiders view' to counteract that. All i could say is that is normal behavior for dominant people/group/business/country to get their own way.
However for WC racers, if the dominant nation has got its way with the rule change, how does it favor it's own competitors over other nations with the radius change - its the same for all.
I understand the point about probably the change would have been better for SL events. Isn't it the case that there are more competitors doing combined 'technical disciplines' of GS and SL rather than GS / SG/ DH so i can see it messing up the performance of the 'technical disciplines' skiers more than the 'speed' skiers. But again, it doesn't bias any nations skiers more than any other unless all you do is, SL / SG / DH.
Your last point about FIS racers skiing on less well prepared slopes than WC races i understand, but do all FIS racers agree with you. When Ted L. says the new skis are now a non-issue, does the FIS racers all cry out 'it would be if you skied on what we have to!'
I have no personal objective view having not done racing. I have heard Bode Miller talk about how 'stiff' and 'unfeeling' the new GS skis are though.
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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feef, racers are into speed, so less friction / drag / suction resistance to motion etc. AND more importantly, speed from one turn into another, minimising 'transition' time from curve edge to curve edge is imperative. Any ski wider than their boot, the ski edge force encountered, having further to go would not immediately be transferred into the skiers body, this increases, NOT decreases their reaction time thus putting them into danger hence, racers skis are very narrow. Their boots don't dig into the snow at high edge angles due to additional
'riser plate' underneath their bindings ( or so i believe). ps. i'm not a racer.
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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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finestgreen, just wanna say, i too am reading' Ultimate Skiing'. It's a great book!
Really everyone - terrific stocking filler!
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Tim Heeney, There are rumors going around that, FIS will be going back to 30m for men as the experiment has not worked, Even with Ted's dominance he is still complaining about the skis, the first race in Solden last season shown just how bad those skis are in Variable conditions. The quote you have selected above is something I have heard repeated a lot by various people involved in racing. Is it true probably not, is there a grain of truth in it? Maybe. 
And yes Ultimate skiing is a cracking read.
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You know it makes sense.
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During the winter i run a dedicated multidisciplinary ski injury clinic. My ski injury clinic sees between 5 and 10 ACL ruptures per week throughout the winter. I am dedicated to trying to get skiers back skiing safely.
I see many racers, especially school age, who are skiing at national level. We see large numbers of recreational skiers and professionals travelling from Europe.
I do not think that fat skiis are the problem.
Jonathan Bell
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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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Jonathan Bell, You should have your number at the bottom of that post!  Educated and informed opinion is always nice to have around here!
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Poster: A snowHead
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| Jonathan Bell wrote: |
I do not think that fat skis are the problem.
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Neither do I.
I'm not saying they cause knee injuries nor ACL ruptures, just that they are adding a lateral force to the knee that we have, until recently, not been subject to. Whether that will go on to contribute to injuries in the future, I have no idea. The incidence of fat-ski use on piste is still relatively low so I doubt it would show up statistically until it's more prevalent.
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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Jonathan Bell,
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| I do not think that fat skiis are the problem. |
No offence, as you're clearly an expert, but it seems to me that all the injuries you're dealing with are trauma injuries.
What about the long term effects of the additional lateral stress on the knees through the use of fat skis?
There's plenty of anecdotal evidence from people above (including myself) that skiing on fat skis with a worn or damaged knee joint causes swelling and pain more quickly than narrow skis (presumably because of the increased torque on the joint). An already damaged joint will obviously react more adversely and more quickly than a healthy one to adverse stress and therefore may be an effective indicator of a potential long term problem.
Fat skis haven't been around very long so there's no long term evidence. So who's to say that 20-30 years of skiing on fat skis won't cause early onset arthritis through the additional stress on the joint, for instance?
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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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Okay, after some further discussion, I've done some more modelling and have some rough figures for the forces in question.
Assuming a body weight of 76Kg and a total lower leg length (knee to base of ski) is 60cm
Also, assuming 1G so a force of 760N acting down through the centre line of the leg (to keep things simple. We don't need a real world calculation of the forces actually acting when skiing, as we're looking to calculate the relative change based on width. That factor should remain constant irrespective of the force's absolute value)
For a ski width of 80mm
The lateral force on knee was observed to be 51 N ±1N
for a ski width of 110mm
The lateral force on knee was observed to be 70N ±1N
Proportional increase base on ski width of 1.375 (i.e. 110/80) matches the proportional increase in observed force on the knee.
So a 80mm ski will put a lateral force on your knee equivalent to about a 5kg weight at 1G.
Under the same conditions, a 110mm ski will put a force of 70N or a 7kg weight onto your knee.
Again, it's an oversimplified model, but I welcome any expansion or correction of my calculations.
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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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I tend to agree. I had a knee injury last season and ended up missing 2 months of skiing and lost most of muscle on the injured leg after 4 weeks in brace and on crutches. I had to get myself narrow piste-style skis (72) when I returned to skiing in the end of March and after two weeks progressed from blues to blacks. My knee didn't seem to complain - though I didn't ski longer than 3-4 hours. But when at the very end of the season on a powder day I decided I could try skiing on my normal skis (100) I realised it was way too soon for my knee. Particularly when I was skiing down to the village. So there is a difference and I could feel the pull on my knee and I wouldn't put it down to weight since the narrow skis are somewhat heavier. So must be the width.
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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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feef, one thing that's missing is an idea of what is a 'bad' amount of force for a healthy knee joint, bearing in mind it's part of supporting a huge amount of weight an is often subject to some hefty forces. That there is more force seems like a no brainer and that will be bad for already compromised joints doubly so. Further in long term use there is also the question of the strengthening of the supporting structure and musculature to compensate.
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