Fat skis and knee issues

http://unofficialnetworks.com/2015/02/15/study-finds-that-fat-skis-are-killing-your-knees/

I’m convinced that somewhere in the mid 80’s width that you have to change your skiing on wider skis.  This is based on my deep understanding of the biomechanics and physics of skiing and my feedback of how a progressively wider ski feels to me.

These guys out there on fat skis on hard snow that don’t think so are fooling themselves or just don’t have good movement patterns.   I’ve had some knee issues this year and talked about it with a very very high ranking Psia examiner who told me that a 84mm width ski on hard pack is the cause.  Planning to go narrower next year and see how that works out.

Note the study says on hard snow and given that the definition of hard snow in Montana is Eastern snow at least 90% of our time.

I’d be interested to hear what others particularly Matt think.  

Not much to go on Z. There is no information in that article to understand what the study really looked at, and how they actually conducted it.

Anecdotal information from aging skiers who are likely to be naturally experiencing knee pain anyway says nothing.

It would seem like some enterprising physics majors / skiers could work out the theoretical stresses of skiing on different skis, with every other thing constant. That would be an interesting starting point to the discussion.

In the real world though, not everything else is constant.

I think skiing regularly on the east coast on skis greater than 90 is dumb.  Wide skis are for powder and spring mush

That said skiers who turn to much work their knees more and as they age that results in more wear and tear.  

Let them skis run!  

Just like 50 is the new 40......107 is the new 90!!  Really, what is considered fat nowadays anyway?

Heck, I’ve only got 7 days in this season, and only 2 on the east coast.  As for letting the skis run, a stable 107 sure likes doing that.  Prez Day weekend I spent all day making snappy short radius turns at the edges where the snow was pretty damned good amongst Sno’s horrifics!

Point being, pair the right ski with the right skier and many rules of thumb go out the window.

I haven’t developed any knee issues since my 90s started gathering dust.  I also know and have skied with professionals, guys who have made the mags and bagged first descents across the globe, from Rainier to the Caucasus, who ski a quiver of one at 106.  Just sayin’!

Could be fat people are causing the increase in knee problems.  

Im going with the above^

Not sure of exact measurements but this is the appropriate width ski for NYS.

ScottyJack wrote

I think skiing regularly on the east coast on skis greater than 90 is dumb.  Wide skis are for powder and spring mush

We get both of those conditions on the east coast. Some skiers only ski when they can get those conditions.

That said skiers who turn to much work their knees more and as they age that results in more wear and tear.  

Sounds like you think turning is "work". I don't think that's necessarily true. Also not sure if the best advice to most skiers is to turn less. I see enough dangerous skiers on the mountain already.

I might write an article on this question, so I don't really want to get too deep into the weeds here, but generally, I agree with Z.

On groomers, the skis need to tilt to achieve certain edge angles to create a desired turn radius. The wider a ski is, the more of a "move" you have to make to achieve the edge angle you were getting with a skinnier ski.

I find that the edge angle on the outside ski is pretty easy to keep relatively similar across ski widths. If we talk about a long outside leg and a short inside leg (along with the PSIA "fundamental movement" of directing pressure to the outside ski), it feels easier to make microadjustments with a longer "lever" (not sure of the physics on that claim. I have to check it out to verify). I think the problem comes with the inside ski.

In order to achieve the same edge angle for the inside ski, we usually roll the inside knee into the hill (when I teach, I use the analogy that you're carrying a beach ball between your legs and you want to drop the beach ball by moving only your inside knee). Depending on stance width, I suspect that repetitive motion of dropping the inside knee to the hill to goose the edge angle of the inside ski can do some damage as ski width increases. (Think about how far over you'd have to move that inside knee if you were skiing on a on a 2x12).

I say "depending on stance width" because I suspect that the wider stance we've been teaching has the potential to be harder on the inside knee than a narrower stance. In powder, when the skis are closer together (acting as one) and the edge angles are not as great, it seems like it would be less pressure on that knee. Also, I like to use more of a retraction type turn in pow on steep terrain, and I think that extending both skis away from the body in the belly of the turn (changing edges while the skis are retracted under the body) might be better (because then, both legs are the "long" leg at the maximum edge angle). I know I feel less pressure on my knees with fat skis (although 105 is my Max width) when I try to do that move instead of the racer carve.

TL;DR: I tentatively agree that fat skis are harder on the knees than narrower skis on groomers. I think the inside ski is the culprit, because the move you have to make to tip it on edge is awkward with a greater width (more awkward than the move you make with the outside ski). You might be able to game your way around it with technique, but I'd probably stick to the 75-90 range for pure groomer days.

Maybe its because people ski harder and longer because FAT SKIS ARE MORE FUNNER.

I like my Masterblasters for everything but a true eastern hard pack day. The sidecut/rocker combination really just requires tipping your ankles a little bit to initiate turning if you want to carve but you can smear them too. My skinny skis are great on hardpack but you have to be much more precise to smear them without catching an edge. I wouldn't go above 100 on a a daily driver EC ski or really even an EC "powder ski". Our "powder" days are hardly ever deep enough where you need a ski with that much lift. I also think 180 length is enough without being too long in EC trees. I would go up to 185-187 if I was out west more. All that being said I know a guy who skis 120 underfoot as a daily driver. I don't think he has any knee issues and he is a ripper.

I am fat, I like fat skis and I already have 2 ACL surgeries under my belt so I guess I am really screwed.

Hasn't skiing pretty much always been bad for knees?
I think of my fat skis as the skis for the conditions I want to ski.
My skinny skis are for the conditions I usually get...

tjf1967 wrote

Could be fat people are causing the increase in knee problems.

Glad I'm skinny when skiing on the skis pictured in my aviator. BTW I'm old school and turn ALOT. Gonna hit 60 this September. Knees fine, though I don't ski those Volkl Ones on the regular. Have them ready to go when conditions warrant busting them out, but do ski them from time to time on groomers. Suspecting other body part(s) will wear out before my knees do, lol.

I agree with this study. I found that going back to sub 98 width on hard pack eliminates my issues.

The study says this impact to the knees is on groomer conditions

In softer conditions this impact goes away as you don’t require the same high edge angles.  Also smearing turns in deeper or softer conditions is a good tactic.  You can smear in hard snow conditions but it’s a decidedly sub optimum way to turn.  If that is your way to ski on a wider ski you are proving the point of the study.

timbly wrote

Hasn't skiing pretty much always been bad for knees?
I think of my fat skis as the skis for the conditions I want to ski.
My skinny skis are for the conditions I usually get...

Awesome.

tjf1967 wrote

Could be fat people are causing the increase in knee problems.

I was told that for every 10 lb. extra, your knees take 40 lb. more stress.

Side note: for every 100 lb. less, I have 100% more comfort in the gondola.

OMG!

 The only thing deeper than your weeds must be old growth forest!!!

Well, because of a bonehead move on my part, I got to ski on narrower skis this past weekend at Whiteface, which was groomer and not powder after the last storm.

I’ll qualify this to say I wasn’t on the right narrow ski (Rossignol Experience 78 from the WF rental stable) to give the greatest evaluation of the difference between a narrow carver and either of my usual skis, at 106/107 under foot, on groomers/ice.  Also didn’t help that the longest ski they had was a 182, and I’m 6’4”.  An all purposes intermediate carver just wasn’t nearly enough ski.

That said, the Experience 78 isn’t a bad ski, I don’t think.  So, from the standpoint of evaluating narrower versus wider on groomers I think I can make at least a few valid observations.  

I can’t argue with Z, a narrower ski is easier to put on edge than a wider ski.  Once the narrower ski is on edge it bites and arcs beautifully.  Of course easier is a relative term, and I don’t find putting my wider skis on edge to be all that difficult.  Maybe my height helps in that regard.  Also, on the narrower ski I find you have to work the ski harder to really keep that beautiful arc.  You have to be on top of it.  That’s a little different than I find with my wider skis which to me are more Ron Popeil, set it and forget it!

The other observation is that a narrower, and as a result lighter, ski is a much less stable platform under foot.  I found the narrower, lighter ski to be a bit squirrelly.  Back to that having to stay on that edge, you just have to be more vigilant and the narrower, lighter ski.  A longer ski would have helped with this.

One last observation, and this probably doesn’t apply to all narrow carvers.  The Experience 78s seemed very one dimensional.  With more advanced, wider skis they play around with materials and such to affect the swing weight of the skis, which makes them very versatile.  I didn’t get that sense of versatility from the narrower ski.

In summation......the narrower ski is a great carving tool that holds an edge on groomed surfaces and hardback like nobody’s business as long as you stay on top of it and work it.  What the ski gains in carving ability and light weight it loses in stabilility and versatility in all conditions.  It’s a great tool to play on if you want to do little more than slash clean arcs on smooth surfaces.  Other than that it’s too much work and not enough play, because the mountain gives us so much more to play on than clean surfaces.

I’ll keep my wider skis, thank you very much!  Even if they are “harder” to put on edge, I like the ability to set it and forget it, and just ride the stable platform through whatever the hill might throw at me.  What I trade in carving ease on the groomers is more than made up for by playfulness on the rest of the mountain.

One observation that I don’t think had anything to do with width was the total lack of rebound energy the Experience 78 had, at least for me.  Short radius turns were just no fun.  No pop, no energy propelling me into the next turn, no ability to get a rhythm.  I think the skis just didn’t have the right materials to do what I wanted them to do.

Interestingly enough, my son....who isn’t a ski tech guy at all....was able (on his own) to express the same observations to me.....great carve but need to work the edge and the squirrelly nature of the ski, although being lighter and shorter he was able to get some good rebound energy out of the ski.

JTG4eva! wrote

Well, because of a bonehead move on my part, I got to ski on narrower skis this past weekend at Whiteface, which was groomer and not powder after the last storm.

I’ll qualify this to say I wasn’t on the right narrow ski (Rossignol Experience 78 from the WF rental stable) to give the greatest evaluation of the difference between a narrow carver and either of my usual skis, at 106/107 under foot, on groomers/ice.  Also didn’t help that the longest ski they had was a 182, and I’m 6’4”.  An all purposes intermediate carver just wasn’t nearly enough ski.

That said, the Experience 78 isn’t a bad ski, I don’t think.  So, from the standpoint of evaluating narrower versus wider on groomers I think I can make at least a few valid observations.  

I can’t argue with Z, a narrower ski is easier to put on edge than a wider ski.  Once the narrower ski is on edge it bites and arcs beautifully.  Of course easier is a relative term, and I don’t find putting my wider skis on edge to be all that difficult.  Maybe my height helps in that regard.  Also, on the narrower ski I find you have to work the ski harder to really keep that beautiful arc.  You have to be on top of it.  That’s a little different than I find with my wider skis which to me are more Ron Popeil, set it and forget it!

The other observation is that a narrower, and as a result lighter, ski is a much less stable platform under foot.  I found the narrower, lighter ski to be a bit squirrelly.  Back to that having to stay on that edge, you just have to be more vigilant and the narrower, lighter ski.  A longer ski would have helped with this.

One last observation, and this probably doesn’t apply to all narrow carvers.  The Experience 78s seemed very one dimensional.  With more advanced, wider skis they play around with materials and such to affect the swing weight of the skis, which makes them very versatile.  I didn’t get that sense of versatility from the narrower ski.

In summation......the narrower ski is a great carving tool that holds an edge on groomed surfaces and hardback like nobody’s business as long as you stay on top of it and work it.  What the ski gains in carving ability and light weight it loses in stabilility and versatility in all conditions.  It’s a great tool to play on if you want to do little more than slash clean arcs on smooth surfaces.  Other than that it’s too much work and not enough play, because the mountain gives us so much more to play on than clean surfaces.

I’ll keep my wider skis, thank you very much!  Even if they are “harder” to put on edge, I like the ability to set it and forget it, and just ride the stable platform through whatever the hill might throw at me.  What I trade in carving ease on the groomers is more than made up for by playfulness on the rest of the mountain.

One observation that I don’t think had anything to do with width was the total lack of rebound energy the Experience 78 had, at least for me.  Short radius turns were just no fun.  No pop, no energy propelling me into the next turn, no ability to get a rhythm.  I think the skis just didn’t have the right materials to do what I wanted them to do.

Interestingly enough, my son....who isn’t a ski tech guy at all....was able (on his own) to express the same observations to me.....great carve but need to work the edge and the squirrelly nature of the ski, although being lighter and shorter he was able to get some good rebound energy out of the ski.

You should have stopped writing after your second paragraph. You were skiing on a 2013/2014 intermediate, feel good ski that you would have hated if it was new, let alone with 4-5 years of rental service. The rest of your observations are accurate about this worn out Rossi Exp 78, but have nothing to do with the multitude of high level front side carvers that you can buy. Justifying your wide skis by comparing them to this particular ski is silly. Demo a high performance carver or a beer league GS ski and you will be on a ski that matches your skills.

Carver ski - Rossi pursuit HP - one step below a race ski, exceptional for WF anytime.  Not any pursuit, but the HP.

Eh, probably!

Those skis did suck.  My son is using a pair of my older Nordica Hot Rod Nitrous ca skis, without the metal, that ski so much better (still) than the Experience 78.  I think my observations still have some validity, as everything I said applies in comparison of the Experience 78 to my older Nordica Hot Rod Pro Helldiver skis at 90 under foot.

I knew the rentals sucked, I guess I didn’t realize just how much!