Are Fat Skis Killing Your Knees?

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Are Fat Skis Killing Your Knees?

Postby Max_501 » Tue Feb 27, 2018 9:11 pm

http://www.montanakaimin.com/news/your- ... b192c.html

Originally designed for powder, more people are using fat skis for everyday use, and new research suggests they could end your season early.

John Seifert, an associate professor of health and human development and avid skier at Montana State University, researched the effects of wide skis on knees and ankles.

Using leg sensors, Seifert monitored muscle and joint strain on skiers.

Seifert said when skiing hard-packed snow on a ski wider than 80 mm underfoot, the force needed to turn the skis puts an undo amount of stress on knee and ankle joints.

“It appears right now there is a threshold in the mid 80s, and an additional lever arm,” Seifert said. “That additional lever arm provides extra torque, and is causing sore knees and ankles.”
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Re: Are Fat Skis Killing Your Knees?

Postby skiffie » Wed Feb 28, 2018 12:39 am

I can personally confirm this! I had a pair of wide skis (108 underfoot) that I bought before PMTS... then I had left my narrow skis in Europe and they were all I had to ski back home (this was with HSS-fitted boots). I don't know about vertical torque, but they definitely put side to side (twisting) torque on my knees - it was worst on any sort of road where it felt like my knees were twisting back and forth multiple times a second - should probably have loosened the boots lol. Knees felt like jelly after each run, and even though I only skied 3 days that year I ended up with patellofemoral syndrome because my ligaments had been torqued enough to loosen them and it turned out I had an underlying (unrelated) muscle imbalance. The next year I skied on 88mm all-mountain carvers and even though they're a bit wide for PMTS, no knee problems.

Also this article in case anyone is interested. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4541126/
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Re: Are Fat Skis Killing Your Knees?

Postby jbotti » Wed Feb 28, 2018 8:49 am

It would be interesting to see a study of effects on the knee from skiing fatter skis using high level PMTS skiers versus the general skiing public. I notice fatter skis requiring stronger tipping and having more of an impact on the knees but I think for those that tip to get edge angles the impact is substantially less than for those that are using knee drive (which just destroys the knees).
Balance: Essential in skiing and in life!
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Re: Are Fat Skis Killing Your Knees?

Postby John B » Wed Feb 28, 2018 8:52 am

Totally agree. The times that I have demoed stuff that wide on the typical conditions that we see around here [good firm cord], I have returned them after no more than three runs. "Big fatties" for me, means 83 wide Stockli Scale Deltas.
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Re: Are Fat Skis Killing Your Knees?

Postby skiffie » Wed Feb 28, 2018 11:43 am

jbotti wrote:It would be interesting to see a study of effects on the knee from skiing fatter skis using high level PMTS skiers versus the general skiing public. I notice fatter skis requiring stronger tipping and having more of an impact on the knees but I think for those that tip to get edge angles the impact is substantially less than for those that are using knee drive (which just destroys the knees).


Before PMTS and with my old (much looser) boots, I had no knee pain with the wide skis. They were just really fun in soft snow because they floated - it was kind of like being on a hovercraft. After the new boots that feeling was gone lol.
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Re: Are Fat Skis Killing Your Knees?

Postby Vailsteve » Thu Mar 01, 2018 6:05 pm

Yes.

Next question.

Vailsteve

PS. Ok — true if you tip on and off your edges. If you twist and rotate and skid, the knees are fine.
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Re: Are Fat Skis Killing Your Knees?

Postby Vailsteve » Thu Mar 01, 2018 6:40 pm

One more thought.... I have a pair of the older Head RnR’s— 94mm under foot. They are both my powder skis and, in my opinion, a very good training ski to REALLY practice my tipping. My theory is if I can tip a pair of 94mm waisted skis, I can tip a 66 mm ski.

After a day of using them on the frontside groomers here at Vail, I really don’t notice any difference in knee pain— I don’t have any. But they do require more effort and focus to tip on and off the edges. HH has written extensively about relaxing while skiing—which, after my heart surgery I really do focus on— so maybe I am getting better.

One of my all time favorite videos is Harald skiing a pair of the RnR’s on Youtube. Amazing skiing — and ANOTHER unbelievable skill to emulate.

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Re: Are Fat Skis Killing Your Knees?

Postby DougD » Fri Mar 02, 2018 6:44 am

Vailsteve wrote:One of my all time favorite videos is Harald skiing a pair of the RnR’s on Youtube. Amazing skiing — and ANOTHER unbelievable skill to emulate.

Vailsteve

If I could tip 66mm SuperShapes like HH tips RnR's, I'd be happy...
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Re: Are Fat Skis Killing Your Knees?

Postby Max_501 » Fri Mar 02, 2018 8:14 am

Vailsteve wrote:One more thought.... I have a pair of the older Head RnR’s— 94mm under foot. They are both my powder skis and, in my opinion, a very good training ski to REALLY practice my tipping. My theory is if I can tip a pair of 94mm waisted skis, I can tip a 66 mm ski.


How are you confirming your theory? Many skiers I see on wider boards are getting them on edge with a good deal of banking if they are carving or using rotary if they are bushing. When I want to know how my tipping is going I get video and look at my inside foot to make sure it is leading. Then I check the high C to confirm that I'm getting early edge angles. After that I'm looking at the distance from the snow to my hips and radius reduction (two things that I want to decrease). HH is a master of this and that is why he makes the RnR look like a carving machine.
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Re: Are Fat Skis Killing Your Knees?

Postby Vailsteve » Fri Mar 02, 2018 6:21 pm

Good question Max501. My answer is that I ski a few milk runs every week with a fellow PMTS enthusiast here in the locker room. We usually pick a drill or two and take turns leading and following. We certainly can tell if we are flexing and tipping versus leaning and skidding.

Tipping has been a long long time focus for me. And at this stage, I feel somewhat comfortable in knowing my cues when I am doing a certain drill correctly. Plus, when skiing with James and Geoff (and Diana!!) at ABasin —rest assured they are not shy in telling in when I am NOT doing something right!

My big SMIM this year is foot pullback. It has truly begun to change my CA and CB. This year I finally feel in control on somme of the steeper runs here at Vail— sweet and sour, pepi’s face, jade glade etc. I could not carve these runs without tipping and foot pullback. And the ability to decrease a turn radius by tipping more and counteracting more is a great feeling!!

I do like the head RnR’s, bit I also ski the Stockli Y77’s. 77 underfoot, but with a BIG 128mm shovel. Tipping those is also a challenge.

Anyway, absolutely a fair question and one that I continue to constantly ask myself—am I really doing “XYZ” correctly? A second pair of eyes helps.

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Re: Are Fat Skis Killing Your Knees?

Postby krazzy legs » Tue Mar 06, 2018 8:52 pm

Max_501 wrote:[quote="


After that I'm looking at the distance from the snow to my hips and radius reduction (two things that I want to decrease). HH is a master of this and that is why he makes the RnR look like a carving machine.[/quote]

Is it better to use hips for distance from snow then inside knee distance for snow ?
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Re: Are Fat Skis Killing Your Knees?

Postby Max_501 » Tue Mar 06, 2018 10:14 pm

krazzy legs wrote:Is it better to use hips for distance from snow then inside knee distance for snow ?


If your hip is on the snow where is your knee?
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Re: Are Fat Skis Killing Your Knees?

Postby Darren » Tue Mar 06, 2018 11:40 pm

Max the knee is close to or on the snow also.

Some of the videos I have seen with Reilly skiing locked on edge carving his hips come very close to the snow. The videos I have seen of Greg skiing his inside knee comes very close to the snow. Both are excellent skiers. It is hard to tell from the videos. To me it looks likes Gregs inside knee come closer to the snow compared to his hip then Reilly. I kinda like Gregs locked on carving better as the knee is closer to the start of the Kenetic chain so my thinking is it is faster from edge to edge. Knee or hip to the snow it is very good :)
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