• For more information on how to avoid pop-up ads and still support SkiTalk click HERE.

geepers

Skiing the powder
Skier
Joined
May 12, 2018
Posts
4,256
Location
Wanaka, New Zealand
Interesting presentation from the PSIA National Academy 2019 on research on the effect of ski width on muscle and joint stress in alpine skiing.


At 90 minutes needs some more review however this item seems very relevant to anyone undertaking instructor certification. (Not surprising given the type of moves that need to be demo-ed.)

Ski-Widthvs-PSIAExam-Score.jpg

This slide is around 58 minutes.
 

LiquidFeet

instructor
Instructor
Joined
Nov 12, 2015
Posts
6,697
Location
New England
I was there for that presentation. That exam score slide was the part of his talk that made the biggest impression on me.

Playing devil's advocate here. The conclusion implied by the slide either represents the impact of ski waist width on the candidates' overall quality of skiing, or the correlation of exam tasks with the skills that 70-80 mm waist widths support. Those two are not necessarily the same.

I wonder what people think about this. I respect the exam tasks for the most part and how they are scored, thus the "devil's advocate" thing.
 
Last edited:

LiquidFeet

instructor
Instructor
Joined
Nov 12, 2015
Posts
6,697
Location
New England
He never said, or I didn't catch it. I don't think he said what year they were from, either. I'd like to see him write this report up for 32 Degrees, with footnotes and citations and all the details. Those numbers are worth thinking about.
 

MattFromCanada

Professional Something-or-another
Skier
Joined
Nov 12, 2015
Posts
101
Location
Vancouver/Whistler
As a CSIAer, two questions:

First, what’s a passing score?

Second, is it possible that the people who show up on 110s for exams are just so out to lunch that they wouldn’t have passed even on an appropriate ski?
 

Kneale Brownson

Making fresh tracks forever on the other side
Instructor
Joined
Nov 12, 2015
Posts
1,863
I'd like to see him write this report up for 32 Degrees, with footnotes and citations and all the details. Those numbers are worth thinking about.

Has that been suggested to him or PSIA?

A really old rule of thumb for exam candidates: Ski the type of ski the examiners use.
 

mdf

entering the Big Couloir
Skier
Team Gathermeister
SkiTalk Supporter
Joined
Nov 12, 2015
Posts
7,215
Location
Boston Suburbs
As a CSIAer, two questions:

...is it possible that the people who show up on 110s for exams are just so out to lunch that they wouldn’t have passed even on an appropriate ski?

I wondered that too. And more generally, if we are seeing a correlation of competece with width preference, rather than a causal effect of the actual width.

A really old rule of thumb for exam candidates: Ski the type of ski the examiners use.

Because that is the right tool that day, or because it predisposes the examiner to unconsciously (or consciously, I suppose) prejudge you favorably?
 

Mike King

AKA Habacomike
Instructor
Joined
Nov 13, 2015
Posts
3,381
Location
Louisville CO/Aspen Snowmass
As a CSIAer, two questions:

First, what’s a passing score?

Second, is it possible that the people who show up on 110s for exams are just so out to lunch that they wouldn’t have passed even on an appropriate ski?
If you watch the entire presentation, you will find that there are differences in technique resulting from the differences in forces resulting from wide skis. Showing up for an exam on 110's probably means that you don't have a narrow ski. And that probably means that you haven't learned the ski technique that the examiner is looking for. In other words, the biomechanics that result from skiing wide skis don't lead to the ski performance that the examiners are looking for.

Mike
 

Kneale Brownson

Making fresh tracks forever on the other side
Instructor
Joined
Nov 12, 2015
Posts
1,863
Because that is the right tool that day, or because it predisposes the examiner to unconsciously (or consciously, I suppose) prejudge you favorably?

Because it's likely the right tool for the location. Most certification exams require prior participation in a precourse. What the examiners use there are likely what they will use on exam day too.
 

fatbob

Not responding
Skier
Joined
Nov 12, 2015
Posts
6,288
Hmm correlation with tasks that can best be performed with a 70-80mm ski?
Is anyone surprised instructor examination tasks being what they are?
 

Mike King

AKA Habacomike
Instructor
Joined
Nov 13, 2015
Posts
3,381
Location
Louisville CO/Aspen Snowmass
Thing is, movements you develop on traditional widths apply just fine on wider skis. The inverse may not.
@Kneale Brownson, did you watch the entire video? The implication of the video is that because of the greater ground reaction forces on the knee, hip, and musculature caused by the wider width, there are significant differences that arise in biomechanics. There is greater rotation of the lower leg, there is less knee flexion, and there is less dynamic range in flexion. There is also a difference in turn shape, with maximum pressure arising later in the finish of the turn. There's also less edge angle, and more pressure on the inside ski. And these results are for high level skiers: WC, National Champions, and demo team members. What's a mere mortal trying to pass their level 2 or 3 exam to do?

What the members of the PSIA-RM Alpine Committee I've skied with (Jonathan Ballou, the outgoing chair, Josh Fogg, Neil Conners, et. al.) plus members of the demo team (Ballou, Fogg, Smith, Simpson) and former demo team members say they are looking for is ski performance, namely that the ski is engaged at edge change, the ski is bent before the apex of the turn, maximum pressure comes at the apex or slightly later, and there is flow/energy that is conserved and taken through the finish of the turn into the start of the new turn. Given the changes in biomechanics that come from managing the forces imposed by a wide ski, it's unlikely you will achieve those on a wide ski.

So, the takeaway I get from this is that if you want to maximize your likelihood of passing a Level 2 or 3 exam, get yourself on a narrow ski and figure out how to get ski performance from it. It is a much harder task to accomplish on a wide ski.

Mike
 

James

Out There
Instructor
Joined
Dec 2, 2015
Posts
24,440
From the graph, use slalom type ski for level 3 or under 75ish mm.
But use what you feel comfortable on.
110's for a level 3? Maybe not.
But let's have 12 pgs of why this is archaic.

There is greater rotation of the lower leg, there is less knee flexion, and there is less dynamic range in flexion. There is also a difference in turn shape, with maximum pressure arising later in the finish of the turn. There's also less edge angle, and more pressure on the inside ski. And these results are for high level skiers: WC, National Champions, and demo team members. What's a mere mortal trying to pass their level 2 or 3 exam to do?

That's the theory anyway. The big difference is a narrow ski responds to subtle ankle movement laterally. On a wide ski, you've got to use a lot more lower leg inclination right away.
But, it's easy to get into a tail pushing or pivoting habit on a wide ski.

IMG_6541.PNG

Marcus Caston. That's at least a Bonafide at 98mm. Maybe Ballou and the demo team should ski with him?

The other issue is that a 110mm ski is likely to have gobs of rocker. That's not usually beneficial in an exam. Plus really wide skis aren't great in bumps.

At some point they should include mandatory skiing of different ski designs. Should be a random pick a fat, rockered demo ski by lottery. Figure it out in one run.

 

Erik Timmerman

So much better than a pro
Instructor
Joined
Nov 12, 2015
Posts
6,302
Marcus Caston makes my knees hurt. If anything, I think that video proves the OP's point. Even Robby Kelley goes from awesome to above-average on the 100mm skis. And don't get me wrong, I like the fat boys, I ski on them often, and I don't think exams should be done on 30m FIS skis.
 

fatbob

Not responding
Skier
Joined
Nov 12, 2015
Posts
6,288
At some point they should include mandatory skiing of different ski designs. Should be a random pick a fat, rockered demo ski by lottery. Figure it out in one run.

Great idea. Certainly seen BASI folk struggle a bit on an unfamiliar ski.
 

LiquidFeet

instructor
Instructor
Joined
Nov 12, 2015
Posts
6,697
Location
New England
I'm not willing to watch that talk again after being there for the original thing. It's too long. But I just took a look at my notes. Here are some things I wrote down.

--75% of sales last season were "fat" skis. Manufacturers depend on the resulting revenue.
--What's "fat" is not concretely defined. But anything under 80 at the waist would not be considered "fat."
--Most recreational skiers ski 8 days a season, on groomers.
--Manufacturers tend to market fat skis to recreational skiers as all-mountain do-it-all skis.
--PSIA exam candidates who scored the best were on skis measuring 80 and lower at the waist.

The research on how fat skis impact the skier's movements was done well. The researchers put a device on Deb Armstrong's feet/boots that measures what the boot/ski is doing edge-wise and how the pressure moves through each turn and so on. Deb skied the same set of gates on the same run with three different skis having three different waist widths, and as she skied the device recorded what the skis did. They got Deb Armstrong to do the skiing because her turns are extremely consistent. That meant that any ski performance variations through the course as the skis were changed would be due to the ski differences. I did not write down the ski models and don't remember if the speaker told us about that, but it was obvious that the study was designed to minimize the impact of any other factors besides waist width.

In post #12 @Mike King discussed some of the conclusions of the researchers. Given the precision of the study, I'm willing to trust their conclusions.

During the Q&A, I asked the speaker if getting this paper published was possible, given the needs of manufacturers who advertise in most ski magazines. I did not get a straight answer, but the audience chuckled. @Mike King, did you listen to the very end and was that question on the video?
 
Last edited:

James

Out There
Instructor
Joined
Dec 2, 2015
Posts
24,440
Because that is the right tool that day, or because it predisposes the examiner to unconsciously (or consciously, I suppose) prejudge you favorably?
More like fat is neg prejudgement, but if you can deal with it, you can pass.

Marcus Caston makes my knees hurt. If anything, I think that video proves the OP's point. Even Robby Kelley goes from awesome to above-average on the 100mm skis. And don't get me wrong, I like the fat boys, I ski on them often, and I don't think exams should be done on 30m FIS skis.
While I agree, most wcup racers just look average on video free skiing. Show me Robby Kelley looking awesome free skiing. That was partly my point in the other thread.
 
Thread Starter
TS
geepers

geepers

Skiing the powder
Skier
Joined
May 12, 2018
Posts
4,256
Location
Wanaka, New Zealand
I was there for that presentation. That exam score slide was the part of his talk that made the biggest impression on me.

Playing devil's advocate here. The conclusion implied by the slide either represents the impact of ski waist width on the candidates' overall quality of skiing, or the correlation of exam tasks with the skills that 70-80 mm waist widths support. Those two are not necessarily the same.

Apparently it was data the presenter gathered with Ron Kipp on 248 candidates for L2, L3 (57:30). It was for an article for 32 Degrees - a few years back he says.

The candidate's score in the graph is an average for all the tasks they need to perform.

Given that the correlation is almost identical for L2 and L3 and it is for a reasonable sample size (just over 120 for each level) I'd take hazard a guess that your second conclusion was the better fit.

First, what’s a passing score?

Some-one in the audience asks - presenter says he thought it was 3.

See, that's why our CSIA is optimal - we have to score at least 6.:P (Spinal Tap.)

That's the theory anyway.

The presenter goes through the findings of 4 research studies. What @Mike King posted re difference in loads/techniques are the conclusions of those studies. So maybe more than theory - unless you are using the word 'theory' with its scientific meaning.
 

oooh

In the parking lot (formerly "At the base lodge")
Skier
Joined
Apr 5, 2018
Posts
2
In the East, the passing score is 4 on a scale of 1-6. But the slide appears to show that they use a scale of 0-5 there.
 

Kreative1

Booting up
Skier
Joined
Feb 7, 2019
Posts
10
A quick Google search says that Ron Kipp works in the Intermountain Division of PSIA not sure who asked that before.

In the East, the passing score is 4 on a scale of 1-6. But the slide appears to show that they use a scale of 0-5 there.

I don't think I have heard of anyone Averaging a score of 6 for an exam (which would mean they got straight 6's on everything). I reckon that an average of 4.5 - 5 would be the highest you would see 99% of the time. That failure rate looks about right for a level 3 skiing exam anyway, what is it historically like 10% pass?

Some-one in the audience asks - presenter says he thought it was 3.

You need an average of 4. Each division is slightly different on tasks/activities they are scored on but you need an average of 4 in each of the 3 categories. For Intermountain it looks like they have "Highlighted Fundamentals", "Application of Fundamentals" and "Versatility Elements". In the "Application of Fundamentals they have to do Basic Parallel, Medium/Long Radius Dynamic Turns, Short Radius Dynamic Turns, Moguls, and Dynamic Free Ski. If someone from Intermountain would care to elaborate on what the typical tasks/activities are for the other categories that would be great. As others have surmised it is easier to ski in a variety of ways on a narrow ski and harder to do so on a wider ski as this whole presentation has described in great detail.

For further information on the scoring here is the PSIA National Score Descriptions
1: Essential elements were not observed
2: Essential elements are beginning to appear
3: Essential elements appear but not with consistency
4: Essential elements appear regularly at a satisfactory level
5: Essential elements appear frequently above the require level
6: Essential elements appear continuously at a superior level
 

Sponsor

Staff online

  • Andy Mink
    Everyone loves spring skiing but not in January
Top