Pilates rotating discs for femur rotation training?

[Steve]

Oh I rotate them more and manage how much they rotate compared to each other. But it supports and builds muscle memory for creating rotation from flexion/extension as well as pivoting.

 

[Steve]

 

[LiquidFeet]

....
I like to drill pure pivot slips first thing in the AM, on corduroy. I pick a few ridges in the corduroy, and try to keep the distal point of my tibia right on those few ridges - no forward. No back. Looking back on my tracks I can use the visual features of the corduroy and my tracks, to gauge how precise my movements were.....

I wish more instructors would focus on keeping that underfoot pivot point - and pressure point - right there under the tibia... which is at the back of the arch/front of the heel. Just for clarification, in this image the bigger leg bone is the tibia. It intersects the foot at the very back of the arch area.

It's hard to find a diagram that shows how the tibia meets the foot relative to the arch. That model above of the right foot is photographed from the outside of the foot, where the arch does not show up. Below is a drawing of the right foot showing its inside half (so hard to find). The arch is visible, and it's clear the tibia, bearing all the weight of the body above it, comes down onto the foot at the very back of the arch.

I think the reason PSIA doesn't emphasize this back-of-the-arch business is that so many people ski with lower legs rising straight up from the ski. They have light shin-tongue contact, if any, so skiing with underfoot pressure under the tibia will put them in the back seat. @martyg, have I got that right?

 

[Steve]

With any forward lean, either in the boot, or just in a natural stance with the ankles slightly closed, the pressure point is not directly under the tibia. It's more forward of that.

 

[LiquidFeet]

@Steve, I worked continually this last season on having reliable shin-tongue contact (not a problem as I've worked on this for years) while having the underfoot pressure point at the back-of-the-arch/front-of-the-heel (new to me as in the past I've worked on having that pressure under the middle of the arch).

It can be done. Once the shin-tongue contact is securely held in place, one needs to move the CoM carefully fore-aft to fine-tune where the underfoot pressure is. I repeated to myself the mantra, "arch-heel," "arch-heel," "arch-heel." The results were unquestionably good.

I'm sure someone will proclaim now, on this forum and in this thread, that (a) what I just described is impossible, and/or that (b) the results were not good. They will be wrong.

 

[Steve]

Yes I agree that we move that pressure fore and aft throughout the turn. I was just making a general comment that showing the bones of a foot and say therefore the pressure point is under the tibia, didn't take the lower leg shaft angle into consideration.

I agree with you that the "center" is further back than PSIA says.

 

[martyg]

Yes I agree that we move that pressure fore and aft throughout the turn. I was just making a general comment that showing the bones of a foot and say therefore the pressure point is under the tibia, didn't take the lower leg shaft angle into consideration.

I agree with you that the "center" is further back than PSIA says.

What does PSIA say? Who is your Source of the Truth in PSIA? What is the last National Academy that you attended? When was the last time you skied with D-Team people?

 

[LiquidFeet]

What does PSIA say? Who is your Source of the Truth in PSIA? What is the last National Academy that you attended? When was the last time you skied with D-Team people?

I'll answer.
I went to National Academy at Big Sky not last year because, well, I cancelled, but the year before that and the two previous years before that. I did indeed ski with team members at those events, and at other events. I also ski yearlywith one retired team member for a private lesson. I've only discussed underfoot pressure with one of those people.

But I also ski with local trainers who are not so lofty in the organization and they did not all get the memo. Now whose fault is that? I'd say that PSIA is partially responsible.

In the most recent Alpine Manual (2014) there's a glossary at the end. In the entries for base of support, pivot point, pressure, balance, and pressure management, there's no mention of where under the foot the pressure might be. One entry does say pressure should generally be in the middle of the ski. That's pretty much under the ball-of-foot when we are talking about standard binding mounts. There is no entry in the glossary for arch, ball-of-foot, balance point, or underfoot pressure. There is no index. I have the print version.

PSIA could print refrigerator magnets proclaiming skiers should adjust underfoot pressure to be at the back of the arch. They could print bumper stickers. Helmet stickers. They could sell bobble head skiers with jerseys proclaiming it for the locker room. How about knitting it into wool beanies? I can see locker rooms with battery driven wall clocks whose faces say BACK OF THE ARCH BACK OF THE ARCH BACK OF THE ARCH (that's 12 words for 12 points on the clock). It wouldn't be that hard to promote this should PSIA decide to do it. People would get the message, even if they didn't like it.

 

[martyg]

I think the reason PSIA doesn't emphasize this back-of-the-arch business is that so many people ski with lower legs rising straight up from the ski. They have light shin-tongue contact, if any, so skiing with underfoot pressure under the tibia will put them in the back seat. @martyg, have I got that right?

It depends on who your Source of the Truth is in PSIA.

A bit of contact with the tongue is a good axiom / touch point for more entry level skiers. It definitely helps them get in a more athletic stance. It helps them capture a sensation that we can build on.

As skiers progress - and I have said this elsewhere, and particularly if they have footbeds made by a master like Jeff Grey or Aaron Anderson - I do diagnostics on their stance, focusing on that point that you describe and helping the student achieve greater range of motion through optimizing their stance. I then shim their boot cuffs on the hill with trail maps so that pressure is equal fore and aft. Once they get off the hill they go see the bootfitter to make it permanent.

If you are working with an instructor who is insisting on cuff pressure, ask why. All good if it is to help you capture a sensation. If they tell you that you should be on the balls of your feet, find another instructor. They likely haven't been to any clinics in the last 10 years to upgrade their understanding.

There is a sect within PSIA that really embraces human mechanics and elements of dance and Martial Arts. It is embodied by the Edwin Terrell Memorial Clinic that is held in PSIA-RM. I am a big fan of that methodology. The langauge is a bit more "wax on / wax off", less mechanical. We discuss less about COM and more about energy. And consistently, that point of neutral, of power, and balance, is standing on your tibia. It is your center.

 

[LiquidFeet]

@martyg, have you encountered people who take into account where the body weight is dominant in different people's anatomy? There are some of us with narrow torsos and no muscles to speak of above the belly button, but plenty of muscle (and fat too) below it. Shin-tongue pressure is more important for such people if their bindings don't put their feet forward of the usual mount point. Most recreational skiers don't move their bindings to fine-tune their balance point.

On the other hand, maybe shin-tongue contact (not pressure, contact) is actually good for all skiers most of the time. Are you so sure it's not? I'm surprised at your disregard for it.

 

[bud heishman]

View attachment 108863

Hey that looks like fun!