Foot orthoses and skiing

Hi Jeff,
I have read that "holiday skiers " can have foot pain on the first few days back on the slopes due to intrinsic foot muscle deconditioning over the summer months, and that some podiatrists recommend foot strengthening before going back onto the slopes after a long period away. Do you also make this recommendation ?

 

I was talking about the literature. I was questioning your citation of Winter's article as evidence for ML balance being only at the hip. Winter did talk about ML balance from the ankle (STJ).

 

Your definition of closed chain pronation is wrong.

Pronation and eversion are often used interchangeably. There is no joint, within its usual range of motion, that will give you only eversion. To get eversion at the subtalar joint you will simultaneously get some dorsiflexion and some abduction.

Lower leg muscles can cause pronation (and eversion)

 

We would first need to talk more about the skier and what pain the skier is experiencing while skiing. Many types of ski boot pain.

New boots or rental boots?
Is the size and fit correct for this foot type?
Custom shell work needed for a correct fit?
Use of a custom orthotic device?
Use of buckles?
Number of days skied each season?

Where do you feel the pain?
How would you describe the pain feeling?
Are there any movement that increase the pain, or make it less painful?
How quickly do you feel the pain after putting them on?
Does the pain go completely away after having the boots off for more than twenty minutes?
Were there any on-hill adjustment that you made to the boot that helped reduce the pain?

The pain qualification question elimination game helps us to zero in on the real causes of ski boot pain. So the first task is to use the pain history information to eliminate common problems and find the real issue so we don’t waste skiers vacation days.

Holiday skiers can have short term ski boot pain as well as most skiers using high performance ski boots. Even the most experienced skiers will experience some pain when starting back up using alpine ski boots after a long off season.

As ski bootfitters we joke that we spend the whole first half of the season loosening up the new boots that are too tight, then spend the second half of the season tightening back down those same new boots.

The situation you ask about seems to be more related to compression over the instep, the impeding of blood flow, and the foot not being accustom to the ski boot pressures.

A ski boot fit can have a lot of causes of pain, some temporary types of pain (compression) are not exclusively related to a poor fit, but more related to being accustomed to the ski boots demands and correctly using the closing buckles.
Some compression fit issues go away as the skiers uses the boot more often. The foot can eventually tolerate the same pressure that once caused the pain/discomfort. The cycle is repeated after a long period of not using the ski boot.

Non temporary ski boot pain is usually related to the shapes and movements of the foot inside the boots and tolerances that are too close between the foot and rigid shell.
Once these shape and movement issues are addressed those fit problems are eliminated for the life of that fit (high quality materials, when done correctly). Once the width is correct is will not be addressed again during the life of the boot.


I hike long distances in very mountainous areas all year long. I have no foot strength issues.
I have custom foam liners that are years old now. The former liner material does not compress much with use/age. They are the best performing liners, the firmest liners material you can get and when made correctly also the most comfortable fitting. Most custom foam liners are made in a way to contain the foot, and allow some foot/ankle movements. The liner gets softer as you move forward to the toe pocket where no foam is injected but overall the liners compression does not change much.

The first few days on the hill of each season I can barely even buckle up the shell with the buckles adjusted all the way out. After just a few days my feet are fine and I start bringing the buckles in shorter but use the same catches to position the buckles. Eventually the buckles are screwed all the way out and I start to close the shell more by using the further catches.

•Ski Boot Compression Syndrome
The problem most holiday skiers encounter is not enough time for the foot/body to become accustomed to a ski boot’s compressive fit over the top of the foot.

The important part when skiing on holiday is to not over buckle the boots too tight, especially right after putting them on. Give the foot a little town to get used to the boot environment. You won’t need the boot buckled tightly until you are on top of the hill about to ski.
We suggest you buckle the second buckle from the top (ankle buckle) medium tight to help contain the foot in its heel pocket. Attach the top buckle up loose to the first catch, and leave the bottom buckles undone.

Flex the foot forward aggressively a few times to move the foot back (better use of leverage than kicking your heel back). This reduces the pressure over the instep and allows good blood flow. Important to get the foot back before closing the buckles tightly.

The ski boot has a real heel pocket with depth below the achilles area which is much more aggressive than any shoe for walking. When you flex aggressively forward you should feel your toe room change (get more space) and this shows your foot moved back into the right place. Now go do all the other things you need to do, get in the line, sit on the chair. Once at the top of the run you can now buckle your boots to performance tightness.
The upper buckles warping the leg can take more bucking pressure than the lower buckles over the top of the foot. Very important not to over buckle the instep positioned buckle. The toe buckle only needs to close enough to seal the front from wind and snow entering. When in the right fitting ski boot shell the lower buckles need very little pressure to contain the foot. Use the lower buckles in micro adjust mode to fine tune the pressure in this location of the foot, more than just changing catches. In my ski boot there is a difference of three to four turns of the buckle to adjust over a performance fit.

If you allow just a few minutes of time for your foot to be in the boot loose first, then the foot will not get shocked so abruptly when using those ski boots your foot is not familiar with.

Only use the pressure you need to contain the foot in the boot, don’t rush to over pressuring your foot until it tells you it’s ok.

You should always be doing some work to maintain foot strength and flexibility. That’s also good advice.

- I’m not aware of any specific ski boot fitting pain issues related to the general intrinsic strength of the foot?

In a retail setting we track customer satisfaction (you can return boots for a full refund) in my shops we only see one or two returns each season because of a fit we can’t solve our of hundreds of boots sold each year. We solve the majority of ski boot fits.

I would estimate not using the buckles correctly accounts for about 60% of all ski boot pain.
If skiers take the time to find the right buckle pressure you are exerting on the foot. Many more would enjoy their ski boots.
You start too loose, tighten a little bit, then ski, tighten a bit more, ski more… at a certain point the boot will start to hurt, now back it off and start to use the micro adjust features to fine tune.
If you do this bracketing, you will find too tight, and feel the too loose position. The right boot pressure is in the middle. The amount of pressure needed on the foot changes with technique, terrain and snow conditions.

•Movements
Uncontrolled movements with too large range of motion inside the rigid ski shell last can cause pain
•Shapes
Differences in foot shape to shell last shape and volume can cause pain
•Compression
Most problems not relate to shape and movement.


*That’s a long one, I’m tired from working all day and I’m not going to proof read it five times. Sorry if there are mistakes in the writing.

Have a great holiday

 

And that would have been a great opportunity for use to use a example of your evidence. Maybe even just one quote??

like this one here:
Summary and Conclusions
“Depending on the stance position taken, many combinations of an ankle mechanism and a hip (load/un- load) mechanism are evident. In side-by-side stance, A/P balance is totally under ankle (plantar/dorsiflexor) control, whereas M/L balance is under hip (abductor/adductor) control.”
Winter 1996

Another question:
What’s the difference between a moment and a movement?
Like as in, Pronation is a moment in a lower extremity eversion movement.

Closed chain
The foot is fixed and significant movement happens from above.
The skier is interested in movements they can improve, not involuntary moments they have no control over.

tag off, your turn.

 

“feet as the steering wheel in skiing”

No, not really. The feet are the end of the balance, control, power system of the lower extremity. The feet act more like the tire absorbing and reacting to balance issues.

•Athletic Stance as a tool
The small fore-aft ankle movements inside a ski boot are reactionary and balanced based. Pressure distribution on the ski is also controlled by the stance on the ski. Forward pressure to start the turn, balanced neutral stance against the largest forces in the apex of the turn, then moving to the rear as we release pressure on the ski which can create acceleration in racing at the finish of the turn.

•Lateral tools
Initial edge angle and ski attack angle are set with inclination as the turn starts. The higher the speed of the turn the more dominate inclination becomes a tool as the body balances against higher forces.

•Rotary tools
The edge angle is controlled with the fine tuning of angulation of the lower extremity. Angulation of the knee (adduction of femur in a flexed position) is the quickest method to increase edge angle at slower speeds, but may be unstable at higher speeds. Hip angulation is more dominate in higher speed turns. Hip and knee angulation creates a strong position to resists the most force on steep runs.

•Vertical
The larger power movements are vertical in nature, extension - flexion of the LE (shank, thigh, hip) which include the use of weighting and unweighting within the timing of the turn transition.

The movements in skiing are based on the larger limbs bracing against the powerful trunk to exert force to the snow while at the same time absorbing disturbances.

People hate it when I say this but, we don’t ski with the feet.
The feet are very important in balance tasks while moving at speed in most all sports and they aid in stabilizing the big limb movements of the body while skiing but they have no engine. The feet are all suspension and no pop.



The feet are the base of support and in most high performance carved turns the BOS is well away from the centerline of the body.

I would not position the foot in a pronated position while using a direct foot molding method because of the inclination of the whole body away from the BOS.
I would try to achieve the STN neutral position of the foot using STN palpation, observing STN range of motion, observing navicular shape change and drop, and skin fold movements during ROM while using a direct foot mold method for skiing and sports performance.

 

Closed chain pronation moment (corrected)
Eversion, adduction and plantar flexion

Eversion is the lateral component of both. ✔️

When you explain how the foot works, are you explaining how the foot works in walking gait, or how the foot works after it enters a confined environment with compression holding the foot down with enough force to not allow the heel to lift even with extreme forces compared to walking or running. The foot which in some top aggressive turns on hard snow might be a foot or two out away from the COM. The foot which can be thrust forward and balanced against in a rearward body position to create acceleration in finish of a turn. The foot ankle in skiing is not the same device used for liner waking and running. The needs, demands and results of movements are different.

The foot in skiing is not just an adapted walking tool. It’s a whole different action with completely different goals and intentions of how to get out of one turn and into another.


Pronation of the foot is not a alpine skiing term.
Just because you use it everyday in your work on the foot does not mean it’s an important moment inside a well fitting ski boot.

The movements needed to tip a ski on to its edge come from above the ankle. The large muscles of the lower limbs are used against the torso to create accurate and complete changes of direction. We use whole body movements in skiing to deal with forces that can be three times body weight during the apex of a turn.

I tell my customers when the boot fits right, you should not have to think about your feet when performing skiing actions.

Rec skiing on a lower level pitch in soft with slow speeds. There are an amazing number of ways people make the ski turn. There are few high consequence turns in rec skiing at a resort.

In the dangerous environment of alpine ski racing performance and big mountain backcountry skiing we have very clear movements we concentrate on to improve technique.

The foot-ankle balancing and stabilization moment reactions are essential within the larger movements in skiing and those small micro reactions at the foot-ankle level create the stability for the rest of the body to change position while gliding in motion on a sloped unstable surface. The foot ankle is a net negative joint that spends more energy absorbing forces than producing them. Even more so when the instep is compressed by the performance fitting ski boot. The foot-ankle is the bone attachment point for the big muscles connected to the limbs above. Action of the muscle moves the limb which effects pressure at the foot with connectivity.

The ski boot assists in creating a cone of stability around the skiers base of support to be use with large muscle movements.
The movements themselves to control and change direction in alpine skiing come from above the foot-ankle level and are whole body movements. Whole body movements with the base of support well outside the COM resisting against a somewhat predictable force.

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The Winter paper was talking about side by side stance. I was talking about single limb stance. Winter also did a paper on medial lateral balance in gait and did mention that STJ inversion and eversion could fine tune the gross balance that was determined by foot placement.

Newton's 2nd law for angular motion. Moment = moment of inertia x angular acceleration. Moment is what causes the motion (angular acceleration.) Moment is the same as torque.

Do you have a quote for your assertion on closed chain motion. You see eversion with closed chain pronation.

 

In my mind we are talking about a method to initiate the ski turn. “Pronate the foot to initiate the turn”
Many ski instructors are now using the term pronation as an action term to start the new turn?? Replacing the traditional terms.

After transition we are balancing on both feet and then we shift our balance from centered two footed balanced position to more over the inside edge. The confusing part of applying this to skiing is that we use a lead in skiing. The inside foot is ahead of the outside foot at some points of a turn. But this ski lead stance only happens because of steepness of the slope and our traverse angle balance requirements to the slope (John Howe Skiing Mechanics 1983, Ron LaMaster Ultimate Skiing Human Kinetics 2010)
When a skier is between turns the weight is balanced between two feet, then shifts to one footed balance. From a straight running position (with no slope influence) to a turning position with a traverse aspect included and the lead starts after the weight shift to the one footed stance.


Closed chain pronation
Sorry, I checked three sources??

Again I’m trying to think of the foot compressed inside the tight confining ski boot. Foot joint moments and movements are available with a boot fit, but at a much smaller range. The heel is only allowed to lift a few mm.

Ohio State
https://ouhsc.edu/bserdac/dthompso/web/gait/knmatics/stjclose.htm

Dr Glass DMP
Video


Is this incorrect?
Around 3:10 for fixed plane movement.
Around 6:00 in for closed chain pronation

Thanks for taking the time to help me with this.
I am listening to everything you state.

The thing I learned here in this discussion is that moments of the shank relative to the ankle (AP and ML) include some tri plane moments or movements in the balancing aspects of LE movement in general.

 

Control of whole body balance in the frontal plane during human walking.
MacKinnon CD, Winter DA. J Biomech. 1993 Jun;26(6):633-44.

Boot preventing motion:
It's not so much the motion of pronation, but using the muscles of the leg to shift the location of force underneath the foot. This shifting of force can occur with very little foot motion. The peroneus longus muscle should be a very important muscle for skiing because it can shift force to the medial side of the ski faster than moving the whole leg to push the boot to evert the ski. As you said there are many ways to make a turn. I would bet the better skier uses all of them.

Open and closed chain.
I have not found this concept to be very useful. Once you understand that with ankle joint dorsiflexion the talar head moves closer to the anterior aspect of the tibia, you don't really care if it is open chain or closed chain. Dorsiflexion is dorsiflexion.

On the video in previous post.
Some good parts, some bad parts. It seems like google is getting worse. If you searched closed chain motion of the subtalar joint and that's what you got, the results weren't very good. I tried searching function of peroneal muscles and the first three hits were quite vague.

 

Many types of turns
It’s why I’m doing this research on the the techniques. The tools of skiing. The most confusing part about discussions around this sport is all the different combinations of techniques and tactics that could be used in the same situation. So, people are often seeing it from different technique and tactical points of view.
I’m not talking about what technique is best, just looking at the mechanics. To do that, I look at the very top most aggressive racing turns because that is the functional technique that takes the style factors out. In rec skiing we have a lot of styles, terrains, surfaces alone with some very different athletic capabilities. The top races use all the tools without style favor and show the extreme limits of what is possible when they make great turns, and more so when they make mistakes and quickly recover losing less time than other skiers.

•That’s why I came here for some help from the passionate professionals. I appreciate your time and the discussion.

The books on mechanics I listed, along with the most current research (with references) is the consistent source for skiing info.

•We have some new technology coming along soon and I’m guessing there will be some creative differentiation in selling these products. We need solid well understood principles with clear terms or it will easily get all mucked up.

Happy skiing ⛷

Ron LaMaster’s 2010 book is one of the best overall currently. Ultimate Skiing is published by Human Kinetics which is science based.