One footed balance and boot alignment

[Si]

Hi Harald,

I'm very well vested in the approach you take to boot alignment. I think what you do makes perfect sense which is why I had you do my footbeds and assess my alignment. I have previously done the external canting on my boots myself, but it was based on your assessment (which I spent a lot of time verifying on slope with one-footed straight runs, one-footed traverses, and free skiing).

With my new boots this past season I initially used temporary external cants taped to my soles to reassess my alignment needs and found the optimal canting to be just about the same as previously (within 1/2 degree). However, I also tried one thing that I don't think you use (and I have doubt you would think is an appropriate part of the alignment process). However, I thought I'd present it to get your feedback.

With the footbeds you made for me, I tested my one footed balance (without ski boots) and tried different (full-length lateral canting) wedges under the footbed to determine which would give me the most optimal one-footed balance. To this degree of wedge I added or subtracted the boot board canting which I measured. I then added the final prescribed degree of canting wedge under the footbed in the boot.

When I did an on snow assessment I found the the addition of the prescribed amount of "pronation support wedge" inside the boot under the footbed gave me balance and alignment that was as good as the temporary external canting I had been using. This assessment was again based on one-footed straight runs, one-footed traverses, and free skiing. While it did improve my knee tracking alignment it did not bring it into as good of alignment as the external canting wedges but did bring it much closer to what it should optimally be.

As I did this at the end of my season I did not have time to adequately explore how much more improvement I could achieve through appropriate addition of external canting wedges but it is on the agenda for next season. In the mean time my impression is that I have already achieved "functional" alignment as good as I have ever felt.

So, my bottom line question is what you thing about this addition of a one footed balance assessment for determining an appropriate amount of footbed cant? My (over simplified?) understanding is that you determine the appropriate amount of cant for the footbed through measurements of range of motion of the foot while working to ensure that the ankle is in a stable position. My most recent experience tells me that adding a dynamic one footed balance assessment for the foot (with footbed outside of the boot) potentially has something to offer. Comments?

[h.harb]

Hi Si,

I am familiar with this approach, I?ve seen it out there and available. Some footbed makers have been for many years adding tremendous inversion to there footbeds, already in the molding and posting process, (lifting the whole medial side).

If you look at the biomechanics, you are essentially inverting the foot and ankle, which initially brings or forces the knee mass lateral or worst, it uses up ankle and foot inversion and blocks eversion range of the subtler joint (making the peroneals useless. .) It may also cause forefoot problems.

This then causes skiers to use more adductor leverage to bring the knee mass back inside the ski edge. This is possibly a ski technique by itself, but not one I advocate, as it adds stress to the knee and it also causes greater rotational forces to occur from higher in the body. I try to reduce these gross influences, with shaped skis especially. This approach will also have some bearing and may cause difficulty for some widths of skis and the effect on the access to tipping of those skis. I?m talking about ski width. A wide ski already requires more leverage to tip. On hard snow the resistance is strong from such skis. If the foot and ankle are locked up by a device induced inverted position, the ankle has little capability for leveraging the boot, co-contraction (balancing movements and stabilizing the joint) or adding controlled fine tuning balance.

My approach is to make the footbed properly from the start. If more posting is desired or if the foot bed is old, some posting can extend the life of the footbed for a short period. But it depends tremendously on the type of foot. This approach would be very harmful to the cavus foot with little range or flexibility.

With Erik Schlopy for example, we do the exact opposite, we make the medial side of the boot board compressible by 2 mm. This helps him evert his foot, as his feet are very rigid and he has difficulty getting his ankle to move medially toward the side of the boot. (a related topic for further disscussion would be foot and ankle movements for levering the boot and ski, and why is it necessary to access the medial side of the boot with the ankle to control edging and make fine tuning adjustments.)

We have done the same with other skiers and athletes with great success. So I guess what I?m saying is that this is a personal preference issue and one that requires experimentation. I would not use it as a universal approach. I am much too influenced by the good measuring process we already have in place and by the results we generate with it. It is a scientific approach and little voodoo is inserted even in the molding and posting process.

What I find is more usual out in the ski world, is that the worst of all combinations are being used and applied to feet and ankles that are totally functional and are actually being compromised with footbed devices. Example: A hard or rigid arched footbed with a radically lifted arch applied, made with no regard for the measurements of individuals or consideration of subtler alignment and no forefoot position taken in consideration.


There may be some benefits to strengthening the medial side of the foot by lifting the footbed or boot board. It sure makes a skier feel like there is a strong edge on the ski, but this is often not a high edge angle or strong edging. There is a difference between the performance related outcomes of these definitions.

A locked or restricted foot causes balancing to occur higher in the kinetic chain. I look at these things logically and I try not to overdo any particular point in the system or joint areas. If you make the footbed with good measuring applied, with proper posting density, in the first place, very little needs to be done inside the ski boot except for special cases. Remember a five to eight year dynamic footbed, like the ones we make at Harb Ski Systems, will get weak after 3 to 4 years of use, (average ski days 30 days a year) that is what you might be experiencing. A pronating foot works a footbed much more than a rigid or strong foot.

Remember, we can all sometimes be fooled by what we perceive as a good adjustment, just because it feels different, not because it is actually producing better performance. The body has a great ability to adjust, especially to incorrect alignment, and after awhile it may even begin to feel natural.

I am, just as most skiers are, susceptible to even extreme alignment variations, sometimes I think I?m accessing my edges and angles better, but after I see some video and analyze the situation, I usually go back to the tried and true measurement. Our bodies are very good at fooling us.

[Ken]

the ankle has little capability for leveraging the boot,

At what point does a recreational skier benefit from punching out the ankle area in the ski boot for room for more ankle movement? Ever?


Ken

[Si]

Thanks Harald for that perspective. I will be rereading that and referencing it when I get back on the snow for further evaluation. I think you make many sound points.

One thing I would ask is whether establishing a point of "best/easiest" balance at the midpoint (and one from which both eversion and inversion are equally and easily achieved) provides some assurance that there is appropriate motion for tipping in both directions, kind of the opposite of a locked foot?

I also understand how alignment farther the leg can be compromised. However, if the knee is originally tracking isnside and is moved laterally nearer center (but not beyond) with this type of inversion canting is that really a bad thing (assuming foot motion is not compromised)?

Thanks for the help with this.

BTW, I did add a little posting on my (4 year old) right footbed which made a noticable improvement as I believe the footbed had gottensoft enough that my foot was always collapsed into pronation. Sounds to me like what you were talking about with footbed weakness and maybe it's time for me to get a new pair?

Best, Si

[h.harb]

Si

I also understand how alignment farther (up) the leg can be compromised. However, if the knee is originally tracking inside and is moved laterally nearer center (but not beyond) with this type of inversion canting is that really a bad thing (assuming foot motion is not compromised)?

If you have a foot and ankle with some range of motion, inversion is typically not the limitation, in 80% of the population, but if you do the canting under the footbed you will first effect foot and ankle range, after that is used up, the lifting will transfer higher to the knee. As you know the knee only moves by femur rotation in the hip joint. So indeed, to have an effect for the knee, you have to certainly to use up all available range of motion in the foot and ankle. Depending on the original degrees of range this could require up to 3mm of medial lift before the knee moves. There just isn't a way around this one, as that's how we humans are built. If the foot and ankle have little range to begin with, you will have almost immediate transfer to the knee, but the skier in this situation will have no co-contraction at the ankle only at the hip. The only way this skier will be able to create leverage over the ski is by using knee drive.

I will suggest that is why so many PSIA gurus are so into leg steering . It?s because they don?t have access to ankle use or understanding of skiing with the feet and ankles. Also notice how little attention is paid by these instructors, to real balance. In PSIA balance is given lip service, they know it?s important, but they can?t figure out how it fits into skiing movements. Their total disregard for the sciences of the body force them to conjure up these weird skiing anomalies they call ATS.

[BigE]

Harald,

There is a saying: If you measure it, you can manage it.

I believe you are right in saying that the effect of ankle movements are very misunderstood. Normally, we are taught how to do MA by looking at the snow, leg and body angles, the boots being hidden from sight by pants.

So, if all you measure is leg and body angles and their impact on the snow, then these are the things that you would address when teaching.

The hidden movements of the feet/ankles in the boots are not seen, so they cannot be measured and therefore are not taught.

[4Slide]

Great thread, thanks!

For kids in particular, and possibly others with very flexible feet and ankles, do you then recommend a more-rigid footbed to maintain the available medial movement within a given range, or does the boot effectively take care of this anyway?

[h.harb]

Big E, I think you are right about instructors not understanding what is happening in the ski boot. I made footbeds for a number of demo team members years ago. At first they hated the footbeds, because they were so used to having a locked foot feeling. They had no co-contraction and never used their ankles. I forced them to stay with the footbeds and after six to ten days of skiing, all of a sudden they began to realize new levels of balance. Most instructors just go out to their local ski shop and have them punch out the generic hard ached product, with no understanding of how this is limiting their skiing. No one on the US ski team uses rigid orthodics.

We measure numerous kids under fourteen. They have huge ranges of motion compared to adults. As we grow older we lose tremendous range of motion, beneficial range, sometimes 80 or more percent of what we had. I therefore do not limit range in kids by building an over posted or overly strong footbed. Why limit a range that you will lose as you grow?

My experience tells me that we lose range of movement because we don?t use it. I prefer to build footbeds for kids that are neutral and properly aligned. I allow for eversion as that is the movement that is most important and the one we lose almost completely. The peroneals muscles activate the eversion movement. Most people don?t have functional use of the peroneals, which are extremely important in skiing balance. The invertors also, are often shut down due to overly supported or hard posted footbeds. Therefore the co-contractors of the ankles never get a chance to develop properly.

So I suggest letting the ankle and foot in young skiers float from a well aligned heel. Let the natural adoption process take place, so balance and movement can be learned to achieve muscle use and co-contraction from lower ankle and foot muscles. The ski boot offers plenty of support for edging and levering the boot.