THE BOOT BOARD FACTOR


While the Ottawa researchers did not explore this aspect, they correctly identified that equipment, including custom insoles, technical skills and ski technique might explain why the pressures recorded under the heel and the head of the first metatarsal of some instructors were much higher than the pressures seen in the same locations in other instructors.  The University of Ottawa studies are the only ones I am aware where the researchers considered the effect  of what is known in research as uncontrolled variables on their findings. Poor technique and interference with the function of the foot and leg caused by the ski boot can ensure that COP remains under the heel.

Although boot board ramp angle and shape have an undeniable impact on the function of the feet and lower limbs, as evidenced by the photographs below of a sampling of boot boards, there does not appear to be any continuity, let alone any standard for boot board ramp angle and the form of the surface that interfaces with the sole of the foot.

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When the effect of  binding ramp angle, which appears to have even more variation than boot board ramp angle, is added to ramp angle equation to arrive at Net Ramp Angle, the possible combinations that make up Net Ramp Angles becomes unlimited and can range from as little as two to as much as ten degrees.

As if the lack of any apparent standard for boot board and binding ramp angles were not causing enough of an impact on skier/racer performance, there is a factor that appears to be compounding the issue by introducing a layer of inconsistency; boot base shell deformation under loads typical of recreational skiing.

I will discuss boot base shell  deformation in a future post. In my next post I will propose a starting point for a boot board standard.

6 comments

  1. From my experience to this point, zero NRA for skiing doesn’t work for the steep terrain. Steep is relative to the individual and so is the NRA so I’m purposely leaving a wide margin for error! But I still feel that starting at zero and moving up as needed is the easiest from the added experience that it is easy to fine tune at the binding heel piece vs. the toe piece. If I didn’t make it clear enough, it’s a selfish vote on my part and will just need to continue to deal with what we’re dealt with by the ski companies. This also comes from experience of everyday foot wear; I don’t know of any place around home to try on any zero drop footwear and at least I can eventually try via internet thanks to some leads you’ve given me:) Regular foot wear is worse than ski boots because you can at least take them apart and attempt to fix the boot board. Prior to those internet leads I was seriously trying to perfect a method of removing heel material from existing shoes and that is a total disaster!!

    1. “But I still feel that starting at zero and moving up as needed is the easiest”

      I agree. I will post of this soon. The starting point is to learn how to assume a strong stance while standing barefoot on a flat, smooth, level surface. A strong ski stance is not natural. It must be learned and acquired through kinaesthetic rehearsal. Once a kinaesthetic sense of strong stance has been acquired, the next step is to move to a stance ramp and assume the stance with a 2.5 degree ramp angle. Once a kinaesthetic feel has been acquired, the next step is to experiment by adding shims that increase or decrease ramp angle by 0.1 degrees. When the best angle is sensed, that becomes the base or reference angle for Net Ramp Angle. This does not mean that it will never need to be adjusted. I do not know of any way to arrive at the optimal angle. This is an area where the ski industry should have an ongoing research program. But so far, they appear to have given this issue little attention.

  2. Then to compound the problem, an over zealous boot fitter grinds the boot board down at some random angle for who knows what reason…. Possibly because the boot boards are manufactured with infinite twists and angles most boot fitters and people don’t realize how important it is to have a precise platform to stand on.

    1. How about a stable platform and a consistent standard that serves as a reference with which to assess the effect, whether positive or negative, of interventions such as arch supports, custom insoles and prescription orthotics?

      1. I guess the ‘problem’ is that if all ski boots had a logical working standard as a starting point then it would be hard to market ones’ own brand over others? Returning to this after a half hour of feeding the horses gave me a chance to ponder; selective hearing is part of the reason. Most equipment designers were probably successful racers/skiers so the equipment worked for them so why screw up a good thing? I realized in that half hour I do the same thing; I hear what I’m familiar with or want to, and don’t what isn’t even if it is the correct answer. The items you present in your posts that I’ve thought about or experimented with already I can quickly incorporate into my equipment. Other things like your method of keeping the foot held down at the instep I’ve had great difficulty with and no understanding that is satisfactory to me as yet.

        I’m easy; ideally I would start with the boot board a flat plate in all directions and parallel with the bottom of the boot. From there I believe one would never have to raise the toe, always raise the heel to what ever is the correct NRA for that individual skier. That only works if the ankle can flex and shank angle to the degree you have been advocating for decades. Then NRA would be adjusted at the boot (Raichle did that and I believe Dalbello has a couple models today) or at the binding (which I have a working model thereof I’ve skied for over a decade) which is the correct place to do it because once the boot is set up properly, DON”T TOUCH IT unless something ain’t working!!!!!!! Done properly at the binding, one gains a number of things beyond just correct NRA and thus improves ones skiing ability way beyond what a pair of skis can.

      2. I suspect that the lack of any standard for such things as boot boards has to do with the lack of any standards, let alone any accountability, in the shoe industry in general where foot function can be adversely affected with impunity. It has been known for decades that raising the heel more than a small amount in footwear will cause shortening of the Achilles tendon and a re-alignment of the major segments of the body that makes in impossible to walk the way we were intended to walk. I was one of the early adopters of the minimal, low to zero drop, shoes. It quickly became apparent to me that I had to go through a long, slow transition period to “get my feet back on the ground”. A good read on this issue is Katy Bowman’s ‘Whole Body Barefoot, Transitioning Well to Minimal Footwear’. While I think it unlikely that zero Net Ramp Angle may turn out to be optimal, the effect of shoes with elevated heels has a significant effect on the ability to ‘get over’ the head of the 1st MT until the Achilles and the muscles of the lower limbs have adjusted to a lower Net Ramp Angle.

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