THE SKI BOOT AS A HANDLE, THE LEG AS A LEVER THEORY


There is a predominant camp in skiing who claim that the ski boot is a handle that skiers use to put their skis on edge. This is the central theme of the pure carved turn camp that posits that expert skiing is simply a matter of holding both skis on edge at the same angle and letting the sidecut of the ski make take control and ‘do their thing’.

Try this. Stand in sock feet or even in shoes on a floor or other firm, level surface. Drive one of your knees towards the L-R center of your body as if you were driving the knee into a turn (i.e. – angulating the knee). What happens? Nothing. The foot stays flat on the floor and the joints of the ankle accommodate the knee angulation (ad-adbuction/internal-external rotation). Put a ski boot on one foot. Now balance on that foot and try to “drive your knee into the turn” (towards the center of the body). What happens? Not much. Why? Because the weight of your body (COP) is under your heel where it is pressing down on the center of the boot where it is preventing it from rotating onto the inner edge of the sole. When the shaft of a ski boot is used in this manner, COP will always be under the heel. High pressure first metatarsal COP and heel-first metatarsal pressure differential management are not possible.

In order for a ski boot to act as handle with which to rotate a ski onto its edge inside, the weight of the body must to be raised off the surface the skier is standing. When a ski instructor demonstrates how driving the knee of one leg into the turn puts a ski on edge on flat terrain (A-frame), most of their weight is on the other foot and leg. If the instructor demonstrates knee angulation while standing on both skis in traverse, the shafts of both boots are already pre-loaded on the legs which are acting as a source of GRF for the GRF that is missing under the portion of the skis outboard of the edges. These demonstrations are nothing more than amateur parlour tricks, illusions from a carnival sideshow magicians act. They bear no resemblance to what the worlds best skiers are doing,  and have been doing for close to a hundred years. In all these parlour tricks, COP is under the heel. In this position COP is distributed along the center axis of a ski towards the shovel and tail. No force is acting across the inside edge. The problem is not with those who make such illogical demonstrations but with those who fail to see through the obvious illusion and accept the premise without question, even though the manner in which the instructor skis usually bears no resemblance to what he or she teaches.

In my next post I will describe the mechanical and biomechanical differences of heel only COP and heel/first metatarsal COPs and the effect on the ski of the resulting pressure differential management. This is the central issue in skiing, the meat in the sandwich.

 

7 comments

  1. After exhaustive testing with my ramp angle, I figure I need in the realm of 2″ of heel lift. That is way more than what you recommend. I think that must be 10 degrees. (Size 8.5 feet) Any less and the tail of my outside ski tends to want to abstem. With that much angle my ankle feels like it’s able flex forward
    and inward giving me more of the pronation effect you’re talking about. I built special wedges/shims that are 3/4″ thick and are installed between the shell and liner giving me a radial canting effect. Without those interior wedges there exists a hollowness there and the outside ski is hard to find. Now with my
    footbeds reformed with ball pockets, my ramp angle set, and radial cuff wedges installed I feel like I’m finally on the right track with my boot set up. Skiing is becoming so much easier and fun.
    Thanks so much for putting your time and energy into The Manifesto! The information you present is awesome-don’t worry about the various opinions out there- this is the age of Narcissus
    after all where everyone knows everything about everything.

    1. For the record, I am currently skiing in about a 15 year old Head Comp. The reason it is that old is that I did not ski for 8 years. My wife’s boots are older. The reason I do not buy new boots every few years is that it is a pain in the ass for me to modify them so my wife and I can ski in the boots. I spent about 35 hours on my wife’s boots. The work included, among other things, disassembling the cuff from the shell, reducing the height, dramatically reducing the forward lean and changing the side cant so it angles inward. It sounds like you are very creative in finding solutions. For this, I commend you.

      “With that much angle my ankle feels like it’s able flex forward and inward giving me more of the pronation effect you’re talking about.”
      When you say your ankle feels like it can finally flex forward do you mean you can finally flex the cuff forward by pressing your shin against it? Or do you have some sort of pathological issue in your ankle from a very short achilles or a serious injury that limits the amount of (doors) flexion? It makes a big difference.

    2. Lee, I have an adjustable ramp/delta device (BE) which I’ve used extensively. Go back and do David’s ‘tonguectomy’ and that will greatly reduce the need for that much ramp. That was exactly how I started, couldn’t put enough heel lifts in my boots so I built the BE. As I was able to increase the mobility in my feet (well get them to normal as outside of the boots!) ramp has to go down or you fall on your nose! Also get rid of the footbed per David, I make the best ones I ever skied on and I don’t use those anymore because it’s better without them. Also see my test results below;

      Finally made it out skiing today, great coverage, one run of 500 vertical was almost completely covered with snow!!
      Here are the results of closely observing the pressure under foot; I started determining pressure of 1st MT and heel finding that the heel was receiving at least 50% pressure. Two things I liked, first is that my skiing isn’t as far from your methods so I felt pretty competent! 2nd is that I really like the results of pressuring your ‘1st MT point’ because the whole body instinctively aligns itself in relation to it and the ski. This is exactly what I feel when I run with fore foot strike instead of heel strike. After about 3 runs I wasn’t satisfied, feeling there was too much heel pressure so I raised the toe end of my adjustable ramp/delta device (which I call the BalancEnhancer, BE for short) 1 notch= 1/8″ or about 1 degree. ( In the evening I measured the boot board angle [net ramp] clipped into the skis I was using and it is 4 degrees) What a difference!! Now the greater pressure was at 1 MT. In short, fall line turns I could almost have been 100% on the ball of my foot with heel slightly up if desired and made controlled pivot-ty turns with ease. For longer radius turns I found more heel pressure helped the tail hold (with less tail chatter than the first setting) and felt really good. I felt an extra ability to move fluidly with a greater range of motion, something so amazing that one has to be able to experience that difference on the same run, on the same day to truly believe in my opinion. Not pretending there isn’t more to adjust on other aspects of the boots etc. and don’t guarantee how this would perform on ‘real’ terrain but definitely enjoyed the last position tremendously and really was in tune with the 1st MT pressure point. I like your focal point as the most refined move that I’ve ever used to date!! In the past I went from having to think ‘segmented’ about many different things, hand here, throw hips, there etc. which proves how misaligned I was. Up until this topic of yours I was focused on moving from the feet up but this method is much more accurate and thus more efficient thank you very much!
      Day 2; Had to run for brake parts this PM so stopped at the bunny hill for a couple runs. Raised the toe 1 degree from where I liked it yesterday and that put me too far back. I split the difference, dropped it 1/2 degree and really liked it a lot. (net ramp angle now of 3.5*) That was the best for leaving lines in the snow but have to admit I’m not an expert at it so that tells me maybe the boots need more refinement or maybe that’s where I need a real set of skis rather than these low end ‘race’ skis. Again, this is all with a grain of salt because this is such a flat ski area. It’ll be interesting to see what happens when I move west, and will update this info at that time. What I’m discovering is that when the skier’s (mine!) ankles were locked up it was advantageous to increase ramp/delta sometimes to 10* but as I’ve freed the feet and ankles have greatly reduced that amount. It proves that one needs to fix the problem where it is happening, not where it is convenient…. A perfect example is grinding boot soles for tons of money when the real issue is inside the boot with most being the foot bed/orthotic the same tech just made you for $ssss. I think the future would be to have a BE with infinite adjustment range to really fine tune the ramp/delta. I think the ability to do that would be a wonderful final adjustment AFTER the boot work is finished.

      1. “Two things I liked, first is that my skiing isn’t as far from your methods so I felt pretty competent! 2nd is that I really like the results of pressuring your ‘1st MT point’ because the whole body instinctively aligns itself in relation to it and the ski.”

        Michael is referring to my methods when he refers to “your methods”. The ability to apply, not just pressure, but high pressure to the 1st MT point, is the outcome of whole body neuromuscular alignment. The ability to maintain high pressure on the 1st MT point and manage the differential with the heel pressure is confirmation that the boot is set up correctly or very close to it. The only issue that remains uncertain is whether a skier is able to create the maximum 1st MT pressure. If you can create and maintain the force, that is about all you need to know and do; “Feel it, Run with it, Ski like the Best. Simple.

  2. This is very interesting and informative. I am finding it making perfect sense as I stand on the living room floor, feeling the pressures in my foot. I can’t wait until I get back to the mountain to feel the pressure in my boots on skis. I’m looking forward to the next blog. Thanks for posting this.

    1. Tim, once it has been confirmed that the structures of the foot do not impinge on the 3-dimensional movement in space of the inside (medial) ankle bone and navicular and that there is sufficient width for the forefoot to fully spread, ramp angle becomes critical. The ramp angle of the best racers is in the order of 2.7 degrees. I calculate it mathematically because I don’t have a device that will allow me to measure it to 0.1 degrees. But this angle is right for elite skiers and racers. Short Achilles tendons is a factor that can require a steeper ramp angle, perhaps as much as 3.5 degrees or slightly more. The only way to nail it down is to start with a reference angle of about 3 degrees then try adding a 1 mm shim under the heels to see what happens. This may not seem like much. But I have tried it and too much or too little ramp angle can instantly reduce an elite skier to a beginner. The best way I have found to establish the right direction (should I increase or reduce ramp angle?) is to increase it slightly. If this is the wrong direction, you will know right away. The good news is that you can reverse it by removing the shims.

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