I believe that the best way to understand how something works is to actually experience it myself, not just take someone’s word for it. When I read articles in ski magazines years ago about how important boot flex is to skiing I just had to try it myself. I was especially intrigued by the claim that only the best skiers have muscles strong enough to flex a stiff race boot. To me this was saying that if you can flex with the best, you can ski with the best. Game on! So I went up on the ski hill one day and tried flexing my boots as deeply as I could under different conditions and in different parts of a turn. I had to try and figure out when to flex and when not to flex because the experts who stress the importance of having boots with the right flex index didn’t say how and when flex should be used. But if the experts said flex is important, I had to find out if they were right. And that is exactly what I did.

Going up on a ski hill and flexing boots during actual ski maneuvers is a lot of work. And to be quite honest, I found it more than a little tricky. Maybe it was just me. But I wasn’t very good at flexing my boots in order to put pressure on the shovel of my ski to start it turning. It didn’t help my understanding of how to use boot flex when I studied the best skiers like Ligety and noticed that the shank angle of their outside leg changes very little especially in the high load phase in the bottom of a  turn. It must be an illusion. It’s probably caused by the distortion of the long camera lenses.

So how good a skier you are? Here’s a easy way to find out.  Put your boots on and buckle them up. Sit down and place your feet (with the boots on) on a hassock or even a box. Now flex your boot flex muscles and see how much you can flex your boots.  If your boots are too stiff  you could perhaps prevail on a local ski shop to see if they will let you flex tests some boots. You could even make an afternoon of it. Have a boot flexing competition with your buddies. Find out who’s the best.

If, you can’t flex your boots, better hit the gym. Maybe hire a fitness instructor. Pump those boot flex muscles up. Remember, boot flex is critical in skiing.


  1. It’s a viable theory and it should be look at as a viable theory. It’s fun to see how much people with no real evidence are 100% sure of their theory because it’s what they learn. You are not the first I heard who say that the foot as to be able to naturally work to keep a good balance, even if it’s against the mainstream opinion. But until someone prove without any doubt one or the other, both are still gonna be theory. So don’t act like you’ve got the truth if you can’t prove it. At least he’s trying to prove is theory.

    Different people, different foot, different ski technique = different theory on how to fit boot

    So choose you’re way to fit boot and keep you’re good work, but before we goot real evidence, it will be a theory. It’s fun to talk to a lot of experienced bootfitter who all think they’ve got the best way to fit boot having big difference in their opionion on how to fit boots.

    Ps: sorry for my english, it’s not my first language.
    pps: Very interessant website with nice idea.

    1. If you go to the Appendix you will find documents on my nomination for the gold medal in applied science & engineering in the 1995 British Columbia Science & Engineering Awards for the research done in 1991 that validated my hypothetical model on the mechanics, biomechanics and physics of skiing using a research vehicle that captured data during actual ski maneuvers on the 3 dimensional forces applied by the foot and leg of skiers to the interfaces of the research vehicle. Validated means that the key aspects of the hypothesis were proven in a 2-step process; 1) the data was predicted in advance and, 2) the actual data coroborated the predicted data. This is the essence of the scientific method. To the best of my knowledge this is the first time research of this nature and thoroughness has ever been done. So until such time as someone refutes the findings of this research which was designed and conducted by an accredited scientist everyone else has theories and I have facts.

  2. I recall an ex National team skier telling me in the very old days that you have to push forward so hard into the front of the yellow topped lange comp boots that you will lose your shin hair right away,,,If there is any shin hair left after a month then we are not skiing right…Well I do see that I have NO shin hair now , nor do most long time skiers….but maybe because we got fooled..
    Pushing so hard forward is obviously not correct now….Then ? who knows? I doubt it?
    Back then they also bragged about the vast back support for the Lange comp ??? It had virtually none…We made our own jet sticks for back support to do JC Killy jet turns…Took a few years to figure out that he really did not ski that way…but he did ,,,,in recovery,…and that is why he too had the tongue depressers in his Le Trappeur boots. He was WAY ahead of his time then.
    Also …way back I had 207 Dynamic Vr 17 skis….the ones I thought Killy used in the 1968 Olympics……They had the tip and tail flex marked on the tip…We all assumed that the flex needed to be stiff so I got a stiff pair and I only weighed 148 Pounds….we were all fooled …Killy had a soft flex ! that was part of the secret to bending the ski…but back then almost no one got that…they went stiffer the better…too funny..

    1. In the early days of skiing the design of equipment was mainly the domain of artisans and hobbyists; people who were experimenting, trying to find what worked by trial and error. These people had little insight and probably even less knowledge of the underlying biomechanics. Ski instruction was similar. Back then I used to joke that if a racer fell before the finish and won the race and did this 2 races in a row within a week every racer would be skiing this way. Robert Lange who invented the Lange ski boot sounds like the archetypical all American. He flew Lockheed P-38 Lightning airplanes for the United States Army and earned a degree at Harvard University, where he studied economics and engineering. No mention of physiology or functional anatomy. Nor have I been able to find any reference to Lange having had his idea validated or of anyone doing diligence after the fact. Racers winning a few races in Langes boots seems to all that took for everyone buy into the immobilize the foot idea. Jet sticks are a good example. Someone came up with the idea with zero investigation It was just another good story. Overnight, all the hot skiers are hanging off the backs of their Jet Stix looking cool right up until Ettlinger and Johnson pointed out the drawer shift knee injury caused by the phantom foot. No big deal. The industry just carried on. Yeah, Killy had soft skis with the same top sheet as the stiff skis. Fooled a lot of people. That’s an old trick. I have been in the ski factories. Top sheets fool people. The skis racers are on are seldom what skiers get. It’s all about marketing.

  3. I found this discussion : PRONATION 101.4 – DIAGNOSING PRONATION. but the discussion is closed. After reading the post, I can see why he cut off discussion. The assumptions of someone who is clearly confused about the biomechanics of the foot and ankle, is not science.

    1. I agree there is a lot of confusion. I hear all the time that skiers are told that any amount of pronation is abnormal. It seems that there was some sort of evolutionary defect in the ankle complex and lower limb. It should only have one DoF. I am sure there are people who are at work fixing this as I write.

    2. Robert, speaking of science here’s a link to a great article, ‘Close Look at Orthotics Raises a Welter of Doubts’
      “Anecdotally, we know what designs work and what designs don’t work” for foot orthotics, said Mr. Cummings, who is an orthotist and prosthetist at Next Step in Manchester, N.H. But when it comes to science and rigorous studies, he added, “comparatively, there isn’t a whole lot of evidence out there.”

      Not a whole lot of evidence? Isn’t science supposed to be based on evidence? Have you read Nigg’s book, ‘Biomechanics of Sports Shoes’? It’s a great read. I’ll provide a bunch of nice citations when I get time. Meantime, here’s a quote from Benno, “Nigg admits foot orthotic industry is now a billion-dollar industry, but accepts it is still unclear how they work and how they correct mechanical-alignments such as shin splints, knee and foot pain. The author concludes prescribers cannot yet predict the effect of a given foot orthoses.” Can’t predict? Unclear? Say what? This is science? I don’t think so.

    3. Cutting off comments is standard procedure with blogs to reduce spam. You might want to do some homework before posting comments like this.

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