THE ELEMENTS OF FLUID SKIING


A recent paper, Dynamics of carving runs in alpine skiing. The centrifugal pendulum by S.S. Komissarov, provided me with insights as to the differences between elite and lesser skiers.

Komissarov clarifies that the context of proficient skiers being well-balanced simply describes the observation that the skiers do not appear to be in danger of falling. The signature of good skiers is that they move effortlessly from turn to turn in a smooth, continuous rhythmic manner much like a metronome or inverted pendulum.

A key point is Komissarov’s comment that elite skiers somehow manage to ski faster than the theory of ideal carving predicts. He also states that the fluidity of the pendulum action of the elite skier does not actually require a forceful participation from the skier and that the skier has to make sure that they do not inhibit this natural process but just “get on board and enjoy the ride!”.

The reference to fluid skiing being a natural process requiring no forceful (conscious) participation from the skier in terms of the associated neurobiomechanics responsible for the pendulum action is one reason why I am shifting the focus of my blog away from ski technique (which is consciously mediated process) to the elements of fluid skiing and especially factors that interfere with the natural processes that enable humans to ski as easily as they walk so that analyses can focus on the why not the what.

 

10 comments

  1. Hello David,

    Very very interesting exchage of views between you and Doru Nica: “Relaxing the outside leg implies a conscious action which he correctly states will interfere with fluid skiing. In dynamic fluid skiing a catapult action releases the skis and COM of the skier”

    I fully agree with the first sentence, if only because I can clearly relate that conscious action in my own Skiing
    The second sentence is exactly where I am currently lost in my Skiing improvement efforts. Could you Please elaborate a bit on this so called CATAPULT ACTION mechanism?….and, wouldnt this action also imply some sort of conscious action(s) to release the skis and COM of the skier?

    Has this catapult mechanism been described in any of your old posts? I have read most, if not all, of them, and I am not aware of having grasped this concept….and especially not as it being the result of an unconscious action

    1. My series posts on the SR Stance (Spinal Reflex Stance) are based on fascial tensioning that includes the catapult mechanism. Information bias due to the lack of recognition of the role and especially the value of a stance based on fascial tensioning in official narrative of skiing has rendered this subject and key words invisible. Here’s a link to a good starter post – https://wp.me/p3vZhu-1wT

      1. Excellent post, thank you very much David. I have read many if not all of the SRStance posts. The SRStance is such a groundbraking concept to me that I find it difficult to implement to its adequate/full extent. I Will re-read related post series with even more attention to detail trying to better understand some of their corollaries….and I am very much looking forward to grasping this catapult mechanism you write about. Again, Thanks a lot.

      2. The SR Stance is a light state of fascial tensioning from the balls of the feet to the hands that trains and primes the human body to charge and release stored energy with the explosive catapult mechanism. Without reading all my posts on the SR Stance i can’t recall whether I discussed the catapult mechanism.

        A good explanation is by Divo G. Müller and Robert Schleip in an article that appeared in Anatomy Trains called ‘Fascial Fitness: Fascia oriented training for bodywork and movement therapies’.

        There is also a 2 part series by Pete McCall called ‘Cutting Edge Training: Fascial Network’.

        Dr. Emily Splichal (EBFA) also discusses fascial tensioning.

        You should be able to find these articles with a search engine.

  2. Have not read the article yet, but my personal experience is telling me that it makes sense. If I’m not trying to accelerate (using my body muscles) I do not have to put much effort when carving. It is fluid and pleasant almost addictive.

  3. very interesting paper indeed. Although the maths included in that paper are completely above my understanding, the conclusions are easier to grasp and very informative. It seems the author has presented a very robust and elegant mathematical models. Great job. I can imagine you must have had an awsome time reading through it all…

    The paper seems to conclude/suggest that the most effective way (in order to maintaing Dynamic balance in Skiing) to execute the transition between turns is by flexing the legs (some call it retraction) as opposed to the more traditional upward extension/no retraction. This would fit well with my own feelings while transitioning by retraction, then extending the stance leg throughout the turn. So far so good.

    The most exciting part will come when you share with us the relationship between those mathematical models and the steering actions, and more importantly with the neuromuscular activities behind those movements….Since I first read about it in your posts, whenever I have felt the Stretch Réflex Stance helping me maintain Dynamic balance it has felt awsome…now it seems you are suggesting there is even more to it as it may also be of application to the steering movement…

    Is it possible/likety that this new paradigm that you are reflecting on might substantially change/simplify your view on how to execute the transition?, or only affects the execution of “the rest of the turn”?

    1. At this point I think it unlikely that anyone has explored the issues in depth that I am finally seeing. While Komissarov is solid in his application of physics he missed the mark in his graphic when he shows the normal reaction force manifesting at the inside edge of the outside. I will discuss this in a future post. He also misses the mark when he suggests relaxing the outside leg to start a turn. But Komissarov gave me a jolt of reality when he states that dynamic skiers are never in balance because the external forces acting on them are in a state of flux. This gave me an epiphany; bipeds are never in balance when they walk. Movement from the stance or support limb on one foot to the opposite foot involves a complex, seamless, multi-plane, multi-axial interaction of a number of factors that produces progressive tensioning (stiffening) of the foot and stance leg in conjunction with the neural equivalent of GPS that calulates where to place the swing foot to establish a dynamic base of support.

      This is an extremely complex subject that would take a team of diverse expertise to thoroughly explore. I am going to start with very basic principles of the biomechanics of walking and then tie them to the ski turn cycle.

      1. I’m not sure why you are saying he missed the mark when suggesting relaxing the outside leg at the end of the turn. That is a well known technique used from racers – it is faster than extending the inside leg or you can combine the two for so call “pass through”, to adaptive and senior skiers – it is very energy efficient.

      2. Relaxing the outside leg implies a conscious action which he correctly states will interfere with fluid skiing. In dynamic fluid skiing a catapult action releases the skis and COM of the skier causing the skis to project forward and the COM to diverge or fall into what will become the next turn. The decay of momentum on COM creates a natural arc that will eventually end with the skier in the fall line. The legs are relaxed in this process because COM has limited ability to apply force to the skis until their direction in relation to the fall line is reverse direction with steering. The best WC racers can literally extend their outside like the landing gear of an airplance and land on their line. In between they feel light. Muhammed Ali described it when he said, “Float like a butterfly, sting like a bee”.

  4. Thank you for this (very) interesting paper.

    It is indeed quite a long journey to understand, envision, feel, trust this expert “pendulum” dynamic turn, which is not really taught as an overall objective, even in advanced classes to instructors (which I have attended this winter for the first time, at the age of 64), which rather tend to concentrate on mechanical, “step-by-step” moves or techniques.

    I have thoroughly read and enjoyed your thought provoking Manifesto, almost from its beginning. I also, like many others, would like to be able to access or archive it if you decide to end it.

    Thanks, best regards,

    François Couturier

    Le mar. 17 mars 2020 12:14, The Skier’s Manifesto a écrit :

    > skikinetics posted: “A recent pape, Dynamics of carving runs in alpine > skiing. The centrifugal pendulum by S.S. Komissarov, provided me with > insights as to the differences between elite and lesser skiers. Komissarov > clarifies that the context of proficient skiers being wel” >

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