The short answer to this question is that the 4 racers share a stance with the muscles of the biokinetic chain in isometric contraction during what I term the Load Phase of a turn sequence and the ability to use the elastic recoil energy created during the Load Phase for acceleration.
One of the key visual cues of an isometric stance is an extended outside leg with small angles at the knee and ankle and a forward position of the pelvis. Another key visual cue is high hands with arms reaching forward as if the racer is trying to reach forward and hug a large barrel.
The screen shot below is of Marcel Hirscher in the December 16, 2018 Alta Bada GS that he won by 2.53 seconds.
The screen shot below is of Tessa Worley in the 2018-19 Soelden GS.
A longer answer to the question posed by the title of this post, one that I will expand on in future posts, is that Hirscher, Brignone, Worely and Shiffrin are examples of the application of the principles of an emerging paradigm that is challenging the fundamental way in which muscular anatomy has long perceived muscles as separate systems with specific functions. In the new paradigm that has arisen out of recent discoveries muscles function in conjunction with the myofascial network as a wholly integrated system; one that responds and adapts to the stresses imposed on it. Since these discoveries are almost ten years old the odds are that the dominant technique of Hirscher, Brignone, Worely and Shiffrin is not by chance.
In previous posts, I described a stance based on isometric contraction as the SR Stance. SR is an abbreviation for the Stretch Reflex. Technically, a better term for the stretch reflex is the stretch-shorten cycle
The reason I chose SR for the name of the stance is that isometric contraction and the stretch reflex are not part of the narrative of ski technique. I discuss the three forms of muscle contraction in my post I-C-E: SR (2.) which I have recently updated.
The reason a ski stance based on isometric contraction provides a huge competitive advantage has to do with recent finding discussed in a 2009 article (1.) in which ultrasound imaging that allowed for quantitative assessment of the mechanisms for elastic energy storage and return at the ankle joint during human walking found that the Achilles tendon stores elastic energy as the mid stance phase progresses until the energy peaks in late midstance and is released to produce a rapid recoil with very high peak power output. The researchers named this the Catapult Mechanism (3.).
An important feature of the ankle ‘catapult mechanism’ is that the stretch and recoil of the Achilles tendon allows muscle fibers to remain nearly isometric producing high forces with very little mechanical work. In the isometric state, muscles expend much less metabolic energy to produce force when compared to muscles shortening in concentric (positive work) contractions.
Recent research has also found that during explosive movements, the contractile elements of a muscle remain in an isometric state to increase tension in the non-contractile components in an effort to produce higher levels of force. The enhanced stiffness from the contractile component can help the connective tissue rapidly store mechanical energy during the lengthening (recoil) phase delivering greater power output during the shortening phase. (4.), (5.)
What all this means is that the power advantage seen in racers like Hirscher, Brignone, Worely and Shiffrin results from an integrated system. But the human body can only function as an integrated system under conditions which allow multi-plane movement, something conventional ski boots intentionally interfere with.
In my next post I will start from what I see as the fundamental element of a ski stance based on isometric contraction and progress upward from there.
- It Pays to Have a Spring in Your Step – 2009 Gregory S. Sawicki1, Cara L. Lewis2, and Daniel P. Ferris2 – 1. Department of Ecology and Evolutionary Biology, Brown University, Providence, RI; and 2. School of Kinesiology, University of Michigan, Ann Arbor, MI
- Fascial Fitness: Fascia oriented training for bodywork and movement therapies – Divo G. Muller, Robert Schleip
- Cutting Edge: Training the Fascial Network (Part 1) by Pete McCall M.S.
- Cutting Edge: Training the Fascial Network (Part 2) by Pete McCall M.S.