LIGETY’S MOMENT OF TRUTH – STEP 1


 “I step on the new (uphill) ski while it is still on the edge it was currently on in that turn (ergo the uphill edge)” – On Giant Slalom: Ted Ligety – Video – NY Times.com

The objective of stepping on the uphill ski while it is still on its uphill edge is apparently to eventually get the forces acting on the ski going into the new turn. While Ligety and the NY Times hint at where this is going, they leave the viewer hanging, or at least they left me hanging. That they were on first and goal with their explanation and couldn’t take the play into the end zone for a TD suggests to me that Ligety and the NY Times don’t know the whole story behind what Ligety is  doing. But the question we should be asking ourselves is, “Why is Ligety going to such great lengths to get his ski on edge?” Experts have been telling us for years that when we clamp our leg in a rigid ski boot it becomes the equivalent of a 2″ x 4″ that we use to hold a ski on edge and apply force to the front of the ski with. According some experts, holding an edge isn’t that complicated. In fact, it’s pretty simple. Drive your knees into the turn. Voila, instant edge set! If the experts are right, we would actually be better off if the useless appendage in the foot were amputated at the ankle. Apparently, the foot gets in the way of good technique.

The Times comments give us some clues that suggest that much of what the experts in skiing have been telling us for years is not just wrong, it is spectacularly wrong. When the Times says, “No skier in the World carves the way Ligety does” they are suggesting (and I agree) that Ligety is making some very different moves compared to the rest of the competition. I agree to a point that Ligety is the only one using this technique. Shiffrin uses the same technique. But Ligety loads his new ski more than Shiffrin (Memo to Mikaela Shiffrin – follow my blog).

In watching the 2014 Olympic Alpine events, it looks to me like there are two categories of racers on course. One category is for racers such as Ligety and Shiffrin who are using their human performance potential. The second category is for the artificially disabled racers who are competing in what amounts to a version of Survivor Sochi or perhaps the ski racing version of the Hunger Games. If indeed no other skier in the world carves the way Ligety does then I say everyone else is skidding, not really carving at all. If Ligety is carving the right way, and we want to ski like him, we need to know what he is doing and why he is doing what he does. Stepping on the uphill ski in the transition when it is still on its uphill edge is the first step towards better carving. It it were that simple everyone would be skiing like Ligety within 5 minutes of viewing the NY Times video. But what Ligety is doing is anything but simple. Stepping on the uphill ski is just the first step. Several more steps are needed before Ligety gets to the point that I like to call The Moment of Truth.

While Ligety’s ultimate goal is to get the forces on his new outside ski flowing into the new turn, the process initiates when the current inside ski is still on its uphill (inside turn) edge. The place to start is by looking at the forces at work between Ligety’s uphill foot and the snow at the uphill edge of the current inside ski. In order to be in the position to step onto the uphill ski the way Ligety does, he needs to have a dynamically balanced base of support on the current downhill (outside) foot from which to initiate the move to the uphill ski.

According to many of experts in skiing, a neutral configuration of the feet and body alignment is ideal for skiing especially for optimal edge hold. The graphic below shows two figures with their feet in neutral. Technically, neutral means that the foot can neither pronate (the sole of the foot everts or turns away from the L-R centre of the body) or supinate (the sole of the foot inverts or turns towards the L-R centre of the body). The reality is that a custom orthotic or insole can only reduce or prevent pronation. These devices cannot reduce or prevent supination for reasons I will explain in future posts. What is missing from the images below is the force in the soles feet that is acting on the supporting surface and especially the centre of the force or Centre of Pressure (CoP) as it is called in biomechanics. We specifically need to know where CoP is in order to arrive at any conclusions pertaining to skier balance and especially balance as it pertains to forces between the sole of the foot of a skier and the snow surface.  The inclusion of CoP is essential for any meaningful discussion of edging forces in skiing. But for reasons that aren’t clear to me, I have yet to see an article or discussion of ski technique that mentions CoP.

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Here is the same graphic showing CoP and rotation points at contact points of the feet on the sloped surface. According many of the experts the neutral configuration of the feet on the sloped surface will be maintained.  How is this possible? It isn’t. Unfortunately, the animated sequence in NY Times video shows the pressure in the proximate center of the foot; where it would be in a neutral foot. What will the feet tend to do? The downhill foot will tend to rotate towards the little toe side of the foot; ergo – supinate. The uphill foot will tend to rotate about the rotation point towards the big toe side of the foot; ergo – pronate

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The graphic below shows what the feet want to do when supported on one of their inside or outside margins. The foot will tend to rotate about the contact point and ‘seek ground’  with the heel and heads of the metatarsals as it has done in the left image of the first graphic above. Encasing the foot and leg within the rigid confines of a ski boot, even a form-fitting ski boot does not eliminate this tendency. It is impossible to balance the forces that tend to rotate the uphill foot of a turn in the direction of pronation.

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I consider the point where the initiation of a new turn begins as the transition phase ends to be a Moment of Truth. It is a Moment of Truth because Ligety and Shiffrin have a very narrow window in which to set up an over-centre mechanism that uses the external forces acting on them to drive the forces acting on the ski into the turn. There are two directions the external forces can go; to the inside of the turn or to the outside of the turn. This tendency creates a different kind of moment, a Moment of Force.  A Moment of a Force is a measure of the tendency of a force acting on a body to cause that body to rotate about a specific point or axis. In skiing, the body is the stack of equipment that resides between the sole of the outside foot of a turn and the snow surface. The specific point or axis about which the rotation tends to occur is the inside edge of the outside ski of a turn.

When Ligety steps on the uphill foot while the uphill ski is still on its uphill edge he is provoking the tendency for his foot to evert, ergo to pronate. Eversion is one component of pronation. In the next post I will discuss the other component of pronation, coupled, vertical axial rotation of the associated leg.