Mikaela Shiffrin

WHY HIRSCHER AND SHIFFRIN CAN CROSS THE LINE

There has been a huge surge in interest in my post HIRSCHER AND SHIFFRIN WIN BY CROSSING THE LINE.

The reason Hirscher and Shiffrin can ski this way is that they have the ability to cross the rise line and establish balance on their outside foot and leg in milliseconds. This enables them to make what amounts to a hairpin turn. They are on and off their edges like a flat stone skipping off the water. The reason they can do what few other racers can is because their boot setup supports the requisite neurobiomechanics. I discuss this in my last post WHY HIRSCHER AND SHIFFRIN ARE DOMINATING.

WHY SHIFFRIN AND HIRSCHER ARE DOMINATING

Existing footwear does not provide for the dynamic nature of the architecture of the foot by providing a fit system with dynamic and predictable qualities to substantially match those of the foot and lower leg.

MacPhail, US Patent 5,265,350 – November 30, 1993

Of all the figures who have influenced the development of the plastic shell ski boot over the years, the Australian, Sven Coomer, stands tall as one of the most significant and innovative. More recently, Coomer was involved with the development of Atomic’s race boot, the Redster, used by Marcel Hirscher and Mikaela Shiffrin. Coomer claims that the Redster allows the skier’s forefoot to flex and move naturally within the confines of the shell.

A 2014 article by Jackson Hogen quoted Coomer as saying:

This liberation of the previously stunted, frozen and crushed forefoot is what allows for the subtle edging and foot steering that initiates the slalom turns of World Cup champions Marcel Hirscher and Mikaela Shiffrin. (1.)

Four years, later Hirscher and Shiffrin are dominating the technical disciplines of the World Cup circuit.

The ability to establish balance on the outside foot and ski in milliseconds is dependent on the ability of the forefoot to fully spread and acquire fascial tensioning that extends to the ankle and knee. This is called time-to-stabilization. Although Coomer doesn’t mention them, a myriad of other factors are also critical; including the alignment of the big toe on the long axis of the foot and the optimal ramp angle.

Coomer suspects that if racers would only fit their boots more accurately, coupled with a dynamic molding inner boot medium between the foot and shell, and without down-sizing into short, narrow, thick-sidewall shells, their results just might improve. (1.)

In order to realize their maximum potential it is critical that racers and even recreational skiers have a ski boot fit with dynamic and predictable qualities that substantially match those of the foot and lower leg. Yet Coomer readily acknowledges:

Many racers believe they need downsized, super-stiff, ultra-narrow boots. The most accomplished alpine ski boot designer of the plastic era, Sven Coomer, believes that’s changing.(1.)

But then, he seems to retract his optimism when he says that after forty-five years as the Cassandra of the ski boot world, he knows all too well that just because you can prove you’re right, it doesn’t mean your advice will be heeded.

My observation is that since Hogen’s 2014 article, the situation with downsized, hyper-restrictive ski boots that severely compromise the dynamic nature of the architecture of the foot, has gotten worse. I have seen instances where after having ski boots properly fit, it took several full seasons for the competence of the balance to be fully restored after a skier or racer’s feet and legs were constrained for years in ski boots that were too small and too tightly fit.

Marcel Hirscher and Mikaela Shiffrin have heeded Coomer’s advice. Others choose to ignore him at their own peril. In so doing, they handicap their efforts and limit their race results.

In my next post I will start a series of posts on how to build a ski boot from the snow up; one that provides a fit with dynamic and predictable qualities that substantially match those of the foot and lower leg.


  1. The Master Boot Laster by Jackson Hogen: The International Skiing History Association – Article Date: Tuesday, June 3, 2014

IS SHIFFRIN ON THE LEVEL?

By on the level, I am suggesting that Shiffrin may have a much lower zeppa-delta ramp angle than her competition.

Here are some screen shots from the March 18, 2018 Are Slalom where Shiffrin won by  1.58 seconds. She is on and off her edges in milliseconds as she just seems to pop from turn to turn – Total Domination From Shiffrin (1.)

Compare the angles of Shiffrin’s ankle, knee and hip in the photo below to those of her competition in the second and third photos below.

Notice how extended Shiffrin’s lower body is as she exits the rise line and enters the bottom of the turn in the photo below from a training session earlier in the year.

Extended in the Are Slalom.

Out of the start her knees and ankles are almost straight!

In my next post I will explain what I think is happening and why.


  1. https://youtu.be/gQu-LkyfsRQ?list=PLo6mlcgIm9mzWPBpeXnH2CpFOXrWhBiEB

HIRSCHER AND SHIFFRIN WIN BY CROSSING THE LINE

When a World Cup racer wins a GS by a commanding margin, it’s a sure sign they’ve crossed the line and the gravity of the situation is significant. But I’m not talking about  breaking any rules. Instead, I’m referring to Hirscher and Shiffrin mobilizing the force of gravity by jumping across the rise line above the gate and/or minimizing pressure while rotating their skis across the rise line towards the gate so the edges of their outside ski progressively engage and lock up as they extend and incline closing the kinetic chain. Knee extension, in combination with ankle extension, uses the momentum of COM in conjunction with the force of gravity to progressively engage and apply force to the outside ski.

Reilly McGlashan has an excellent YouTube analysis of Marcel Hirscher using this technique in the 2017 Alta Badia GS (1.) The technique Hirscher and now Mikaela Shiffrin are using relates directly to the second rocker/internal rotation, impulse loading mechanism I described in a series of posts. The text below is excerpted from a comment I posted on McGlashan’s YouTube video analysis of Hirscher.

Hirscher progressively engages his edges, especially on his outside ski then hooks a tight arc close to the gate to establish his line. Once he has established his line, he no longer needs his outside ski. He gets off it in milliseconds and uses the rebound energy to project forward with only enough pressure on his uphill (new outside) ski to influence his trajectory of inertia so his COM enters the rise line at a low angle of intersection. He gets rebound energy from the loading  of his outside ski and from what amounts to a plyometric release of muscle tension from the biokinetic chain of muscles extending from the balls of his outside foot to his pelvis. The energy is created by the vertical drop from above the gate to below the gate similar to jumping off a box, landing and then making a plyometric rebound. Hirscher is skiing the optimal way and it shows on the clock and leader board.

Replicating the mechanism in a static environment is not possible because there is no inertia. But a device I have designed and constructed enables the mechanism to be rehearsed with the same feeling as in skiing.

The key is loading the forebody of the outside ski with a shovel down position as the leg is rotating the ski into the turn. This sets up the second rocker impulse loading mechanism that tips the ski onto its inside edge. Extending the knee and ankle uses momentum to exert a force on the snow with the ski.

The photo below shows the training mechanism head on. The white horizontal arms represent the sidecut of the ski. The platform under the foot can be adjusted transversely to change the sensitivity. Vertical plates set beside the ball of the foot and on the outer corner and behind the heel transfer turntable rotation torque to the ski created by rotating the leg internally with the glutes. The platform will only tilt under impulse loading if the second rocker can engage. Few skiers can use this mechanism because their ski boots do not accommodate second rocker biomechanics.

The link below is to a video that shows the effect of extending the knee and ankle while moving the hips forward and over the support foot (monopedal function). The stack height and minimum profile width of are FIS 93 mm/63 mm. Rotation in itself will not cause the device to tip onto its inside edge if centre of pressure is on the anatomic centre of the foot (through the centre of the heel and ball of the second toe).

Dr. Emily Splichal’s recent webinar on the Science of Sensory Sequencing and Afferent Stimulation (2.) is relevant to motor control and cognitive development associated with high performance skiing. Pay careful attention to Dr. Splichal’s discussion of the role of mechanoceptors and the fact there are none on the inner (medial) aspect of the arches of the feet which is why footbeds or anything that impinges on the inner arch is a bad thing. I will discuss the implications of Dr. Splichal’s webinar in a future post.

In my next post, I will provide detailed information on the training device.


  1. https://youtu.be/OxqEp7LS_24
  2. https://www.youtube.com/watch?v=2qPnrQ85uec&feature=youtu.be

 

 

THE SHOCKING TRUTH ABOUT POWER STRAPS REVISITED

Since I started this blog with my first post, A CINDERELLA STORY: THE ‘MYTH’ OF THE PERFECT FIT (1.) on 2013-05-11, THE SHOCKING TRUTH ABOUT POWER STRAPS (2.) is by far the most widely viewed post. This is significant because the content of this post challenges premises that are widely embraced and cited as knowledge that is fundamental to skiing.

The greatest enemy of knowledge is not ignorance; it is the illusion of knowledge.

                                                                                    – attributed to Stephen Hawking

Widely accepted false beliefs can negate incentives to pursue the acquisition of knowledge necessary to understand complex issues that fall outside the limits of established paradigms. A prime example being the ability to balance perfectly on the outside ski.

Observing great skiers like Marc Giardelli or Ingemar and more recently, Mikaela Shiffrin, Lindsey Vonn and Marcel Hirscher balance perfectly on their outside ski suggests it is possible. But uninformed observation in itself does not impart, let alone lead to, an understanding of the associated mechanics, biomechanics and physics of perfect balance on the outside ski as it equates with neuromuscular mediated dynamic balance of triplanar torques acting across the joints of the ankle/foot complex, knee and hip. The intrinsic need of those who regarded as authorities on ski technique to provide plausible explanations for the actions of elite skiers led to the fabrication of terms such as knee angulation that served to create an illusion of knowledge of the mechanism of balance on the outside ski. Knee angulation also provided an effective mechanism with which to demonstrate the mechanics of edge hold.

To raise new questions, new possibilities, to regard old problems from a new angle, requires creative imagination and marks real advance in science.

                                                                                                                          – Albert Einstein

While knee angulation provides a plausible explanation for a mechanism with which to rotate a ski onto it’s edge, it does not explain the mechanism of perfect balance on the outside ski in accordance with Newton’s Laws and the principles of functional anatomy. Solving this mystery required raising new possibilities and creating a new paradigm; one that looked at the function of the human lower limbs from a new perspective with new possibilities.

It took me from 1980 to 1990 to discover how the mechanism of balance on the outside ski works. Trying to impart an understanding of this mechanism to others has presented significant challenges because the illusion of knowledge within the ranks of the ski industry has resulted in a hardened mental model that makes the real mechanism all but invisible. The resulting information bias causes people to seek information that supports what they believe while filtering out information that conflicts with what they believe; i.e.

I don’t need new information on how to balance perfectly on my outside ski because I have been doing this for years and I don’t need to know anything more.

But the reality is, that with rare exception, while elite skiers and even World Cup racers may think they can balance on their outside ski they have no way of recognizing the correct feeling, let alone confirming that they are actually doing what they think they are doing.

I have designed and fabricated a device with which to train skiers/racers to create a platform under their outside ski on which to stand and balance perfectly on. The device can be used to capture what I call a skier’s personal Balance Signature using technologies like CARV. More on this in my next post.


  1. https://wp.me/p3vZhu-p
  2. https://wp.me/p3vZhu-UB

THE MECHANICS OF EDGE CHANGE

Comments made by followers of my blog suggest that significant confusion exists 0n the meaning of terms and representations of mechanics, biomechanics and physics used in typical explanations of ski technique and ski mechanics. In particular, there appears to be confusion between pressure and the representation of point forces.

Pressure is a physical force applied to an object that is distributed over the surface of the object.

Center of Pressure or COP is the point center of ground reaction force opposing a corresponding center of applied force acting on a object supported on the ground or a stable surface that acts in the capacity of ground in terms of providing a source of reaction force.

Torque or Moment of Force results from an offset between the centers of opposing physical forces acting on either side of an object.  This offset results in a torque or moment arm that tends ti create rotation about a center. When one force has a greater magnitude than the other force, rotation of the object will occur around the point of rotation.

Why typical balance explanations of skier balance are wrong

Balance in skiing is often depicted as a simple alignment of opposing point forces, usually a resultant force R acting in opposition to a snow reaction force S. The mechanics that make the edges of a ski grip are often shown as a simple alignment of opposing forces acting a single point on the edge. Explanations of this nature are physically impossible. What the authorities in skiing seem to conveniently be ignoring is the fact that pressure is applied by the snow along the entire running surface of the edge in contact with the the snow while an opposing area of pressure applied by the weight of the skier is acting on the body of the ski with an offset between the two centers of pressure. The authorities in skiing also seem to conveniently ignore what is arguably the key even in establishing a platform under the outside ski for the skier to stand and balance on, edge change.

Mikaela Shiffrin’s Get Over It drill on the Burke Mountain YouTube site makes a good segue to an explanation of the Mechanics of Edge change in the my next post – https://youtu.be/Bh7KF49GzOc

Bridget Currier is the model every skier should aspire to. She perfectly executes what I call the skimove. The skimove engages the external forces at ski-flat/edge-change to drive multi-plane torques acting about her outside ski into the turn while setting up a solid platform under her outside foot for her to stand on. Magnificent! This video should have at least a million views.

My comment from 2 years ago

Note carefully Currier’s stance in balance on her new outside ski, in particular, the angle of her torso with the snow. This is key to loading the ball of her outside foot.

Note carefully Shiffrin’s comment to move forward onto her new ski and how she used to think the movement was a lateral (sideways) move.

Most important of all – Patient Initiation. The reason? Shiffrin and Currier, don’t tip their outside ski on edge. They rock it on edge with a rocker impulse loading mechanism. The sequence is Rock, Roll n’ Rotate then Rotate the outside leg.

ADDENDUM TO THE ORIGINS OF KNEE ANGULATION

The intent of my last post was to create an awareness of the lower limb alignment indicative of stability and how a lack of stability, whether intrinsic or caused by footwear, especially ski boots, will cause a skier to default to the use of knee angulation in what will be a failed attempt to hold the edge of the outside ski.

A skier will be unable to develop the requisite biomechanics to balance on their outside ski if they lack stability in barefoot monopedal stance under the minimal challenges associated with a flat, level unperturbed surface. If they lack lower limb/pelvic stability, there could endless combinations of causes which is why I listed a number of resources to help address this deficiency.

If a skier/racer exhibits good to excellent  stability under this basic test and they become unstable with the addition of any form of footwear, it suggests, but does not unequivocally prove, that the footwear is the cause. In more 4 decades of working with skiers and racers at all levels, I have consistently found that I can turn monopedal stability off and on at will. That I can do this without limitation, is indicative of cause and effect. In the 2 world class racers I am presently working with, even a small change in a liner or the over-tensioning of a shaft buckle or power strap has an immediate and noticeable effect on outside limb/pelvic stability and balance.

A key exercise I like to use with racers and elite skies I am working with is the vertical stacking exercise shown in the graphic below. This exercise is performed by starting from bipedal stance with the feet stacked under the heads of the femurs and the head and torso vertical and then making fluid arcing movement of the COM over the ball of the big toe while keeping the torso and head stacked vertically and the pelvis and shoulders horizontal as indicated by orange vertical and horizontal references in the graphic below. The torso should be aligned with the transverse or frontal plane, square with the foot.

A lack of stability in the biokinetic chain is typically evidenced by a drop of the opposite side of the pelvis and a leaning in the opposite direction of the torso and/or the head or both. While this reduces the load on the pelvis side of the  leg it creates a myriad of issues. Inside hip drop will cause the inside leg of a turn to assume the load as the skier inclines thus creating further instability on the outside leg.

Elite skiers and racers like Shiffrin are able to get over it (find stability on their outside foot and ski) in milliseconds. This enables them to retract the inside foot and ski with knee flexion as they incline into a turn similar to the mechanics cyclists use when they corner; outside leg extends, inside leg retracts.

The vertical stacking exercise is best performed in front of a mirror.