alignment

THE IDEAL SKIER’S FOOT AND LEG

Do you have the ideal shape foot and leg for ski boots? Let’s find out.

Not long after I starting working on ski boots, I began to notice that the best skiers, those who made high performance skiing look easy, seemed to be able to ski in boots right out of the box that usually required major modifications for most skiers just to get their feet into. This small group of elite skiers consistently had very specific foot characteristics, especially the shape of their feet and legs. Although there were some exceptions, the feet of elite male skiers tended to be US size 8 or 9. Podborksi’s foot was a US men’s size 6. The feet of elite female skiers tended to be the equivalent of US men’s size 5 or 6 with some feet as small as size 4. As I worked on the boots of more National Ski Team racers I soon developed a reputation for being able to describe how a racer skied by studying their feet. On one occasion I was with a group of racers in the waiting area of a steak house. Unseen by me, Dave Murray came into the room. He snuck up on me while I was on my knees on the floor studying a racer’s foot. Dave put his bare foot in my face so to speak. Without looking up and without missing a beat I said, “What are you doing here Dave?”

The image below shows the characteristics I have identified as common to racers like Ligety, Shiffrin, Vonn and other World Cup racers. The characteristics of their feet and legs enables them to create the mechanics and biomechanics within the ski boot necessary for them to engage the external forces to drive their outside ski into a turn. Depending on a number of factors, including luck, racer’s with these foot characteristics can often ski in a boot right out of the box with minimal or no modifications. Modifications take their skiing to another whole level.  I believe that young racers such as Shiffrin make the connection with the right feel early in their career. Once a racer, or any sensitive skier, connects with the right feel, especially at an early age, they know as soon as they take a run in a new ski boot whether it will work for them. This group of skiers has the ‘magic touch’.

 

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Here’s what the right shape of leg looks like in the cuff of a ski boot. I align the cuff so the leg is centred in the cuff when the skier is standing on two feet in the boot shells with the feet hip width under the pelvis. Note the amount of space on either side of the shin. This is critical for reasons I will explain in a future post.

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In my next post I will show what problematic foot and leg shapes look like and the challenges presented in creating a functional environment in a ski boot.

 

THE DREADED DIAGNOSIS: PRONATION

You may have been told by a boot-fitter or even a ski pro or coach that your feet pronate and that this will make it difficult, if not impossible, for you to hold an edge and/or control your skis. Or you may have overheard a boot-fitter run through a pronation diagnostic drill with a customer having a boot fit and/or alignment session. It goes something like this.

Boot-fitter to customer: Now stand with the weight even on both feet and flex your boots. Oh yes, I see your problem. Look down at your knees when you flex forward. See what happens. Your knees move towards each other. This explains why you are having so much trouble skiing. Your feet are pronating.

Customer, fearing their situation is terminal: Is this bad? Is there any hope? Can you help me?

Boot-fitter:  Yes, pronation is very bad. But don’t worry. I can help you. A pair of custom footbeds and an alignment job and you will be a World Cup star.

Customer: Wow! Sign me up!

It all sounds good. But there’s one small problem……. OK, it’s a big problem. Standing on two feet and flexing ski boots has nothing to do with skiing. In fact, it has nothing to do with the normal function of the lower limbs (ergo – the legs). The boot-fitter may not realize it, but the boot-flex procedure is something of a con, a sleight of hand. The basic balance strategy of the body when standing erect on two feet is to maintain position Centre of Mass slightly in front of the ankle joint so that gravity tends to disturb balance and cause a forward fall by causing the ankle to flex forward. This tendency is opposed by muscles in back of the leg starting with the soleus.

The soleus is an extensor muscle. It’s job is to extend or plantarflex the ankle so that the forefoot is pushed down; towards the floor. This pushes Centre of Mass backward, against the force of gravity to the isometric contraction position.

The foot is configured for standing on one foot so that gravity will tend to cause the foot to evert or pronate. Eversion is the turning of the sole of the foot away from the centre of the body. The tendency of gravity to cause the foot to evert or pronate is opposed by a group of muscles that I refer to as the inverter sling. Here’s the kicker. The inverter muscles of the everter sling are also extensors.

Think of the front of the boot cuff as a resister of forward ankle flexion. Guess what happens when the resistance of the boot cuff starts to support your weight when you flex forward and your shins press against the front of the shaft? Your hard working extensor muscles start to go on vacation because there is less and less for work for them to do. Since the inverters have also turned off, guess what happens next? The feet relax and fall inward in a quasi-pronation movement. It’s not the same as functional pronation. The knees turn inward towards each other more than they would when the extensors and inverters are in isometric contraction. There’s nothing wrong with your feet. It is just that muscles only do their job when they have something to do. Things are not really what they appear to be. But the illusion sells footbeds and alignment programs.