Thursday, October 27, 2022

Leg and bone curvatures for skiers, greatly influence your edge holding ability!

One of the realizations we noted studying ski racers for 50-plus years and performing alignment assessments for 40 years is the differences in bone curves and how they influence skiing biomechanics. 

For the layman all you have to do is look at this photo to see the curve in the shin; this is a high tib-fib varum. Few experts, even those that deal with anatomy or foot alignment like podiatrists, differentiate between this curve and the standard bowed legs. Both are curves in the shin however in skiing they have and should be addressed differently for optimizing boot setup or alignment. 

In this photo, the knee mass is lined up with the ski edge rather than with the center of the foot. As the suits and ski pants became tighter in fit around the lower leg and shin, leg curves become more apparent. Not all shin curves are the same and they all affect your skiing technique and ability to hold an edge differently. You might even say that there is a certain predisposed natural selection for success based on an ideal leg curve for ski racing. Going back as far as Pirmin Zurbriggen, his high tibial varum was obvious to us and so was his skiing success, that correlation repeats itself with a high percentage of successful ski racers.

The biggest part of this curve is near the top of the shin.

How do we treat the differences between a lower tibia varum coming out of a ski boot compared to a high tib-fit varum as shown by the skier in the photo? The low curve is optimized by cuff adjustment, the overall curve as in the graphic below is adjusted mostly with under-boot canting and high tib fib varum mostly requires only fine-tuning of both boot components. (this is also always influenced by ankle and foot range of motion capability)

A perfect example is Erick Schlopy, a bronze medalist at the world championships. His high tib-fib varum needed no under-boot canting and only slight cuff adjustment. However, due to his rigid strong foot and ankle, our boot board modifications significantly improved his edging ability.

This type of optimization requires a complete assessment of all functioning moving parts that influence skiing. The ankle and foot lateral inversion and eversion movement capability and the ski boot's influence on foot/ankle movement included, including all of these measurements must be taken into account before adjustments can be finalized.

As you can see by this graphic from the Cleveland Clinic, which has been treating lower leg deformities and creating footbeds for these conditions for 100 years, no reference is made to bow legs being part of a shin curve. This graphic illustrates a bowed leg condition based on Retroversion in the hips rather than a shin curvature. 

This is an example of the commonly understood bowlegged low-shin curve anatomy.

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