NOTICE TO THE READER
I have never met Simon Zuchhuber or, to the best of my knowledge, any of the people associated with the FreeMotion ski boot project. Nor, do I have any involvement or financial interest in the FreeMotion ski boot project or do I expect to receive any form of compensation for any contributions I might make. My sole motivation in assisting Simon is to advance the design of ski boots based on anatomical principles and objective science and further the understanding of the mechanics. biomechanics and physics of alpine skiing, in particular, the informed analysis of skier technique.
Simons’ Response to my preliminary observations
To your summary of your observations I can make a few statements.
1.The primary innovation appears to be a U-shaped spring that opposes forward rotation of the Exo Cuff thus transferring force to the front of the shell lower.
This is completely true, even without German language knowledge you summed it up completely correct!
2.There does not appear to be any hard limit to the rearward movement of the shank of the skier.
This is perfectly true as well and was one of the first things I realized when testing the boot! I had a feeling of falling back when I was trying to lean back (both when standing and driving) In our concept we already added a “stopping element” to prevent too much shank movement backwards.
- There does not appear to be a forward lean (forward angle) adjustment for the exo cuff.
True again. There is no forward lean adjustment for the exo cuff. They only offer plastic elements that you can place beneath the liner inside the boot to change your forward lean angle. Would you think it necessary to have an adjustment for the exo cuff?
MY RESPONSE: Yes. An adjustment that allows the correct shank angle for isometric contraction of the soleus is essential. In a future post, I will discuss the Birdcage findings on this issue.
- There does not appear to be any means to adjust the resistance curve of the spring.
True, you cannot adjust anything when it comes to the spring. Do you think there’s a possibility to make it adjustable?
MY RESPONSE: Absolutely.
- If the Heel Retention Mechanism is securely tensioned, it is likely to obstruct the glide path of the distal tibia on the talus. This can cause the center of force on the shank at the buckle secured to the Exo Cuff to rapidly drop down the shank.
This heel retention mechanism is in the patent, but has not been applied to the existing boot series. You can see in the video that on the outside there’s only the buckle to tighten and the zipper to close, they did not apply this heel retention mechanism.
MY RESPONSE: An instep restraint system is essential. I will present several options that can be incorporated into the FreeMotion ski boot.
6.The resistance to forward movement of the shank provided by the spring mechanism appears to be introduced too early and rises too quickly.
What countermeasures would you take? Give the spring more distance to bend for example?
MY RESPONSE: I will sketch and post some options.
Thank you once again for your time, I’m looking forward to hearing from you!
Simon has advised me that the timeline for his project has been extended. I will make every effort to accommodate Simon.
For those with an interest in the application of principles of functional anatomy to the design of the ski boot and this project, I suggest that you obtain a copy of The Shoe in Sport (orginally published in German in 1987 as Der Schu Im Sport) and read the section on The Ski Boot, in particular, the paper by Dr. Martin Pfeiffer of the University of Salzburg whose teachings contributed greatly to my knowledge and the success of the Birdcage research. I would like to recognize the dedication and committment of Dr. Pfeiffer to a ski boot based on anatomical principles.