Yesterday, I found the following comment waiting in que for my review and approval.

Dear David! I am currently working on a project as a student for the FH Salzburg, Austria! We have the task of analyzing a specific ski boot and implementing improvements! Since this is a short project and we are not experts on ski boots, I wanted to ask you for profound feedback on this boot! It can be seen on the website

The boot’s concept is that instead of having a hard plastic-shell to deal with the forces, it uses a metal spring that starts at the forefoot and goes through the ankle-axis all the way back over the heel! We already tested it and were quite surprised, how well it worked, but maybe you can add a few thoughts that come to your mind when you check the boot?
I know, it’s very hard to give feedback without having the boot to test, but maybe you can still give some feedback? Thank you very much!!!

With greetings from Austria
Simon Zachhuber

It goes without saying that I offered my assistance to Simon. As Simon said, “it’s very hard to give feedback without having the boot to test”.

While it is hard to assess the FreeMotion boot without being able to examine it and test and evaluate it during ski maneuvers, from what I am able to see in the photos and videos. I believe that the concept holds promise. In important ways, the FreeMotion is remarkably similar to the exoskeleton format of the Rise ski boot that was based on the Birdcage shown below.


My vision for a a new ski boot was embodied in the minimalist concept, exo-skeleton Birdcage that I designed in 1991 with biomedical engineer, Alex Sochaniwskyj. MACPOD engaged Alex to consult on the ski boot project. Since the Birdcage was a research vehicle designed to test my hypothesis on the mechanics, biomechanics and physics of skiing and acquire the data needed to design a ski boot based on anatomical principles, aesthetics were not a consideration.

Here is what the Rise ski boot looked like that eventully evolved out of the Birdcage.


Here is a design concept sketch of the Rise ski boot.


Here is a photo of the FreeMotion ski boot.


The red arrow in the photo below shows the rubber wedge at the rear of the shaft of the Rise concept. The wedge was compressed by rotation of the shaft as to arrest forward travel after a specified amount of rotation. The actual Rise boot used a rubber stop in front of the cuff to perform the same function.


The FreeMotion boot uses spring mechanism running along each side of the shell lower body to the back of the hinged shaft. The spring is bent as the cuff rotates forward so as to arrest forward rotation.

Here is the FreeMotion promotional video.

Here is the Rise promotional video.

Here is the promotional material for the Rise ski boot.



Unfortunately, due to limitations in materials and manufacturing processes that could not be overcome, the Rise ski boot never made it to market.

In my next post, I will review the development process that saw the principles of the Birdcage applied to the Rise ski boot and how the FreeMotion project can benefit from the knowledge gleaned from the Rise project.