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D Benoit
11-10-2002, 11:30 PM
Dear All,

Here are the responses to my query on alpine ski boot biomechanics.


Thank you to all who replied, especially those who have forwarded some of
their work on the subject.

To summarise, the majority of the information is related to injury and not
to performance of the boots per se. Furthermore, most work has been
published in the ASTM Skiing Symposium books. In these books there is also
research related to comfort and methods for testing boot flexion stiffness
(dorsi-plantar flexion). as of yet, I have not come across any research
relating to boot lateral or rotational stiffness, even though it would seem
that these are most important in trying to 'steer' a ski and transfer power
from edge to edge. I also have not found any work that has attempted to
correlate boot characteristics with skiing performance.

Once again, Thank You to All who replied.

Below are the complete responses.


******************
1.
My advisor in graduate school did some research on skiing and boot bindings.
His name is Malcolm Pope. Here is a reference to one of his earlier works.
Hopefully, it will help.

J Sports Med 1974 Nov-Dec;2(6):299-307 Related Articles, Links
Ski injuries and equipment function.
Johnson RJ, Pope MH, Ettlinger C.

Kristin (Bolte) Poland, Ph.D.
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2.
I am a boot fitter and have researched foot orthotics for my master'sHowever, recent research was for Nordica on ski binding location. I too
have heard much about claimed performance with all associated buzz words but
agree there is very little else. As you probably know Lange makes a boot
designed to reduce knee loads in backwards falls. However, I am unaware of
research that shows it works and am skeptical.

So, although I may not be able to add much to your knowledge, I would be
interested if you can pass along anything else you may learn from other
colleagues.

Louis B. Rosenfeld
---------------------------------------
3.
I did my Undergraduate thesis in the area of ski orthotics used in ski
boots. We measured muscle fatigue in the vastus lateralis using EMG and
found it to be a realiable measure in our case. We also examined mechanical
failure (i.e. when they could not sustain the skier's squat or 'schuss'
positionfor any longer). The project was lab based and therefore the
contraction was isometric.

There is lots of literature out there focusing on lower leg alignment in
skiing and how orthotics are used to reduce the amount of tibia vara, etc
....
Some interesting articles you may want to find are ....

1) Chesneau, B. (1999). Skiez au mieux de vos capacités naturelles …
comment? Par l'optimisation de votre alignement. L'entraîneur de Ski Alpin,
30, 28-33.

2) Hertel, J., Denegar, C.R., Buckley, W.E., Sharkey, N.A. & Stokes, W.L.
(2001). Effect of Rear-Foot Orthotics on Postural Control in Healthy
Subjects. Journal of Sport Rehabilitation, 10, 36-47.

3) Macintyre, J.G. & Matheson, G.O. (1988). Clinical Biomechanics of Skiing.
Canadian Family Physician, 34, 107-114.

4) Santoro, J.P., Cachia, V.V., Tilley, G.E., Cartwright, D. & Grumbie, N.A.
(1989). Effect of the Orthosis on Performance in Alpine Skiing: A
Preliminary Report. Podiatric Sports Medicine, 79, 93-99.


Importantly, you should also look at the idea of "canting" a ski boot which
is adjusting the boot cuff to the leg. The idea behind correcting lower leg
alignment is that when the foot is in a more neutral position, it
facilitates the proper execution of ski turns, therefore more power, less
fatigue ......

As well, keep in mind there are different levels of ski boots, for the
recreational skier they tend to be softer and more flexible than the high
performance boots. High level skiers will opt for very tight fitting boots
to reduce the amount of movement at the ankle joints. This does not
necessarily reflect comfort levels though.

I am an avid skier and would like to pursue more studies in this sort of
area.

Natalie
---------------------------------------
4.
I am a podiatrist with a special interest in biomechanics practising in the
UK
Don't know if these are of use but I have been looking for info on the use
of orthoses in ski boots.

Non-prescription custom insoles for ski boots Petrov O et al Journal of the
American Podiatric Medical AssociationVol78 No.8 August 1988

The effect of the orthosis on performancw in alpine skiing, Santoro JP et al
Journal of the American Podiatric Association Vol 79 No 2 February 1989

Jilly Burrows
BSc(Hons) SRCh MChS
---------------------------------------
5.
If you are interested, I could forward portions of my Master's thesis to
you, which was on a 2-D dynamics model of the effect of ski boot design on
heel retention force in traditional heel-toe bindings. The Introduction /
Background Literature might be of the most interest since it reviewed
prior research on ski boot design and lower extremity injuries. However,
this material may be dated since my thesis was written in 1994. My
Master's research advisor was Prof. Jasper Shealey at Rochester Institute
of Technology, in Rochester NY USA. Prof. Shealey, prior to his
retirement, was considered to be one of America's experts in ski-related
injuries.

This material was presented at an ASTM Snow Skiing summer symposium in
1994; however, we never turned it into a publication.

Regards,
Liz Hsiao-Wecksler
---------------------------------------

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