Before I got frustrated with and moved on from the "Discussions" forum in the members-only "Community" section of the PSIA National website, I posted a thread on Bumps (because personally I can’t ski, and the moguls prove it) and, in response to a video I linked, a member said that the bump skier was in the "back seat." Which intuitively I knew could not be true, because the video was of an Olympic or otherwise expert bump skier. To his credit a Level III (I will amend this post to include his name to give him credit) posted that while it looked like the skier’s butt was back, his Center of Mass ("CoM") was actually stacked over his Base of Support ("BoS") because the skier was going up the uphill face of the bump.
That got me thinking, that if you do your Movement Analysis ("MA") only with respect to "vertical" or to Earth Gravity ("EG"), or even with respect to snow slope, you could be missing the fact that when the skis move up the uphill face of a bump, or up the wall of a half-pipe, or laterally in a high speed carved arc, that MA must start by identifying the largest applicable Gravity ("G")-force. Which at least Bob Barnes refers to as the "Resultant Force." But I, personally, think I like G-force better. Because there is only G-Force, which either is existent 1-G Earth Gravity or the 2or3-G's which "result" from centrifugal action in a turn. But they are all G-forces.
So, the concept of adding "Where is the G-force" to my MA checklist I think would be very helpful.
[Edit: Everything I said above is wrong. But it was a good start for me to understand the truth, which as you will find below took me a long time to comprehend.]
Some of the pictures of GS racers in Mr.GolfAnalogy’s recent "Help with Counter thread" furthered my thought processes which I would like to discuss with you.
A GS skier in a high speed carved arc is not "inclined" at all.
The Herminator (i.e. Hermann Maier.)
True he is "inclined" with respect to the snow surface and with respect to EG, but these two things are irrelevant to the turn.
Rather, if you turn the above picture counter-clockwise 90 degrees, you will see that the skier is actually "standing" with respect to the largest applicable G-force. And standing with his skeleton stacked, which is the way the anatomy of us land-living animals is designed to deal with gravitational forces.
Above image from Paul Lorenz. http://www.paullorenzclinics.com/
This is a break through in MA for me. So, in the spirit of exposing my ignorance for you all to help cure, I note that this has been covered before by some of the currently active members and by Bob Barnes who posted some really helpful pictures
and diagrams and even animations in the thread below:
Edited by Tim Hodgson - 9/16/16 at 10:12am