Originally Posted by Jamt
The vaulting over the outside leg starts to stop when that leg is retracted. The CM continues to move up because of the upwards velocity it already has. It will eventually start moving down again because of gravity. If that upwards velocity was driven by a 3G push on the inside leg the CoM would have continued upwards for a lot longer.
Think about it this way, jamt.
Once weight is transferred to old inside (uphill) ski, and for as long as the old inside leg is kept rigid, even if it is not still extending, vaulting will continue throughout the process of rolling off edge. And here's the proof. If at any point during that vaulting process the rigid uphill leg were to be relaxed, the skier's path of travel would change. It would level out from that which it would be if the leg is kept rigid all the way to edge angle neutral. It rises further when the uphill leg remains rigid because of vaulting.
Are you familiar with the concept proof by contradiction?
If the transition is made by extending the inside leg without vaulting over the outside it implies that the inside extension lift about 3G in a very short amount of time. This is not possible hence there must be some vaulting over the outside leg.
Thinking about what you're saying here, and on the surface it sounds reasonable, but knowing what I feel when I do this, I find the two don't jive. I do not feel like I'm lifting a such a large load when I ILE, and from watching the video of Mikaela do it it does not appear she is overly straining to get it done either. I think the conflict can be partially answered in the theory that we are not working agains the entirety of the 3g force as we extend the uphill leg. We're only having to combat a portion of it, because we are not in balance. Much of the 3g force load is being used to lift us and move us across our skis.
I suspect the vaulting is helping power the extension also, making it feel more effortless than the 3g force would have us believe it should, because all through the vaulting process a momentum is produced that seeks to drive our CM further from our foot. Vaulting initially takes us along a curved path, but centrifugal force, inertia, momentum, what ever you want to call it, develops that wants to send the CM away from the foot, which involves a lengthening of the leg. By extending we are adding that little bit of extra force needed to actually make it happen, or make it happen more, or make it happen faster, depending on the nature of the turn we're transitioning out of. That extra force applied via ILE when done in real life feels quite small, requiring very little effort.
Jamt, thanks for prompting this discussion. It got me thinking even more deeply about the whys of what happens happens in vaulting, and how it affects ILE. Why we feel what we feel, beyond just knowing what is felt. Why it feels as effortless as it does, in the face of often large forces which at first glance one would think would make it a herculean task. I've connected a few more dots.