Originally Posted by Uncle Louie
First attempt- I stood straight, left the floor, rotated the upper body, everything else rotated and I landed facing the other direction.
Second attempt- I stood with the upper body facing as close to 180 from my feet as possible before take-off (take-off ...I like that
), I left the floor and the feet realigned with the upper body before landing.
The results- The first way was much easier. Interestingly the second way required far more use of my quads (pre launch) to effect the move. If this were to be the same on the snow.....that would mean you actually use your legs muscles more to anticipate to "allow" the legs to turn??????
(I can just see all of you now trying this in the Living room or at work
(I also suspect this is going to be a whole new arguement
I used to teach gymnastics and tumbling classes. After classes, sometimes the coaches would goof around on the trampolines and play silly games. One of our favorites was to jump straight up in the air and have someone call for a particular skill while you were airborne. Sometimes, they were simple ("spin left," "spin right," etc.) Other times, they'd get more difficult ("backflip"). By having someone else call the skill, we basically eliminated the potential for subconscious "intent" or anything of that sort.
Generally, the ability to successfully execute the called skill depended a LOT on timing of the call. The longer your waited to call the skill, the harder it was for the person to complete it. Adjustments made on the way up were always the easier ones. It was always very hard to make any changes at all if your arms were held tight to your sides. In that case, the spins would end up being all corkscrewy and snaking around, rather than being clean, and any flip would peter out halfway through. The best way to be prepared to make a clean spin (in either direction) was always to start with your arms wide and legs slightly spread when you jump, then pull the legs together and arms to the chest pulling towards the direction of the desired spin.
In other words, I think it may be possible to make some of the changes we're discussing mid-air without pre-intent given perfect technique and timing, but only those in which the the CM is not made to deviate from its initial path (which is, I think, what's been said here, for the most part). I don't believe it would be possible to jump straight up and get a command like "move 5 feet to the right" and complete that successfully, because it would require a major relocation of the CM.
Of course, this has little relation to trying with skis on, since the CM will move a great deal (lower) with the addition of boots and skis. The change in CM will also be complicated by the change in the moment of inertia introduced by the increased radius of the person+ski vs. person alone. I suppose that by pulling the skis to to as close to vertical as possible (bring them up behind the body by bending knees) it may be possible to significantly reduce the difference in the moment between the two models (thereby putting us closer to the "person alone" model, and making things closer to the trampoline game). All I know is that I definitely am not ready to try that!