When doing somi or twist rotations is there different scores for body shape and grabs, is it preferable to grab the board, therefore have a tucked up body or would you get more points for performing a somi with a straight body with no grab because its more difficult to perform?
I also note that on somi skills most riders throw their heads back at take off, is this considered bad form/technique? I know you can see better when the heads put back, but this makes it harder for body to tuck up during flight
Performing grabs and tweaking them definitely scores higher with judges for style. While grabbing and tucking stabilizes spins, flips and corks (off axis flips) in the air by reducing your mass moment of inertia about your center of gravity, it also is difficult in that it takes control and awareness because you have a approximately 10 pound object strapped to your feet which also limits your limbs ability to move independently. This is the main difference from trampolining and snowboarding in terms of mechanics. If you can find a cheap snowboard (the cheaper, the better perhaps because cheaper equipment isn't usually as light) and you can tape up the edges to protect your tramp surface, try jumping on a trampoline to get a feel for the difference.
Therefore, the ability to strike "poses" with different grabs and exaggerate them for effect demonstrates control which is why it given technical credence. It also looks pretty damned cool Here is a video on the "method" air (a backside shifty combined with a tweak melon or lien grab), the most infamous grab amongst boardsports:
As to your general interest in designing and building a cross-discipline trampolining program for snowboarding, I would personally find myself interested in it as a way to progress freestyle. However, from a braoder snowboarding prospective, I would estimate there would limited interest in a purely trampolining program. This is because of the approach and philosophy snowboarders have for freestyle. Most snowboarders learn and progress through use of the ATML method: approach, takeoff, maneuver and landing. The approach and takeoff aspects are something that can't be taught by trampolining and this is where foam pits, air bags and progression parks (features that get gradually bigger) are of the biggest value. The approach and takeoff aspects are also the most critical to building a foundation for freestyle and dialing in new tricks as well as progression.
So, while trampolining is a valuable tool in learning (mostly the M=maneuver aspect) freestyle, it's really only so when included as part of a more complete snowboard training program. A very motivated and educated student might be able to piece together his own program and make use of a trampolining only program, but they are going to be a smaller market.
Thanks for the info and advice, its given me a lot to think about.
I went out on the trampoline today to simulate double, triple and quadruple twists both left and right with fixed legs to see how it felt and the effects the larger body shape would have on my rotation, being a right twister in trampolining I though I may find going left a problem, but I can do both nearly, equally as well.
It felt really odd taking off and landing with feet wider than my shoulders and not being able to move my legs felt really weird especially when I was off balance.
I'm going to look at cheap boards as suggested, and I agree that any program would have to be linked to and in conjunction with actual snowboard training.
Add in the fact that initiating an ariel rotation while riding and popping off the lip of a kicker has a technique unto itself and you can see that the actual in-air aspects of snowboarding ariels isn't the majority of the trick.
Try craigslist or ebay. Anything will work, mens board, womens board, a board with cracks, chips, delamming, base completely tore to shit etc.
If you are heavier, you'll want a longer board both because the flex pattern being extended over a surface area will support a bigger rider and it likely will be beefier. However, tramp boarding, none of the dynamics for snowboarding are really going to apply. Almost anything will work.
Snowboarding bindings are meant to strap in snowboarding boots, but again, since you aren't going to be actually sliding on snow, so the lack of control that a pair of shoes or normal boots would create won't be a problem.
I've decided to visit our nearest fridge (50 shocking miles away!!!) and make an arse of myself learning to board so I can have a better understanding of it first-hand. I know I'll love it as I used to skateboard back in the day and could burn some serious hand slides and rails. Just worried about injury a little, cos I teach, teachers how to become tramp instructors (hope that makes sense?) for a living and need to earn a crust.
If it goes well I'm going to invest in a cheap learning board that will do both snow and tramp, may as well practice with the real deal on the tramp as it'll benefit the snowboarding. I'll let you know how it goes! can't wait.