The way Learn Wake teaches to cut is by using the entire body as leverage. Their reasoning behind it is that you have alot more leverage standing tall, than you do if you kink at the waist. (This is besides the point of whether your doing a tal or seated type edge) Physics wise it makes 100% sense and when you go out to the flats and try to cut, standing tall gets you much lower than kinking at the waist. So the idea is that on an ideal cut, if your ass touches the water your shoulders should as well.
However, when you look at good riders and pro's, its pretty apparent that most of them keep their upper body pretty upright and only cut with the lower body (kinking at their waist).
I guess Raley tricks are a perfect for this example since they require the deepest cuts. So here is an example of both....
1. If you look at the king of raleys, Shaun Murray, he stays mostly unkinked while doing a hard hard cuts:
https://www.youtube.com/watch?v=m0mCITtl4Ws
It's not as clear on the cut in, but you can definitely see it on his aggressive cut out. His upper back is basically as close to the water as his ass.
EDIT: Here's actually a better video of a close up of Shaun :
https://www.youtube.com/watch?v=pXa6lmilQrI
2. Now look at Mark at 10 seconds in (sorry for putting you on the spot!):
still ends up with an extremely aggressive cut and HUGE air, but it's apparent his upper body is pretty upright.
So whats the deal? I can only assume that the 2nd version is done by pro's because they have so much strength that the 'less efficient' way doesn't result in any tangible disadvantage. Which method would you guys recommend for people learning raleys and how to cut extremely hard?