Re: Should obese aikidoka do break falls?
I'm not convinced that the slapping hand really is taking most of the impact, even when it's the first thing that makes contact and even when it feels like it's taking a lot of impact. I just think given the forces involved (gravity to start with, let alone additional the additional force of a throw), we would be seeing far more hand and arm injuries if that were the case, and many serious ones.
I slipped once skating as a teenager and put out my hand to stop myself -- immediate broken wrist. And I was going very slowly (basically stopped, stepped onto the snow at the side of the pond, didn't realize there was ice under the snow) and there was no force other than gravity. Sure a different angle would have made a difference, but that's just a lot of force for the small bones of the hand to take in a direct impact.
Personally, it feels and looks to me as if proper body position (and change of position throughout a breakfall) allows the body to be (comparatively) very gradually decelerated without putting large forces on any part of the body... I.e., either more like an 'elastic' collision, with significant deformation of the 'object', or with transformation of the linear momentum into rotation. Certainly friction is a part too...
I suspect that's what slapping with the arm actually does... allows the whole body to act more like a spring and change shape over the course of the fall
I know that I rarely feel like there's a lot of impact on my body when I fall... not sure what precisely is happening, though.