The idea that kongs (and most other vaults, but especially kongs) are actually quadrupedal movement has been knocking around in my head for the last few weeks. I've been meaning to write something more stodgy and authoritative sounding, but since I've been too busy to do so I'm just going to throw it out there. The idea occurred to me when I was working on double kongs because the way I gained confidence in my arms was to bend forward and fall or jump onto them and feel how they supported my body movement. I had to feel like I could control myself with them as much as with my legs. Bouncing back and forth between hands and feet started to feel as much like QM as vaulting.
Even after successfully and repeatedly executing double kongs over my chosen obstacle, I wondered if it would be more efficient and perhaps also faster to leap forward bringing my feet up close to my torso and land at the near edge of the obstacle then level kong the length of the obstacle. Certainly this would feel safer when slightly tired during a run or with added weight such as a backpack, at least at my level of confidence in my abilities (Foucan doing it in the 007 chase is another thing).
Then, in another conversation about multi-kongs v. "bear" vaults (which is my default- I feel much more relaxed with that technique, especially when touching more than twice with my hands) where my fellow conversationalist felt that the bear technique was a bail-out for multiples, not so much valid on its own. But in a way that's like the difference between split-foot and paired-feet takeoffs- the former tends to more powerful vertically while the latter tends to be smoother when trying to maintain level movement.
To get a little conceptual, while legs are certainly stronger than arms in humans (we are bipeds, after all), the point of all these the techniques we practice isn't to jump over an obstacle or leap a gap, it's to move. The way I see movement is that the limbs serve primarily to redirect the core; ideally, the the ground (or walls, rails, window frames, etc.) aren't hard surfaces to push against but edges of air that are occasionally checked for balance. The difference between a pass and a vault may seem pedantic when looking at one movement, but it's essential when moving on to flow.
So given that, I'd be interested in making T-shirts with a thick, easily-visible-from-fifteen-yards-away, solid line printed across the chest (or abdomen for women) at approximately the center of gravity of the wearer. This would make it very easy to see how much the c.o.g. moves in comparison to the contortions we put ourselves through to find an efficient line. Plus it could be a neato design element.