I saw this posted, and it has some interesting implications for Martial Arts. It talks about how, while learning physical activities, even minor changes in the actions you take can have a significant impact on how fast you learn. The given example was that with a test action where people learned to control a robot, changing the position of the target caused people to learn 50% faster than with just the simple motion of an object with a fixed position. There was also the implication the body learns specific muscle activations which are different between something like Kata and something where you have actual resistance.

I'm planning on going through the actual paper, this seems like it's interesting stuff.