In a word MMA. Which was what I always did while doing other things.
Okay fair answer to a poorly expressed question. I _meant_ a different question:
Assuming you are fundimentally convinced that Osensei's and Takeda sensei's martial arts were martially effective against other martial arts - that they were then and they must still be now. And you want that but don't have a very direct way of approaching those skills yourself. What do you do?
Some, have tried to up the progressive resistance looking for inspiration. I believe that is what David's video represents and also what I have seen from Chris H. I respect the attempts.
Some look at the approach and recognize that getting there without different help is unrealistic so they decide it is pointless and give up on that aspect. I can understand such an attitude but I'm just not wired that way.
I'm sure that there are other flavors too. I just dislike the transcend devoid of transform approach. I think it is delusional at best and snake oil at worst.