I don't think anyone here has any first hand knowledge of what you are talking about, in regards to Ota sensei. What you have to understand is you will not get street realistic attacks in the dojo. The street is a random place, the dojo is not. If the Uke in Ota sensei's dojo are walking up to nage and at the last second launching an attack with no sign as to what the attack was, basically a "sucker punch" situation in the street, well, that's about as realistic as you can get. But at the same time, if Nage starts to apply a joint lock type of technique, it's foolish to think that uke is resisting with all his strength during the entire technique, otherwise there would be injury. There is just no way to avoid that. If you lock your arm up and try really hard to resist an ikkyo on someone with very strong technique, it will hurt. Having done it, I know. But I still relaxed and went with it at one point or another, where as on the street, that would probably not been the case. I can easily see my rotator cuff tearing from that. I think it's a case of not fully understanding what Ota Sensei means when he says "street speed aikido". while I don't dispute Ota sensei training with considerable speed and intensity, it's not going to be street realistic. There are far too many factors that will prevent that from happening. Perhaps you should contact Ota sensei though.