Aikido is in a lucky position currently, it is still relatively close to it's source. But lets look 5 generations from now after all the people who knew people who knew Ueshiba, or even Ueshiba's students are long dead. If nobody is sparing, how do they even know what they are doing is even close to what he did?
Sure they can do some resistance drills, and it helps keep people a little honest. Its in my experience though that what I refer to as resistance drills is usually looked as sparing by most aikidoka. What I see most aikidoka refer to as resistance drills are just the same kata only grabbing stronger or trying to use muscle to prevent them from moving your arm,etc. When I say resistance drill, I'm talking from the prospective of the mount escape drill. I put you in mount, you work your best to escape, I resist you and counter you at varing levels of resistance. We go until you escape, or I submit you, then we reset and do it again. While some aikido schools do this, it seems to me they are a minority.
In fact I've posted the kind of drills I'm talking about once before.
These can go a long way in keeping sure that the techniques you do are in the spirit of the techniques you were taught.
And yes it is true that sparing only can not keep your art pure. It requires instructors with good character. Anyone can water down sparing with useless rules, a few deadly myths, and light to no contact, then turn their art into a money grubing empire. But arts with real sparing, judo, bjj, boxing, MT, Kokoshin karate(spelling?) and it's like have all been able to keep their effectiveness without doubt. Further more, because of MMA, arts like bjj have been able to flaws in their art and many work to fix them. This means there will be evolution in the art, it will grow beyond and has already grown beyond the gracies. For example, my club has noticed that in our matches in mma and bjj competition that our lack of good throws has cost us many a match, and relying on single and double legs is losing some effectiveness now that people are learning how to work with those takedowns. A lot of us are seeking out judo to fill this hole, learning how to use judo in the context of bjj and mma. This is nothing new to fighting, but future generations of bjj students will be taught by people who are doing this and other things. So their bjj will not be lacking and they won't need to go cross train in judo. This fact is even further reflected in MMA. MMA in the past was going to a club to learn bjj, then MT or boxing, or some other mix of arts. And this is still done, but it is slowly becoming history. It is now possible to go to a gym that trains MMA. It's not put on a gi learn some bjj for an hour, then go put on some gloves and learn some boxing and then maybe if you are lucky do some mma sparing. It's all MMA, all focused only on MMA, and no longer is it a mix of arts, but a single unit designed to be effective in MMA. This is good evolution, though testing.
Phil, Yes, MMA is about winning and losing, it is a sport. But sparing and testing is not about winning or losing. When I go to a competition, I'm trying to win. I play different, I'm using everything I've got with no regard for my partner beyond the rules. I trust that my ref will keep him safe as long as I obey the rules. If I armbar him and he chooses not to tap, I will choose to continue my armbar to it's logical end.
But sparing is different in MMA, bjj, judo, etc. It is most defiantly not about winning. It is about exploration of technique and learning about yourself and how you respond to pressure. The focus of the session depends on the quality of partners, our own goals, and how we structure the session. I'm not caring about winning in this situation. If I get an armbar and my partner will not tap, I do not hurt him, rather I use this as a change to work on a transition and move on to something else. If it was about winning, I'd break his arm.
I am not saying people need to compete. That is silly. While I think competition is a good thing, and can be very healthy when done in the right context, I know it is not for everyone. I do think however sparing is a requirement for effective martial arts. You need the whole gambit of training.
Drills with motion
Drills with motion and timing
Drills with motion timing and resistance
And you need to do some of this now and then with people who are not from the art you train. There is group think in martial arts, even the awesomeness that is bjj has group think. So you need sparing with guys who don't think like you. To make sure you are doing good technique, and not just good technique against guys trained to act like you do.