Re: Does one's size or weight affect one's Aikido?
Power is not generated from fat, its from technique. Relying on weight for power is nearly the equivalent of relying on strength for muscling through technique. That, and being needlessly overweight is unhealthy. Many of the most powerful aikidoka I've seen are rather small...to include Ueshiba Morihei Sensei (well I didn't see him, of course). To get to his level when he created aikido, Ueshiba Sensei worked very hard on physical fitness and effective technique. Some feel they can start where Ueshiba Sensei finished, which is fine; but for my training I rely on repetition, focus, correct form, robust/austere training for tanren, repetition, etc. Certainly weight begets mass, and mass can be applied to technique....but I feel this argument, which I've heard before, recommends a dangerous pursuit of training.
This reply is for the average aikidoka, not the exception like those with gout, rare blood disorders, paraplegics (the one sensei I know is quite fit, actually), someone with half a lung (actually that sensei is also quite fit and competes jujitsu as well as teach aikido, I think), or what other type of ailness that inhibits fitness.