Ruth McWilliam wrote:
So what happens when some big chump grabs you and powers up his muscles to effectively stop you moving in any direction you try to move?...
I know I could have gotten him to move by aiming my knee at his testicles, but that's not going to teach him not to be a jerk. Ruth
Of course, uke needs to take your experience into account for succesful training, but don't feel threatened by this person. They are giving you an opportunity to try out the aikido principles. From stationary it is very difficult to move someone. However that does not mean that you are incapacitated (indeed, they are). You can move your whole body anywhere around this point of contact, and as you say, you can move other limbs.
Always see a stationary grab as one less fist they have to hit you with! Now, if they use that to pull or push you, then you can work with it.
Although he may have been a jerk for this type of action, by not allowing him to grab in the first place, you could have generated the movement. Ueshiba said about even the strongest person being weak when you draw them out of their sphere of power i.e. timing and coordination are required. Of course, when things go stationary its more difficult, and thus atemi is useful to generate movement again (unless you are quite happy staying there unharmed, which can sometimes be OK).
From practical experience I would say that strength is of no benefit to an attacker if you are prepared to move your body. Indeed, I would say the easiest fights I have been in are those with a really big and strong opponent because they often believe that they can hold you, or destroy you with a single strike - and it just isn't true if you move properly.(I'm only little and weedy at 11 stone)
(PS I agree with Bridget, next time kick him in the nuts - its good training for both of you!) In fact, do so even before he grabs and it'll stop him thinking 2-dimensionally!
P.P.S. one of the main reasons I was attracted to aikido was a girl who must have been no more than 8 st who could throw me around like I was a leaf (of course, she was a dan grade, but is was amazing to an aikido novice and a thug like me).