Re: Aikido against strong people...
Speaking as a strong person who many newer stdents feel is impossible to throw,
No. Using more muscle to try to force the technique won't work. What it will do is tick off the strong person and potentially get you punched. Not that I ever punch beginners but boy sometimes when a newbie is cranking as hard as they can and all the while they have me locked in place sending force straight down my leg, making it nearly impossible to move, it can be hard to resist.
When you find yourself in such a situation ask your teacher to help you to understand the the technique and how to do it with that particular person's body type. If the strong person is senior to you he/she is probably not trying to be impossible to throw. If he/she is truly grounding you out and making it impossible ,on purpose, your teacher will recognise it and help them to better understand their proper role as a senior uke.
Eventually strong people realise that using their strength to oppose nage just sets them up for an even bigger fall and not the one they were expecting. They also learn that making it impossible for beginners to do techniques means they will soon run out of people to practice with.
Being the senior student in the dojo is nice and all, but being the only student in the dojo isn't at all a good thing.