Re: YouTube: Push Test to Nikkyo
"As an exercise, this was just designed to show how the correlation between a push test and a base technique. With structure, tori isn't forced to "move off the line and blend". As tori, I'm not under any load or force and am free to turn into uke's force. My upper body isn't receiving the push at all."
I think you're using a different definition of 'force' than I'm used to? I have an engineering background so I'm used to a pretty precise, narrow definition. I.e., he is pushing, so his mass is exerting a force F1. The system is not in motion, so there is an equal opposing force F2 where F2 = -F1, so the net force is 0, since F = ma and you have a mass and are clearly not accelerating... I imagine you're trying to express something more subtle than that with your choice of words (something about what the opposing force actually is? I get that you're saying the muscles are relaxed), but the language you're using isn't matching with my knowledge of the words.