What is solid and charged with energy?

(insert your cleverest answer:___________)


Something I note recently about Aikido practice--while practicing tenkan(the changing-direction exercise), it 'works' with a variety of training partners.

I've been working on maintaining a solidness through the exercise from the arm, through the shoulder, and through the turn. Not a rigidness with force, but a solidness in the curve of my arm to my pinky. And, well, maintaining it through my wrist being grabbed.
And sort of charging my body with energy while doing this. I discovered that by extending my arms during rowing practice, I could up my energy with the extension. People always told me to 'extend, extend,' but I think I've been extending and sort of giving away whatever energy came from that extension. But now I want to work to understand what's happening and to build that energy and cultivate it.

I got a couple of 'mmm...'s from my partner at practice last night, instead of the usual 'no, do it this way,' and such. Similar thing happened with someone else.

I want to go into this deeper...