Ten-year-old boys move differently than middle-aged women, who move differently than athletic guys, who move differently than government bureaucrats.
If you look at a lot of animated movies, they don't pay attention to how things move through space.
I think if you have a really big, heavy person, there's a feeling of an invisible puppeteer jerking them around in space. They don't feel like they are moving themselves.
If you move something 10 pounds through space and then stop suddenly, there's a little overshoot. When you transfer weight from one leg to another, there's a certain way that it happens
Even in hand drawn animation, humans are widely considered to be the most difficult to execute, because everybody has a feeling for how they move.