Whenever i'm in a lucid dream, i have no problem with flying, jumping high and such as long as i use a prop. Like if i want to fly i often use a jetpack, and if i want to jump high, i use fly jumpers. But whenever i try to do something physically like running fast or flying with just my body, i just can't seem to do it. I guess it's about anticipation, but do anyone have any suggestion what i should do?