Lifting hand or foot while sleeping

Anybody else lift an arm or leg while sleeping?

Others have told me that I will lift one arm straight up into the air while in deep sleep. If I happen to be sleeping face down I may bend my leg so that a foot is in the air. This is not on purpose. I don't ever recall doing it or even seriously thought about till now. I used to think it was a joke that my boyfriend made up. He insisted it was true. I spent the night at a friend's place and the friend spoke to me about it. Not sure about duration or how often it occurs.