I think most people have these…you are lying in bed falling asleep and suddenly your body does one convulsion - it feels like all your muscles simultanously contract and release - or like someone pressed your reset button.
Does anyone know what they are? What causes them?
It sounds similar to something I have experienced in dreams where i’m falling. I wake up just as I hit the ground and my body convulses, it feels like I fall from a height of about 6 inches above the bed. Perhaps in those cases it is the body reacting to the dream just like people may thrash about if they are drowning in a dream, just a WAG.