During night when I just start sleeping, not sure some automatic reflex action happens and my one hand or one leg jerks out. It happens so instant that I am not able to make out what has happened and why my hand/leg has jerked out. This disturbs my sleep and I wake up immediately. This is happing since last few months. I dont know how to control it. My husband noticed that this is happening multiple time during initial period of sleep. I hope I am able to explain my problem. Please let me know if this is normal? Please suggest how to control it?