If you move all over the bed or wake tangled in the covers you may suffer from restless leg syndrome.
Restless Leg Syndrome (or RLS) is muscular jerking that wakes you out of sleep. This is the case for Restless Leg Syndrome as well as a related problem, Periodic Limb Movement Disorder (PLMD).
Similar to Sleep Apnea, restless leg syndrome is a disorder related to a lack of REM sleep. As you jostle around the bed you are prevented from going into a deep REM sleep, and are woken up by muscle jerks. This muscle jerk ripping you out of your REM sleep from restless leg syndrome is similar to Sleep Apnea where your loss of oxygen triggers an exit from REM sleep.
There is no proof that treating Sleep Apnea will cure Restless Leg Syndrome as the conditions are unrelated. There is anecdotal evidence that compliance with CPAP equipment may help relieve Restless Leg Syndrome, but that hasn't been proven yet. See a doctor if you think you have RLS.