My Son Who Is 19 Y/o And Very Active, Has

My son who is 19 y/o and very active, has found it difficult to sleep for a few years. He thought it was that he was getting symptoms of ADHD. I watched him try to nap today and this is what I observed: every few minutes his arms would jerk, hard. A couple of minutes later his left leg would follow with a hard upward kick. This of course would wake him up. I also noticed that he would try desperately to return to sleep by folding his hands into his chest. Yet they still would manage to jerk him awake. Followed shortly thereafter by a leg kick.
Is this restless limb syndrome?