Unfortunately not a cramp. This happens to me a lot in the past year if I immobilize my hands or arms at all...even if it's just having them in the same position without moving or stretching them (like me holding the duster for extended periods of time or the fishing pole when I went fishing or also if I am stitching and my one arm doesn't move much). It's not just a cramp...it's total freezing and I have to forcibly move that limb usually with my other arm. God forbid it ever happens to both sides at the same time...I'll be a useless mess! I try to be good with this stuff and not let myself immobilize but sometimes with the things like dusting or fishing or stitching I don't even realize I am doing it until hours later when I try to set the duster, fishing pole, or stitching down. Once I know that these things cause the freezing I just have to make myself move the limb every 5-10 minutes. Frustrating how much life changes when you have RSD...even when things are going good you can't stop and take a break from it at all or "forget" you have it and the things you need to do for treatment/therapy. Oh well...things are generally going so awesome...this is just a tiny blip on the radar.