muscle spasm
"I'm an aging jock.  I have many old injuries, but take Robaxin primarily for spinal pain - (L1-L2-L3) disk problems.   I start dosing 3 days before I am scheduled to do something stupid, dose through the activity, then wind down for a day or two later.  It makes my 60 y.o. body work like a 30 y.o.  Unfortunately, that doesn't always work out so well, but with an NSAID like Naproxin Sodium, and a muscle relaxant like methocarb, I can stay immature for many more years.  I find my only side effects come from playing too hard.  I have experienced no other ones."