I decided to do cardio at the end of my workout rather than at the beginning. I was on the bike for less than a minute when my right calf muscle got all tightened and balled up. It looked all fucked up, like someone cut half my calf off. I spent like 10 mins massaging it to try to get it to loosen up then i hobbled out of the gym and went home. it hurt like hell and im still hobbling around today. My question is, why did this happen and how do i prevent it? I stretched a little bit at the beginning of my workout and i was drinking plenty of water. I've had this happen to me before but never at the gym. The previous times it was in the morning right after waking up from a night of heavy drinking.