Hi, im 15, male, 5 8 , and about 115lb. I m not sure If what I had was a cramp , My calf muscle just got really hard like if I was flexing but i had it completely relaxed. It happened while I was swimming yesterday. Its very rare, it only happened once before about a year ago. It also happens on the bottom of my foot under my big toe around the middle left area. But that happens more often and doesnt hurt as much. It lasts longer on my calf and hurts WAY more than it does on my foot. What could this be?