Wholly Crap, I had a cramp in my calf that felt like a heart attack. It was not my whole calf either. It was just a spot that was about the size of an old fashioned half dollar. It was weird because that spot sunk down about half an inch, stayed that way for about a minute then started throbbing in and out for another 3 minutes. And finally subsided completely, except it was just sore for the rest of the day. I could hardly put my foot on the ground until Sunday Morning.