Yes, the cramp can tighten the muscle so much it can cause microtears just like you get when you pull a muscle. I know from experience that a cramp in a calf can also lead to a torn muscle. A few days after the Shenandoah 100 in 2006 my calf cramped just as I was getting out of my car and it actually ripped my calf 1/3 of the way through and put me on crutches for 6 weeks. :mad2: