Chances are if you visit this website you're no stranger to the dread of a muscle cramp. We've seen some of the strongest athletes completely shut down to them, and you've probably succumbed to the same fate before. Tribook released an interesting article detailing a technique called reciprocal inhibition. The technique basically says that if you have a cramp, flex the opposing muscle group. For example:

If the cramp is in your hamstring, activate your quadriceps by straightening your leg.
If the cramp is in your quad, activate your hamstrings (bend your knee).
If the bottom of your foot is cramping, lift your foot and spread out your toes.

More information can be found at the video below -