It has never happened to me and I drink about 8 cups of coffee a day…I’m a teacher - it’s almost required. Having said that we are all different and I have certainly had cramps - usually in the adductors after (but never during strangely) hard turbo sessions as turbo training is supposed to place a little more stress on these muscles. I think it is more the fatigue levels than any caffeine effect. That said only one way to find out - by some decaf and see if it goes away! 