Originally Posted by
livedarklions
I've found that stretching does absolutely nothing for me, and I regularly ride centuries without cramps. I'm 60 y.o. I think you're missing the point of the comments--there's no scientific answer to your question, and no one here can answer what's going to work for you.
Don't take this the wrong way, but I don't think it's normal to get crampy after a 5 mile ride unless you're doing it very fast.