text: I had the same problem sometimes too.\n\nNow I drink at least five glasses of water a day to stay hydrated (but don't drink a lot just before running though).\n\nAlso, I eat at least one banana every day (usually in the morning with breakfast).  Bananas contain lots of potassium, which helps prevent cramps.\n\nAlso, do a full-body stretch (not just your legs) before -- and after -- running.  Besides stretching your legs, also stretch your arms, shoulders, back, and obliques (sides).  \n\nTo stretch the obliques, clasp your fingers together and then put them above your head, with your palms facing up.  Then dip your left shoulder down to stretch your right obliques.  Dip your right shoulder down to stretch the left obliques.