Ginny-I had cramps like that during one of my races. Cleveland! at first I felt like someone softly drew their finger tip up the back of my calf. Hmm.. that was odd I thought. Then not so softly. Then it was like someone reached in and pulled on the calf muscle such that my toes were forced down like my foot was pointed. For a split second I tried stretching it up against a curb. Ha! Piano string was still taut so no stretching allowed. Eventually I could do more than shuffle but it took awhile. At Cincinnati after the race I couldn't move. I told Mike to meet me in the W staging area since I couldn't walk. I think it's an Ohio thing.
Seriously, electrolytes do sound like the thing. Those two races were ones that I know I either didn't drink enough or tried using more water. I know that we are all different but for me I do take the electrolytes and hydration seriously. In this weather even for 5 mile run I make sure I have water with me. Anything past that and I start putting Gatorade in the mix. I will dilute but not 50% and when it's really hot where I know I'll be sweating buckets I don't dilute at all. Then again, I've trained my stomach to accept the sugar part. You can do Nuun or G2 which doesn't have sugar but I find that they make my stomach acidy. I've also added Nuun tablets to Gatorade on hot long trail runs to have extra electrolytes. That's just me though but I don't really cramp up as long as I drink electrolyte filled drink.
Lisa