I don't think I've ever had cramp, either on a ride or anywhere else, but a few times I've felt something that I thought might be the onset of cramp. It seems to happen just after I crest a steep hill (can't feel it on the way up) and it's like a feeling that something's not quite right in the top of my calf, as though the muscle might suddenly tighten up and lock solid. I then ease off the effort, and it never amounts to anything.
Is that likely to be cramp? This has only started happening in the last couple of years, and I wonder if it's because I'm getting older (now 38). Or could it be because I'm fitter now than before, and am tackling hills harder than I used to? I stretch regularly and keep hydrated; is there anything else I should be doing to make sure it doesn't develop into real cramp (which from how people talk about it I'm keen to avoid if possible).