I suffer regularly from cramping in the calves in races. Recently at Wasdale I got initial cramps before and during the climb up Seatallen and at the weekend was cramping by mile 10 of the Lakeland 50 - both races were compromised by having to manage twinges and then full-on cramp attacks. It happens on far less initimidating races though - Winster Hill being a recent example.
In the past I've put it down to lack of sufficient training - but I've prepared for and completed a BGR this year (and at no point suffered during that). I also take salt tablets and electrolytes.
Any views on this and how to avoid?