Did the etape last weekend, about 10mls from end suffered really bad cramps front thigh both legs, but painfully kept going. Regularly do 50 & 60 mile runs so don't think fitness was the issue. Drank and ate plenty on route but did not take any isotonic drinks could
low salt levels have caused it ?[/QUOTE]
Possibly.
However, I suffer cramp as well. I have done a fair bit of googling to try and find the answer - but there doesn't seem to be a definitive one
The conlcusion I came to (in my case) was that it was caused by dehydration. Not necessarily by not drinking on the ride itself, but by lack of fluids earlier in the day or the day before.
During a ride I probably drink more than most anyway as I sweat a lot but I don't think it can make up for it if you are already dehydrated. Usually I have a 50/50 mix of water and pure orange juice but I always add a Nuun electrolyte tablet as well.
There were a couple of times when I suffered and thought about the potential causes afterwards and realised that I had not drunk enough the previous day.
Just my thoughts anyway!
Gary.