Muscle Cramping

squired

For some time now I've been having a problem with my left leg. As soon as I start riding hard I get a sort of cramping running down the outside of my left hamstring (from the buttock down almost all the way to the side of the knee). I'm convinced it isn't my bike, as I get it on any bike I ride, so have been focusing on stretching, but that doesn't seem to have helped either. Any thoughts on a possible cause or cure would be appreciated, as it really limits the efforts I can put in.

Lifeson

Make sure you are not dehydrated
I have found using dioralyte helps with re hydration replacing the salts lost