I don't know what it is, cold water or that I"am out of shape but lately I've been cramping my hamstrings and calfs after about 2 hours in the water. It happened to me this past Friday paddling for into a wave.... it wasen't nice I ate it!!!!!!! Any suggestion to help ease the cramping. I already streach and do some yoga. Could it be those tight a$$ bootys and fins? Any suggestions would help.