Ok, I'm a bit stupid, but yesterday I tried to cylce 100km without any previous training. I'm just an amateur, and hadnt cylced very far before. I had cramps after about 50km. I would ride and all of a sudden i would get this sharp pain in my leg, so i would stop and rest for a while, but as i kept going, it got worse, untill after about 80km, i could hardly even walk. A friend says salt and water helps, is this true? I'm thinking maybe I should have just trained a bit beforehand. I had the energy to go on, but my legs hurt too much. Any Advice?