On my ride the other day not going much harder or longer then usual. I experienced the worst cramping . Both thighs compleatly knoted up and i was forced to lay down my bike . I could'nt bend either leg for a couple of minutes. Finally I was able to painfully bend at the knee. I slowly pedaled the last 10 miles home. That was 2 days ago . No more cramping but both thighs still very sore. Is this normal ? anyone else have this type of experience? Any idea's on how to prevent this from reoccurring Thanks for any advice.