Spartan Racing

Hey everyone....I'm hoping to get a little advice here from some veteran Spartan racers....I completed my first Spartan Sprint race in April this year...then did the Super three weeks ago.....got through all the obstacles without any issues...but about halfway into the Super (in Asheville NC) my quads cramped up and absolutely crippled me. It was honestly the worse cramp pain I have ever experienced. To be honest, I did not carb load the day before and I didn't have much to eat the morning of the race. I have been doing lots of cardio and running outside so I really don't think my muscles were that surprised to shut down. I'm registered to do a Spartan Beast in Nov as I really want to get my trifecta. I've already increased my cardio sessions but I'm wondering if the cramping I experienced was more of a nutritional problem or electrolyte deficiency....can anyone please offer advice on carb loading, pre-race fueling?? I've already invested in a camal-bak and gu pouches as I am doing another Sprint race this Sat for a little redemption. Thanks for the help.
Paddy648