i have 2 months until the arnold's and i was wanting to know the best way to improve your cardio for jiujitsu. I assume rolling is the best but i dont always have someone to roll with.. so will running and jump rope work? or will that just mean i can run for a long time and still get gassed when i roll? i know literally nothing about cardio. Ive never even bothered until my last tournament. i just assumed i wouldnt get tired via magic.. but apparently magic wasnt allowed at that one because i was dead tired by the last match. and i know the arnolds are bigger than the OGC. so anyone have any tips? or is running sufficient?