Most top level MMA fighters do two training sessions a day; one conditioning, and one skill training, with each being 2-3 hours long, sometimes longer. When I say skill training I mean BJJ, Kickboxing, Wrestling and shit like that. For conditioning they usually run, swim, do plyometerics, and sometimes light weightlifting. All in all, you are looking at between 4-6 hour days to train for fighting.