founder alonzo wilson a former college athlete, was a simple philosophy that your entire body should be moving and don't stop. >> we don't have dumbbells. just your body weight. just using your body in a different way that you haven't used it before. >> reporter: just the warm up a series of burpees and sprints is a reality check. it's best to leave your ego at the door. >> hardest workout i've done. that's just the warmup. there are resistance cords and ropes to challenge you through a few cycles of agony. bear claws, mountain climbers and situps. people come in for the first time and stop and don't finish? >> the thing is they do. you try to -- we have a system where we go and try to you know we call it save them. >> reporter: he says this killer class can burn a thousand calories. >> since i started i've lost 50 pounds. >> reporter: 50 pounds?