. >> at the orange county jail, we covered the story of inmate jeremy bowles, whose sweaty workout routineseft his cell window covered in condensation. >> can you see me? >> yeah. >> and sure enough he wiped the steam away and it made a dynamic shot. >> bowles later invited director of photography brian kelly to experience mattress curling. one of his improvised in-cell workouts. >> stick your ass out, like you're taking a squat. guarantee that will [ bleep ] you up quick. >> it's heavy. >> yeah. you feel it? >> oh, yeah. >> my arms are bigger than his. >> look at the guns. >> it was as if i was doing a barbell curl. i don't know what the weight was but there was some resistance there and it was an effective exercise for these guys to actually work their biceps. it was great. i'm going to go back to work. >> while prisons are full of male inmates, sweating and grunting through their workouts, we've noticed many female inmates take a more relaxed approach to fitness. >> by far, male inmates work out much more than female inmates. it's -- it's very rare to see a male inmate that doesn't work