. >> we followed katherine hines out to the exercise yard to see part of their daily routine. >> thisr exercise cage. we get it every other day. it's four hours of exercise. we look forward to it, for sure. sunlight, it's a big deal. so -- >> just getting sunlight. it's like a lizard, takes a minute to get going. >> are you going to work out? >> yeah. >> then nearly two minutes pass, with nothing happening. our camera operator walked in between exercise cages waiting for the session to begin. finally our crew was informed it wouldn't start until they left. >> when our crew went back indoors, they learned that kern valley's dominant hispanic gang controlled the exercise session. because all their practices are shrouded in secrecy, they would not work out in front of our cameras. but they can't avoid prison surveillance cameras. >> notice right now you have what a call a cadence call. it's an exercise routine, there's a certain group of inmates that initiate it. and, therefore, the race have to follow as long as they show respect. everything in prison is about respect. >> we found anoth