you can do a full body workout and maintain in jail or prison, sometimes when one is incarcerated the depression and lifestyle you have to lead can discourage a person from keeping themselves up, theres no excuses, no theories, bottom line is when your locked up you have to eat what you can and exercise every other day at the minimum to keep yourself up, in california in prison the people in charge often starve you out by not allowing you to go to canteen store to get the essentials, it can be challenging.