Do the four basic drills of push ups, sit ups, leg raises and squats using a staff to move the body. For example push yourself up and down in a push up when you are leaning on a staff against a corner in the wall or if you can control the tension against the floor and your body just on the ground (note how your feet support you when your attention is elsewhere, pay attention to everything or you will pay for it) Do a sit up raising your body off the ground using your arms and the staff (think of rowing) and the rest think of by yourself and vary. Not everything will work all the time. Be free in your thought.