This move can be done whenever you get a free thirty seconds. Try this every time you rest your eyes from the computer screen (which should be able once eery 20-30 minutes!) "This works your core and arms. Sit in your chair with your legs crossed and your feet on the seat. Then place your hands on the armrests, suck in your gut and raise yourself a few inches above the seat, using your belly muscles and hands. Hold for 10 to 20 seconds. Rest for 30 seconds. Repeat five times."