After years of trying to find comfortable, ergonomic desk chairs, many workers are opting to ditch the chairs altogether to sit on an exercise ball during their workdays.

Sitting on a stability ball challenges your balance and engages your core muscles (abs, lower back, hips, and obliques) more than a stable surface like a regular chair. Plus, sitting "actively" can improve posture. It also causes sitters to change their position more frequently, which many experts believe to be better than sitting in one place for extended periods of time.

Sitting on a stability ball for prolonged periods can tire out both large and small muscle groups that are working hard to keep your body upright. Try to use a stability ball for 30 minutes at a time, and switch between the ball and your chair at your own comfort level.

Time Involved: As long as you like

Body Benefit: Better posture