Despite my weight fluctuating about 10-15 pounds throughout the year, one feature that I'm always proud of are my core, which range from a full-on six pack at best and noticeable definition at the very least.
The trick is not in doing an inhumane amount of crunches every single day, but from one very simple substitution -- switching out my chair for a stability ball, a.k.a. Swiss/exercise/balance ball, something I've done at both my workplace and at home for four years and counting.
The underlying idea is simple, by using a stability ball as a chair, the core muscles are being continually engaged on a low-intensity level -- stabilizing the body due to the ball's innate imbalance. And if you are like me and glued to the desk for most of the day, that's a good 7-8 hours of effortless ab workout.
And the ball also gives me chances to do some mini-exercises during downtimes at work. From the upgraded swiss ball crunch in above video to pelvic tilts, or even just a relaxing ab & back stretch -- it's great knowing I am already sitting on the only equipment I need for those exercises, and that I can do them whenever I want.
As an additional perk, since I am on a ball, it forces me to maintain a proper posture instead of slouching against the back of a chair.
Of course, if you already have existing back problems, check with your doctor first before committing yourself to a ball for chair (not to mention the HR/safety departments if you're doing it at work.) And if you still want the occasional back support, good alternatives include using a balance ball chair, or a Bosu on top of your existing chair. And when you do invest in a stability for a chair or just for workouts, be sure to get the right size (as a general rule, your thighs should run parallel to the floor when sitting, and your shins vertical and perpendicular)
