Now, stand with your back to a wall. Both your shoulder blades and the back of your head should kiss the wall.

If you're like most people, you won't have passed this test. And if you failed, when you sit at your computer, or watch TV, or drive, you'll probably have hunched shoulders, a rounded back and a forward-leaning head. No wonder you often complain of headaches, neck aches and backaches. Why? You haven't been properly supporting your head or spine. Instead of your musculature holding your body erect, you're relying on ligaments and bones, which weren't designed for that purpose.

Interestingly, even those who work out religiously aren't immune from poor posture. Whether you lift weights, ride a bike, run or ski cross-country, the motions involved probably don't require good posture. As far as I know, the only exercise that in and of itself can improve posture is yoga, which frequently requires you to expand your chest and pull your shoulder blades back.

But yoga's not the only cure for poor posture. My personal prescription is to strengthen your rhomboids, which are the muscles between your shoulders. Even people who lift weights rarely remember to work their rhomboids.

To locate your rhomboids, pinch your shoulder blades together. Then, to strengthen them through isometrics, pinch several times (a day) and hold for a count of five each time.

Another good rhomboids exercise can be done by sitting in a chair and leaning forward so that your chest rests on your thighs. Now, stretch out your arms and, with thumbs pointed to the ceiling, lift your arms straight up until (if you're able) the tips of your thumbs touch.