Good posture is more than having a straight back. Standing tall can help you appear more confident and slender, improve circulation and digestion, and reduce back and shoulder pain, according to Aaron Parnell, author of The Dynamic Dance of Great Posture (PZQ Press, 2006). Unfortunately, most of our best posture efforts are undone by long hours spent hunched over the computer, slouched on the couch, or even bent on a bike. Get out of the slump with these three tips from Parnell.

Strengthen your upper back muscles to hold your shoulders back. With your chest high and shoulders back, reach your arms up overhead with your palms facing inward. Make eight large circles with your arms, maintaining correct shoulder position—your shoulders pulled back and your arms rotating behind your body's midline. Stop with your arms at your side and notice where your shoulders are. Try to hold that position. Repeat as often as possible during the day.

Wear flat shoes at least 95 percent of the time. Flat shoes help the body start out at the correct angle, which is a vertical pelvis and straight back. If you have collapsed arches, invest in a pair of orthotic shoe inserts.

Stretch your hip flexors, the muscles located where the legs meet the hips, so that your pelvis goes into vertical position instead of tipping forward in a common form of bad posture called "swaybacked." Bend your knee and pull your calf behind you until your foot touches your buttocks, or as close to it as you can get. Then tilt your pelvis forward to increase the stretch. Hold for 30 seconds to 1 minute, then repeat with the other leg. Perform this stretch daily, as often as three times per day.