Talk of proper posture may seem more Junior League than Major League — the chat of the crudit‰ crowd rather than the carbo-loading bunch — but as improbable as it may sound, an athlete stands to gain considerably from paying closer attention to his everyday profile. “The ones who end up suffering the most by not making posture an all-day effort are sports-minded people,” says Marcus Elliott, a sports-medicine consultant for the U.S. Olympic Training Center who’s renowned among his peers for his expertise in the field. “Watching your form doesn’t end once you’re through exercising. In fact, that’s when it starts.”

Aside from simply making a bad first impression, going through the day with hunched shoulders, a bent back, or an off-kilter pelvis can have a long-term and negative impact on your musculature and your skeleton. Let that collection of 33 vertebrae known as the spine sag, and you’re forcing muscles and tendons and ligaments in the neck, shoulders, lower back, and legs to support the body instead. Over time, these tissues will essentially conform to the spine’s unnatural cant like shrink-wrapping to a T-bone. “Regardless of whether this is harmful, the body simply recognizes poor posture as the norm,” says physiologist and trainer Ann Marie Miller, who should know about such things, given that she recently helped devise a workout for the New York City Ballet troupe. “That deteriorates proper technique in your sport.” As Miller has witnessed, you can’t expect your body to snap out of a postural funk merely for the several hours a week that you choose to perfect your butterfly stroke or puzzle through a vexing 5.12 route.

Indeed, all you need to do to recognize the athletic usefulness of making your body tall is to take a look at Olympic sprinter Michael Johnson, whose events are too brief to afford even minor inefficiencies. “His posture’s perfect,” says Roch Frey, who for 12 years has coached professional triathletes, including his wife, 1997 Hawaii Ironman winner Heather Fuhr. “It has to be, because he needs to hold perfect form when he runs, which happens to mean keeping the back straight.” Frey notes that while posture ties into technique, the two really are separate matters. For example, a cyclist may not want to strive for a straight spine on the bike for aerodynamic reasons — it’s more efficient to ride with the back and shoulders slightly rounded. “But can he benefit from maintaining proper posture throughout the day?” Frey asks. “The answer is still yes, because all that practice out of posture needs to be counterbalanced.”

The Dope on Straightness

Beyond obvious biomechanical advantages, holding your spine bolt upright can also improve your breathing. Rounding the back presses the rib cage and the organs within the chest cavity against the lungs and diaphragm, keeping them from expanding as far as they otherwise might. “Less oxygen in the lungs means less oxygen molecules to get absorbed into the bloodstream,” says Elliott. That, of course, means subpar endurance.

Not incentive enough? Add this: Shabby posture restricts the flow of blood through the muscles, which means there’s less of a “flush” to remove metabolic waste — including lactic acid, that richly painful by-product of muscle contraction. So it just pools up in your muscles, increasing the wince factor exponentially.

And since the spinal column moonlights as one of your body’s primary shock absorbers, letting it bow in any activity also greatly increases your risk of back injury. “Whenever you run or jump, the disks between vertebrae absorb the trauma by displacing it throughout the spinal column,” says Miller. “But the cushioning loses its effectiveness if the spine is arched beyond normal.” This can actually cause certain vertebrae to grind against one another, perhaps forcing the disks to slip, rupture, or herniate.

The last area affected by poor posture is the most subtle, yet also of the greatest importance to any committed athlete. “Balance, coordination, and flexibility all begin with good posture,” says Elliott. “Without this underpinning, it’s much harder to teach the body to improve any of these things.”

Finding Your Alignment

Fortunately, it’s simple to grade your posture. What to do? Freeze — in the position you’re in, whether it be sitting or standing. Now, readjust yourself until your back is straight. “The farther you had to accustom yourself, the more unnecessary stress you’re probably placing on your body in an average day,” says Frey. To identify problems with more specificity, stand in the position that feels most comfortable and have someone snap a Polaroid of you from the side. Next, draw a straight line on the photo from your ear to the back of your heel. Ideally, the line should bisect your shoulder, pass through the hip, and graze the back of your leg at the knee. Any or all of these areas could be in need of adjustment.

If your hips sit forward of the line (and thus your spine), you may suffer from excessive posterior pelvic tilt. This causes the gluteal muscles and hamstrings to tighten from constantly contracting, and weakens the lower back muscles.

If your hips fall anywhere behind the line, it indicates an excessive anterior pelvic tilt, which you might have already noticed asa C-shaped curve in the lower back — imagine the posture of a baseball slugger standing at the plate. This condition, which Miller says is the most typical postural misalignment, weakens the abdominals by overstretching them, while forcing the hip flexors to function as the torso’s sole support.

If the shoulders sink forward of the line, you have a rounded back, or kyphosis. Consider yourself lucky: This is the easiest postural malady to fix because the shoulders have less weight tugging them out of whack. Painless as correcting kyphosis may be, it should rank as the athlete’s first priority, since this is the position that most inhibits your breathing, and it also places the neck under undue stress when you’re in motion.

All these problems may sound menacing, but thankfully they can almost always be reversed. What’s required is an extra bit of concentration throughout the day (see “These Are Spinal Tips”) and a little bit of extra exercise (see “So Many Vertebrae, So Little Time”). Because whether you’re slumping behind the wheel of the car or striding around the office hunched over like Victor Hugo’s beleaguered bell-ringer, it’s certainly easier to let gravity do the work. However, as Frey points out, “Good posture can keep your body from letting you down, but bad posture is something your body never lets you forget.”

Jack Hammond is a New York-based freelancer.