AUSTIN, Texas — If you're a runner and you can't extend your hip well behind you on your stride, Jay Dicharry has bad news: You're never going to be a great runner.

[bug id="sxsw2012"]This doesn't mean you should hang up your shoes. You can still run, and run well, but not everyone can attain the ideal stride needed to be a truly great runner.

Dicharry is the director of the Speed Performance Clinic and the Motion Analysis Lab Coordinator At The University Of Virginia. In discussing the biomechanics of running here at South by Southwest Interactive he recalled his Louisiana roots to emphasize his point.

"I'm from New Orleans, and there's great food there," he said, by way of understatement. "But if you have bad shrimp in a dish, you're doing to have a bad dish. You can't make a good meal with bad ingredients. Everyone may not have certain attributes that make ideal form possible."

Most runners don't extend their hips, Dicharry said. Tight hips might be genetic, or maybe they occur over time after sitting for long stretches. But as you run, you'll lose the power that propels you forward if your leg doesn't extend back behind you far enough on your stride before you bring it forward again.

Along with a lack of hip extension, overstriding is one of the biggest sins. If your foot lands ahead of its center of gravity, your stride is too long. Allowing your posture to break down — specifically, arching your back as you strain to squeeze out those final strides — is a killer as well.

Even elite athletes can fall prey to these pitfalls in form, as Dicharry demonstrated with a tape of the mens' 800-meter finals at the 2011 NCAA outdoor track and field championships. Virginia's Robby Andrews started at the back of the pack, then made his move in the final 200 meters. Dicharry paused the tape as the runners came down the stretch and noted how each runner was about to fail.

"Look at their gait," he said. "This one's head is bobbing up and down. This one's arm swing is taking him side to side. That one is arching his back."

Only Andrews maintained textbook form for the whole race, finishing first in 1:44.71, just .01 off the meet record.

"There's more to it than just running," Dicharry said of winning.

One common mistake is thinking that piling on the miles will make you faster. It isn't true, and the added mileage may exacerbate problems, or cause them to come to the fore. Don't increase your mileage by more than 10 percent per week, Dicharry advises.

"Optimal running adaptations occur when the training stimulus is in the appropriate window," said Dicharry, who noted that 82 percent of runners will suffer some form of injury from running too much. Trying to run too far, or not running far enough, will actually impede progress.

Good posture matters, Dicharry said, whether that in achieving good form while running or just getting through everyday life. The alignment of your trunk is important, because that affects your center of mass. Get your shoulders back, just like Mom said, but don't arch your back. Flexibility, strength, and muscle memory are key to good form.

And don't let all this dire talk make you think you're doomed. Regardless of your skills or natural constraints, you can improve your form. Dicharry led the audience through some easy exercises to improve balance and form.

First, stand on one foot for 15 to 30 seconds, then stand on the other. Then repeat the process with your eyes closed. This is something you can do anytime, even while brushing your teeth or cooking dinner.

Second, stand with your shins against the front of a chair. Squat to the floor. Keep your shins and back as close to vertical as possible, engaging the major muscle groups at the back of your legs.

Third, kneel on one knee. Ensure your ankle is directly under your knee. Tilt your pelvis forward until you feel a stretch in the front of your thigh. Don't arch your back.

Finally, Dicharry said, to become a better runner, make sure your training includes activities that stress stability and balance, like stand-up paddling or longboarding.

"Don't train for what you know," he said, quoting surfer Laird Hamilton, "train for what you don't know."