NEW YORK - Fitness experts have long advised clients choosing running shoes to forget fashion and consider the roll or pronation - the way the foot leans inward upon impact.
Analysing the roll of the foot remains standard practice among fitness and medical professionals in the belief it will lead to a better shoe fit and fewer injuries.
"When it comes to shoe choice, the amount of pronation control is extremely important," said Dr Jane Andersen, a podiatrist in private practice in Chapel Hill, North Carolina.
"Some people need more than others. It can cause a lot of problems if you have the wrong one."
Dr Andersen, a runner herself and past president of the American Association for Women Podiatrists, said the No. 1 cause of the overuse injuries she sees, from stress fractures to tendonitis to Plantar fasciitis (heel pain), is shoes that are worn out or the wrong fit.
There are three basic levels of control for standard running shoes: neutral, stability and motion control.
"Neutral is generally good for a high-arch foot; it doesn't provide extra control for pronation," she said. "The stability shoe works for people who need more support; motion control is for the super flat-footed."
At Jack Rabbit Sports store in New York City, clients' arches are observed before they hit the treadmill for runs that are videotaped for slow-motion analysis.
"The basic premise is that most people land on their heel (and) overpronate or underpronate," said Ms Johanna Bjorken, the store's merchandise director. "This causes running injuries and shoes can address this. This has been the model."
Ms Bjorken said neutral shoes account for 60 to 63 per cent of the running shoes sold in her store; 30 to 35 per cent are stability shoes. The mobility category is very small and usually follows on doctor's advice.
"Some rolling in is natural, normal and beneficial," she explained. "Compared to 20 years ago, running shoes are really much more flexible, lightweight and well designed to work with movements of running."
Dr Mark Kelly, spokesman for the American Council on Exercise and a runner for 35 years, is a self-described underpronator who believes in heeding an individual's "biomechanical tendencies".
"Get a certified trainer to look at the biomechanics of how you're running," Dr Kelly said. "How are you turning your foot? Are you a forefoot striker, midfoot striker, heel striker, or extreme heel striker?"
Connecticut-based exercise physiologist Tom Holland, author of The Marathon Method, thinks many of the common running-related injuries, such as runner's knee, shin splints and hip issues, are related to and exacerbated by improper footwear.
"Once you find a shoe that works for you, stick with it," he said.
Nevertheless, a recent Danish study cast doubt on whether shoes that control pronation do actually cut down on injury. But the scientists said more work is needed to determine if highly-pronated feet face a higher risk of injury than neutral feet.