When buying running shoes, first assess your foot-strike style, then invest in motion control, stability or cushioned models accordingly. That’s what just about any running guru will tell you. But get this — a study published in the June 2010 issue of the The American Journal of Sports Medicine suggests that that advice is mostly bunk. Working with the U.S. Marine Corps, researchers provided more than700 male and female recruits with arch-specific shoes. A second group of roughly the same number got stability shoes, regardless of plantar shape. After 12 weeks, researchers found virtually no difference in injury risk between the two groups. We’re sure Nike and Adidas marketing honchos don’t want you to hear this, but the resulting advice is pretty simple. To stay safe, just go for shoes that fit comfortably from the get-go, and always look both ways before crossing the street.