The next time a clerk at a running store asks you to step on a treadmill to measure your stride, don't take his or her advice too seriously. A study published in the British Journal of Sports Medicine found that pronation – how your foot comes into contact with the ground as you run, rolling inward (overpronation), outward (underpronation), or straight over the big toe (normal pronation) – may not influence chances of injury. Danish researchers gave 927 novice runners neutral shoes, regardless of their pronation, and followed them for one year. They found that runners faced the same risk of injury regardless of the shoe. "Novice runners are better off choosing shoes based on comfort rather than foot type," says study leader Rasmus Østergaard Nielsen. This means that if you're happy with your shoes, there's no need to switch them to ones that are engineered to support a certain type of pronation. But if you're running in minimalist shoes and have pain, you might want to switch to supportive ones.