A stress fracture is a hairline fracture common to athletes and endurance sports enthusiasts. Repeated stress and strain on a bone can cause slim cracks, as can repeated force from hard surfaces such as concrete. Distance runners may be especially susceptible to this in the feet and lower legs. These can impede athletic performance and worsen over time. They typically don't require a splint or a cast, but doctors advise limited use of the affected bones until the cracks have fully healed, to prevent complications.

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