Medical personnel work outside the medical tent in the aftermath of two explosions near the finish line of the Boston Marathon on Monday. At area hospitals, doctors say they were confronted with the kinds of injuries U.S. troops get in Iraq and Afghanistan. Elise Amendola/AP hide caption

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In 2009, more than 30 percent of ER visits for lower limb injuries came from sprains and strains, a study found. / hide caption

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