Hamstring injuries
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These strains and tears are common in sports with lots of cutting movement, like soccer. If they aren't aggravated, they usually repair themselves. People generally feel better after two to three weeks of recovery time, but they should wait more like four to six. If they don't, they can end up with lingering pain for many months or even a year.

The Fix: Flexibility will be a big help in avoiding this one, especially as people get older. Basic foam-roller stretches are probably going to give the best results.