Straining your hamstrings -- the muscles in the back of your thighs -- may be one of the most debilitating sports injuries. It's also one of the likeliest to recur if there hasn't been ample healing time.

Prevention is the best medicine in this case. To protect your hamstrings, strengthen them with exercises such as leg presses. Perhaps more importantly, never exercise or play a sport without warming up your muscles first with 10 minutes of light activity. Stretch your hamstrings -- but, again, only when the muscles are already warm.