When the Hamstring muscle is overstretched, it can cause some of the fibres to tear. The injury can be graded between 1, 2 and 3. Grade 1 is the least severe and grade 3 means a full rupture of the muscle. Depending on the extent of the injury, a grade 1 tear will usually heal within two weeks. It's a good idea to follow the PRICE routine following a muscle injury. This is Protection, Rest, Ice Compression and Elevation. This can help enhance healing and prevent the tear from getting worse. Or, it can stop it from developing into a grade 2 strain. Compression shorts can help to ease symptoms of swelling, inflammation and pain. If a return to activity is made too early, it can exacerbate the tear. This can then prolong the healing process.