Hamstring Strains are among the top of the list for common sports injuries. They are defined as excessive stretch or tear on a muscle and surrounding tissue resulting in injury. The hamstring group is composed of:
Biceps Femoris (long head and short head)
Of these the biceps femoris is the most commonly injured.
Strains are graded as follows:
Grade 1: Minor tearing of muscle fibers with no visible discoloration or swelling.
Recovery to full activity = 3 weeks +
Grade 2: More moderate tearing of muscle fibers with discoloration present and swelling. Significant pain with stretching and contraction of the hamstring.
Recovery to full activity = 6 weeks +
Grade 3: Complete tear. Inability to walk without pain. Discoloration and swelling present. Divot or depression sometimes seen at the site of the tear as well as a lump of muscle above. Likely requires surgery.
Recovery = 3 months +
There is one very important hamstring injury to note that is not categorized by grades but has the same mechanism of injury. This is the avulsion injury and it is the most severe of hamstring injuries. In this type of injury the hamstring is pulled away from its bony attachment at the pelvis.
There is a high rate of re-injury for hamstring strains. It is important to follow a proper treatment plan and avoid returning to activity too early.