Your hamstring muscles run down the back of your thigh, and the most common injury to this muscle group is a strain caused by sudden starting and stopping. If you play a sport that involves sprinting, like soccer, football or basketball, you may be more likely to incur a hamstring injury. Most hamstring injuries happen in the central part of the muscle or where the muscles and tendons meet.
Hamstring muscle strains can be rated a grade 1, which is mild and will heal quickly, to a grade 3, which happens when the muscle tears completely and require months of rest to fully heal.
Another type of hamstring injury is called an avulsion injury, and occurs when the tendon separates from the bone.
Athletes who have muscle imbalances, where one group of muscles is much better trained and stronger than another, are more susceptible to hamstring injuries. Injuries can also occur when athletes work too hard without stretching their muscles first or if they are not properly conditioned for the activity they are performing.
A hamstring injury will produce a sudden, sharp pain in the back of the thigh, usually during activity. Some people feel a tearing or popping sensation when the muscle is injured.
As the muscle continues to hurt, you may also experience swelling and bruising. It can be painful to put weight on the leg that has the injury.
A hamstring injury is caused when the hamstring muscles or tendons are stretched beyond their limit of flexibility.
This often occurs because the muscle is contracting and stretching at the same time. For example, when pushing off from sprint blocks, the hamstrings are contracting, which causes the lower legs to push against the blocks and helps to drive the hips forward. But, at the same time, the legs are straightening, so the hamstrings are simultaneously being stretched.
To visualize this, take an elastic band, and see how far you can stretch it. Then tie a knot in the middle of it, representing the contracted muscle. If you try to stretch it to the same degree now, it may tear or break.
Hamstring injuries can also be caused because the muscles are tight or cold, or if they are not strong enough to handle the load being placed on them.
People who take part in sports with explosive movements like football, athletics, soccer or basketball are at greater risk of hamstring injuries, as are weightlifters and bodybuilders.
Minor hamstring injuries respond well to the RICE protocol.
RICE stands for Rest, Ice, Compression and Elevation – four things you can do in combination to help the afflicted muscles. Stay off the leg, use ice packs and wear compression tights to reduce swelling, and keep your leg slightly raised when resting.
Serious injuries may require physical therapy to improve. Your therapist will give you exercises that can strengthen the muscles without causing further injury.
In some situations, surgery may be necessary, especially in the case of avulsion injuries. Your surgeon will reattach the tendon to the bone. Rarely, surgery to repair an injured muscle may be necessary.
You can minimize the risk of a hamstring injury by warming up and stretching the hamstrings before exercising. Note that you should only conduct stretches when the muscles are warm.
Where the hamstring will be placed under a load, such as sprinting, jumping, or resistance training, build up the load gradually. For example, if you are weightlifting, perform several warm-up sets, gradually increasing the weight. This allows the nervous system to acclimatise and recruit more of the muscle when you start exercising.
Weaker muscles are less able to handle loads and therefore more likely to become injured. Always ensure that the intensity of the exercise you plan to perform is appropriate to your level of conditioning. Likewise, the more you work the hamstrings, the weaker they become, so you should also stop training when the hamstrings are fatigued.