Hamstring Strains: How it happens and how you may be able to prevent them by Drake Webster
[This is a guest blog by one of our Athletic Interns, Drake Webster, an Exercise Science student from ECU]
Many times injuries are freak accidents that can’t be avoided, but a lot of the hamstring strains are not this. Hamstrings strains are involved with sports that include sprinting, jumping, kicking, and also highly skilled movements. Most if not all sports involve these movements, so that’s why hamstrings have become one of the most prevalent injuries. In an article that was published in the Journal of Strength and Conditioning a study was done about hamstring strain prevalence in the national football league. The study results show that hamstring strains were the second most injury seen, behind only knee sprains. The reason for the high occurrence of hamstring strains is because of the mechanism of injury during sprinting. Sprinting is the most common time you will see an athlete have an injury to the hamstrings.
Mechanism of injury- The reason for the high occurrence of hamstring strains is because of the mechanism of injury during sprinting. Sprinting is the most common time you will see an athlete have an injury to the hamstrings. This is because when sprinting, hamstrings receive a lot of force at extreme lengths. An Eccentric contraction is a type of muscle activation that increases tension on a muscle as it lengthens. This eccentric contraction happens to the hamstrings on the front leg during sprinting right before foot contact. Once the foot hits the ground the force that comes with sprinting is now absorbed by the hamstrings. A lot of times your hamstrings are not able to handle this force at that length at the time the foot contacts the ground; this is when hamstrings strain occur.
Biceps Femoris- There are three hamstrings which are all located on posterior part of the thigh and attach at the pelvis and back of the knee. The main one that is injured is the biceps femoris. The reason for this is because of the amount of change in length occurring in the biceps femoris during that eccentric contraction and also the amount of force that is absorbed by the biceps femoris during the same eccentric contraction. These are the two reasons for the high occurrence of injury of the biceps femoris.
The mechanism of injury shows that hamstring strains are not freak accidents but preventable injuries that with training can be avoided. The same article that was published in the Journal of Strength and Conditioning showed types of training that can be beneficial for preventing hamstring strains. The three things that can be the most beneficial are dynamic warm-ups, eccentric training, and also trunk stabilization training.
Dynamic Warm-ups- These should be longer in length if you know you will be sprinting, jumping, or kicking. They should included things that mimic the activity you will be doing. The warm-ups should have sprinting drills, mechanics and also hamstring functions involved. A 5 to 10 minutes is the usual protocol for warm-ups but for activities that involve such force such as sprinting, warm-ups should be longer in length if possible.
Eccentric training- This type of training will help ready the body for this type of contraction that you will be putting your hamstrings through. This type of training also increases the number of sarcomeres, the basic unit of a muscle, which will distribute the force and also allow more stretch in the hamstrings. The hamstrings are going through eccentric contractions when sprinting whether you train them or not, so why not train them to be ready when they are called upon.
Trunk Stabilization Training- This type of training deals with the hips and pelvis. There is a connection to hip extension to hamstring stretch. The key of this training is to try to limit anterior pelvic tilt. This will cause the hamstring to be less tight which will benefit in hamstring strains. Another muscle that is important to train is the iliopsoas or hip flexor. A tight hip flexor will pull on the pelvis and keep it in an anterior pelvic tilt.
Hamstring strains happen all the time in sports, but why? There is research out there with solutions on how to prevent them and how to keep them from happening again. Instead of having a retroactive look at hamstring strains, take a proactive look and try and stop the problem before it happens.
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