There are three muscles in the back of the thigh that are collectively called the hamstrings. They are named biceps femoris, semitendinosis and semimembranosis. The two attachment sites for the hamstrings are the ischial tuberosity (the bony prominence felt under each buttock when sitting), and the back of the knee at the tibia (shin bone).
Contraction of the hamstring can cause the knee to flex, bringing the heel toward the buttock. The hamstrings also cause the hip to extend the thigh backwards when the knee is straight. The hamstring muscles provide control to the pelvis when bending forward with the knees straight. When walking or running, the hamstrings function to decelerate the leg
and foot as it rapidly moves forward to land on the ground.
A hamstring strain is an excessive stretch or tearing of muscle fibers and related tissues. Hamstring strains can occur at one of the attachment sites or at any point along the length of the muscle. They are classified as either1st, 2nd, or 3rd degree, with a grade 3 hamstring stain being the most severe.
A pulled hamstring muscle most commonly presents as a sudden pain in the back of the thigh during fast running or sprinting, when there are great force demands on the muscle. Although hamstring strains often occur while sprinting, they also can occur during jumping and other activities where quick starts and stops are required. High risk sports for hamstring strains are: soccer, football, rugby, baseball, basketball, water skiing and many track and field events. Runners are especially susceptible to chronic hamstring strains due to the repetitive nature of the sport. Also, when there is an imbalance of the strength of the hamstring muscles with relation to the quadriceps muscles, the risk of hamstring strain is greater.
Severity of Muscle Strains. Muscle strains are graded as mild, moderate and severe. The more severe the strain, the longer the time to recover.
First Degree (Mild). This injury is the most common and usually the most minor. This injury is a ‘pulled muscle’ with a structural disruption of less than 5 percent. With a first-degree injury, you can expect to be back to sports within 1 to 3 weeks.
Second Degree (Moderate). This injury consists of a more significant, but still incomplete muscle tear. This a partial muscle tear and require 3 to 6 weeks of rest and recovery before you can return to full activity.
Third Degree (Severe). This injury results in complete tearing of the muscle–tendon unit. A third-degree muscle strain can take many weeks or months to fully heal.
Rest from the activity that caused the muscle strain allows for healing to occur. Immediately following the muscle strain, ice should be applied over the painful area for 20 min. Periodic icing (2-3 times per day) will help to control swelling and reduce pain. Heat should not be applied to the area during the first 7-10 days since this may increase swelling and bleeding within the muscle. An elastic wrap or compressive stocking may be applied to the area to assist with swelling control. If the compressive device causes increased discomfort or "pins and needles" in any part of your leg, it is probably too tight. Lying down periodically with your leg elevated allows gravity to assist with your effort to control the swelling. Though some experts believe early stretching to be valuable, caution should be taken to avoid aggressive stretching (stretching beyond the point of mild discomfort) which may disrupt healing. NO stretching or resistive exercise should be done during the first 3 weeks following injury. As a general rule of thumb, any activity that elicits pain at or near the injured site may be causing further injury and will only hamper your recovery effort. A gradual conditioning program, specific to your sport, will prepare the hamstrings for the high demands placed upon them during athletics. Don't forget to incorporate a proper warm-up and stretching session into your conditioning program and athletic competition.
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