Hamstring Strain

There are three muscles that form the hamstrings which are situated on the posterior thigh. These are the semimembranosus, semitendinosus and bicep femoris are response for generating knee flexion and hip extension based movements.

These muscles originate from the ischial tuberosities (the bony prominence that you sit on) and attach below the knee joint line on the medial tibia and the head of fibula. 

Hamstring strains are usually cause by a rapid contraction or violent stretch of the hamstring muscles causing high mechanical stress which ultimately leads to failure of the tissue. Muscle strains are labelled from grade 1 -3 following thorough assessment taking into consideration pain, weakness and loss of range of movement.

During the subjective history there may reports of either a high velocity type movement such as sprinting of trauma such as excessive stretching of the tissue. People may also report a popping or tearing sensation at the point of injury. 

During the objective assessment there may be evident swelling or bruising, however the latter may take a few days to appear. In severe cases there may be difficulty in weight bearing on the injured side. Further assessment would potentially identify:

• Pain and tenderness

• Loss of range of movement and length of hamstrings

• Decreased strength

• On rare occasions there may be irritation to the sciatic nerve that passed through back of the thigh.

A hamstring strain is generally classed under 3 categories:

• Grade 1 (mild): Only a few muscle fibres are affected. There is minimal pain and walking is not affected. There may be some mild stiffness first thing in the morning however strength is largely unaffected and full range of movement is still evident.

• Grade 2 (medium): A moderate number of muscle fibres have been affected with reports of acute, sudden pain, swelling and mild loss of function. There may be a mild limp with pain on palpation around the affected area as well as pain with resisted knee flexion

• Grader 3 (severe): A significant proportion of muscle fibres affected with the possibility of feeling a defect within the muscle belly. There may be severe acute pain where the person cannot continue their activity with a significant limp, swelling and eventually bruising. Active range of movement and strength will be affected.

Following a detailed subjective history, a thorough physical examination will take place which will incorporate a visual inspection of the area, as well as palpation of the soft tissues. Your provocative movement will also be examined as well as active and passive movements of the knee and hip to examine the strength and available length of the hamstrings. 

This is important as other conditions that could generate symptoms in the posterior thigh such as insertional hamstring tendinopathy, sciatic nerve pathology, adductor strains, avulsion injury or referred symptoms from the lumbar spine.

Once a confirmed diagnosis of a hamstring strain has been established, physiotherapists can help with:

Advice and education

Massage and soft tissue work

KTaping 

Graded exercise programme

Mobility practice

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