The Hamstrings

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The hamstrings are a group of 3 muscles that are located at the back (posterior) of your thigh – the biceps femoris, the semitendinosus and the semimembranosus. The term ‘hamstring’ has a rather gruesome origin dating back to the 18th century when English butchers displayed hung pig carcasses by the long tendons at the back of the knee in their shop windows (the strings of the ham so to speak).

In comparison to the quadriceps muscles at the front (anterior) side of the thigh, the hamstrings are a smaller muscle group but they are strong hip extensors and knee flexors.

Attachment and function

The hamstrings have a common origin at the Ischial Tuberosity – or sitting bone. Their insertion points, however, differ.  The semitendinosus attaches to the proximal, medial shaft of the tibia and the semimembranosus at the medial condyle of the tibia.  The biceps femoris, as the name implies actually divides into 2, – a long and short head.  Whilst both muscles insert at the head of the fibula, the short head’s origin is at the linea aspera on the shaft of the femur.

Biceps Femoris long head
Biceps Femoris (long head)

With the exception of the short head of the biceps femoris, the hamstrings are 2-joint muscles covering the hip and the knee.  This means that they play an important role in the movement of both joints.


As already mentioned, the hamstrings flex the knee, extend the hip and posteriorly tilt the pelvis.  The semitendinosus and semimembranosus also medially rotate the flexed knee, whilst the biceps femoris laterally rotate the flexed knee.


in extending the hip, the hamstrings work with the gluteus maximus. Poor gluteal muscle strength means that the hamstrings work harder and can become overused if they have to become the primary muscle in hip extension.

Hamstring injuries

The hamstrings can be prone to strains and ruptures. Strains occur when they are asked to stretch or contract suddenly or forceably.  An easy way to picture this is when a footballer or athlete needs to suddenly sprint and we see them just as quickly come to a sudden stop clutching their hamstrings. Muscle fatigue, inadequate warm-ups and poor muscle technique can make hamstring injury more likely.

Ruptures usually occur as a result of excessive, forceful contraction during knee flexing or hip extension. The rupture can be located anywhere along the length of the hamstring.  There will a sudden pain which can be associated with the activity and sometimes a ‘popping’ sound will be heard. In addition to pain (especially when flexing the knee) there will be swelling and skin discoloration. You doctor will make a diagnosis and may send you for an ultrasound or MRI scan, depending on the severity.

Rest, Ice, Compression and Elevation (RICE) may help initially and recovery is based upon a relief from pain and improved motion. Recovery and return to activity can take 2-4 weeks for mild strains; 6-8 weeks for moderate strains and 4-6 months for ruptures. You must give your hamstrings time to heal properly to prevent the risk of the injury returning or becoming worse, involving your sciatic nerve.

Hamstring warm-up and strengthening

Warm-up hamstring stretches are good before undertaking any activity or sport.  Strengthening exercises assist in rehabilitation from injury.

Warm-up 1:

Stand with 1 knee bent and the other straight out in front.  Lean forward keeping your back straight and resting your hands on your bent knee. Repeat with your other leg.

Warm-up 2:

Sit with both legs straight our in front with your toes pointing up.   Keeping your back straight reach forwards towards your toes. An alternative stretch is to widen your legs and reach your hands forwards along the floor.

If you are recovering from a hamstring injury make sure you are not experiencing pain and seek medical opinion if in any doubt before beginning any rehabilitation. A good first step is to try deep-water pool jogging for 20 minutes without pain.

Strengthening 1: The Bridge

This activates gluteals and back extensors. It is a stabilising rehabilitative exercise.

Lie on your back, knees bent and feet flat, hip-width apart.  Engage your core and lift your buttocks slowly off the floor until your body is in a straight line from knees to shoulders. Keep your hips level. Pause and return to the starting position. Do 3 sets x 10 reps.

Strengthening 2:  Leg Flexion

This works your hips and hamstrings. Although it moves one leg at a time, both the moving and stabilising leg are worked at once.

Stand on one leg with the other slightly behind the line of your body and resting on tiptoes (use a wall for support). Bring the resting leg forwards in front of you keeping the knee as straight as possible.  Hold it for a few seconds at your highest point and then lower. Repeat with other leg. Aim for 4 sets x 10 reps.