Hamstring Injury

The hamstring muscles are a thigh muscle group sited in the posterior thigh (back of the upper leg) and which are a common location of injury and persistent pain in sporting people. The typical areas which are preferentially injured are higher in the thigh near the buttock and towards the outer side of the leg. The muscles of the hamstrings have not been given common names and retain their Latin ones: biceps femoris; semitendinosus and semimembranosus. The most commonly injured of these three muscles is the biceps femoris.

Hamstring injuries are classified for ease of diagnosis and treatment into various grades of severity. The least serious injury with a number of damaged muscle fibres is a grade 1 injury, rated as a mild muscle strain. More serious involves a larger number of muscle fibres being damaged and a reduction of muscle strength which is obvious on testing and this is a grade 2 injury. In the most serious or grade 3 injury there is a rupture right through the substance of the tendon and muscle. Most injuries are located at the muscle and tendon junction and high up near the buttock, although the biceps femoris has a very long junction, most of its length.

The origin of the hamstring tendons is the bones in the buttock which we sit on, known formally as the ischial tuberosities. The tendons are attached to this bony area and a violent movement into hip bend with a large overall movement range can avulse (tear off) the tendon’s junction from its bony bed. Water skiing is a risky activity for this problem. Most hamstring injuries occur in younger people who overwhelmingly perform athletic activities, with typical sports for this injury being field sports, contact sports, track activities such as sprinting, football or rugby.

Starting at the ischial tuberosity insertion in the buttock, the hamstrings course down the posterior thigh and insert into the upper areas of the shin bone. If the hamstrings are loaded at the same time as they are lengthening (so called eccentric contraction), often occurring in rugby and running events, the risk of injury can be high. Contusions to the muscles can occur from direct blows while if a water skier falls forward suddenly with a straight knee then the hamstring origin can be damaged by avulsion. When a hamstring injury occurs, the patient often reports a clearly audible pop of the muscle and the onset is sudden.

Immediate pain is noticed in the posterior thigh area and people may be vulnerable early in the process before they are warmed up or later on when they may be becoming tired. If the damage is not severe then function can be preserved although with pain such as on stair climbing or walking up a hill. Examination of the back of the thigh may reveal little but it may well be painful if the patient is asked to bend their knee and the physiotherapist resists the movement. Rupture of one of the hamstrings may show by it balling up on contraction along with reduced strength on assessment.

An increase in the risk of suffering from a hamstring injury is thought to occur if the quadriceps and hamstring strength ratios are incorrect, the person is tired, there is a poor warm up or a limitation of flexibility. A previous history of hamstring injury is a significant risk of having a recurrent strain. The approach to treatment of the injury is dictated by the severity of the muscle and tendinous damage and a physiotherapist will progress someone with a minor strain quickly onto strength training from range of movement work while more serious injuries may even need surgery.

Physiotherapy for a moderate level injury initially addresses the reduction of local swelling and inflammation and control of the pain which is often significant. The physio will use the PRICE guidelines for treatment: Protection of the injured tissues is vital at first which can include crutch use or braces; Rest is essential to a degree to allow tissue healing to proceed; Ice application for up to 20 minutes reduces pain and inflammation; Compression can be effected by wrapping elasticated bandages around the limb; Elevation is not simple due to the area of the damage and that the patient may prefer a bent knee.

Jonathan Blood Smyth is the Superintendent of Physiotherapy at an NHS hospital in the South-West of the UK. He writes articles about back pain, neck pain, and injury management. If you are looking for Sheffield Physiotherapist visit his website.