In the back of the upper leg (the posterior thigh) lie the hamstrings, a group of muscles which are particularly vulnerable to injuries and ongoing pain problems in athletic individuals. The upper part of the muscles in the upper thigh and lower buttock are injured much more often than other parts, with the outer side of the leg also more affected. There are no normal names for the three muscles involved which are called the semitendinosus, biceps femoris and semimembranosus, with the biceps femoris being most often involved.
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.
The hamstrings run down from their origin at the ischial tuberosity deep in the buttock along the posterior upper leg and insert into the upper tibial area. If the hamstrings are under eccentric contraction, i.e. they are both contracting under load and lengthening at the same time, they are particularly susceptible to a strain. Direct blows in contact sports can cause a contusion of the muscle and an avulsion fracture can occur when a water skier falls forward violently at the hip with their legs straight. Patients typically report hamstring injuries as coming on very suddenly and that they can clearly hear the muscle go pop.
When an injury occurs the patient reports an immediate pain in the back of the upper leg with the event occurring either when the patient has got tired late on in the activity or before they got warmed up in the beginning. In less severe injuries there might be minor interruptions in functional activities such as pain on going uphill or climbing stairs. Physiotherapy examination of the back of the leg will often reveal little but resisted knee flexion is often painful, where the physiotherapist pushes against the ankle as the knee is bending.
The likelihood of suffering from an injury to the hamstring is thought to be related to factors such as tiredness, inadequate warm up, flexibility restrictions or if the strength ratio between the hamstrings and the quadriceps is incorrect. Having previously incurred a hamstring injury is enough to raise the risk of having another one. How an injury will be treated depends entirely on its severity with one end of the spectrum seeing the physio progress the patient speedily on to strength work and at the other end of the spectrum some injuries require the intervention of a surgeon.
The first aims of physiotherapy for an injury of a moderate level would be to limit the degree of local swelling and reduce the pain and inflammation from the soft tissue damage. Physios use the PRICE principles in these cases: Protection of the damaged tissues to prevent further damaging stresses being applied; Rest from normal activity and sport to allow the healing process to proceed; Ice in 20 minute bursts to control inflammation and pain; Compression over the damaged area with elastic wraps; Elevation of the part is not simple due to its location and that the patient wants to keep their knee bent.
Author: Jonathan Blood-Smyth