HAMSTRING INJURIES

running and sprinting but also sitting (particularly driving) Assessment: Resisted testing of the hamstrings may be weak but should normally be pain free. Straight leg raise will be limited and painful particularly when adding the sensitising manoeuvres, for instance ankle dorsi-flexion (Fig.3), the slump tests (Figs.4a+b) is also useful in distinguishing this condition Treatment/rehabilitation: Mobilisation of the sciatic nerve can be carried out using the slump technique or straight leg raise, but when using both techniques care must be taken not to stretch the nerve as excessive elongation of the nerve causes ischaemia and further damage to the nerve. Repetitive movements (mobilisation) are therefore carried out to the point in the available range of movement short of pain or resistance to stretch. The site of the tethering of the nerve at the various soft tissue interfaces may also be treated to improve range of motion using soft tissue mobilisation techniques or where applicable joint mobilisation or manipulation.

6. Piriformis syndrome Definition: Pain in the buttock or in the posterior thigh as a result of irritation of the sciatic nerve as it runs through the piriformis muscle (Fig.1) Cause: Piriformis becomes inflamed, shortened or in spasm which effectively tethers the sciatic nerve with resultant friction causing irritation of the nerve Presentation: The pain is frequently described as a deep cramping or aching pain in the buttock and/or the hamstring. The pain increases with activity and is relieved by rest Assessment: The piriformis muscle is tender on palpation and fre- quently hypertrophied or in spasm. Resisted internal rotation of the hip and passive stretching of the hip, external rotation in 90o hip flexion is often provocative Treatment/rehabilitation: Stretching of the muscle along with trigger point release techniques is often very effective.

Box 1 - Differentiation of hamstring pain from pain of neural origin using the ‘slump’ and ‘straight leg raise’ tests

Straight leg raise test Purpose: The straight leg raise (SLR) test can be used to ascer- tain hamstring length and its response to stretch and differenti- ate any pathological response from that due to stretching neur- al tissue Rationale: By combining hip flexion with knee extension in the test, the full extent of the hamstring is tested at both the hip and the knee. This manoeuvre will also have the effect of increasing tension in the sciatic nerve and lumbo-sacral nerve roots. To differentiate between pain felt from stretching the hamstring or sciatic nerve, ankle dorsi-flexion is added to the test. This will have no effect on the hamstrings, but will increase tension in the sciatic nerve Method: With the patient lying supine the practitioner (while ensuring the pelvis remains stabilised) applies full ankle dorsi- flexion to the patient. The practitioner then raises one leg with the knee straight. At the point where resistance and/or pain is encountered ankle dorsi-flexion is released, this will have no effect on hamstrings and the range should remain the same, but the sciatic nerve is implicated if range of movement can then be increased before resistance and/or pain is again encountered.

Figure 4a: Neck and trunk flexion in a slump test

Figure 4b: Addition of ankle dorsi- flexion and knee extension in a slump test

Figure 3: Straight leg raise 8 SportEX

Slump test Purpose: The slump test can be used to assess the mobility of the spinal cord, nerve roots and their connected peripheral nerves. The slump test is much more likely to produce neural symptoms than the SLR alone as it produces a considerably greater increase in tension within the neural system Rationale: By combining neck and trunk flexion with knee extension and ankle dorsi-flexion in the test, the spinal cord, the nerve roots related to the sciatic nerve and the sciatic nerve itself will be fully lengthened. This manoeuvre will also have the effect of increasing tension in the hamstrings. To differentiate between pain felt from stretching the hamstring or sciatic nerve, the patient extends their neck. This will have no effect on the hamstrings but will decrease tension in the sciatic nerve. Reduced symptoms of pain or resistance to stretch of neck exten- sion would implicate the neural structures Method: The patient sits unsupported on the side of the couch. The thighs must be supported by the couch and the knees flexed to 90o. The patient should be asked to flex their chin to their chest. Neck flexion, then full trunk flexion are applied to ten- sion the spinal nerve trunks, the ankle is dorsi-flexed, then the knee is extended. At the point resistance and/or pain is encoun- tered, the patient extends their neck, if this relieves pain and/or resistance to knee extension, then abnormal tension within the neural system is implicated.