Athletic Training and Sports Health Care

Pearls of Practice 

Neurodynamic Mobilizations for Hamstring Strain Injuries

Andrea Di Trani Lobacz, MS, ATC

Abstract

From the Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware.

The author has no financial or proprietary interest in the materials presented herein.

Hamstring strain injury (HSI) remains one of the most common injuries in athletics, and is associated with slow healing, prolonged symptoms, and an alarmingly high re-injury rate.1 An often-overlooked component in HSI management is the mobility and mechanical sensitivity of the nervous system. The mechanical strain that occurs during injury can overstretch the sciatic nerve or the nerve may adhere to muscle tissue following HSI. In both cases, decreased nerve mobility occurs, altering the normal movement of the nerve within its adjacent soft tissue structures, known as adverse mechanical tension.2 This produces symptoms of pain, decreased range of motion and increased resting muscle tone,3 all of which may increase the likelihood of re-injury.4 Neurodynamic mobilizations are therapeutic techniques performed actively or passively that aim to restore the nerve’s ability to withstand the regular stress of activity through improved nerve mobility, circulation and viscoelasticity, and reducing sensitivity.5 Incorporating neurodynamic mobilizations to treat decreased neural mobility and neural mechanosensitivity may also help to reduce chronic symptoms associated with HSI.6

An inflamed sciatic nerve with reduced mobility can present as HSI, or may be a cause or consequence of the injury.6 Aside from acute injuries, assessment of nerve mobility and mechanosensitivity is particularly useful with a patient history of prolonged symptoms, especially with faster running and cutting activities,7 or reporting chronic “hamstring tightness.” The athletic trainer can use special tests to determine the involvement of the sciatic nerve in HSI, including the Slump test (Figure 1) and Straight-Leg Raise test (Figure 2). A high incidence of positive slump tests was previously found in Rugby Football Union and Australian Rules Football club athletes with a history of HSI.4,6 A positive result is indicated by either a reproduction of symptoms or an improvement of symptoms when stopping or modifying the exacerbating motion, or most especially any side-to-side differences such as asymmetries in range of motion, neurological responses, and resistance to testing movement.5 For the Straight-Leg Raise test, reproduction of symptoms in 35° to 70° of hip flexion in the hamstring, especially when the hip is internally rotated and adducted, is believed to be associated with neural involvement.3 However, there is currently limited support for the use of these tests in the diagnosis of adverse mechanical tension.

Tensioners tend to be a more aggressive approach and the athletic trainer’s discretion is advised during use, especially in the acute phase of HSI. The patient should be involved in the decision regarding repetitions and intensity,5 and the athletic trainer should be aware of any exacerbation of symptoms and alter treatment accordingly.

Furthermore, care should be taken when employing any type of neurodynamic technique, because aggressive mobilization can further irritate a sensitive nerve, and all patients may not respond well.6 It is prudent to remain within a pain-free range of motion and gradually progress as pain allows, avoiding overstretching within the acute phase of injury. Although no established guidelines exist for neurodynamic mobilizations in HSI, these techniques can be incorporated into a rehabilitation program as an adjunct and as symptoms allow. Neurodynamic mobilizations used in conjunction with traditional HSI management has been shown to result in quicker return to play.4 A systematic review of randomized controlled trials using neurodynamic mobilizations for various conditions concluded that most studies demonstrated decreased reports of pain and disability, but a lack of high quality evidence suggests only limited support of their use.8 Hence, high-quality outcome studies are needed in this area, but the limited evidence supports a…

From the Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware.

The author has no financial or proprietary interest in the materials presented herein.

Correspondence: Andrea Di Trani Lobacz, MS, ATC, 541 South College Avenue, University of Delaware, Newark, DE 19716. E-mail: aditrani@udel.edu

Hamstring strain injury (HSI) remains one of the most common injuries in athletics, and is associated with slow healing, prolonged symptoms, and an alarmingly high re-injury rate.1 An often-overlooked component in HSI management is the mobility and mechanical sensitivity of the nervous system. The mechanical strain that occurs during injury can overstretch the sciatic nerve or the nerve may adhere to muscle tissue following HSI. In both cases, decreased nerve mobility occurs, altering the normal movement of the nerve within its adjacent soft tissue structures, known as adverse mechanical tension.2 This produces symptoms of pain, decreased range of motion and increased resting muscle tone,3 all of which may increase the likelihood of re-injury.4 Neurodynamic mobilizations are therapeutic techniques performed actively or passively that aim to restore the nerve’s ability to withstand the regular stress of activity through improved nerve mobility, circulation and viscoelasticity, and reducing sensitivity.5 Incorporating neurodynamic mobilizations to treat decreased neural mobility and neural mechanosensitivity may also help to reduce chronic symptoms associated with HSI.6

An inflamed sciatic nerve with reduced mobility can present as HSI, or may be a cause or consequence of the injury.6 Aside from acute injuries, assessment of nerve mobility and mechanosensitivity is particularly useful with a patient history of prolonged symptoms, especially with faster running and cutting activities,7 or reporting chronic “hamstring tightness.” The athletic trainer can use special tests to determine the involvement of the sciatic nerve in HSI, including the Slump test (Figure 1) and Straight-Leg Raise test (Figure 2). A high incidence of positive slump tests was previously found in Rugby Football Union and Australian Rules Football club athletes with a history of HSI.4,6 A positive result is indicated by either a reproduction of symptoms or an improvement of symptoms when stopping or modifying the exacerbating motion, or most especially any side-to-side differences such as asymmetries in range of motion, neurological responses, and resistance to testing movement.5 For the Straight-Leg Raise test, reproduction of symptoms in 35° to 70° of hip flexion in the hamstring, especially when the hip is internally rotated and adducted, is believed to be associated with neural involvement.3 However, there is currently limited support for the use of these tests in the diagnosis of adverse mechanical tension.

Slump test.

Figure 1.

Slump test.

Straight-Leg Raise test.

Figure 2.

Straight-Leg Raise test.

The sciatic nerve can be mobilized using neural gliding/flossing techniques or nerve tensioners. These techniques are not used to stretch muscle tissue as in dynamic or static stretching, but the primary objective is to mobilize the sciatic nerve within its own sheath and within the surrounding musculature. Gliding mobilizations create a sliding of the nerve within the surrounding soft tissues and are performed within a pain-free range.5

Begin with the patient supine on a table, in a starting position of 90° of hip flexion with the knee at rest in full flexion. Then, give instruction for the patient to actively and slowly extend the knee while keeping the hip flexed to 90° (Figure 3). The knee should actively extend as far as pain permits and then slowly return to the starting position. Have the patient perform continual repetitions moving from knee flexion to extension over a period of approximately 5 seconds. Dorsiflexion and externally rotating the lower leg will target the tibial portion of the sciatic nerve. Hip flexion and knee flexion angles can be increased as symptoms allow. The athletic trainer may also provide local manual compression using the thumbs to palpable areas of adhesions or tightness in the muscle as the patient actively moves into knee extension.

Patient lies supine, supports the leg at the knee, and slowly moves from knee flexion to knee extension continually.

Figure 3.

Patient lies supine, supports the leg at the knee, and slowly moves from knee flexion to knee extension continually.

Tensioners aim to help the nerve adapt to normal range of motion. While a stretch of the nerve is applied, it is important to understand that tensioners are not a static stretching technique and are applied in an oscillatory manner.7 Increased tension and mild neurological symptoms such as a burning or warming sensation or a twinge feeling behind the knee and in the hamstring are expected. Centrally produced neurological symptoms in the lumbar region should not be elicited during these neurodynamic techniques and further evaluation is warranted with such presentation.

Nerve tensioners are performed while seated at the end of a table with the knee in full extension and the cervical spine in flexion (Figure 4). The patient remains in this position while slowly and continually moving the ankle into dorsiflexion and plantarflexion, with each movement taking approximately 2 seconds. An additional tensioner technique (“windshield wipers”) is performed standing upright with one leg supported on a surface between hip and knee height, with the knee extended and the ankle dorsiflexed (Figure 5). The patient actively inverts and everts the ankle while keeping the thigh and lower leg still (Figure 6) at a controlled rate. A set of 20 repetitions should take 20 to 30 seconds to complete. A second set repeated with the trunk rotated toward the respective leg, intensifying the neural sensation, is suggested if symptoms allow.

Tensioner performed in the Slump test position. Patient continually moves the ankle into dorsiflexion and plantarflexion in a controlled motion.

Figure 4.

Tensioner performed in the Slump test position. Patient continually moves the ankle into dorsiflexion and plantarflexion in a controlled motion.

“Windshield wipers” performed in the upright standing position with the leg supported on a table in full knee extension and the ankle in dorsiflexion.

Figure 5.

“Windshield wipers” performed in the upright standing position with the leg supported on a table in full knee extension and the ankle in dorsiflexion.

While the thigh and lower leg remain steady, the ankle is actively moved into (A) inversion and (B) eversion.

Figure 6.

While the thigh and lower leg remain steady, the ankle is actively moved into (A) inversion and (B) eversion.

Tensioners tend to be a more aggressive approach and the athletic trainer’s discretion is advised during use, especially in the acute phase of HSI. The patient should be involved in the decision regarding repetitions and intensity,5 and the athletic trainer should be aware of any exacerbation of symptoms and alter treatment accordingly.

Furthermore, care should be taken when employing any type of neurodynamic technique, because aggressive mobilization can further irritate a sensitive nerve, and all patients may not respond well.6 It is prudent to remain within a pain-free range of motion and gradually progress as pain allows, avoiding overstretching within the acute phase of injury. Although no established guidelines exist for neurodynamic mobilizations in HSI, these techniques can be incorporated into a rehabilitation program as an adjunct and as symptoms allow. Neurodynamic mobilizations used in conjunction with traditional HSI management has been shown to result in quicker return to play.4 A systematic review of randomized controlled trials using neurodynamic mobilizations for various conditions concluded that most studies demonstrated decreased reports of pain and disability, but a lack of high quality evidence suggests only limited support of their use.8 Hence, high-quality outcome studies are needed in this area, but the limited evidence supports a thorough evaluation of HSI including the nervous system.3

Successful management of poor sciatic nerve mobility and mechanosensitivity during HSI requires effective mobilization of the neural tissue, rather than just static stretching.2 Prior to the implementation of neurodynamic techniques the athletic trainer should identify contra-indications, such as other contributors to positive findings in neural testing, including pain of radicular and central nervous system origin. Soft tissue structures should also be assessed for proper biomechanical functioning to reduce any additional stresses that could be placed on the nerve.5 For instance, an overactive hip flexor causing an anterior tilt of the pelvis may increase the tension on the sciatic nerve.

Proper management of poor neural mobility and mechanosensitivity, including sciatic nerve assessment and treatment, may assist the athletic trainer in the challenging process of modulating symptoms following HSI. Based on success in clinical practice, it is recommended that neurodynamic techniques are initiated as an early mobilization technique within a pain-free range of motion. Neurodynamic mobilizations have also been helpful in treating hamstring tightness and discomfort when there is no reported mechanism of injury. Anecdotally, patient education has also been identified as a critical component of effective integration of neurodynamic mobilizations into the HSI management plan. Well-informed patients who understand their injury, symptoms, and the need for improved nerve mobility will be more compliant and cautious with performing neurodynamic mobilizations. Athletic trainers are encouraged to consider these techniques as a supplement to their existing protocols to develop a more comprehensive approach to HSI management.

References

  1. Orchard J, Seward H. Epidemiology of injuries in the Australian Football League, seasons 1997–2000. Br J Sports Med. 2002;36:39–45. doi:10.1136/bjsm.36.1.39 [CrossRef]
  2. Butler D. Adverse mechanical tension in the nervous system: a model for assessment and treatment. Austr J Physiother. 1989;35:227–238. doi:10.1016/S0004-9514(14)60511-0 [CrossRef]
  3. Gallant S. Assessing adverse neural tension in athletes. J Sport Rehab. 1998;7:128–139.
  4. Kornberg C, Lew P. The effect of stretching neural structures on grade one hamstring injuries. J Orthop Sports Phys Ther. 1989;10:481–487. doi:10.2519/jospt.1989.10.12.481 [CrossRef]
  5. Butler D. The Sensitive Nervous System. Adelaide City West, Australia: Noigroup Publications; 2000.
  6. Turl S, George K. Adverse neural tension: a factor in repetitive hamstring strain?J Orthop Sports Phys Ther. 1998;27:16–21. doi:10.2519/jospt.1998.27.1.16 [CrossRef]
  7. Butler D. Mobilization of the Nervous System. Melbourne, Australia: Churchill Livingstone; 1991.
  8. Ellis R, Hing W. Neural mobilization: a systematic review of randomized controlled trials with an analysis of therapeutic efficacy. J Man Manip Ther. 2008;16:8–22. doi:10.1179/106698108790818594 [CrossRef]

10.3928/19425864-20150422-02

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