Friday, January 11, 2013

Chronic Hamstring Strain & the Pelvis


Chronic Hamstring Strain & the Pelvis 

By Stephanie Panayi


 Introduction
Perhaps the most prevalent injury in Australian Rules Football, hamstring strain can be a major problem for elite athletes. Because of the attachment of biceps femoris into the ischial tuberosity and sacrum via the sacrotuberous ligament, the biomechanics of the sacroiliac joint and hip, along with lumbar-pelvic stability, play a significant role in hamstring function.

Generally speaking, while localised assessment is acceptable for acute injury, a more global approach is often appropriate when addressing chronic musculoskeletal pain. When treating someone for chronic or recurring hamstring strain, it is therefore pertinent to assess the lumbar-pelvic region for contributing factors.

Posture
Lumbar hyperlordosis, anterior tilt of the pelvis, and sacroiliac joint (SIJ) dysfunction have all been implicated in chronic hamstring strain (Cibulka et al 1986; Hennessey & Watson 1993; Hoskins & Pollard 2005).

An excessive lumbar lordosis usually correlates with more than optimal anterior tilt of the pelvis. Anterior pelvic tilt places strain on the origin of the biceps femoris at the ischial tuberosity, resulting in hamstring pathology (Cibulka et al 1986). Because of the origin of biceps femoris, the position and freedom of movement of the sacrum may also be influencial in hamstring function.

Sacroiliac Joint (SIJ) dysfunction occurs when there is asymmetry between the left and right innominates. The amount of joint play at the SIJ is very small but this small movement allows the left and right innominates rotate posteriorly and anteriorly when we walk. This movement of the innominates causes the sacrum to rotate and side bend. If any of these movements becomes impeded, SIJ dysfunction can occur. In other words, the sacrum gets stuck!

Ideally, during hip flexion the innominate on the same side rotates in a posterior and inferior direction (using the posterior superior iliac spine as the reference), moving the ischial tuberosity anteriorly and reducing hamstring strain. If however, the innominate is fixed in anterior rotation, the ischium will not move anteriorly during hip flexion and this will increase stress at the origin of the hamstrings.

Over time, unilateral muscle tightness can produce rotational forces in the innominates, and this is particularly true of athletes overtraining with unilateral loading as in kicking or throwing (Ross 2000). For example, a tight rectus femoris could produce anterior-inferior rotation force on the anterior superior iliac spine, while a tight biceps femoris could produce posterior-inferior rotational force at the ischial tuberosity and sacrum. Mobilising the SIJ can reduce asymmetry in the tilts of innomates and therefore reduce stress on the biceps femoris (Cibulka et al 1986). SIJ dysfunction has also been associated with hamstring spasm (Dowling 2004).


Joint Influences
We are all familiar with the terms “agonist” and “antagonist” in relation to muscle pairing based on opposing functions. What is not often remembered however, is that during contraction of agonist muscles, the antagonists do no behave passively, but are actively inhibited by the central nervous system. This is Sherrington’s principle of reciprocal innervations (Day et al 1984). This mechanism is thought to be partly mediated by joint receptors, which form arthrokinetic reflex (AKR) circuits that can inhibit or facilitate muscle tone (Makofsky et al 2007). In other words, by mobilising a joint in a particular way for a specific effect, we can help “switch on” or “off” a muscle group by influencing reflexes generated from within the joint capsule.

In relation to chronic hamstring pain, for example, a tightened anterior hip capsule would facilitate the iliopsoas muscle while inhibiting the gluteus maximus through the arthrokinetic reflex (Yerys et al 2002). Muscle wasting of the gluteals is often visible when tightness is present in the iliopsoas. Since gluteus maximus is a prime mover in hip extension, its inhibition places undue loads on its hamstring synergists making them more prone to injury.
Mobilisations performed on the anterior hip capsule have been shown to significantly increase gluteus maximus strength (Yerys et al 2002), and muscle weakness may therefore be influenced by inhibition related to capsular hypomobility of the underlying joint. In other words, the gluteus maximus is inhibited each time the hip extends against its restrictive barrier of motion.

When there are joint restrictions, mechanoreceptor inputs to the CNS can cause active weakening (or inhibition) of muscles whose action could take the joint beyond its restrictive barrier. Therefore, trying to strengthen a muscle that is being inhibited before mobilising the joint may be counterproductive. It is more beneficial to lengthen the chronically contracted myofascial units and mobilise the associated joint, prior to strengthening muscles that are weak. 

Joint mechanoreceptors can also be stimulated during tasks that maximise sensory input to the central nervous system and elicit subconscious and automatic responses in muscles. This is most effectively done by providing balance-challenging exercises which stimulate the sub-cortical systems which regulate movement and balance (Janda et al 2006).


Lumbar/Pelvic Stabilisation Exercises
For dynamic stability and optimum kinetic chain muscle activation patterns, it is important that there is normal length-tension relationships across the pelvis. A key influence in developing and maintaining such relationships is lumbar-pelvic stabilisation achieved through targeted exercises. The main muscles of lumbar-pelvic stabilisation are the multifidus, transverses abdominus and internal obliques (Elphington 2008). The oblique abdominals and transversus abdominus are particularly important in spinal stability due to their connections with the thoracolumbar fascia. The gluteal group is also an important contributor to dynamic pelvic stability.

In stability training, the client’s attention to the exercise is crucial. This is not only important so that the exercise is performed properly, but attention is likely to aid in the facilitation of muscles which have become reflexively inactive. Imagining movement has been shown to facilitate motorneurons of the agonist muscle while having an inhibitory effect on those of the antagonist muscle (Duk Yang et al (2005). This suggests that focussed attention to specific muscular contraction can play a significant role in muscle facilitation and reciprocal inhibition.


Summary
The aetiology of hamstring strain is often multifactorial and difficult to define. It is possible however, that chronic or recurring strain may be related to lumbar-pelvic imbalances which increase the functional load on the hamstrings by defacilitating the gluteus maximus, and/or increasing the tensile stress on the biceps femoris origin.  Apart from working to increase hamstring flexibility and address scar tissue formation, successful resolution of hamstring strain may involve the following:
  • Lengthening myofascial components that contribute to excessive lumbar lordosis, anterior pelvic tilt, and pelvic obliquity
  • Mobilising the SIJ and/or the anterior hip joint to stimulate joint receptors and facilitate gluteus maximus and the hamstrings
  • Balance-challenging exercises to further stimulate joint proprioceptor activity and enhance gluteal strength
  • Strengthening exercises for the lumbar-pelvic stabiliser muscles to create and maintain a balanced pelvis. 

References
Cibulka MT, Rose SJ, Delitto A, Sinacore DR 1986 Hamstring muscle strain treated by mobilizing the SIJ. Physical Therapy, 66(8): 1220-1223

Day BL, Marsden CD, Obeso JA, Rothwell JC 1984 Reciprocal inhibition between the muscles of the human forearm. Journal of Physiology, 349: 519-534

Duk Yang H, Ki Minn Y, Hong Son I, Han Suk S 2005 Facilitation and reciprocal inhibition by imagining thumb abduction. Journal of Clinical Neuroscience, 13(2): 245-248

Dowling DJ 2004 Evaluation of the pelvis. In: DiGiovanna EL et al (eds) An Osteopathic Approach to Diagnosis and Treatment. Lippincott Williams & Wilkins, Philadelphia
Elphington E 2008 Stability, Sport and Performance Movement: Great Technique Without Injury. North Atlantic Books, California

Janda V, Vavrova M, Herbenova A, Veverkova M 2006 Sensory motor stimulation. In: Liebenson C Rehabilitation of the Spine: A Practitioner’s Manual (2nd Ed). Lippincott Williams & Wilkins, Philadelphia

Makofsky H, Panicker S, Abbruzzese J, Aridas C, Camp M, Drakes J, Franco C, Sileo R 2007 Immediate effect of grade IV inferior hip joint mobilization on hip abductor torque: A pilot study. The Journal of Manual & Manipulative Therapy, 15 (2): 103-111

Yerys S, Makofsky H, Byrd C, Pennachio J, Cinkay J 2002 Effect of mobilization of the anterior hip capsule on gluteus maximus strength. The Journal of Manual & Manipulative Therapy, 10 (4): 218-224


About the Author
Stephanie Panayi is a Rolfing® practitioner. Her practice is located in Melbourne, Australia. You can contact here at: steph.rolfer@yahoo.com.au
This article is an abridged version of an article by the author published in the July 2010 issue of the Journal of Bodywork and Movement Therapies  titled “The need for lumbar–pelvic assessment in the resolution of chronic hamstring strain “.

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