Yoga: Cause or Cure for Chronic Low Back Pain?.
Part 1: Introduction.
This paper is an attempt to raise awareness of care and safety of the low back in practising yoga and the potential rehabilitative qualities of yoga postures. It is intended for teachers and experienced practitioners of yoga who will be familiar with the detail of posture work. It offers an outline of the anatomy and basic physiology to illustrate what happens to the low back when yoga postures are performed. This is a prerequisite to explaining the pathology or what can go wrong resulting in pain during or after practice of yoga postures. The paper also offers strategies to prevent injury in performing postures and using the practice of postures themselves as a tool in pre and rehabilitation of the low back.
A major reason for doing yoga is maintenance of strength and flexibility of the back. However, care must be taken to ensure postures are suited to the abilities of the person and are performed with regard to the structure and function of the low back and the body as a whole. We are likely to be more successful if avoiding back pain by having some insight into the structures and workings of the back and the causes of pain. We also need to identify poor posture and movement that may result in injury and back pain and posture and exercise work that prevent pain by preventing injury, re-injury and recurrence.
Before performing sport or exercise the advice is always to check with a doctor for assurance it is safe to do the activity. This is particularly pertinent if pain or discomfort is already evident. The causes of low back pain are, however, multifarious and are not always easily diagnosed. This does not necessarily prevent exercise or posture work that may benefit the condition being performed with suitable care and precautions. Yoga practitioners with low back pain are usually suffering with a chronic condition or over-use injury. The condition or injury may have developed from poor yoga practice or through posture or movements adopted in other activities including work and sports. Low back pain resulting from a specific recent trauma or acute injury is less common and will not be discussed in detail.
It is not intended to reproduce full instructions of a comprehensive range of postures but to indicate postures that are useful to rehabilitate chronic low back pain.
How the Structures of the Spine Relate to Low Back Pain:
The spine has 24 bony vertebrae of which five are in the lumbar. Between each vertebra is an intervertebral disc. The outer part of the disc is made of tough fibro-cartilage enclosing a gel like nucleus that serves to absorb and disperse shock and compression. The discs are located in front of spinal cord and act as shock absorbers. They are able to absorb shock by containing fluid drawn in from surrounding structures whilst the spine is at rest at night and squeezed under compression during the day. The fluid contains nutrients essential to disc health as the discs have no blood supply of their own.
The nerves in the spinal cord pass through an opening in the bony body and exit the spinal canal at all vertebral junctions. The nerves exiting the lumbar spine innervate the hips and legs. Behind the disc are the facet joints that directly link the bony vertebral bodies. The joints are enclosed in fibrous capsules that contain synovial fluid that lubricate the joints. Facet joints linking the intervertebral bodies become swollen when strained and can put pressure against nearby nerves causing pain.
Over stretching the ligaments adjacent to the discs can cause pain the loss of their ability to hold discs in place. A prolapsed disc occurs when the nucleus is pushed out of the posterior wall of the disc. The protruding disc puts pressure on surrounding ligaments and tissues causing pain. The prolapsed disc also exudes chemicals that irritate surrounding tissues. Intervertebral discs degenerate with excessive wear and tear. Disc degeneration and consequent loss of disc height may cause chronic back pain that is felt at the site of the disc or as referred pain in the hip or leg. Loss of disc height and causes the facet joints to become deranged increasing their potential for strain and subsequent development of arthrosis. The tissues of the fibrous capsule can be strained with resultant pain in response to spinal derangement. The space between adjoining vertebra through which spinal nerves exit the spinal cord becomes narrower as disc height is lost. This results in the surrounding structures including the facet joints pressing on nerves. This can cause pain that may be perceived at the site of pressure or referred and felt in the hip, leg or foot as in sciatica.
Muscles attach to the vertebral bodies facilitating movement of the spine but also providing a source of pain if strained. The relative strength and flexibility of muscles attached to the spine and the hips help determine the curves in the spine. The curves in the spine provide longitudinal shock‑absorption and resistance to axial compression. Balance of strength and flexibility is needed to maintain a correct lordotic curve that, together with the intervertebral discs, serves to bear weight and absorb shock. Minimal stress on the lumbar spine is possible when vertebrae are aligned and balanced within the normal spinal curves. The lumbar curve has considerable effect on the health of the lower spine. In swayback or excessive lordosis the lumbar arch is abnormally increased and weight that is normally evenly distributed over the entire lumbar curve is concentrated at the peak of the arch. This results in slackening of supporting ligaments and consequent instability. The excessive movement then allowed between vertebrae contributes to disc deterioration and consequent changes in bony structures such as the development of bone spurs in an adaptive effort to bear the increased stresses. Swayback also pinches together the posterior vertebrae producing compression on the posterior lumbar discs restricting the flow of nutrients into the discs resulting in deterioration and shrinkage. Reduced height in the discs reduces the space between facet joints and their subsequent grating can produce arthritic changes. Facet joint pathology in turn places further stress on the discs creating a vicious circle.
A flat lumbar curve can also create serious problems as loss of the normal curve reduces the ability of the spine to absorb longitudinal shock. A flattened lumbar also results in supporting ligaments becoming excessively taut thereby holding adjacent vertebrae together too tightly limiting motion and compromising disc nutrition. A flat lumbar will also push weight normally borne by the facet joints onto the discs resulting in disc degeneration through compression and poor nourishment.
The relative strength and flexibility of the muscles that flex and extend the trunk and hips affect the shape of the lumbar lordosis. Tight quadriceps especially if combined with weak hamstrings will tend to tilt the pelvis forward resulting in an excessive lordosis. Tight hamstrings especially if combined with weak quadriceps will tilt the pelvis back resulting in a flattened lordosis. Similarly paired tight abdominal muscles and weak back extensors will result in flatback and vice versa in swayback. Tight hip flexors will cause excessive lordosis especially if combined with weak hip extensors and the reverse will result in flatback.
Preventative back care and rehabilitation requires an awareness of the affects of posture on the spine and the development of skills of alignment. Muscle strength and flexibility need to be balanced across spinal joints. The erector spinae muscles act like 'guy' wires holding the spine in alignment when equally balanced. Weakness on one side pulls the spine out of alignment causing stress and possible pain. Joints should be capable of full range of movement to maintain alignment. Stiff joints are obstacles to good alignment and restricted movement inhibits production of the lubricating synovial fluid so compounding restriction. Stiff parts of the spine are compensated by other parts of the spine working harder to maintain overall spinal mobility. This will incur wear and tear on spinal structures that can lead to overuse injuries.
Abdominal and back muscles need respective balance of strength and flexibility as do front and back thigh muscles as these respective muscle groups exert a pull and consequent influence on the positioning of the pelvis. Weight is transmitted from the spine to the lower limbs via the pelvis so mobility around the hip joints is essential if it is to take the strain off the spine. Back problems result when hip mobility is compromised and unable to perform a full range of movement whereby the spine compensates to obtain trunk mobility but in doing so is liable to stress and possible injury. It is therefore necessary to balance muscle strength and flexibility at all regions controlling the movements of the lower back viz:
Tight muscles need to be stretched and areas of hypermobility should be protected from over-stretch. Stability should be maintained whilst stretching to ensure precision and alignment. Stretching is particularly important if backache is associated with previous injury. The tissue repair process involves the laying of collagen fibres, initially formed randomly, but aligned in response to muscle contraction and stretching. Fibres failing to align form excessive and inflexible scar tissue preventing restoration of the previous range of movement making the part vulnerable to future injury. Injury that has not resolved with full range of movement and strength may result in detrimentally altering posture. Poor posture unavoidably imposed during injury may become habitual after the injury has otherwise healed. Posture detrimental to the back can be established through mimicry of peers or parents or adopted in response to emotional factors. Postural training or re-education is then needed.
Tension held in muscles around a previous injury may contribute to back pain. Muscle tension increases as a protective mechanism around the site of a trauma to limit movement so avoiding further injury. Tension may persist long after the injury has otherwise healed becoming chronic and habitual. Pain occurs when movement goes beyond the limited range of motion. Pain, in turn, stimulates muscle tension resulting in the establishment of a viscous circle with increased muscle tension and limited range of movement installed as the new norm. Spinal structures and their relation to each other have the primary influence over posture but posture, both good and bad, is learned from mimicry of peers and parents. Rehabilitation of the lower back therefore requires postural training to achieve correct lordosis.
Chronic back pain is often through re-injury so it is important to know what caused the injury and what causes it to recur. Back-pain usually fluctuates with posture and movements so positions should be adopted that improve comfort and reduce pain. This can help identify appropriate exercise to begin rehabilitation. Movement that causes pain to radiate over a wider area should be avoided and those that centralise or diminish pain should be encouraged. To avoid injury awareness should be developed of strain induced by standing, sitting, bending and lifting as well as movements performed in yoga.
Trunk or core stability is necessary to maintain the spine and pelvis in a mechanical position that control and protect the structures of the back. Core stability requires the abdominal and spinal muscles to be of adequate strength to act as a muscular corset to protect the lower back.
Adequate shoulder flexibility is needed to prevent over extension of the lumbar spine when attempting to raise the arms above the head.
Preventing injury whilst doing yoga postures:
Discs, joints and other soft tissue can be strained through excessive spinal movements. Movements of the trunk require the engagement of the hips otherwise the lumbar spine risks strain through overworking to compensate. Inadequate hip movement may be due to inflexibility or lack of awareness or postural habit.
Compensatory overworking of the spine may result in
The comprehensive range of available yoga postures and their variations provide adequate facility for back injury prevention and rehabilitation. Postures and exercises to maintain and improve flexibility and strength and enhance the healing process should be done within pain tolerance. Initial exercises for strength may need to be restricted to isometric muscle contractions that, together with stretching, will need to be done in a position that is non-weight bearing for the spine. When pain tolerance and range of movement allow the patient should perform isotonic contractions and stretching exercises and postures of partial weight bearing progressing to full weight bearing. Dynamic core stabilisation and motor skills including proprioception should be added and a return to full functional rehabilitation should occur as soon as pain free range of movement and strength allow.
Muscles are strengthened using progressive overloading in accordance with the principle of specific adaptations to increased demand. Increasing the weight imposed on muscle specifically increases muscle strength. Increasing the number of repetitions at a given weight increases muscle endurance. In yoga postures the weight is provided by the positioning of the body and endurance by the duration of the posture or the number of times it or others embracing similar movement are performed. Working progressively from initial low level exercises to those more demanding there is a need to continuously monitor for pain and modify the programme accordingly. Analysis of component parts of activities and movement will help the athlete to identify the most advantageous mechanical positioning for the strengthening and rehabilitation of their back.
Using yoga to prevent and rehabilitate back injury requires a programme that
The following programme is a general one for rehabilitation of chronic back pain whether caused by strain on the intervertebral discs, facet joints or other soft tissue overuse injury. It may be performed at various levels of flexibility or strength with postures modified to suit ability. Practice of one to one and a half hours three times per week is optimal. Experienced yoga practitioners presenting with chronic back pain are likely to have reasonable mobility and able to perform spinal weight bearing or at least partial weight bearing exercises. Once other serious pathology has been ruled out the principle point for rehabilitating chronic back pain is usually training in correct back use to maintain optimal balance of strength and flexibility. This should be functional, that is, developed within the context of yoga. The postures therefore need to be modified to allow them to be done safely and with theraputic benefit.
Principles learned in developing correct posture for yoga should carry through to everyday activities ensuring safe practice in movement and lifting as well as correct lordosis for sitting and standing. For example when sitting for long periods when driving or at the computer appropriate support should be placed behind the lumbar to maintain lordosis. When working in standing positions one should stay upright as far as practicable and come out of position occasionally. Heavy objects should not be lifted with a rounded back as this increases pressure on the discs. Objects should be held close when lifted with the back upright. Lowering to pick up an object should be by bending the knees and lifting should be done by straightening the knees. Turning should be with the feet and not the trunk
Treatment for acute injuries is mainly modalities and pain relief. One should avoid the injurious activity; apply ice for pain relief and reduction of inflammation and rest the injured part whilst maintaining general fitness. Acute injuries often present as very painful leaving the athlete unable to bear weight so exercise rehabilitation needs to start with isometric non-weight bearing exercises moving on to the postures and exercises described in this text when there is sufficient pain free range of movement.
In conclusion this teaching package provides a convenient portable reference easily and cheaply reproduced. The many illustrations should help the reader understand the practical concepts involved in the postures and exercises. However yoga is experiential and the student needs to receive feedback from the teacher. Rehabilitation of chronic low back pain is a large subject and the neither these articles nor the literature review can be exhaustive. Many other postures and back conditions might have been discussed but the objective is to convey to the reader that the choice and intensity of the postures and exercises is dependent on the ability of the practitioner and related to the condition of the back. These articles are intended to generate awareness of the problem and identify routes the practitioner may begin to go down in using yoga to rehabilitate or prevent back pain.
Copyright David Tierney