1.      Introduction

Low Back Pain (LBP) is a very common musculoskeletal condition affecting 80% of people [1]. It can be acute (Less than 4 weeks), sub- acute (4-12 weeks) or chronic (more than 12 weeks) [2]. When acute pain is perceived as non-threatening, patients are likely to maintain engagement in daily activities, through which functional recovery is promoted. Personal and environmental contextual factors may play significant intervening roles in the disablement. Some of them after an acute episode remain sedentary because of fear that movement will produce pain. If the complaints continue, the psychosocial factors like stress, distress, anxiety and depression can contribute in the transition from acute to chronic pain [3-5]. Physiotherapy interventions used for patients with LBP include manual therapy, electrical modalities and specific exercise training programs all of them aim at reducing pain and disability and restoring normal functions and can provide marked improvements in the patient’s condition, but some residual pain and disability can be left [6].

Central sensitization of pain can occur in most Chronic Low Back Pain (CLBP) disorders to varying degrees. This is due to increased excitability of the Central Nervous System (CNS) due to sustained peripheral nociceptive inputs. It tends to make changes at spinal cord and cortical levels. The nervous system undergoes changes to its cortical mapping and possesses a pain ‘memory’ which may leave it pre-sensitized to the exacerbation and recurrence of pain [7-11]. Pain related fear that is fear of pain or physical activity or re-injury may be more disabling than pain itself. Studies have suggested that anticipated pain before physical activity may strongly influence a patient’s physical performance as well as beliefs regarding their overall status. In acute LBP elevated Fear Avoidance Beliefs (FABs) are decreased during recovery but they tend to remain unchanged in chronic low back pain over time. Elevated fear-avoidance beliefs are a maladaptive emotional response toward an excessive fear of pain that can eventually lead to avoidance behaviour. Avoidance refers to behaviour which is aimed at postponing or preventing an aversive or unpleasant situation from occurring. A vicious circle may be initiated when the pain is catastrophically misinterpreted. Pain catastrophizing, the tendency to fear the worst, is a psychological construct related to fear-avoidance [12-15]. These dysfunctional interpretations give rise to pain-related fear, and associated safety seeking behaviours such as avoidance/escape and hyper vigilance, that can be adaptive in the acute pain stage and worsen the problem in the case of long-lasting pain [16]. Several studies have found that the presence of elevated fear avoidance beliefs is predictive of the development of chronic disability and they exhibit avoidance behaviour, altered movement patterns, and reduced physical activity, which in turn contributes to the persistence of pain and disability [12,17]. The Fear-Avoidance Belief Questionnaire (FABQ) quantifies pain-related fears in relation to work and physical activity [17]. Pain catastrophizing is a psychological construct related to fear-avoidance. It is characterized by patients magnifying their feelings about painful situations and constantly thinking about these situations. Pain Catastrophizing Scale (PCS) is designed to assess catastrophic thoughts and feelings exhibited in response to pain [18]. The Roland Morris Disability Questionnaire (RMDQ), a reliable and valid measurement of self-perceived disability due to LBP [19].

Given the importance of psychosocial factors in CLBP, it isn’t clear whether physical interventions alone are of benefit in treating the disorder. In some patients, these psychosocial factors are thought to be enduring barriers to improvement. These patients may obtain more benefit from programs that directly address cognitive and psychological aspects of pain in addition with Physiotherapy interventions. An educational booklet in the Europe known as ‘Back Book’ had shown a significant beneficial effect on patient’s beliefs and disability with non-specific LBP [20]. Another study says that cognitive behavioural therapy is an effective intervention for patients with disability having a persistent pain [21]. The use of education which guides the patients to change their beliefs and perceptions about low back pain would possibly minimize the fear related to physical activity. Therefore, this would promote better function; and minimize disability. Also it will encourage them to stay active and reduce concerns about LBP. Currently, there is paucity of literature in India addressing the issue of fear-avoidance beliefs in physiotherapy management for LBP which include patient education program. Thus, this study was conducted to identify fear avoidance beliefs, pain catastrophizing thoughts and disability in patients with chronic low back pain. And to determine the effect of structured patient education combined with physiotherapy treatment among CLBP patients on these components.

2.1. Purpose of the Study

Recent evidence suggests that fear avoidance beliefs may be the most important risk factor for recurrence in disability in patients with chronic low back pain. Combined physiotherapy and patient education is efficacious in patients with chronic low backache and there is paucity of literature in Indian population. Hence, the purpose of this study is to find out the effect of structured patient education with conventional physiotherapy intervention in comparison to routine education delivered during conventional physiotherapy intervention in patients with chronic low back pain, with fear avoidance beliefs.

2.2. Aim

To study the effect of structured patient education program in patients with chronic low back pain with fear avoidance beliefs.

2.3. Objectives

To assess-

1. Fear avoidance beliefs by using Fear Avoidance Belief Questionnaire (FABQ),

Emotional distress due to catastrophic thoughts the Pain Catastrophizing Scale (PCS),

Self-perceived disability by using Roland Morris Disability Questionnaire (RMDQ),

Pain levels using Numerical Pain Rating Scale (NRS) pre and post intervention, in both Group A and Group B.

2. To compare and find out the difference in fear avoidance beliefs post intervention in both group A and group B using above mentioned outcome measures.

3.      Materials and Methods

3.1. Materials

1.       Projector

2.       Measuring tape

3.       Skin- marking pen

3.2.  Methodology

Study design: - Pilot prospective assessor blind randomized interventional study

Sample size: - 60 divided into 2 groups by computerised randomisation sheet (30 each group)

Study setup: Physiotherapy Out Patient Department, tertiary care hospital.

Duration of the study: total 4 weeks, Physiotherapy treatment program sessions were given 2 times per week to both groups. Structured patient education was given once per week 20-30 minutes to Group A (one to one session) for 4 weeks (4 sessions).

Patient selection: The patients were selected as per the inclusion and exclusion criteria.

3.3.  Inclusion criteria

3.3.1.  Patients between the ages of 18 to 65 years with low back pain duration more than 3 months and are willing to participate in the study.

3.3.2.   Fear avoidance belief questionnaire physical subscale cut off score was taken more than 15 and work subscale cut-off score was taken more than 29.

3.4.  Exclusion criteria

Patients with acute or sub-acute low back pain, spinal malignancy, infection or inflammation, fractures and structural deformities, Cauda equina syndrome, ongoing pregnancy, history of previous lumbar surgeries and history of primary psychiatric disease or alcohol abuse, prolapsed Intervertebral disc.

3.5.  Procedure

Approval was taken from Institutional ethics committee. All subjects fulfilling inclusion criteria participated in this study and written informed consent was taken from them. Patients got divided into 2 groups (group A and B) by using computerized randomization sheet. Subjective and physical examination to find the impairments, activity limitations and participation restriction was done using assessment sheet. All the self reported questionnaires scores were documented by another therapist. Pain at rest, on movement and on activity was taken on Numerical pain rating scale. Pre and post treatment assessment was done which included range, strength, flexibility of muscles and neurodynamic testing. Both the groups received conventional physiotherapy treatment sessions depending on individual patient assessment, twice per week, for 4 weeks. Group A, in addition received structured patient education once per week, for 4 weeks as per patient’s understanding. Education was delivered by one to one session with audio visual aids and practical demonstration. All the queries were answered by the end of each session. Subjects in both the groups were given home exercise program. Post study, all self-reported outcome measures FABQ, PCS and RMDQ and Numerical Pain Rating Scale were again assessed by the same therapist.

Outcome Measures: Questionnaires: Fear avoidance belief Questionnaire [22], Pain catastrophizing scale [23], Roland Morris Disability questionnaire [24] and Numerical pain rating scale [25]

4.  Structured Patient Education

Group A received education in the audio-visual format on the projector for 20- 30 minutes once per week and session was conducted on one to one based for 4 weeks (4 sessions). The knowledge on functional anatomy and mechanics was explained in pictorial and video format. How movements occur at the spine was shown with the help of videos. The right patterns of the movements at work and at home and postures to be achieved during Activities of Daily Living (ADL) were demonstrated. Reasoning of why they have to perform activities in certain manner was provided at every step so that they can perform those activities efficiently. Importance of exercise was explained. In every session they were asked whether they have modified the right movement patterns during ADL or not. Reinforcement was given at every session. Education was provided to give a new insight and changing his/her perception, emphasising the positive aspects rather than focusing on possible abnormalities and developed more confidence in managing the condition into the future. Components of education program included- pain, types of pain (central and peripheral) and its effects. Risk factors like sedentary life style, bad postures or wrong techniques while carrying out any movements, obesity and stress; how they contribute to low back pain was explained. Importance of education was given to update their information, to reduce their fear avoidance beliefs to improve physical performance. Functional anatomy the information on postural curves of the spine, pictorial presentation of structures of the spine (bones and the joints of the spine, the intervertebral disc, the trunk and back muscles) and how they help while carrying movement was explained. Function of muscles stabilising spine was also explained. Importance of each structure and how load sharing or forces act on the spine according to different postures were explained. This information was explained with pictures and videos for better impact and understanding. Also Importance and benefits of exercises were explained. How exercises give stability to the spine which is helpful in reduction of pain and improving performance was explained. Ergonomic advices at work place and at home were explained. They were taught correct techniques of lifting loads, good and bad postures in standing, sitting and walking. Also proper body mechanics to be achieved during activities of daily living tasks including cleaning, cooking, wearing shoes, lifting bags while shopping and standing in the kitchen. Energy conservation techniques like prioritizing, planning, modifying environment to avoid excessive bending, carrying and reaching were explained. They were explained that taking frequent short breaks between activities rather than one long break at the end to save energy. Reinforcement was given every time patients used to come.

5.  Results

Data was analysed using SPSS version 16.

NS- Not significant,

NPRS- Numerical pain rating scale,

FABQ PA- Fear avoidance belief questionnaire physical activity subscale score,

FABQ W- Fear avoidance belief questionnaire work subscale score,

PCS- Pain catastrophizing scale,

RMDQ- Rolland Morris disability questionnaire

The above table explains that all pre- treatment median scores in Group A and B were not statistically significant.

The data on Numerical pain rating scale, FABQ scale, PCS scale, RMDQ scales are ordinal type of data, so Non- parametric tests (for intra group comparison Wilcoxon and intergroup comparison Mann Whitney test) were used.

Fear Avoidance Belief Questionnaire Physical Activity Subscale

6. Discussion

The mean age of subjects involved was 43.33 in group A and 46.43 in group B and the median of pain on activity was 7 for both group A and B. This study demonstrated that structured education combined with conventional physiotherapy which included thermal therapy, manual therapy, ergonomic advices, exercises and home exercise program resulted in reduction of fear-avoidance beliefs, pain catastrophizing thoughts, disability and pain than conventional physiotherapy management alone. Reduction in the scores of FABQ physical activity subscale (p<0.0001), FABQ work subscale (p<0.0001) and PCS (p <0.0001) could be attributed to the effects of structured patient education in addition to conventional physiotherapy treatment. On physical examination, it was found that posture and lumbo-pelvic rhythm were altered. Altered posture gives rise to muscle- length imbalance which leads to weakness of the muscles. And when they are not in the co-ordination, patients do perform asymmetrical or guarded movements [26]. When movements of the lumbar spine were checked, they were stiff or hypomobile and it was compensated either from thoracic spine or pelvis or hip joint. Due to all these reasons, during static and dynamic postures there is an abnormal loading on the intervertebral disk and facet joints of the spine. This was explained in pictorial and video format. Further, education regarding age related degenerative changes and the excessive loads due to above mentioned factors on degeneration were explained. This leads to increase in pain and this vicious cycle continues. Along with that they were explained how distress, anxiety, depression and inappropriate fears and beliefs affect their performance in day today activities which make them feel less confident. 

So they were explained, how activities which they were initially performing in an altered manner where stress on the tender joints was giving rise to pain which was increasing their fears to perform movements. So they were explained functional anatomy of the spine, how exactly lumbar spine moves and how this mechanics takes place with videos and pictures which could have help them to incorporate right pattern of movement. One of the studies concluded that educational program was beneficial in reducing fear avoidance beliefs as compare to individual symptom- based physical training programme. Their education program was based on creating confidence that back is strong and emphasis was given to facilitate more natural and less painful movements which are beneficial to stay physically active [27]. Information given with respect to kinematics and kinetics and loading of the spine in this study may have also facilitated reduction in the elevated avoidance behaviour and catastrophizing thoughts. They were also explained about ergonomics at work place and at home with the help of videos and pictures. Correction was demonstrated and they were asked to follow these techniques in activities of daily living which may have resulted in improved efficiency and performance. Subjects were also explained the importance of performing exercises and how exercises can improve stability of the spine. And how this will improve abnormal movements performed. During activities of daily living and further it will help to reduce pain. Along with that, energy conservation techniques like prioritizing, modifying environment and taking rest breaks were explained. Crombez et al. in their study found that there is a significant relationship between disability and fear-avoidance belief for physical activity and fear-avoidance belief for work. The pain-related fear and the fear of movement lead to disabling low back pain. Reductions in fear avoidance beliefs about work and physical activity as well as increased perceptions of control over pain, have been associated with reductions in disability [28]. Johann et al. concluded that functional restoration program which including counseling, exercises, aerobic activities, manual handling and lifting techniques, muscle strengthening using machines, stretching and relaxation was effective to improve work-and-leisure activities score in patients with chronic LBP [29]. Hence structured patient education targeted on their fear avoidance beliefs, which helped to reduce negative perceptions like they should stop doing their work and remain sedentary and a catastrophic interpretation that activity will cause injury and exacerbate the pain. This normalisation of pain cognitions were associated with active participation and improved physical performance as seen in the reduction of the scores for disability with RMDQ (p< 0.0001) observed in group A.

Both the groups received exercises targeting lumbo-pelvic-hip stability and flexibility. Functional stability of the spine is dependent on integrated local and global muscle function.

Studies report increased fatigability, changes in muscle fiber composition and motor control in people with acute and chronic LBP [30]. When structures get overloaded because of imbalance beyond tissue tolerance, there is a pain and related pathology. When these patients perceive pain in a threatening catastrophizing manner; there are increased fear avoidance beliefs. There is also increase in the anxiety level which lowers pain threshold [31]. And it has been suggested that increased stiffness is a biomechanical manifestation of pain [32].

Exercise is widely used in the rehabilitation of CLBP patients. However, no studies exist as to the most effective exercise programme for LBP. Evidence says that exercises decreased pain, disability, secondary physical deconditioning or time off work in patients with chronic low back pain [33-37]. There is a study which gives moderate evidence that exercise was more effective than a placebo or no treatment [38]. It is also thought to decrease fear avoidance behaviour and facilitate functional improvement, despite ongoing pain [39]. Hence, as these maladaptive emotional responses, fear avoidance beliefs and pain catastrophizing thoughts reduce, the disability also reduces hence physical performance improves.

Therefore this study concludes that structured patient education along with conventional physiotherapy is more effective as compare to conventional physiotherapy in patients with chronic low back pain.

7.  Conclusion

Fear Avoidance Beliefs, Pain Catastrophizing thoughts, self perceived disability and pain intensity were high in patients with chronic low back pain. They decreased post intervention in both groups A and B, which was statistically significant. It was also found that group A shows statistical significant improvement as compare to group B which received structured patient education along with conventional physiotherapy treatment. Therefore, structured patient education along with conventional physiotherapy is more effective as compare to only conventional physiotherapy in patients with chronic low back pain.

8.   Clinical Implication

Structured patient education should be given with the conventional physiotherapy treatment in patients with chronic low back pain.

Table 1: Baseline demographic data.

Table 2: Intra group comparison.

*S- significant, Intra group comparison- Wilcoxon test

Table 3: Intergroup comparison.

#S- significant, Intergroup comparison- Mannwhitney test

The score of Fear avoidance belief physical activity subscale statistically significantly reduced in Group A (p< 0.0001) and in Group B. (p< 0.0001)

Between two groups comparison the score of Fear avoidance belief physical activity subscale statistically significantly reduced in Group A. (p= 0.000)

Comparison of Score on Fear Avoidance Belief Questionnaire Work Subscale

Table 3: Intra group comparison.

*S- significant, intra group comparison- Wilcoxon test

Table 4: Intergroup comparison.

#S- significant, intergroup comparison- Mann Whitney test

The score of Fear avoidance belief work subscale statistically significantly reduced in group A (p< 0.0001) and in group B. (p<0.0001)

Between two groups comparison the score of Fear avoidance belief work subscale statistically significantly reduced in Group A. (p= 0.000)

Comparison of Score on Pain Catastrophizing Scale

Table 5: Intra group comparison.

*S- significant, intra group comparison- Wilcoxon test

Table 6: Intergroup comparison.

#S- significant, intergroup comparison- Mann Whitney test

The score of Pain catastrophizing scale statistically significantly reduced in Group A

(p< 0.0001) and in group B. (p< 0.0001)

Between two groups comparison the score of Pain catastrophizing scale is statistically significantly reduced in Group A as compare to group B (p= 0.000)

Comparison of Score on Rolland Morris Disability Questionnaire

Table 7: Intra group comparison.

*S- significant, intra group comparison- Wilcoxon test

Table 8: Intergroup comparison.

#S- significant, intergroup comparison- Mann Whitney test

The score of Roland Morris disability questionnaire statistically significantly reduced in group A (p< 0.0001) and in Group B. (p<0.0044)

Between two groups comparison the score of Roland Morris disability questionnaire is statistically significantly reduced in group A (p= 0.000)

Comparison of Score on Numerical Pain Rating Scale

Table 9: Intra group comparison.

* S- Significant, for intra group comparison: Wilcoxon test

Table 10: Intergroup comparison.

#S- Significant, intergroup comparison: Mann Whitney test

The score of Numerical Pain Rating scale statistically significantly reduced in Group A

(p< 0.0001) and in Group B. (p=0.0001)

Between two groups comparison the score of Numerical Pain Rating scale is statistically significantly reduced in Group A. (p= 0.000)

1. Michael Feuerstein, Paul Beattie (1995) Biobehavioral Factors Affecting Pain and Disability in LowBackPain: Mechanisms and Assessment. Phys Ther 75: 267-280.
2. S Brent Brodtzman, Kevin Wilk, et al. (2003) Clinical Orthopaedic Rehabilitation. 2^nd edition. Mosby.
3. Uebelhart, Andre Aeschlimann, Steiner WA, Ryser L, Huber E, et al. (2002) Tool in Physical Therapy and Rehabilitation Medicine Use of the ICF Model as a Clinical Problem-Solving. Phys Ther 82: 1098-1107.
4. Urban Schwegler, Jessica Anner, Brach M, De Boer W, et al. (2014) Towards comprehensive and transparent reporting: context-specific additions to the ICF taxonomy for medical evaluations of work capacity involving claimants with chronic widespread pain and low back pain. BMC Health Services Research 14: 1-13.
5. Sean D Rundell, Todd E Davenport, Wagner T (2009) Physical Therapist Management of Acute and Chronic Low Back Pain Using the World Health Organization's International Classification of Functioning, Disability and Health. Phys Ther 89: 82-90.
6. C.G. Maher (2004) Effective physical treatment for chronic low back pain. Orthop Clin N Am 35: 57-64.
7. Keith Smart, Catherine Doody (2007) The clinical reasoning of pain by experienced musculoskeletal physiotherapists. Manual Therapy 12: 40-49.
8. Clifford J. Woolf (2011) Central sensitization: Implications for the diagnosis and treatment of pain. PAIN 152: 2-15.
9. Shacklock MO (1999) Central pain mechanisms: A new horizon in manual therapy. Australian Journalof Physiotherapy 45: 83-92.
10. Clifford J. Woolf (2011) Central sensitization: Implications for the diagnosis and treatment of pain. Pain152: 2-15.
11. Alban Latremoliere, Clifford J. Woolf (2009) Central Sensitization: A Generator of Pain Hypersensitivity by Central Neural Plasticity. Pain 10: 895-926.
12. Margreth Grotle, Nina K Vollestad, Veierød MB, Brox JI (2004) Fear-avoidance beliefs and distress in relation to disability in acute and chronic low back pain. Pain 112: 343-352.
13. Julie M Fritz, Steven Z George, Delitto A (2001) The role of fear-avoidance beliefs in acute low back pain: relationships with current and future disability and work status. Pain 94: 7-15.
14. S Poiraudeau, F. Rannou, Baron G, Le Henanff A, Coudeyre E, et al. (2006) Fear-avoidance beliefs about back pain in patients with subacute low back pain. Pain 124: 305-311.
15. Darren Q Calley, Jackson S, Collins H, George SZ (2010) Identifying Patient Fear-Avoidance Beliefs by Physical Therapists Managing Patients with Low Back Pain. Orthop Sports Phys Ther 40: 774-783.
16. Michele Curatolo, Arendt-Nielsen L, Petersen-Felix S (2006) Central hypersensitivity in chronic pain: Mechanism and clinical implication. Phys Med Rehabil Clin N Am17: 287-302.
17. Waddell G, Newton M, Henderson I, Somerville D, Main CJ (1993) A Fear-Avoidance Beliefs Questionnaire (FABQ) and the role of fear-avoidance beliefs in chronic low back pain and disability. Pain 52: 157-168.
18. Sullivan M J L, Bishop S, Pivik J (1995) The Pain catastrophizing Scale: Development and validation. Psychol Assess 7: 524-532.
19. Roland M, Morris R (1983) A study of the natural history of back pain. Part I: development of a reliable and sensitive measure of disability in low-back pain. Spine 8: 141-144.
20. Zarina Zahari, Kamaruddin Kamaria, Othman, Ida Rosmini, Justine Maria, et al. (2014) Effect of patient education combined with physiotherapy treatment on Fear avoidance belief in low back pain sufferers. Int J Pharm Bio sci 5: 640-648.
21. Sean D. Rundell, Davenport TE (2010) Patient education based on principles of cognitive behavioural therapy for a patient with persistent low back pain: Case report. J Orthop Sports Phys Ther 40: 494-501.
22. Gordon Waddell, Mary Newton, Iain Henderson, Douglas Somerville, Chris J. Main (1993) A Fear-Avoidance Beliefs Questionnaire (FABQ) and the role of fear-avoidance beliefs in chronic low back pain and disability. Pain.52: 157-168,166.
23. Sullivan M, Bishop S, Pivik J (1995) The pain catastrophizing scale: development and validation. Psychol Assess 7: 524-532.
24. Roland M, et al. (1983) Spine (Phila Pa 1976) 8:145-150.
25. Breivik EK, Björnsson GA, Skovlund E (2000) Comparison of pain rating scales by sampling from clinical trial data, Clin J Pain 16: 22-81.
26. Jeanine A Verbunt, Henk A Seelen, Vlaeyen JW, van de Heijden GJ, Heuts PH, et al. (2003) Disuse and deconditioning in chronic low back pain: concepts and hypotheses on contributing mechanisms. European Journal of Pain 7: 9-21.
27. Pia H Sorensen, et al. (2010) An educational approach based on a non-injury model compared with individual symptom-based physical training in chronic LBP. A pragmatic, randomised trial with a one-year follow-up. BMC Musculoskeletal Disorders 11: 1-13.
28. Crombez G, Hermans D, et al. (2000) The emotional stroop task and chronic low back pain: what is threatening for chronic pain sufferers? Eur J Pain 4: 37- 44.
29. Johann Beaudreuil, Kone H, Lasbleiz S, Vicaut E, Richette P, et al. (2010) Efficacy of a functional restoration program for chronic low back pain: Prospective 1-year study. Joint Bone Spine 77: 435-439.
30. Paul W. Hodges (2003) Core stability exrcises in chronic low back pain. Orthop Clin N Am 34: 245-254.
31. Michele Curatolo, Arendt-Nielsen L, Petersen-Felix S (2006) Central hypersensitivity in chronic pain: Mechanism and clinical implication. Phys Med Rehabil Clin N Am 17: 287-302.
32. Nicholas V. Karayannis et al. (2013) Fear of Movement Is Related to Trunk Stiffness in Low Back Pain. Plos one 8: 1-7.
33. Rainville J, Hartigan C, Martinez E, Limke J, Jouve C, et al. (2004) Exercise as a treatment for chronic low back pain. Spine J 4: 106-15.
34. Koes BW, van Tulder MW, Thomas S (2006)  Diagnosis and treatment of low back pain. BMJ 332: 1430-1434.
35. Van Tulder MW, Koes BW, Bouter LM (1997) Conservative treatment of acute and chronic nonspecific low back pain. A systematic review of randomized control trials of the most common interventions. Spine 22: 2128-56.
36. Liddle SD, Baxter GD, Gracey JH (2004) Exercise and chronic low back pain: what works? Pain 107: 176-90.
37. Hayden JA, van TulderMW, Malmivaara AV, Koes BW (2005) Metaanalysis: exercise therapy for nonspecific low back pain. Ann Intern Med 142: 765-75.
38. Abenhaim L, Rossignol M, Valat JP, Nordin M, Avouac B, et al. (2000) The role of activity in the therapeutic management of back pain. Report of the International Paris Task Force on Back Pain. Spine 25(4 Suppl). 1S-33S.
39. Sarah Dianne Liddle, Baxter GD, Gracey JH (2004) Exercise and chronic low back pain: what works. Pain 107: 176-190.