The perspectives of physiotherapists on managing nonspecific low back pain following a training programme in cognitive functional therapy: A qualitative study
Abstract
Background:It has long been acknowledged that nonspecific chronic low back pain (NSCLBP) is associated with a complex combination of biopsychosocial (BPS) factors, and recent guidelines advocate that the management of back pain should reflect this multidimensional complexity. Cognitive functional therapy (CFT) is a behaviourally oriented intervention that targets patients' individual BPS profiles. Although the efficacy of CFT has been demonstrated in primary care, little evidence exists about the training requirements of this approach. Methods:Qualitative semistructured interviews were conducted with 10 physiotherapists working in primary care, who had undergone a formal training programme in CFT. A purposive sampling method was employed to seek the broadest perspectives. Thematic analysis was used to analyse the interview transcripts and capture the emergent themes. Results:Five main themes emerged: (i) the learning challenge; (ii) self‐reported changes in confidence; (iii) self‐reported changes in communication practice; (iv) self‐reported changes in attitudes and understanding; (v) the physiotherapists felt that CFT was more effective than their usual approach for NSCLBP but identified barriers to successful implementation, which included a lack of time and difficulties in engaging patients with strong biomedical beliefs. Conclusions:The study suggested that training in CFT has the capacity to produce self‐reported changes in physiotherapists' attitudes, confidence and practice. The provision of such training has implications in terms of time and costs; however, this this may be warranted, given the physiotherapists' strong allegiance to the approach compared with their usual practice.
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Current evidence supports the feasible and efficacious delivery of web-based CBT using nontraditional health professionals such as PTs and OTs, with reduced time commitment and treatment costs, and positive self-reported changes in PTs' attitudes, confidence, and practice.
“Current evidence supports the feasible and efficacious delivery of web-based CBT using nontraditional health professionals such as physiotherapists (PTs) and occupational therapists (OTs) [45], with reduced time commitment and treatment costs, and positive self-reported changes in the PTs’ attitudes, confidence, and practice [46-48].”
Cites
Using thematic analysis in psychology
Braun, V., & Clarke, V. (2006) · Qualitative Research in Psychology · doi:10.1191/1478088706qp063oa · Cited by 194,414 · see citing works
Patient-centredness: a conceptual framework and review of the empirical literature
Mead, N., & Bower, P. (2000) · Social Science & Medicine · doi:10.1016/s0277-9536(00)00098-8 · Cited by 2,993 · see citing works
Prevention and treatment of low back pain: evidence, challenges, and promising directions
Foster, N. E., Anema, J. R., Cherkin, D., Chou, R., Cohen, S. P., Gross, D. P., Ferreira, P. H., Fritz, J. M., Koes, B. W., Peul, W., et al. (2018) · The Lancet · doi:10.1016/s0140-6736(18)30489-6 · Cited by 2,398 · see citing works
Doing qualitative research: a practical handbook
Henderson, R. (2011) · Studies in Continuing Education · doi:10.1080/0158037x.2011.609670 · Cited by 1,909 · see citing works
Qualitative Data Analysis: Practical Strategies
Bazeley, P. (2020) · Medical Entomology and Zoology · Cited by 1,388 · see citing works
O’Sullivan, P. (2005) · Manual Therapy · doi:10.1016/j.math.2005.07.001 · Cited by 985 · see citing works
Self-citationMultidisciplinary biopsychosocial rehabilitation for chronic low back pain
Kamper, S. J., Apeldoorn, A. T., Chiarotto, A., Smeets, R. J. E. M., Ostelo, R. W., Guzman, J., & van Tulder, M. W. (2014) · Cochrane Database of Systematic Reviews · doi:10.1002/14651858.cd000963.pub3 · Cited by 629 · see citing works
“Best Practice” for Patient-Centered Communication: A Narrative Review
King, A., & Hoppe, R. B. (2013) · Journal of Graduate Medical Education · doi:10.4300/jgme-d-13-00072.1 · Cited by 588 · see citing works
Fersum, K. V., O’Sullivan, P., Skouen, J. S., Smith, A. J., & Kvåle, A. (2012) · European Journal of Pain · doi:10.1002/j.1532-2149.2012.00252.x · Cited by 472 · see citing works
Self-citationO’Sullivan, P., Cañeiro, J. P., O’Keeffe, M., Smith, A. J., Dankaerts, W., Fersum, K. V., & O’Sullivan, K. (2018) · Physical Therapy · doi:10.1093/ptj/pzy022 · Cited by 442 · see citing works
Self-citationSynnott, A., O’Keeffe, M., Bunzli, S., Dankaerts, W., O'Sullivan, P., & O'Sullivan, K. (2015) · Journal of Physiotherapy · doi:10.1016/j.jphys.2015.02.016 · Cited by 412 · see citing works
Self-citationPatient-centred communication is associated with positive therapeutic alliance: a systematic review
Pinto, R. Z., Ferreira, M. L., Oliveira, V. C., Franco, M. R., Adams, R. D., Maher, C. G., & Ferreira, P. H. (2012) · Journal of physiotherapy · doi:10.1016/s1836-9553(12)70087-5 · Cited by 391 · see citing works
Guidelines: The do’s, don’ts and don’t knows of feedback for clinical education.
Lefroy, J., Watling, C., Teunissen, P. W., & Brand, P. (2015) · Perspectives on Medical Education · doi:10.1007/s40037-015-0231-7 · Cited by 347 · see citing works
Feedback: An essential element of student learning in clinical practice
Clynes, M. P., & Raftery, S. (2008) · Nurse Education in Practice · doi:10.1016/j.nepr.2008.02.003 · Cited by 340 · see citing works
Foster, N. E., & Delitto, A. (2011) · Physical Therapy · doi:10.2522/ptj.20100326 · Cited by 290 · see citing works
Alexanders, J., & Douglas, C. C. (2016) · Physical Therapy Reviews · doi:10.1080/10833196.2016.1274352 · Cited by 243 · see citing works
Ostelo, R., den Berg, S. G. M. S., Vlaeyen, J. W. S., Wolters, P. M. J. C., & de Vet, H. C. W. (2003) · Manual Therapy · doi:10.1016/s1356-689x(03)00013-4 · Cited by 224 · see citing works
Foster, N. E., Hill, J. C., O’Sullivan, P., & Hancock, M. J. (2013) · Best Practice & Research Clinical Rheumatology · doi:10.1016/j.berh.2013.10.005 · Cited by 194 · see citing works
Self-citationUnraveling the Complexity of Low Back Pain
O’Sullivan, P., Cañeiro, J. P., O’Keeffe, M., & O’Sullivan, K. (2016) · Journal of Orthopaedic and Sports Physical Therapy · doi:10.2519/jospt.2016.0609 · Cited by 180 · see citing works
Self-citationSanders, T., Foster, N. E., Bishop, A., & Ong, B. N. (2013) · BMC Musculoskeletal Disorders · doi:10.1186/1471-2474-14-65 · Cited by 168 · see citing works
Psychological factors and treatment opportunities in low back pain
Pincus, T., & McCracken, L. M. (2013) · Best Practice & Research Clinical Rheumatology · doi:10.1016/j.berh.2013.09.010 · Cited by 144 · see citing works
Main, C. J., Sowden, G., Hill, J. C., Watson, P., & Hay, E. M. (2011) · Physiotherapy · doi:10.1016/j.physio.2011.03.003 · Cited by 126 · see citing works
Grieve's Modern Musculoskeletal Physiotherapy
Jull, G. A., Moore, A. P., & Falla, D. (2015) · Medical Entomology and Zoology · Cited by 126 · see citing works
Silva Guerrero, A. V., Maujean, A., Campbell, L., & Sterling, M. (2018) · The Clinical Journal of Pain · doi:10.1097/ajp.0000000000000601 · Cited by 116 · see citing works
Barriers and progress in the treatment of low back pain
Foster, N. E. (2011) · BMC Medicine · doi:10.1186/1741-7015-9-108 · Cited by 114 · see citing works
Overmeer, T., Boersma, K., Denison, E., & Linton, S. J. (2011) · Physical Therapy · doi:10.2522/ptj.20100079 · Cited by 94 · see citing works
O’Keeffe, M., Purtill, H., Kennedy, N., Conneely, M., Hurley, J. A., O’Sullivan, P., Dankaerts, W., & O’Sullivan, K. (2016) · Journal of Pain · doi:10.1016/j.jpain.2016.01.473 · Cited by 89 · see citing works
Self-citationExploring healthcare communication models in private physiotherapy practice
Hiller, A., Guillemin, M. N., & Delany, C. M. (2015) · Patient Education and Counseling · doi:10.1016/j.pec.2015.07.029 · Cited by 86 · see citing works
Zangoni, G., & Thomson, O. P. (2016) · Musculoskeletal Science and Practice · doi:10.1016/j.msksp.2016.12.015 · Cited by 81 · see citing works
Synnott, A., O’Keeffe, M., Bunzli, S., Dankaerts, W., O’Sullivan, P., Robinson, K., & O’Sullivan, K. (2016) · Journal of physiotherapy · doi:10.1016/j.jphys.2016.08.002 · Cited by 79 · see citing works
Self-citationA Cross-cultural Study of the Back Pain Beliefs of Female Undergraduate Healthcare Students
Burnett, A., Sze, C. C., Tam, S. M., Yeung, K. M., Leong, M., Wang, W. T., Tan, B.-K., & O’Sullivan, P. (2008) · Clinical Journal of Pain · doi:10.1097/ajp.0b013e3181805a1e · Cited by 71 · see citing works
Self-citationBérubé, M., Poitras, S., Bastien, M., Laliberté, L.-A., Lacharité, A., & Gross, D. P. (2017) · Physiotherapy · doi:10.1016/j.physio.2017.05.002 · Cited by 66 · see citing works
Ali, N., & Thomson, D. (2008) · European Journal of Pain · doi:10.1016/j.ejpain.2008.02.005 · Cited by 49 · see citing works
The Attitudes to Back Pain Scale in Musculoskeletal Practitioners (ABS-mp)
Pincus, T., Vogel, S. K., Santos, R., Breen, A. C., Foster, N. E., & Underwood, M. R. (2006) · Clinical Journal of Pain · doi:10.1097/01.ajp.0000178223.85636.49 · Cited by 48 · see citing works
Jacobs, C. M., Guildford, B. J., Travers, W., Davies, M., & McCracken, L. M. (2015) · British Journal of Pain · doi:10.1177/2049463715600460 · Cited by 42 · see citing works
Implementing change in physiotherapy: professions, contexts and interventions
Sanders, T., Ong, B. N., Sowden, G., & Foster, N. E. (2014) · Journal of Health Organization and Management · doi:10.1108/jhom-10-2011-0102 · Cited by 40 · see citing works
Walsh, D. A. (2017) · Lara D. Veeken · doi:10.1093/rheumatology/kex060.083 · Cited by 40 · see citing works
Intricacies of good communication in the context of pain
Linton, S. J. (2015) · Pain · doi:10.1097/01.j.pain.0000460297.25831.67 · Cited by 35 · see citing works
Bostick, G. P. (2017) · The Spine Journal · doi:10.1016/j.spinee.2017.07.006 · Cited by 31 · see citing works
Heaney, C., Green, A. J. K., Rostron, C. L., & Walker, N. (2012) · Journal of Physical Therapy Education · doi:10.1097/00001416-201207000-00007 · Cited by 30 · see citing works
Motivational interviewing in musculoskeletal care
Shannon, R., & Hillsdon, M. M. (2007) · Musculoskeletal Care · doi:10.1002/msc.119 · Cited by 19 · see citing works
Therapy talk : conversation analysis in practice
Fitzgerald, P. E. (2013) · Cited by 14 · see citing works
Kalra, R., Modi, J. N., & Vyas, R. (2015) · International Journal of Applied and Basic Medical Research · doi:10.4103/2229-516x.162256 · Cited by 12 · see citing works
Conversation Analysis and Psychotherapy
Fitzgerald, P. E. (2013) · Palgrave Macmillan UK eBooks · doi:10.1057/9781137329530_3 · Cited by 8 · see citing works
Flagged first, then by citations
Cited by
Sorted by citations
A critical review of the biopsychosocial model of low back pain care: time for a new approach?
Mescouto, K. A., Olson, R. E., Hodges, P. W., & Setchell, J. (2020) · Disability and Rehabilitation · doi:10.1080/09638288.2020.1851783 · Cited by 259 · see citing works
Holopainen, R., Simpson, P., Piirainen, A., Karppinen, J., Schütze, R., Smith, A., O'Sullivan, P., & Kent, P. (2020) · Pain · doi:10.1097/j.pain.0000000000001809 · Cited by 180 · see citing works
“This new understanding led to critical reflection of current practices, and a changed view of how pain should be managed.(3,16,34,52,65)”
BackgroundMethodResultInfluentialSelf-citationLeaviss, J., Davis, S., Ren, S., Hamilton, J., Scope, A., Booth, A., Sutton, A., Parry, G. D., Buszewicz, M., Moss-Morris, R. E., et al. (2020) · Health Technology Assessment · doi:10.3310/hta24460 · Cited by 67 · see citing works
From Fear to Safety: A Roadmap to Recovery From Musculoskeletal Pain
Cañeiro, J. P., Smith, A. J., Bunzli, S., Linton, S. J., Moseley, G. L., & O’Sullivan, P. (2021) · Physical Therapy · doi:10.1093/ptj/pzab271 · Cited by 66 · see citing works
Self-citationKinney, A. R., Stearns‐Yoder, K. A., Hoffberg, A. S., Middleton, A., Weaver, J., Roseen, E. J., Juckett, L., & Brenner, L. A. (2023) · Archives of Physical Medicine and Rehabilitation · doi:10.1016/j.apmr.2023.03.005 · Cited by 41 · see citing works
Holopainen, R., Piirainen, A., Karppinen, J., Linton, S., & O'Sullivan, P. (2020) · Physiotherapy Theory and Practice · doi:10.1080/09593985.2020.1753271 · Cited by 27 · see citing works
Self-citationScope, A., Leaviss, J., Booth, A., Sutton, A., Parry, G., Buszewicz, M., & Moss‐Morris, R. (2021) · British Journal of Health Psychology · doi:10.1111/bjhp.12521 · Cited by 18 · see citing works
Krug, R. C., Cañeiro, J. P., Ribeiro, D. C., Darlow, B. J. S., Silva, M. F., & Loss, J. F. (2020) · Brazilian Journal of Physical Therapy · doi:10.1016/j.bjpt.2020.07.001 · Cited by 28 · see citing works
Driver, C., Oprescu, F., & Lovell, G. P. (2020) · Musculoskeletal Care · doi:10.1002/msc.1437 · Cited by 25 · see citing works
Cowell, I., McGregor, A., O’Sullivan, P., O’Sullivan, K., Poyton, R., Schoeb, V., & Murtagh, G. (2021) · Qualitative Health Research · doi:10.1177/10497323211037651 · Cited by 22 · see citing works
Self-citationDriver, C., Lovell, G. P., & Oprescu, F. (2020) · Nursing and Health Sciences · doi:10.1111/nhs.12771 · Cited by 18 · see citing works
Simpson, P., Holopainen, R., Schütze, R., O’Sullivan, P., Smith, A. J., & Kent, P. M. (2022) · Physiotherapy Theory and Practice · doi:10.1080/09593985.2022.2151333 · Cited by 15 · see citing works
Self-citationAdje, M., Steinhäuser, J., Stevenson, K., Mbada, C. E., & Karstens, S. (2022) · BMJ Open · doi:10.1136/bmjopen-2021-059736 · Cited by 14 · see citing works
Babatunde, F. O., MacDermid, J., Grewal, R., Macedo, L., & Szekeres, M. (2020) · JMIR Human Factors · doi:10.2196/17088 · Cited by 12 · see citing works
“…and efficacious delivery of web-based CBT using nontraditional health professionals such as physiotherapists (PTs) and occupational therapists (OTs) [45], with reduced time commitment and treatment costs, and positive self-reported changes in the PTs’ attitudes, confidence, and practice [46-48].”
McGrath, R. L., Parnell, T., Verdon, S. E., MacDonald, J. B., & Smith, M. (2020) · PLoS ONE · doi:10.1371/journal.pone.0238884 · Cited by 12 · see citing works
van der Scheer‐Horst, E. S., Rutten, G. M., Stortenbeker, I. A., Borkent, J. W., Swormink, W. K., Das, E. H. H. J., Staal, J. B., & van Lankveld, W. (2023) · Patient Education and Counseling · doi:10.1016/j.pec.2023.107624 · Cited by 12 · see citing works
Gardner, C., Moseley, G. L., Karran, E. L., Wiles, L., & Hibbert, P. D. (2020) · Canadian Journal of Pain · doi:10.1080/24740527.2020.1732808 · Cited by 11 · see citing works
The use of a biopsychosocial model in the treatment of patients with chronic
Almeida, V. C., Pereira, L. C. D., Machado, S. D. C., Maciel, L. Y. D. S., Neto, J. P. D. F., & Santana‐Filho, V. J. (2023) · Patient Education and Counseling · doi:10.1016/j.pec.2023.108117 · Cited by 12 · see citing works
Vanderstraeten, R., Fourré, A., Demeure, I., Demoulin, C., Michielsen, J., Anthierens, S., Bastiaens, H., & Roussel, N. A. (2023) · International Journal of Environmental Research and Public Health · doi:10.3390/ijerph20105828 · Cited by 8 · see citing works
Maddigan, K., Davis, C., Saville, B., Nishimura, K., Bussel, J. V., Tawiah, A. K., Kowalski, K. L., & Rushton, A. B. (2025) · PLoS ONE · doi:10.1371/journal.pone.0322626 · Cited by 8 · see citing works
Fragility and Back Pain: Lessons From the Frontiers of Biopsychosocial Practice
Nicholls, D. A. (2023) · Physical Therapy · doi:10.1093/ptj/pzad040 · Cited by 8 · see citing works
Singh, G., McNamee, G., Sharpe, L., Lucas, M., Lewis, P. J., Newton, C., O’Sullivan, P., Lin, I. B., & O’Sullivan, K. (2021) · European Journal of Physiotherapy · doi:10.1080/21679169.2021.1950208 · Cited by 7 · see citing works
Self-citationBogaert, L., Brumagne, S., Léonard, C., Lauwers, A., & Peters, S. (2024) · Musculoskeletal Science and Practice · doi:10.1016/j.msksp.2024.103129 · Cited by 6 · see citing works
Cowell, I., McGregor, A. H., O’Sullivan, P., O’Sullivan, K., Poyton, R., & Murtagh, G. (2023) · Musculoskeletal Science and Practice · doi:10.1016/j.msksp.2023.102797 · Cited by 6 · see citing works
Self-citationMingels, S., Granitzer, M., Luedtke, K., & Dankaerts, W. (2024) · Current Pain and Headache Reports · doi:10.1007/s11916-024-01306-7 · Cited by 5 · see citing works
Browne, A., Cahalan, R., & O’Sullivan, K. (2024) · PLoS ONE · doi:10.1371/journal.pone.0305931 · Cited by 5 · see citing works
Self-citationPaukkunen, M., Holopainen, R., Öberg, B. E., Ala‐Mursula, L., Karppinen, J. I., Elo, S., & Abbott, A. D. (2025) · BMC Health Services Research · doi:10.1186/s12913-025-13267-7 · Cited by 4 · see citing works
Klausen, M. D., Lindberg, L., Johansen, S. K., Rathleff, M. S., & Lyng, K. D. (2025) · Musculoskeletal Care · doi:10.1002/msc.70108 · Cited by 3 · see citing works
Newton, C., Singh, G., Nolan, D., Booth, V., Diver, C. J., O’Neill, S., Purtill, H., Logan, P., O’Sullivan, K., & O’Sullivan, P. (2024) · Physiotherapy · doi:10.1016/j.physio.2024.02.003 · Cited by 3 · see citing works
Self-citationRonchi, M., Dognini, S., Giusti, E., & Maggiani, A. (2026) · International journal of osteopathic medicine · doi:10.1016/j.ijosm.2026.100835 · Cited by 2 · see citing works
Simpson, P., Holopainen, R., Schütze, R., O’Sullivan, P., Kent, P. M., Klem, N.-R., & Smith, A. J. (2025) · Disability and Rehabilitation · doi:10.1080/09638288.2025.2495199 · Cited by 2 · see citing works
Self-citationPsychological and behavioural interventions delivered by non-psychologists
Main, C. J., Ballengee, L. A., & Beneciuk, J. M. (2025) · Current Opinion in Psychology · doi:10.1016/j.copsyc.2025.102008 · Cited by 1 · see citing works
Gava, V., Eugênio, J. M. D. S., Meziat‐Filho, N., Almeida, L. A., Maciel, D. G., do Nascimento, J. D. S., de Andrade, P. R., Fonseca, R. N. S., Barbosa, G. M., de Oliveira, V. M. A., et al. (2025) · PLoS ONE · doi:10.1371/journal.pone.0320025 · Cited by 1 · see citing works
Kandeel, M. K., Morsy, M. A., Alkhodair, K. M., & Alhojaily, S. (2024) · Journal of Back and Musculoskeletal Rehabilitation · doi:10.3233/bmr-240230 · Cited by 1 · see citing works
Klausen, M. D., Lindberg, L., Johansen, S. K., Rathleff, M. S., & Lyng, K. D. (2025) · medRxiv · doi:10.1101/2025.01.22.25320947 · Cited by 1 · see citing works
Naye, F., Décary, S., & Tousignant‐Laflamme, Y. (2024) · doi:10.22541/au.170664868.85110090/v1
Beetsma, A. J., Reezigt, R. R., van Dam, S. J., Hobbelen, H. J. S. M., & Reneman, M. F. (2026) · Journal of Physical Therapy Education · doi:10.1097/jte.0000000000000473
Davis, L., Olivier, B., Jacobs, L., & Lord, S. (2026) · South African Journal of Physiotherapy · doi:10.4102/sajp.v82i1.2264
Dickson, C., de Zoete, R. M. J., Berryman, C., Weinstein, P., Didyk, C., Chen, K. K., & Rothmore, P. (2026) · Disability and Rehabilitation · doi:10.1080/09638288.2026.2661156
Zakariyah, M. F., Nugroho, R., Lestari, G. D., & Alisyahbana, I. B. (2026) · International journal of osteopathic medicine · doi:10.1016/j.ijosm.2026.100863
- Authors
- Cowell, I., O'Sullivan, P., O'Sullivan, K., Poyton, R., McGregor, A., & Murtagh, G.
- Affiliations
- Imperial College London (GB)
- School of Physiotherapy and Exercise Science Curtin University Perth WA Australia
- School of Allied Health University of Limerick Limerick Ireland
- Corresponding author
- Cowell, Ian
- Venue
- Musculoskeletal Care
- Publisher
- Wiley
- Published
- 2018-11-23
- Volume
- 17
- Issue
- 1
- Pages
- 79-90
- ISSN
- 1478-2189 (ISSN-L)
- 1557-0681
- OpenAlex
- W2900883344
- Cited by
- 41
- References
- 44
- Citations by year
- 2026: 5 · 2025: 7 · 2024: 6 · 2023: 6 · 2022: 3 · 2021: 4 · 2020: 10
- FWCI
- 2.26
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Musculoskeletal Care (publishedVersion)
- PubMed (publishedVersion)
- Spiral (Imperial College London) (submittedVersion)
- Funders
- Musculoskeletal Association of Chartered Physiotherapists (Doctoral award)
- Private Physiotherapy Educational Foundation (164)
- Topics
- Health Sciences › Medicine › Pharmacology › Musculoskeletal pain and rehabilitation
- Health Sciences › Health Professions › General Health Professions › Health Policy Implementation Science
- Health Sciences › Medicine › Rehabilitation › Musculoskeletal Disorders and Rehabilitation
- Keywords
- cognitive functional therapy, chronic non-specific low back pain, physiotherapists, training program, biopsychosocial model, primary care, clinician attitudes, clinician confidence, clinician-patient communication, implementation barriers
- MeSH terms
- Adult, Clinical Competence, Female, Humans, Health Knowledge, Attitudes, Practice, London, Male, Cognitive Behavioral Therapy, Low Back Pain, Qualitative Research, Physical Therapists
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