The Clinical Research And Practice Podcast

Is the satisfying “crack” during a spinal adjustment just a harmless pop—or something more profound?

In this episode, we dive deep into the mechanics, neuroscience, clinical evidence, and controversies surrounding spinal manipulation therapy. Whether you’re someone who swears by your chiropractor, a skeptical healthcare professional, or just curious about the science behind that famous pop, this episode is for you.

We'll explore:

• The biomechanics behind spinal cavitation (what actually causes the crack?),
• How spinal manipulation affects the nervous and endocrine systems, including hormonal, neurochemical, and sensory changes,
• What the clinical evidence says—and what it doesn’t—about managing low back pain, neck pain, migraines, and more,
• Risks, including rare but serious complications like vertebral artery dissection,
• And where research is heading in a field still hotly debated by clinicians and scientists alike.

We reference over 40 peer-reviewed studies to help clarify the murky waters of clinical outcomes, brain responses, patient safety, and evidence-based practice. You'll hear findings from landmark trials, global consensus reviews, and biochemical investigations—all presented in an accessible, conversational format.

So whether you're lying face down on a treatment table or standing in a lecture hall, this episode will give you a 360-degree view of one of the most polarizing tools in manual therapy.

Let's dive into the often-controversial topic of posture. This episode will introduce a brief history of posture and provide some insight into where much of the interest in posture began. When we explore the history we can understand why some of the beliefs held and shared by many today are still so prevalent, and why that dead horse' continues to be beaten. Come with me and let's pick this one apart.

Is bending your back when you lift really dangerous? Are “straight-back” lifting rules helping us—or hurting us?

In this episode, we take a deep dive into the science behind lifting technique and low back pain. You’ll hear what decades of research say about spinal flexion, fear-based movement, and why the “lift with your legs, not your back” advice may be more myth than medicine.

We explore what actually increases injury risk, why pain-free people fear round-back lifting, and how clinicians can move away from rigid rules toward adaptable, confident movement strategies.

Whether you're a health professional, patient, athlete—or just someone who wants to stop fearing lifting this episode is for you.

References

Caneiro, J., O’Sullivan, P., Lipp, O. V., Mitchinson, L., Oeveraas, N., Bhalvani, P., Abrugiato, R., Thorkildsen, S., & Smith, A. (2018). Evaluation of implicit associations between back posture and safety of bending and lifting in people without pain. Scandinavian Journal of Pain, 18(4), 719-728. 

Coenen, P., Gouttebarge, V., Van der Burght, A. S., Van Dieën, J. H., Frings-Dresen, M. H., Van der Beek, A. J., & Burdorf, A. (2014). The effect of lifting during work on low back pain: A health impact assessment based on a meta-analysis. Occupational and Environmental Medicine, 71(12), 871-877. 

Martimo, K., Verbeek, J., Karppinen, J., Furlan, A. D., Takala, E., Kuijer, P. P., Jauhiainen, M., & Viikari-Juntura, E. (2008). Effect of training and lifting equipment for preventing back pain in lifting and handling: Systematic review. BMJ, 336(7641), 429-431. 

Mawston, G., Holder, L., O’Sullivan, P., & Boocock, M. (2021). Flexed lumbar spine postures are associated with greater strength and efficiency than lordotic postures during a maximal lift in pain-free individuals. Gait & Posture, 86, 245-250. 

Nolan, D., O'Sullivan, K., Newton, C., Singh, G., & Smith, B. (2020). Are there differences in lifting technique between those with and without low back pain? A systematic review. Physiotherapy, 107, e76. 

Saraceni, N., Campbell, A., Kent, P., Ng, L., Straker, L., & O’Sullivan, P. (2021). Exploring lumbar and lower limb kinematics and kinetics for evidence that lifting technique is associated with LBP. PLOS ONE, 16(7), e0254241. 

Smith, K., & Thomson, O. P. (2020). What do UK osteopaths view as the safest lifting posture, and how are these views influenced by their back pain beliefs? International Journal of Osteopathic Medicine, 37, 10-16. 

Von Arx, M., Liechti, M., Connolly, L., Bangerter, C., Meier, M. L., & Schmid, S. (2021). From stoop to squat: A comprehensive analysis of lumbar loading among different lifting styles. Frontiers in Bioengineering and Biotechnology, 9. 

Washmuth, N. B., McAfee, A. D., & Bickel, C. S. (2022). Lifting techniques: Why are we not using evidence to optimize movement? International Journal of Sports Physical Therapy, 17(1). 

Neck pain and posture are frequently linked in many conversations regarding origin or recurrence of neck pain, in desk ergonomics and workplace health education. 

This episode looks into the literature examining the relationship between neck pain and postures involving the head, neck, and shoulder girdle. 

-       Does posture relate to neck pain

-       Is there such a thing as text neck

-       Does correcting posture reduce neck pain?

-       If not posture, then what factors predict neck pain?

Let's see if we can answer these questions...


References

Bement, M. H. (2008). Faculty opinions recommendation of effect of two contrasting types of physical exercise on chronic neck muscle pain. Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature. https://doi.org/10.3410/f.1099466.555735

Damasceno, G. M., Ferreira, A. S., Nogueira, L. A., Reis, F. J., Andrade, I. C., & Meziat-Filho, N. (2018). Text neck and neck pain in 18–21-year-old young adults. European Spine Journal, 27(6), 1249-1254. https://doi.org/10.1007/s00586-017-5444-5

Falla, D., Jull, G., Russell, T., Vicenzino, B., & Hodges, P. (2007). Effect of neck exercise on sitting posture in patients with chronic neck pain. Physical Therapy, 87(4), 408-417. https://doi.org/10.2522/ptj.20060009

Grob, D., Frauenfelder, H., & Mannion, A. F. (2006). The association between cervical spine curvature and neck pain. European Spine Journal, 16(5), 669-678. https://doi.org/10.1007/s00586-006-0254-1

Hush, J. M., Michaleff, Z., Maher, C. G., & Refshauge, K. (2009). Individual, physical and psychological risk factors for neck pain in Australian office workers: A 1-year longitudinal study. European Spine Journal, 18(10), 1532-1540. https://doi.org/10.1007/s00586-009-1011-z

Jahre, H., Grotle, M., Småstuen, M., Guddal, M. H., Smedbråten, K., Richardsen, K. R., Stensland, S., Storheim, K., & Øiestad, B. E. (2021). Risk factors and risk profiles for neck pain in young adults: Prospective analyses from adolescence to young adulthood—The north-trøndelag health study. PLOS ONE, 16(8), e0256006. https://doi.org/10.1371/journal.pone.0256006

Kim, D., Cho, M., Park, Y., & Yang, Y. (2015). Effect of an exercise program for posture correction on musculoskeletal pain. Journal of Physical Therapy Science, 27(6), 1791-1794. https://doi.org/10.1589/jpts.27.1791

Kim, R., Wiest, C., Clark, K., Cook, C., & Horn, M. (2018). Identifying risk factors for first-episode neck pain: A systematic review. Musculoskeletal Science and Practice, 33, 77-83. https://doi.org/10.1016/j.msksp.2017.11.007

Lee, M., Park, S., & Kim, J. (2013). Effects of neck exercise on high-school students’ neck–shoulder posture. Journal of Physical Therapy Science, 25(5), 571-574. https://doi.org/10.1589/jpts.25.571

Louw, S., Makwela, S., Manas, L., Meyer, L., Terblanche, D., & Brink, Y. (2017). Effectiveness of exercise in office workers with neck pain: A systematic review and meta-analysis. South African Journal of Physiotherapy, 73(1). https://doi.org/10.4102/sajp.v73i1.392

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Posture is a widely discussed and debated topic. The workplace, health ad safety, and medical industries have all played a role in the current societal beliefs about posture. This episode aims to identify the origins of the current posture beliefs and explore whether the research supports these beliefs.

References:

Andias, R., & Silva, A. G. (2019). A systematic review with meta‐analysis on functional changes associated with neck pain in adolescents. Musculoskeletal Care, 17(1), 23-36. https://doi.org/10.1002/msc.1377

Dankaerts, W., OʼSullivan, P., Burnett, A., & Straker, L. (2006). Differences in sitting postures are associated with Nonspecific chronic low back pain disorders when patients are Subclassified. Spine, 31(6), 698-704. https://doi.org/10.1097/01.brs.0000202532.76925.d2

De Carvalho, D. E., De Luca, K., Funabashi, M., Breen, A., Wong, A. Y., Johansson, M. S., Ferreira, M. L., Swab, M., Neil Kawchuk, G., Adams, J., & Hartvigsen, J. (2020). Association of exposures to seated postures with immediate increases in back pain: A systematic review of studies with objectively measured sitting time. Journal of Manipulative and Physiological Therapeutics, 43(1), 1-12. https://doi.org/10.1016/j.jmpt.2019.10.001

Gong, H., Sun, L., Yang, R., Pang, J., Chen, B., Qi, R., Gu, X., Zhang, Y., & Zhang, T. (2019). Changes of upright body posture in the sagittal plane of men and women occurring with aging – a cross sectional study. BMC Geriatrics, 19(1). https://doi.org/10.1186/s12877-019-1096-0

Hush, J. M., Michaleff, Z., Maher, C. G., & Refshauge, K. (2009). Individual, physical and psychological risk factors for neck pain in Australian office workers: A 1-year longitudinal study. European Spine Journal, 18(10), 1532-1540. https://doi.org/10.1007/s00586-009-1011-z

Lederman, E. (2011). The fall of the postural-structural-biomechanical model in manual and physical therapies: Exemplified by lower back pain. Journal of Bodywork and Movement Therapies, 15(2), 131-138. https://doi.org/10.1016/j.jbmt.2011.01.011

Mahmoud, N. F., Hassan, K. A., Abdelmajeed, S. F., Moustafa, I. M., & Silva, A. G. (2019). The relationship between forward head posture and neck pain: A systematic review and meta-analysis. Current Reviews in Musculoskeletal Medicine, 12(4), 562-577. https://doi.org/10.1007/s12178-019-09594-y

O’Sullivan, P. B., Dankaerts, W., Burnett, A. F., Farrell, G. T., Jefford, E., Naylor, C. S., & O’Sullivan, K. J. (2006). Effect of different upright sitting postures on spinal-pelvic curvature and trunk muscle activation in a pain-free population. Spine, 31(19), E707-E712. https://doi.org/10.1097/01.brs.0000234735.98075.50

Richards, K. V., Beales, D. J., Smith, A. J., O'Sullivan, P. B., & Straker, L. M. (2016). Neck posture clusters and their association with biopsychosocial factors and neck pain in Australian adolescents. Physical Therapy, 96(10), 1576-1587. https://doi.org/10.2522/ptj.20150660

Silva, A. G., Punt, T. D., Sharples, P., Vilas-Boas, J. P., & Johnson, M. I. (2009). Head posture and neck pain of chronic nontraumatic origin: A comparison between patients and pain-free persons. Archives of Physical Medicine and Rehabilitation, 90(4), 669-674.

It's a topic that comes up a lot in clinical practice......should you use ice/cold or heat? Whether you are an elite athlete, weekend sports-person, or you suffer from occasional aches and pains, this information may be useful to you in deciding which is best to apply.
 In this episode I summarise what the research says about the effects of heat or cold, as well as how and when to use each.
 
 
Algafly, A. A., & George, K. P. (2007). The effect of cryotherapy on nerve conduction velocity, pain threshold and pain tolerance. Br J Sports Med, 41(6), 365-9; discussion 369. doi:10.1136/bjsm.2006.031237

Benson TB , Copp EP: The effects of therapeutic forms of heat and ice on the pain threshold of the normal shoulder. Rhematology and Rehabilitation. 1975. 13:100-104.

Bleakley, C. M., McDonough, S. M., MacAuley, D. C., & Bjordal, J. (2006). Cryotherapy for acute ankle sprains: a randomised controlled study of two different icing protocols. Br J Sports Med, 40(8), 700-5; discussion 705. doi:10.1136/bjsm.2006.025932

Bleakley, C. M., O’Connor, S. R., Tully, M. A., Rocke, L. G., Macauley, D. C., Bradbury, I., . . . McDonough, S. M. (2010). Effect of accelerated rehabilitation on function after ankle sprain: randomised controlled trial. BMJ, 340, c1964. doi:10.1136/bmj.c1964

Bleakley CM, Glasgow P, MacAuley DC. PRICE needs updating, should we call the POLICE? Br J Sports Med 2012. 46(4):220–1

Ewell, M., Griffin, C., & Hull, J. (2014). The use of focal knee joint cryotherapy to improve functional outcomes after total knee arthroplasty: review article. PM R, 6(8), 729-738. doi:10.1016/j.pmrj.2014.02.004

French SD, Cameron M, Walker FB, et al: Superficial heat or cold for low back pain, Cochrane Database Syst Rev. 2006. (1): CD004750

Hubbard TJ., Denegar CR. Does cryotherapy improve outcomes with soft tissue injury? Journal of Athletic Training. 2004. 39(3): 278-279

Malanga, G. A., Yan, N., & Stark, J. (2015). Mechanisms and efficacy of heat and cold therapies for musculoskeletal injury. Postgrad Med, 127(1), 57-65. 
 
Paddington-Jones DJ, Quigley BM. Effect of Cryotherapy on muscle soreness and strength following eccentric exercise. Int J Sports Med. 1997. 18:588-193
 
Peake JM, Roberts LA, Figueiredo VC, Egner I, Krog S, Aas SN, Suzuki K, Markworth JF, Coombes JS, Cameron-Smith D, Raastad T. The effects of cold water immersion and active recovery on inflammation and cell stress responses in human skeletal muscle after resistance exercise. Journal of Physiology. 2017. 595(3):695-711
 
Rutkove SB. Effects of temperature on neuromuscular electrophysiology. Muscle Nerve. 2001. 24: 867-882
 
Sloan JP, Hain R, Pownall R. Clinical benefits of early cold therapy in accident and emergency following ankle sprain. Arch Emerg Med. 1989;6:1–6
 
Taber C., Countryman K., Fhrenbruch J., et al. Measurement of reactive vasodilation during cold gel pack application to non-traumatized ankles. Physical Therapy 1992. 72:294-299
 
Tseng CY, Lee JP, Tsai YS, Lee SD, Kao CL, Liu TC, Lai C, Harris MB, Kuo CH. Topical cooling (icing) delays recovery from eccentric exercise-induced muscle damage. J Strength Cond Res. 2013 May. 27(5):1354-61.

Whether you use joint manipulation/adjustments/HVLA techniques or have had them done, you have probably asked "what actually makes the popping or cracking sound?"
 
 In this episode I delve into the research we currently have available and see if we can come up with an answer to that question
 
 Brodeur R. The audible release associated with joint manipulation. Journal of Manipulative and Physiological Therapeutics. 1995;18(3):155-64.

Cascioli, V., Corr, P., & Till Ag, A. G. (2003). An investigation into the production of intra-articular gas bubbles and increase in joint space in the zygapophyseal joints of the cervical spine in asymptomatic subjects after spinal manipulation. Journal of manipulative and physiological therapeutics, 26(6), 356–364. https://doi.org/10.1016/S0161-4754(03)00075-7

Kawchuk GN, Fryer J, Jaremko JL, Zeng H, Rowe L, Thompson R (2015) Real-Time Visualization of Joint Cavitation. PLoS ONE 10(4): e0119470. https://doi.org/10.1371/journal.pone.0119470

Unsworth, A., Dowson, D., & Wright, V. (1971). 'Cracking joints'. A bioengineering study of cavitation in the metacarpophalangeal joint. Annals of the rheumatic diseases, 30(4), 348–358. https://doi.org/10.1136/ard.30.4.348

The sacroiliac joint (and pelvis as a whole) is a popular area of focus for Osteopaths in training and in practice. We are taught to palpate, examine, and diagnose 'sacroiliac joint dysfunctions' and 'sacral torsions', but is there any evidence that these assessment methods are reliable or valid? 
 We'll discuss the assessments used, the reasoning behind them and their place in clinical practice, and we'll pick apart some research investigating these concepts.
 Come with me as I walk through some of the research findings related to this question.