What you may never have been taught in school about pain

            Over the last 5 years the popularity of pain science has exploded in the health & fitness industries. However, pain science has been around for decades, and many education systems & professional organizations have been slow to adopt and teach pain it. I’m involved with both Western University’s Physical Therapy curriculum and with the University of Waterloo’s Kinesiology program – so I understand how hard it is and how long it takes to make big changes to the educational curriculum. However, many health & fitness professionals are undereducated and misinformed about pain often to the detriment of themselves and their clients.

            The purpose of this article is not to bash the education system but to provide health & fitness professionals (PTs, Chiros, Trainers, Kins, Strength Coaches, MDs and the like) a better understanding of pain.

So without further ado here are a few things that you may not have been taught in school about pain

1) Pain doesn’t always equate to injury or damage

The old Descartes’ model of pain stated that an injury caused a signal to go up to the brain that caused pain. This in many ways is still how people view pain.

However – a large body of research shows that many individuals with no signs or symptoms (within scientific literature this is referred to as “asymptomatic”) have abnormal imaging findings in their knees, hips, back and shoulders. For example:

·         85% of adults without knee pain have knee arthritis on X-Ray¹

·         35% of adults without shoulder pain have full or partial thickness rotator cuff tears on MRI²

·         Even 40% of professional baseball players have rotator cuff tears yet have no pain while playing³!!!

·         Approximately 20-40% of adults aged 20-40 show some form of disc herniation on CT or MRI but walk around without pain⁴

Now to be fair

·         Some research does show a correlation between X-ray findings and symptoms in knee osteoarthritis – although this research is very conflicting⁵

·         Some research shows that patellar & achilles tendon changes on imaging can predict future tendinopathy⁶

·         Some research shows that some MRI findings are more common in people with back pain than in people without back pain⁷

This means, in summary, that tissue injury can still be relevant but it certainly isn’t the sole predictor of pain. Pain is an output of the nervous system in response to threat and can be influenced by many factors (see below).

2) Biomechanics aren’t the sole factor involved in pain

An old model of pain claimed that pain was solely due to postural, structural, and biomechanical abnormalities. Some biomechanical risk factors, such as dynamic knee valgus and ACL injury⁸, are relevant to pain & injury. We know now that pain can be modulated by various biological, psychosocial, and sociological factors.

Biological factors can include

·         Tissue injury and tissue stress (see above)

·         Lack of sleep^9–12

·         Neurological factors such as

o    Decreased or increased pain modulation by the nervous system

o    Changes in the nervous system that can make it more sensitive to inputs ^13,14

Psychosocial factors can include

·         Stress

·         Anxiety

·         Depression

·         Fear avoidance (avoidance of activity due to fear of pain or injury)

·         Kinesiophobia (fear of movement not fear of Kinesiologists J )

·         Passive coping strategies

·         Poor social support

·         PTSD^15,16

Psychosocial factors don’t mean that “the pain is in your head” but they are big risk factors for chronic pain. The theory is that they make the nervous system more sensitive and increase activity of areas of the nervous system that are also involved in pain.

As such it’s important to understand how complex pain is.

3) The wording you use has a big impact on your clients

Going hand in hand with the above points – the way your clients feel about themselves and their pain (if applicable) can have a big impact on

·         Whether or not they experience pain and

·         How well they manage and/or recover from pain

When professionals use negative wording with their clients it can create a “nocebo” effect. Nocebo, the opposite of placebo, is when the expectation of harm causes pain even though nothing physical has happened ¹⁷.

Some examples of nocebo-like wording can include

·         “You have the knees of a 70 year old”

·         “You’re in pain because of poor posture”

·         “Your <insert muscle here> isn’t firing”

·         “Your movement is dysfunctional”

… and so on

Now many postural-structural-biomechanical “dysfunctions” don’t correlate that well with pain and/or can’t be assessed reliably but that’s another discussion for another time – and I will elaborate more on that in future articles about biomechanics, pain science, rehab, and training.

The key takeaway here is to use positive wording as much as possible with your clients to get the desired training/rehab effect while avoiding nocebos.

So to summarize this article

1) Tissue injury may be relevant to pain in some cases but pain doesn’t always mean injury

2) Pain is a lot more complex than biomechanics and is more related to a combination of biological, psychological and social factors

3) Use positive wording with your clients to empower them and avoid creating nocebos

REFERENCES

1.           Bedson J, Croft PR. The discordance between clinical and radiographic knee osteoarthritis: A systematic search and summary of the literature. BMC Musculoskelet Disord. 2008;9(1):116. doi:10.1186/1471-2474-9-116.

2.           Sher JS, Uribe JW, Posada A, Murphy BJ, Zlatkin MB. Abnormal findings on magnetic resonance images of asymptomatic shoulders. J Bone Joint Surg Am. 1995;77(1):10-15. http://www.ncbi.nlm.nih.gov/pubmed/7822341. Accessed June 30, 2017.

3.           Connor PM, Banks DM, Tyson AB, Coumas JS, D’Alessandro DF. Magnetic resonance imaging of the asymptomatic shoulder of overhead athletes: a 5-year follow-up study. Am J Sports Med. 31(5):724-727. doi:10.1177/03635465030310051501.

4.           Brinjikji W, Luetmer PH, Comstock B, et al. Systematic literature review of imaging features of spinal degeneration in asymptomatic populations. AJNR Am J Neuroradiol. 2015;36(4):811-816. doi:10.3174/ajnr.A4173.

5.           Neogi T, Felson D, Niu J, et al. Association between radiographic features of knee osteoarthritis and pain: results from two cohort studies. BMJ. 2009;339:b2844. http://www.ncbi.nlm.nih.gov/pubmed/19700505. Accessed June 30, 2017.

6.           McAuliffe S, McCreesh K, Culloty F, Purtill H, O’Sullivan K. Can ultrasound imaging predict the development of Achilles and patellar tendinopathy? A systematic review and meta-analysis. Br J Sports Med. 2016;50(24):1516-1523. doi:10.1136/bjsports-2016-096288.

7.           Brinjikji W, Diehn FE, Jarvik JG, et al. MRI Findings of Disc Degeneration are More Prevalent in Adults with Low Back Pain than in Asymptomatic Controls: A Systematic Review and Meta-Analysis. AJNR Am J Neuroradiol. 2015;36(12):2394-2399. doi:10.3174/ajnr.A4498.

8.           Hewett TE, Bates NA. Preventive Biomechanics. Am J Sports Med. February 2017:36354651668608. doi:10.1177/0363546516686080.

9.           Choy EHS. The role of sleep in pain and fibromyalgia. Nat Rev Rheumatol. 2015;11(9):513-520. doi:10.1038/nrrheum.2015.56.

10.         Bahouq H, Allali F, Rkain H, Hmamouchi I, Hajjaj-Hassouni N. Prevalence and severity of insomnia in chronic low back pain patients. Rheumatol Int. 2013;33(5):1277-1281. doi:10.1007/s00296-012-2550-x.

11.         Harrison L, Wilson S, Munafò MR. Exploring the associations between sleep problems and chronic musculoskeletal pain in adolescents: a prospective cohort study. Pain Res Manag. 19(5):e139-145. http://www.ncbi.nlm.nih.gov/pubmed/25299477. Accessed June 30, 2017.

12.         Kiri S, Laaksonen M, Rahkonen O, Lahelma E, Leino-Arjas P. Risk factors of chronic neck pain: A prospective study among middle-aged employees. Eur J Pain. 2012;16(6):911-920. doi:10.1002/j.1532-2149.2011.00065.x.

13.         Sandkuhler J. Models and Mechanisms of Hyperalgesia and Allodynia. Physiol Rev. 2009;89(2):707-758. doi:10.1152/physrev.00025.2008.

14.         van Wilgen CP, Keizer D. The sensitization model to explain how chronic pain exists without tissue damage. Pain Manag Nurs. 2012;13(1):60-65. doi:10.1016/j.pmn.2010.03.001.

15.         Innes SI. Psychosocial factors and their role in chronic pain: A brief review of development and current status. Chiropr Osteopat. 2005;13(1):6. doi:10.1186/1746-1340-13-6.

16.         Edwards RR, Dworkin RH, Sullivan MD, Turk DC, Wasan AD. The Role of Psychosocial Processes in the Development and Maintenance of Chronic Pain. J Pain. 2016;17(9):T70-T92. doi:10.1016/j.jpain.2016.01.001.

17.         Petersen GL, Finnerup NB, Colloca L, et al. The magnitude of nocebo effects in pain: A meta-analysis. Pain. 2014;155(8):1426-1434. doi:10.1016/j.pain.2014.04.016.