We've moved away from a fragility mindset towards a resilience mindset.
We have developed an awareness that movement competency, capacity and adaptability are cornerstones to good rehabilitation.
We understand that load adaptation and building load tolerance, stamina, and strength are key components to human health.
I love the topic of adaptation; so much so one of my favourite (personally delivered) presentations is this webinar for patients "Adaptable: Desigend to Move" posted a few years ago.
I am stoked that over the past decade these first principles of rehabilitation have entered the minds and hearts of many MSK clinicians, fitness and movement-based health professionals.
However, two decades in the industry have made me weary of trends that often go too far and fall prey to cognitive biases and an over-reach of research findings; we've become memeified on social media in such an entertaining way that almost no one raises a hand to question, "is it true?"
One such memeification has been the notion that humans have an inherently positive adaptation to load. The ill effects of inactivity combined with the pitfalls of fear avoidance make this a tempting default position. That does not however mean it is universally true.
This brings me to the topic of this post - that intervertebral discs adapt positively to load has encompassed the assumption that it applies to all activity, exercise and sport domains. For example, some folks state that strength training, even strength training in spinal flexion, leads to positive disc adaptation. They draw on basic biological studies to 'prove' this must be true. But is it? To skip to the short answer: no evidence suggests it is.
Does the intervertebral disc adapt POSITIVELY to load?
The answer is: sometimes yes, sometimes no.
Like most things related to human health the answer is nuanced and require consideration for a broad variety of load exposures.
Below I provide you a series of quotations from scientific articles published in peer-reviewed journals, with references for further reading.
"The literature indicates that running and upright endurance sports are either beneficial or at least not detrimental to the disc, whereas sports including swimming, baseball, weightlifting, rowing and equestrian riding are more likely to lead to disc degeneration...
...here, we refer the reader to those review articles and summarise the overall knowledge base from these review articles as follows:
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Static loading of the IVD is not beneficial to it: more cell death is observed, decreased production of matrix components occurs, and increases in catabolic markers are observed along with reductions of anabolic markers in the IVD.
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IVD immobilisation or disuse typically results in losses of glycosaminoglycans in small-animal models.
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Dynamic loading of the IVD can provide a positive response in the IVD. However, the magnitude of the applied load, its frequency and duration play important roles.
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There appears to be a certain ‘physiological range’ of dynamic axial compressive loads that result in an anabolic response in the IVD. Outside of this range, a catabolic response is typically seen in the IVD or IVD cells. One review [72] put this range at 0.2–0.8 MPa, with a frequency of 0.1–1 Hz and duration of 8 h/day.
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The responses of degenerated IVDs, IVDs from older animals or cells from such IVDs are not the same as those seen when a given load is applied to young and/or healthy IVDs. For example, a smaller increase in proteoglycan production was seen in response to loading in cells from older and/or degenerated IVDs [74].
Overall, this body of literature helps to underscore the point that the IVD does adapt to loading and that this response may ‘strengthen’ the IVD, but that loading can also have negative (catabolic) effects." (1)
"Following matched sample analyses, basketball and soccer were the only remaining groups exhibiting beneficial IVD parameters (ie, greater IVD hypertrophy or hydration) compared to controls. Whilst we are unaware of any previous studies that have examined the association between basketball and beneficial IVD characteristics, we previously hypothesized24 that sports involving ballistic and high-impact (jumping) loading patterns would be detrimental to IVD health, in accordance with higher rates of IVD degeneration seen in volleyball players.25 This may imply that basketball could be detrimental to the IVD. Notably, the findings of the current study suggest that this prior hypothesis was incorrect and that basketball is associated with beneficial IVD adaptations. Notably, running, another sport involving high-impact IVD loading patterns, was shown to be associated with greater lumbar IVD hypertrophy compared to nonsporting referents.15 Measurements of intradiscal pressures in running,26 and, therefore, also presumably loading on the IVD during running in basketball and soccer, are likely within the potentially beneficial range of 0.3 to 1.2 MPa.24 Potentially, the ability to maintain the lumbar lordosis during IVD loading may play a role in our current findings seen in these upright sports. Our observations regarding soccer conflicts with a previous study13 in which the sport was associated with greater lumbar IVD degeneration and pathologies compared to shooter referents (ie, light-moderate physical activity). Comparison with this prior work is challenging as the prior study13 evaluated athletes more than 30 years after participation in elite sport and did not appear to implement blinding to athletic group during evaluation of magnetic resonance images. Overall, our findings suggest that basketball and soccer may be associated with beneficial adaptations in the IVDs of younger athletes assessed at the time of their participation in the sport." (2)
"Body weight, lifting strength, and axial disc area were more highly associated with disc degeneration than occupational and leisure physical activity histories, although all had modest influences. Furthermore, higher body mass, greater lifting strength, and heavier work were all associated with more disc height narrowing but less disc desiccation contrary to current views. Smaller discs appeared to have beneficial effects." (3)
"Research from animal model studies suggests the existence of a dose-response relationship between loading and regenerative processes. Although high loading at high volumes and frequencies might accelerate degeneration or produce disc injury, high loading, yet of low volume and at low frequency appears to induce potentially regenerative mechanisms, including improvements in disc proteoglycan content, matrix gene expression, rate of cell apoptosis, and improved fluid flow and solute transport." (4)
"Exercise is a common prescription for those with CLBP; however, the potential for it to specifically promote positive changes in the intervertebral discs is not often considered. It has been suggested that regular movement and exercise of the lumbar spine might counter and perhaps reverse loss in disc hydration.25-27 Nelson et al.28 reported that reduction in pain after isolated lumbar extension (ILEX) exercise was similar in all diagnosed conditions, including degenerative disc disease. Concerns have been expressed regarding the safety of using exercise such as ILEX when considering disc health.29 However, although disc degeneration can be affected negatively by loading, the potential for a “safe window” of disc loading that may stimulate optimal disc health does exist.30,31 Indeed the available animal model research appears to suggest its biological plausibility.32 A relatively high magnitude, low frequency and short duration dynamic loading may produce potentially regenerative effects on the intervertebral disc (including improvements in disc proteoglycan content, matrix gene expression, rate of cell apoptosis, and improved fluid flow and solute transport).33-37
...though further supporting the use of ILEX (isolated lumbar extension) resistance training to improve ILEX strength, pain and disability, did not find any effect on spinal height or shrinkage measures using seated stadiometry. Thus, despite its impact on other aspects of the multifactorial nature of LBP, suggestion that ILEX exercise improves disc condition in CLBP participants is presently not supported and remains a hypothesis requiring further study." (5)
If you have more studies you'd like to discuss, please comment and share!
1. Belavý, D. L., Albracht, K., Bruggemann, G.-P., Vergroesen, P.-P. A., & van Dieën, J. H. (2015). Can Exercise Positively Influence the Intervertebral Disc? Sports Medicine, 46(4), 473–485. doi:10.1007/s40279-015-0444-2
2. , , , , . Mechanical loading influences the lumbar intervertebral disc. A cross-sectional study in 308 athletes and 71 controls. J Orthop Res. 2021; 39: 989–997. https://doi.org/10.1002/jor.24809
3. Videman T, Levälahti E, Battié MC. The effects of anthropometrics, lifting strength, and physical activities in disc degeneration. Spine (Phila Pa 1976). 2007 Jun 1;32(13):1406-13. doi: 10.1097/BRS.0b013e31806011fa. PMID: 17545908.
4. Steele J, Bruce-Low S, Smith D, Osborne N, Thorkeldsen A. Can specific loading through exercise impart healing or regeneration of the intervertebral disc? Spine J. 2015 Oct 1;15(10):2117-21. doi: 10.1016/j.spinee.2014.08.446. PMID: 26409630.
5. Steele J, Bruce-Low S, Smith D, Jessop D, Osborne N. Isolated Lumbar Extension Resistance Training Improves Strength, Pain, and Disability, but Not Spinal Height or Shrinkage ("Creep") in Participants with Chronic Low Back Pain. Cartilage. 2020 Apr;11(2):160-168. doi: 10.1177/1947603517695614. Epub 2017 Feb 1. PMID: 29156985; PMCID: PMC7097984.