Although osteoarthritis has been studied for more than a century, the disease appears to be more common today than ever, and remains the leading disabler of older adults. Often denoted as a disease of the articular cartilage, the tissue lining the ends of bones of freely moving joints such as the knee, this report sought to evaluate the known effects of exercise-almost universally recommended for osteoarthritis care, on measures of cartilage structure that represent the state of attrition or degradation. Exercise was analyzed because it is widely touted as being of value to the patient, and where sedentary behaviors plus muscle weakness may impair overall function and induce inflammation, dysfunction, and pain. Based largely on animal models of osteoarthritis such as the rat exposed to various exercises in those with artificial arthritis 48, it has been proposed exercise adoption will prove beneficial to joint integrity and reduce pain as opposed to a failure to exercise.

Based on the functional requirements of persons with osteoarthritis, as well as the limitations imposed by their joint pathology, it explored if exercises safely improve function and reduce pain in all osteoarthritis cases, and the degree to which this approach can impact its articular cartilage structural features favorably.

Although delimited to: studies of osteoarthritis in the older population this review reveals that despite widespread generic calls across the globe for exercise training and participation for fostering the health of older adults ideally including a combination of aerobic, muscle strengthening, and flexibility exercises for the older or aging adult, this approach may be ill considered for ameliorating cartilage attrition in the sedentary older adult with severely painful osteoarthritis, even if strongly recommended by osteoarthritis experts and others 2685. Commonly recommended regardless of their degree of pathology and/or numbers and extent of any diseased joint, or concurrent comorbidities-often patients who are excluded from exercise studies (eg., 64), most exercise intervention studies used limited variations of subjective measurement approaches, did not focus on disease markers to solidify their conclusions 86 or mechanisms for explaining exercise effects on pain and function 106787 or function in one domain but not another 35586786 even if we did not include all relevant articles.

At the same time although we did review the most extensive medical data sources and those housing meta analyses and conclusions reached by leading reviewers, the body of related meta or umbrella exercise training analyses may not be robust in all respects, nor comparable. They may not for example, provide clear data on adherence issues (eg., 64), nor possible timely data as most reviewed studies were conducted in eras where obesity was not rife (eg., 24) using secondary data sets applied in a single location, and where data collected was largely subjectively assessed 9, and with no baseline osteoarthritis radiographic measure 2436. The lack of inclusivity of the older adult, and the fact the bulk of studies were conducted in funded labs on populations that may not represent those older adults who have no provider, no transport, or insurance coverage or were too impaired to participate or who drop out of programs involving exercise and were not duly followed up.

Why one type of exercise is chosen and not another and how one form of exercise impacts osteoarthritis joints other than the knee or explains non uniform as well as uniform outcomes in varied osteoarthritis studies is consequently very hard to unravel 32. Moreover, untested older adults with osteoarthritis who are often excluded from studies, may not respond in the same way as younger adults to exercises and those that are remotely offered may not yield the same outcomes as carefully supervised exercises. Assuming older adults in pain will readily follow exercise if deemed helpful as a health strategy 10678889, carrying this activity out over time may prove challenging for those in poor health as well as those with multiple physical challenges, plus possible bone, soft tissue, sensory declines, poor endurance, and inflammatory provoking micro impact injuries 64.

In addition, exercise carried out in the absence of patient education 95 may not prove efficacious if it induces excess or non physiological impacts on the diseased tissue 824 even if pain appears to be reduced in various controlled studies 3. What is meant by moderate exercise and evidence for having a null effect in osteoarthritis cases even if advocated 90 must remain in question especially where data are deemed to be generated from lower than desirable quality research 91 and acute exercise effects in young adults 32, or on non radiographic assays and not any other 92.

Indeed, perhaps older adults with osteoarthritis are suffering in excess because even with over 100 exercise based therapy studies espouse benefits on pain and function, they still fail to provide indisputable evidence that pain relief in osteoarthritis and exercise are robustly linked 76 and its multi layered and complex presentation in the older adult in this regard is rarely measured or discussed.

Rather, there is an assumption of a one size fits all osteoarthritis diagnoses, and that its association with exercise is a linear and a universally conclusively favorable one 93 and can be applied based on patient or doctor appraised preferences 96 despite recognition of its somewhat unpredictable site specific joint loading responses that needs to be acknowledged 99. As well, since cartilage is exquisitely sensitive to excess mechanical or suboptimal loading impacts 94, rather than being a passive tissue, it may require sufficient post exercise or intermittent programmatic rest periods to avoid negative deformation associated cartilage load effects as found in healthy young adult men immediately post exercise that could impact metabolic and remodeling processes 97. Alternately, the impact of both appropriate as well as possible poorly selected and implemented exercise modes on damaged cartilage as well as end stage joint degeneration cannot be readily predicted or extrapolated from such studies and needs more thorough investigation in its own right as intimated by Thudium et al. 40. This group found cartilage tissue turnover and cartilage degradation appear to increase in response to a 3-month exercise-related joint loading training program and at 6-month follow-up, with no evident difference in type II collagen formation. Aggrecan remodeling increased more with high-intensity resistance training than with low-intensity exercise. These exploratory biomarker results, indicating more cartilage degeneration in the high-intensity group, in combination with no clinical outcome differences of the VIDEX study, may well argue against high-intensity training even if well tolerated.

In the interim, function, functional performance and life quality as well as research quality in exercise based assays remain questionable at best despite numerous study attempts 78100101. In addition, while deemed safe no matter what mode of exercise is adopted, this cannot be validated readily for older adults and on the basis of structural joint features as well as functions of daily living and for joints other than the knee. This situation and the relevance presently highlighted, plus knowledge gaps and finding inconsistencies surely needs to be addressed promptly in multiple spheres in our view so as to not only eliminate discordant findings, but to help clinicians to better tailor their recommendations and avert modes of high impact exercise that could prove injurious. Research needs to better elaborate on how older adults living in the community safely can confidently pursue exercise recommendations without undue human and other health or societal resource demands and that can be performed regularly at low cost and without stress and fatigue effects.

Alternately, the costs of failing to do this can be expected to rise in multiple ways and especially if exercise impacts on function and life quality cannot be validated and exercise dosages applied that do have a bearing on osteoarthritis pathology remain unknown. In addition costs will rise if for example, only a small number of cases over time appear to do better than those who receive no treatment, or where treatment or its impact is suboptimal, ineffective, or possibly harmful or determined by type or groupings of osteoarthritis 101102103104105106107108109110. As well, if the potential for or limits of averting excess cartilage load, or more importantly enhancing cartilage reparative processes remain unknown, even the best efforts to maximize life quality and mobility options may prove unsuccessful, as well as possibly inducing or encouraging excess drug or costly invasive treatments or both. The fully fledged understanding of recorded post exercise adverse events as well as benefits remains unknown at present and may be inducing rather than alleviating suffering.

While no simplistic approach will be enlightening on its own, to make some headway in this complex realm, in tangible ways, perhaps the use of small workshop collectives, single case studies, and careful n of 1 single subject design efforts or follow ups of current study participants over time, can generate some helpful insights and enlightening data. In addition to careful sample selection, efforts directed towards reducing potential measurement errors, combining animal and human related studies, employing artificial intelligence diagnostic assessments ^AI and others using agreed upon sensitive assays and parameters that allow for advanced statistical analysis of the included demographic, clinical, radiographic, and musculoskeletal profiles are especially recommended.