Where’s the evidence? A systematic review exploring the evidence underpinning exercise dose in clinical trials of rheumatoid arthritis


Selecting what dose to prescribe is an essential step in the development of clinical trials evaluating exercise-based interventions. Therefore, we aimed to evaluate the evidence reported to underpin exercise dose in randomised controlled trials (RCTs) using strengthening exercise in rheumatoid arthritis.


We searched following databases: AMED, CENTRAL, CINAHL, EMBASE, MEDLINE and PEDRO between Jan 2000 to April 2019. We included RCTs, where a main component of the intervention and/or control used strengthening exercise. We adapted the TIDieR checklist to extract information about the intervention including its dose. We identified the evidence cited to underpin the prescribed dose of strengthening exercise and retrieved this for further data extraction. We graded the quality of the underpinning evidence, assessed how consistently it was being used and how applicable it was to the clinical trial population.


Results: Thirty-two RCTs were reviewed. Twenty (62.5%) reported no evidence underpinning dose of strengthening exercise. Four (12.5%) piloted the intervention without using dose-escalation designs commonly seen in drugs trials for optimising dose-response. Where reported, quality, consistency and applicability of the underpinning evidence was a cause for methodological concern.

Conclusion(s): The majority of RCTs did not report the evidence underpinning dose. When reported the evidence was often not applicable to the clinical population. Frequently, the dose used differed to the dose reported/recommended by the underpinning evidence. Our findings illustrate exercise dose may not be optimised for use with clinical populations prior to evaluation by RCT and is a cause for methodological concern.

Cost and savings

No further data 


There are clear scientific imperatives to improve practice in this area of clinical research, including maximising the potential for exercise interventions to deliver benefit. Our results indicate researchers need to improve not only the standard of reporting related to their interventions, but also the evidence they use to justify their decisions about what dose to prescribe. Addressing these weaknesses may contribute to better quality research being conducted. Additionally, funders and peer reviewers should take a careful and critical approach when considering how exercise dose has been formulated. Those interventions that fail to offer evidence supporting dose, or use evidence of low quality and applicability, may in the future not be funded or published, therefore reducing research waste.

Top three learning points

No further data 

Funding acknowledgements

This work was supported by the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care Oxford at Oxford Health NHS Foundation Trust, and supported by the NIHR Biomedical Research Centre, Oxford. Shona Kirtley was funded by Cancer Research UK (grant C49297/A27294).