Here is the design of a clinical trial:

Official Title: Reducing Sedentary Time in Rheumatoid Arthritis: The Take a STAND for Health Study

Included conditions:
- Rheumatoid Arthritis

Study Armgroups:
- {'label': 'Take a STAND for health', 'type': 'EXPERIMENTAL', 'description': 'A newly developed personalized intervention focused on replacing sedentary time with light-(or very light-) intensity physical activity', 'interventionNames': ['Behavioral: Take a STAND for health']}
- {'label': 'Control', 'type': 'NO_INTERVENTION', 'description': 'The control group will receive all regular medical care and advice on healthy lifestyle, including the promotion of recommended physical activity levels and health nutrition.'}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'Take a STAND for health', 'description': 'The Take a STAND for health is a newly developed 4-month goal-setting intervention aimed at reducing sedentary behavior', 'armGroupLabels': ['Take a STAND for health']}

Primary Outcomes:
- {'measure': 'Sedentary behaviour as assessed by ActivPAL™', 'timeFrame': '4 months'}

Please estimate the sample size based on the assumption: 
95% power, 5% significance level, and an estimated dropout rate of approximately 25%.
Sample size
          Sample size calculations were performed using G-PowerÂ® software, v. 3.1 (UniversitÃ¤t DÃ¼sseldorf, DÃ¼sseldorf, Germany), based on the study by Lewis et al. that reported the effects of reducing sedentary behavior in an elderly population (i.e., a reduction of 52âmin in total sitting time) [33]. According to the estimation, 24 patients (12 per arm) are required to achieve 95% power (Î±), with a significance level of 5% (Î²), and assuming an effect size of 0.58 for the primary outcome (i.e., sedentary time). Estimating a dropout rate of ~â25%, at least 30 patients will be recruited. Considering that this sample size could be underpowered for some secondary outcomes, we will try to increase this estimated sample based on the feasibilities of our laboratory (including funding, capacity of research staff and facilities, and available patients), in line with contemporary recommendations [34, 35].