Here is the design of a clinical trial:

Official Title: STEPWISE Parkinson: A Smartphone Based, Titrated Exercise Solution for Patients With Parkinson's Disease in Daily Life

Included conditions:
- Movement Disorders
- Parkinson Disease

Study Armgroups:
- {'label': 'Very high dose', 'type': 'EXPERIMENTAL', 'description': 'Very large proportional increase in stepcount relative to baseline stepcount.', 'interventionNames': ['Behavioral: Step count increase with the use of a motivational smartphone application']}
- {'label': 'High dose', 'type': 'EXPERIMENTAL', 'description': 'Large proportional increase in stepcount relative to baseline stepcount.', 'interventionNames': ['Behavioral: Step count increase with the use of a motivational smartphone application']}
- {'label': 'Intermediate dose', 'type': 'EXPERIMENTAL', 'description': 'Medium proportional increase in stepcount relative to baseline stepcount.', 'interventionNames': ['Behavioral: Step count increase with the use of a motivational smartphone application']}
- {'label': 'Active controls', 'type': 'ACTIVE_COMPARATOR', 'description': 'Small proportional increase in stepcount relative to baseline stepcount.', 'interventionNames': ['Behavioral: Step count increase with the use of a motivational smartphone application']}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'Step count increase with the use of a motivational smartphone application', 'description': "All participants will be given access to an application installed on the participants' own smartphone: the STEPWISE app. The STEPWISE app will encourage participants to increase their long-term physical activity (1 year). Different treatment arms will receive different physical activity goals. Participants will get feedback and support via the smartphone app, that stimulates them to reach their individual physical activity goal (i.e. target percentage increase in stepcount).", 'armGroupLabels': ['Active controls', 'High dose', 'Intermediate dose', 'Very high dose']}

Primary Outcomes:
- {'measure': 'Mean change in step count per day', 'description': "Mean change in step count per day as measured continuously with the participant's smartphone from baseline (week -4 to 0) to follow-up (week 49-52). Higher scores indicate more physical activity (steps).", 'timeFrame': 'Week -4 until 0 and week 49 until 52'}

Please estimate the sample size based on the assumption: 
Assuming an SD of 2000 steps, allowing for up to 20% loss to follow-up, the study will have greater than 90% power to detect a significant increase in step counts over one year based on a two-tailed test at p < 0.05.
Sample size
          The planned sample size is 452 participants. This sample size is based on a previous study of one-year change in step counts in a clinical trial evaluating the use of a smartphone application to increase physical activity of patients with chronic obstructive pulmonary disease (COPD) [37]. Vorrink, Kort [37] reported a person-to-person standard deviation (SD) of change in one-year step count of 1957 in the active arm and 1973 in the control arm [38]. With 452 participants randomized 1:1:1:1 to the treatment arms (active control or intermediate, large or very large dose group), assuming an SD of 2000 steps and allowing for up to 20% loss to follow-up, the study will have greater than 90% power to infer a significant increase in step counts over one year if the expected 52-week increase in steps in the very large dose group relative to the active control group is at least 1000 steps based on a two-tailed test at pâ<â0.05 for this single primary comparison. One thousand steps is within the range of increases associated with exercise interventions among older adults and those with disabilities and chronic illness [39].