Here is the design of a clinical trial:

Official Title: Influence of Different Rehabilitative Aerobic Exercise Programs on (Anti-) Inflammatory Immune Signalling, Cognitive Performance and Processing Skills in Persons With MS - A Randomized Controlled Trial

Included conditions:
- Multiple Sclerosis

Study Armgroups:
- {'label': 'High-intensity Interval Training (HIIT)', 'type': 'EXPERIMENTAL', 'description': 'Participants of the HIIT group will exercise three times per week over a period of three weeks (inpatient rehabilitation) on a cycle ergometer. Exercise intensity will be regulated and heart rate controlled based on the achieved maximum heart rate (HRmax) assessed during the initial Cardiopulmonary Exercise Testing. Each exercise session will last 30 minutes and will be started and finalized with three minutes at low intensity (50% HRmax, warm-up / cool-down). During each exercise session, participants of the HIIT group will perform 5x one-and-a-half Minute high-intensive exercise bouts at 95-100% of their HRmax followed by active breaks of unloaded pedalling over 2 minutes with the aim to achieve 60% HRmax.', 'interventionNames': ['Behavioral: Exercise Training']}
- {'label': 'Moderate Continous Training (ST)', 'type': 'ACTIVE_COMPARATOR', 'description': 'Participants of the ST group will exercise three times per week over a period of three weeks (inpatient rehabilitation) on a cycle ergometer. Exercise intensity will be regulated and heart rate controlled based on the achieved maximum heart rate (HRmax) assessed during the initial Cardiopulmonary Exercise Testing. Each exercise session will last 30 minutes and will be started and finalized with three minutes at low intensity (50% HRmax, warm-up / cool-down). During each exercise session, participants of the ST group will exercise 30 minutes continuously at 65% of HRmax. This moderate continous training program represents the standard care at the local rehabilitation clinic.', 'interventionNames': ['Behavioral: Exercise Training']}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'Exercise Training', 'description': 'Treatment in both arms consists of specific of aerobic exercise training modalities. Exercise has become an efficient strategy within rehabilitative programs and is part of a goal-orientated multidisciplinary approach to improve disability and participation in persons with MS. Recently, short and exhaustive bouts of exercise have gained much attention as a promising option in supportive care in MS.', 'armGroupLabels': ['High-intensity Interval Training (HIIT)', 'Moderate Continous Training (ST)']}

Primary Outcomes:
- {'measure': 'Tregs', 'description': 'Proportion of regulatory T-cells with higher values indicating higher levels of Inflammation.', 'timeFrame': 'Three weeks (day 0 to day 21)'}

Please estimate the sample size based on the assumption: 
alpha of 5%, power (1-β) of 80%, 10% drop-out rate, estimated association between baseline levels and at T1 of ρ = .7
Sample size calculation
        The required sample size to evaluate the between-group effect of the exercise-interventions (HIIT vs. ST) on the primary endpoint (proportion of Tregs in blood samples of persons with MS) in an analysis of covariance model (ANCOVA) was estimated using G*Power 3.1.9.2 [47]. The following parameters were defined for power analysis: medium effect size of dâ=â.5, alpha of 5% and power (1-Î²) of 80%. As covariate in the model participantsâ proportion of Tregs at baseline will be used. Sample size needed to meet the above stated suppositions can be calculated according to the formula described by Borm and colleagues [48] (1-Ï2)*n. An estimated association between participantsâ baseline levels and at T1 of Ïâ=â.7 was used. Calculation of required sample size revealed 33 participants in each group (total NÂ =â66). A 10% drop-out rate was expected. This estimation was done according to the attrition rates in previous similar studies [11]. Against this background, we will recruit 72 participants in total.