Here is the design of a clinical trial:

Official Title: Aerobic Exercise to Improve Mobility in Multiple Sclerosis: Optimizing Design and Execution for a Full-scale Multimodal Remyelination Clinical Trial

Included conditions:
- Multiple Sclerosis
- Sclerosis
- Demyelinating Diseases
- Autoimmune Diseases of the Nervous System
- Nervous System Diseases
- Demyelinating Autoimmune Diseases, CNS
- Exercise

Study Armgroups:
- {'label': 'MS: Cycle', 'type': 'EXPERIMENTAL', 'description': 'Twenty-two participants in the clinical trial arm will be randomized to MS:Cycle: an aerobic exercise intervention on a stationary ergometer. Participants will exercise thrice weekly for 30 minutes with graded supervision for 24 weeks.', 'interventionNames': ['Behavioral: Aerobic exercise']}
- {'label': 'MS: Take Control', 'type': 'ACTIVE_COMPARATOR', 'description': 'Twenty-two participants in the clinical trial arm will be randomized to MS: Take Control (MSTC): a monthly, hour-long MS education control group led by a trained facilitator.', 'interventionNames': ['Behavioral: Education Group Control']}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'Aerobic exercise', 'description': 'Aerobic exercise performed on a stationary ergometer for 30 minutes, thrice weekly, with graded supervision. Participants will participate in the intervention over 24 weeks.', 'armGroupLabels': ['MS: Cycle']}
- {'type': 'BEHAVIORAL', 'name': 'Education Group Control', 'description': 'A monthly, hour-long, class over various MS topics and symptoms, led by a trained facilitator.', 'armGroupLabels': ['MS: Take Control']}

Primary Outcomes:
- {'measure': 'Somatosensory Evoked Potentials (SSEPs)', 'description': 'Measure of functional myelination of the somatosensory tracts of the spinal cord', 'timeFrame': 'From baseline to week 24'}

Please estimate the sample size based on the assumption: 
For part 1, the significance level (Î±) is 0.05, power is 88%. For part 2, the significance level (Î±) is 0.05, power is >80%, and a 20% dropout rate is assumed.
Sample size calculation
          Part 1 of the study will explore the relationship of demyelination with mobility in pwMS. Based on prior studies associating transformed SSEP z-scores and the expanded disability status scale (rho=0.81, p<0.001) in pwMS, n=60 participants would have 88% power to detect a correlation rho=0.40 (Î±=0.05). All power analyses were computed using Power And Sample Size (PASS) software (V.15). For part 2 of the study (to explore if aerobic exercise improves mobility and promotes remyelination), we assume the effect size of z-transformed evoked potential values between baseline and 24âweeks is 0.54 in pwMS based on prior studies.27 Assuming a 20% drop out rate, enrolling 44 participants in the clinical trial would achieve the necessary final sample size of 36 participants, or 18 per group. This will give us >80% power to detect a 50% effect size (Î±=0.05). Our sample size is similar to prior remyelination clinical trials of the pharmacotherapies clemastine and bexarotene in MS using visual evoked potentials, a similar functional myelination biomarker of the visual system.28 29 As this is the first clinical trial of exercise to use SSEP to assess for remyelination, it is unknown if the study intervention, different evoked potential modality or other factors may impact the required sample size.
          To our knowledge, this study is the first clinical trial in MS to use quantitative T1 MWF as a biomarker of structural remyelination and therefore a well-informed power analysis cannot be performed. However, 11 per group is similar to other studies that have demonstrated changes in white matter integrity in pwMS after rehabilitative interventions.30 31 If additional funding is obtained, the sample size of the MRI subset may be increased.