Here is the design of a clinical trial:

Official Title: Multiple Sclerosis Fitness Intervention Training With Pilates Exercises

Included conditions:
- Multiple Sclerosis
- Physical Activity

Study Armgroups:
- {'label': 'MSFIT', 'type': 'EXPERIMENTAL', 'description': 'The MSFIT group will self-manage Pilates exercises at-home through a tool based on XBox Kinect for 12 weeks, performing at least 3 sessions/week for a total of 30 minutes of exercises for each session(also distributed during the day with a minimum slot of 10 minutes). No rehabilitative interventions except sphincter and speech rehabilitation and psychological support, are admitted for the 12 weeks of participation to the project and the following 6 weeks before Follow-up evaluations (a total of 18 weeks). The execution of unspecific physical activities, if not already practiced, will be suggested to the participants.', 'interventionNames': ['Other: MSFIT']}
- {'label': 'CTRL', 'type': 'NO_INTERVENTION', 'description': 'No rehabilitative interventions except sphincter and speech rehabilitation and psychological support, are admitted for the 12 weeks of participation to the project and the following 6 weeks before Follow-up evaluations (a total of 18 weeks). The execution of unspecific physical activities, if not already practiced, will be suggested to the participants.'}

Interventions:
- {'type': 'OTHER', 'name': 'MSFIT', 'description': 'MSFIT, by using the Microsoft Kinect Motion Controller Xbox to deliver adapted physical activity, offers the possibility to transform the Pilates exercises into a virtual reality game. Each exercise is implemented with different levels of difficulty in order to allow the adaptation to the capacities of the user.', 'armGroupLabels': ['MSFIT']}

Primary Outcomes:
- {'measure': 'Change in Timed Up & Go (TUG)', 'description': 'The Timed "Up and Go" Test measures, in seconds, the time taken by an individual to stand up from a standard arm chair (approximate seat height of 46 cm, arm height 65 cm), walk a distance of 3 meters (approximately 10 feet), turn, walk back to the chair, and sit down.', 'timeFrame': 'T0: before intervention; T1: after 12 weeks of intervention; T2: 6 weeks after T1'}

Please estimate the sample size based on the assumption: 
A power of 80%, a significance level (2-sided) of 5%, and a potential loss of 15% of patients at follow-up.
Sample Size
        The sample size was calculated by referring to the TUG change after a Pilates intervention found by Kalron et al [30] in a group of people with MS. The authors found no difference between the group receiving the Pilates intervention and the control group receiving an intervention of physical therapy. The Pilates group improved the TUG performance by about 1.8 seconds, which is clinically relevant for people with MS. Considering a variability of about 3.4 seconds, a power of 80%, a significance level (2-sided) of 5%, and a potential loss of 15% of patients at follow-up, the estimation of the necessary sample size consists of approximately 63 participants for the experimental group (a total of 126).