Here is the design of a clinical trial:

Official Title: Supervised Exercise Following Bariatric Surgery in the Treatment of Severe/Morbid Obesity: a Randomized Controlled Trial

Included conditions:
- Obesity, Morbid
- Bariatric Surgery Candidate

Study Armgroups:
- {'label': 'Exercise', 'type': 'EXPERIMENTAL', 'description': 'Usual care PLUS concurrent (aerobic and strength) supervised exercise program of 16 weeks (3 sessions/week, 60 min/session, progressively increasing in volume and intensity). The program will be conducted by certified Exercise Science professionals.', 'interventionNames': ['Other: Exercise']}
- {'label': 'Control', 'type': 'NO_INTERVENTION', 'description': 'Usual care routinely delivered after bariatric surgery, based on national (Spanish) and international recommendations, focused on nutritional status monitoring and diet/physical activity counseling.'}

Interventions:
- {'type': 'OTHER', 'name': 'Exercise', 'description': 'Concurrent (aerobic and strength) supervised exercise program: the program comprises 3 sessions/week (60 min/session) of aerobic and strength exercises of progressive volume and intensity. The program will follow the Consensus on Exercise Reporting Template (CERT) guidelines.', 'armGroupLabels': ['Exercise'], 'otherNames': ['Exercise training']}

Primary Outcomes:
- {'measure': 'Percent total weight loss (%TWL) [Biospace Co., InBody 270, USA]', 'description': '%TWL = \\[(pre-surgery weight - post-surgery weight) / (pre-surgery weight)\\] x 100', 'timeFrame': 'Changes from baseline to 4-month and 1-year follow-up'}

Please estimate the sample size based on the assumption: 
Alpha error of 0.05, power of 80%, and a potential follow-up loss of up to 20%.
Sample Size
        Assuming an alpha error of 0.05 and a power of 80%, a total of 66 patients (n=33 patients per group) are needed to detect an effect (between group difference) of at least 0.7 standard deviations [16] in the % of total weight loss (% TWL). Anticipating a potential follow-up loss of up to 20%, a total of 80 patients will be recruited (i.e., 40 per group). Based on previous literature and our surgical teamâs experience, 60â80% of the recruited participants are expected to be women.