Here is the design of a clinical trial:

Official Title: Resistance Training Intervention on the Clinical Status in Patients With Post Discharge Symptoms After Covid-19: The "EXER-COVID Study"

Included conditions:
- Covid19
- SARS-CoV2
- Fatigue Syndrome, Chronic
- Stress, Psychological
- Pain, Chronic

Study Armgroups:
- {'label': 'Exercise', 'type': 'EXPERIMENTAL', 'description': 'Resistance training', 'interventionNames': ['Behavioral: Resistance training']}
- {'label': 'Standard care', 'type': 'ACTIVE_COMPARATOR', 'description': 'Non-supervised ACSM exercise guidelines', 'interventionNames': ['Behavioral: Standard care']}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'Resistance training', 'description': 'Participants will complete a 2-days-a-week training routine: Resistance training (RT, 50-75% 1RM (one-repetition maximum), 4 sets, 8-12 repetitions, 4 exercises). The warn up include Light Intensity Continuous Training (8-10 min, 65-70% HRR). Progressions will be individualized and consistent with patient tolerance. Sessions will be supervised by Physiotherapists and Graduated in Sports Sciences.', 'armGroupLabels': ['Exercise']}
- {'type': 'BEHAVIORAL', 'name': 'Standard care', 'description': 'This group will be allocated to standard care and therefore no supervised exercise regimen according to scientific guidelines for general physical activity and return to sport provided by the ACSM guidelines for Chronic Obstructive Pulmonary Disease and Cardiovascular Disease.', 'armGroupLabels': ['Standard care']}

Primary Outcomes:
- {'measure': 'Changes in Cardiorespiratory fitness', 'description': 'Measured with an incremental VO2 protocol on exercise bike by COSMED Quark CPET plus OMNIA (COSMED®, Rome, Italy)', 'timeFrame': 'Baseline, 6 Weeks and 12 Weeks'}

Please estimate the sample size based on the assumption: 
Statistical power of 80% (1-β) with a two-tailed alpha <0.05, adjustment for baseline value and other prognostic covariates. Potential dropout rate of <15-20%.
Sample size
          Given the absence of exercise interventions for patients with persistent COVID-19 symptoms [57], in this area, a conservative approach will be used to estimate the sample size. Inspired by a Lau et al. study [58], it is expected that the exercise group will increase cardiorespiratory fitness at least 1-MET (3.5âmL/kg/min) more than the standard care group with an SD of 5.4%. A sample size of 84 participants (42 per group) provides statistical power (1âÎ²) of 80% using a two-tailed alpha <0.05âand adjustment for baseline value and other prognostic covariates [59]. This sample size will also be sufficient for detecting differences in our secondary biomarkers and patient-reported outcomes. Considering a potential dropout rate of <15â20% based on our previous exercise trials [60, 61], a total of 100 participants (50 per group) will be randomized. This power will also be sufficient for detecting differences in our secondary biomarkers and patient-reported outcomes if the effects are moderate (i.e., effect size of Cohenâs d â¥ 0.6). This power is not sufficient for detecting potentially meaningful differences in any of the exploratory clinical outcomes. Given that the purpose of this phase II trial is to inform larger phase II and III trials, the patient-reported and clinical outcomes will also be interpreted for potential clinical significance based on the direction and magnitude of numerical differences. These calculations were performed with the Power and Sample Size Calculations program, Version 2.1.23.