The purpose of this clinical trial is to study the effects of resistance training program on physical-functional fitness, muscle mass and strength, endothelial function, blood pressure, biochemical markers of cardiovascular risk and bone metabolism, density and microstructure and quality of life of post-bariatric patients (Study 1). To compare the bone and muscle changes in post-bariatric patients by Roux-en-Y Gastric Bypass Surgery with non-bariatric controls, as well as to correlate these health indicators with surgery time and weight loss (Study 2).

Randomized controlled trial (Study 1) will feature post-bariatric patients in outpatient care at the public health unit. The post-bariatric patients will be randomized through a random code generator software (www.randomization.com) at a ratio of 1:1, into two groups: a) Intervention group - that will perform a supervised RT program for 6-months or b) Non-exercised control group - that will receive the standard clinical follow-up and shall not change their physical activity behavior. The exercise sessions will include: a) 10-min specific warm-up, consisting of one set of 20 repetitions with loads corresponding to 50% of the resistance used in the first exercise of the training session; b) 45-min of resistance exercises for the upper and lower body (8 single and multi-joint exercises with free weights and machines, including seated rowing, leg press, bench press, leg flexion, pull down, leg extension, shoulder press, and abdominal exercises), performed with 2-3 sets of 8 to 12 repetitions with loads ≥ 70% of one-repetition maximum (1RM) interspersed with 2 min intervals between sets; c) 5-min recovery with stretch and cool-down exercises. During six months, all training sessions will occur three times a week on nonconsecutive days. The outcomes will be assessed by dual energy X-ray emission densitometry (DXA); high resolution peripheral quantitative computed tomography (HR-pQCT), repetition maximum, handgrip strength; biochemical analysis (blood lipid profile, blood glucose and biomarkers of bone formation and absorption and calcium metabolism); venous occlusion plethysmography and nailfold videocapillaroscopy; blood pressure measurement and 36-Item Short-form Health Survey. The cross-sectional study (Study 2) will have 2 groups: post-bariatric patients group (BG) and control group (CG) - non-bariatric controls. Outcomes will be assessed by DXA; HR-pQCT; handgrip strength and biochemical analysis (blood lipid profile, blood glucose and biomarkers of bone formation and absorption and calcium metabolism).

Inclusion Criteria:

• Patients subjected to Roux-en-Y gastric bypass
• Aging 18 to 50-years
• At least 12 months from surgery

Exclusion criteria:

• Smoking
• Alcoholism
• Gestation
• Cardiovascular disease
• Respiratory disease
• Neurological disease
• Infectious disease
• Endocrine disease
• Musculoskeletal impairments
• Use of hormonal replacement therapy that influence bone metabolism
• Use of medications that influence bone metabolism
• Start some physical exercise program during the study
• Excess weight loss <50%
• Use drugs that interfere with weight
• Revisional bariatric surgery
• Regular physical exercise