Obesity & OverweightBAR-EXNCT07423780
Concurrent Exercise Effects in Post-Bariatric Patients
A study testing Concurrent Exercise Program and Usual Metabolic Rehabilitation Program in people with Obesity & Overweight and Post-bariatric Surgery, run by Universidad Autónoma de Chile at 1 site in Chile.
Trial summary
This study aims to evaluate the effect of a 5-week concurrent exercise program (aerobic and resistance training) on muscle quality, body composition, functional response, and quality of life in individuals undergoing bariatric surgery. Read more about this study
- Who is it for?
- Ages 18 to 60 years
- Conditions the study is for
- Obesity & Overweight, Post-bariatric Surgery
- What is being tested?
- Concurrent Exercise Program and Usual Metabolic Rehabilitation Program
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 87 participants
- Where
- 1 siteChile
- Study dates
- 11 Aug 2025to 31 Dec 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 60 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Adults aged 18-60 years.
- Participants eligible for the institutional PAD (Pago Asociado a Diagnóstico) bariatric surgery program with medical indication for metabolic rehabilitation.
- Undergoing sleeve gastrectomy or Roux-en-Y gastric bypass at Clínica BUPA Santiago.
- Medical indication for metabolic rehabilitation.
- Able and willing to provide written informed consent.
Who cannot join
- Type 1 diabetes mellitus or type 2 diabetes mellitus with severe complications (including stage G4-G5 nephropathy, severe autonomic neuropathy, or high risk of exercise-related hypoglycemia).
- Severe musculoskeletal disorders limiting participation in the exercise program.
- Acute cardiovascular event within the previous 3 months or medical contraindication to supervised exercise.
- Severe cardiorespiratory disease or dyspnea at rest or with minimal exertion.
- Dependence on supplemental oxygen.
- Bariatric surgery complications (e.g., leak, bleeding, stenosis, or intra-abdominal abscess).
- Liver failure, kidney failure, or any other clinical condition compromising safe participation in the exercise program.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Chile1 site, 1 recruiting
- Recruiting
Clínica BUPA, Santiago
Santiago, Santiago Metropolitan, 7820830
Tomás Vergara Soria, Kinesiólogo, +56988289188, tomasvergarasoria21@gmail.com
Sebastian Barrios, Kinesiólogo, +56984513233, se.barriosv@gmail.com
About this study
Official title: Effect of a Concurrent Exercise Program on Muscle Quality, Body Composition, Functional Response, and Quality of Life in Individuals Undergoing Bariatric Surgery: Protocol for a Randomized Controlled Clinical Trial
This study aims to evaluate the effect of a 5-week concurrent exercise program (aerobic and resistance training) on muscle quality, body composition, functional response, and quality of life in individuals undergoing bariatric surgery.
This is a single-center, prospective, longitudinal, randomized controlled clinical trial with two parallel groups: an intervention group and a control group. A total of 87 adults aged 18 to 60 years who have undergone sleeve gastrectomy or Roux-en-Y gastric bypass and have a medical indication for metabolic rehabilitation will be recruited.
Read more
The intervention group will participate in a structured, semi-supervised concurrent exercise program for 5 weeks, consisting of two in-person sessions per week (10 sessions in total), whereas the control group will continue receiving usual kinesiology care and standard clinical management according to the institutional rehabilitation protocol at Clínica BUPA Santiago. All participants will be assessed at two time points: baseline, during the fourth postoperative week, and at week 7.
The primary outcome will be the change in rectus femoris muscle quality assessed by ultrasound (echo intensity). Secondary outcomes will include body composition (bioelectrical impedance analysis), functional response (One-minute Sit-to-Stand Test), and quality of life (Moorehead-Ardelt II questionnaire).
Additionally, adherence to the exercise program in the intervention group will be assessed as the percentage of attendance at supervised exercise sessions, and its association with the magnitude of changes in study outcomes will be explored.
The findings are expected to provide clinically relevant evidence regarding the effectiveness of exercise during the early postoperative period and to contribute to the optimization of metabolic rehabilitation strategies following bariatric surgery.
Read the detailed description
Bariatric surgery is an effective treatment for severe obesity; however, the early postoperative period is frequently associated with loss of lean body mass, reduced muscle strength, and functional decline, which may negatively affect recovery and quality of life. Physical exercise has been proposed as a key component of metabolic rehabilitation, although evidence regarding structured concurrent exercise programs initiated early after bariatric surgery remains limited, particularly with respect to muscle quality.
The aim of this study is to evaluate the effect of a 5-week concurrent exercise program on rectus femoris muscle quality in individuals undergoing bariatric surgery, compared with a control group receiving usual kinesiology care. Secondary objectives include evaluating changes in body composition, functional response, and quality of life, as well as exploring the association between exercise adherence and the magnitude of observed changes.
This is a single-center, prospective, longitudinal, randomized controlled clinical trial with two parallel groups (intervention and control). A total of 87 adults aged 18-60 years who have undergone sleeve gastrectomy or Roux-en-Y gastric bypass at Clínica BUPA Santiago and have a medical indication for metabolic rehabilitation will be recruited. Participants will undergo baseline assessment during the fourth postoperative week and will then be randomly allocated in a 1:1 ratio to the intervention or control group using a sequence generated and administered by an individual independent of the assessors and treating physical therapists.
The intervention group will participate in a structured, semi-supervised 5-week concurrent exercise program designed according to the FITT principle (Frequency, Intensity, Time, and Type of exercise). The program will combine aerobic and resistance training and will include two supervised in-person sessions per week (10 sessions in total) plus one complementary home-based session each week. Aerobic training will progress from continuous moderate-intensity exercise to interval training, whereas resistance training will progressively increase training volume for large muscle groups. Exercise intensity will be monitored using the Borg Rating of Perceived Exertion scale, and resistance loads will be individually adjusted according to each participant's clinical tolerance.
Participants allocated to the control group will continue receiving usual kinesiology care and standard clinical management according to the institutional metabolic rehabilitation protocol at Clínica BUPA Santiago. This program will also follow the FITT principle and will include two supervised sessions per week consisting of continuous aerobic exercise, targeted muscle strengthening, and static stretching, consistent with routine clinical practice, without the structured progression incorporated into the concurrent exercise program.
Following the 5-week intervention period, both groups will complete one week without supervised exercise sessions to minimize the acute effects of exercise on muscle measurements. Final assessments will be performed at week 7.
The primary outcome will be the change in rectus femoris muscle quality assessed by musculoskeletal ultrasound using echo intensity as the primary indicator. Secondary outcomes will include body composition assessed by bioelectrical impedance analysis, functional response assessed using the One-minute Sit-to-Stand Test, and quality of life assessed using the Moorehead-Ardelt II questionnaire.
Exercise adherence will be assessed exclusively in the intervention group as the percentage of attendance at supervised exercise sessions. The association between adherence and the magnitude of outcome changes will also be explored using a dose-response approach.
Statistical analyses will follow the intention-to-treat principle. The primary analysis will be performed using analysis of covariance (ANCOVA), with study group as the fixed factor and baseline values as covariates, adjusting for prespecified clinically relevant covariates when appropriate. Secondary outcomes will be analyzed using the same approach. Complementary analyses will include within- and between-group comparisons using parametric or non-parametric tests according to data distribution, estimation of effect sizes, and exploratory correlation and linear regression analyses to evaluate the association between exercise adherence and changes in study outcomes.
- Conditions
- Obesity & Overweight, Post-bariatric Surgery
- Being tested
- Concurrent Exercise Program, Usual Metabolic Rehabilitation Program
- Keywords
- Muscle quality, Body composition, Functional capacity, Therapeutic exercise, Quality of life, concurrent exercise, one-minute sit-to-stand, ectus femoris ultrasound, bioelectrical impedance analysis
- Medical subject headings
- Obesity, Overweight
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Concurrent Exercise ProgramBehavioural
Also called Concurrent Physical Exercise Program
Concurrent physical exercise program of 5 weeks combining aerobic and resistance training in individuals undergoing bariatric surgery. The program includes two supervised in-person sessions per week (10 sessions total), each lasting approximately 60 minutes, and one recommended weekly home-based session guided by a prescribed exercise plan.
Aerobic exercise is performed at moderate to high intensity, monitored using the Borg Rating of Perceived Exertion scale. Resistance training targets major muscle groups and is prescribed based on an estimated one-repetition maximum (1RM), with progression in volume and intensity according to individual tolerance and safety criteria.
The program begins at postoperative week 4. After completing the 5-week intervention, participants undergo a 1-week period without supervised sessions before the post-intervention assessment.
Usual Metabolic Rehabilitation ProgramBehavioural
Usual institutional metabolic rehabilitation program at Clínica BUPA Santiago based on the FITT principle (Frequency, Intensity, Time, and Type of exercise). The program includes supervised continuous aerobic exercise, targeted muscle strengthening, and stretching delivered twice weekly for 5 weeks according to the institutional clinical protocol.
| Study group | Role | What they receive |
|---|---|---|
| Concurrent Physical Exercise Program | Experimental | Participants allocated to the intervention group will complete a structured, semi-supervised concurrent exercise program during the postoperative period following bariatric surgery. Participants will enter the study during postoperative week 4 and undergo a baseline assessment before starting the intervention. The program will last 5 weeks and will include 10 supervised in-person sessions (2 sessions/week, approximately 60 minutes each) and one complementary home-based session per week. After completion of the intervention, participants will remain one week without supervised exercise sessions before the week 7 follow-up assessment. Receives: Behavioral: Concurrent Exercise Program |
| Usual Metabolic Rehabilitation Program | Active comparator | Participants allocated to the control group will receive the usual metabolic rehabilitation program at Clínica BUPA Santiago. The rehabilitation program will follow the FITT principle (Frequency, Intensity, Time, and Type of exercise) and will include two supervised sessions per week for 5 weeks consisting of continuous aerobic exercise, targeted muscle strengthening, and stretching according to the institutional protocol. All participants will undergo baseline and week 7 assessments. Receives: Behavioral: Usual Metabolic Rehabilitation Program |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in rectus femoris muscle quality (echo intensity; grayscale units 0-255)
Muscle quality will be assessed by ultrasound as echo intensity (mean grayscale value, 0-255) within a standardized region of interest, analyzed using ImageJ, at baseline and post-intervention. Change will be calculated as Δ = post - pre.
Measured: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Secondary outcomes (11)
Change in percent body fat (%)
Body composition will be assessed using bioelectrical impedance analysis (InBody S10) under standardized conditions before and after the intervention. Percent body fat (%) will be recorded at baseline and post-intervention. Change will be calculated as Δ = post - pre.
Measured: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Change in fat mass (kg)
Body composition will be assessed using bioelectrical impedance analysis (InBody S10) under standardized conditions before and after the intervention. Fat mass (kg) will be recorded at baseline and post-intervention. Change will be calculated as Δ = post - pre.
Measured: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Change in skeletal muscle mass (kg)
Body composition will be assessed using bioelectrical impedance analysis (InBody S10) under standardized conditions before and after the intervention. Skeletal muscle mass (kg) will be recorded at baseline and post-intervention. Change will be calculated as Δ = post - pre.
Measured: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Change in 1-minute Sit-to-Stand performance (1min-STST)
Functional response will be assessed using the One-minute Sit-to-Stand Test (1min-STST). The primary metric is the total number of completed repetitions in 60 seconds performed using a standard chair. Perceived exertion (modified Borg scale) may be recorded as a complementary measure.
Measured: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Adherence to the exercise program (supervised in-clinic sessions)
Attendance rate to supervised in-clinic sessions at Clínica BUPA during the intervention. Adherence will be calculated as: adherence (%) = (number of attended sessions / 10) × 100. For descriptive purposes, adherence will be categorized as high (8-10 sessions; ≥80%), moderate (6-7 sessions; 60-79%), and low (0-5 sessions; <60%). Adherence ≥80% will be considered clinically acceptable.
Measured: During the 5-week intervention period (calculated at the end of the program based on attendance to the 10 supervised sessions).
Change in visceral fat area (cm²)
Body composition will be assessed using bioelectrical impedance analysis (InBody S10) under standardized conditions before and after the intervention. Visceral fat area (cm²) will be recorded at baseline and post-intervention. Change will be calculated as Δ = post - pre.
Measured: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Change in basal metabolic rate (kcal/day)
Body composition will be assessed using bioelectrical impedance analysis (InBody S10) under standardized conditions before and after the intervention. Basal metabolic rate (kcal/day) will be recorded at baseline and post-intervention. Change will be calculated as Δ = post - pre.
Measured: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Change in rectus femoris muscle thickness (cm)
ectus femoris muscle thickness (cm) will be assessed by ultrasound under standardized conditions at baseline and post-intervention. Change will be calculated as Δ = post - pre.
Measured: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Change in rectus femoris cross-sectional area (cm²)
Rectus femoris cross-sectional area (cm²) will be assessed by ultrasound under standardized conditions at baseline and post-intervention. Change will be calculated as Δ = post - pre
Measured: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Change in intramuscular fat infiltration assessed by ultrasound echo intensity (grayscale units 0-255)
Intramuscular fat infiltration will be assessed by musculoskeletal ultrasound using rectus femoris echo intensity (grayscale units 0-255) under standardized acquisition conditions. Images will be analyzed using ImageJ. Change will be calculated as Δ = post - pre.
Measured: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of intervention and 1 week of rest).
Change in quality of life assessed by the Moorehead-Ardelt II questionnaire
Quality of life will be assessed using the Moorehead-Ardelt II questionnaire, a bariatric surgery-specific instrument that evaluates domains including self-esteem, physical well-being, social relationships, work, and sexuality. Total score (and domain scores, if applicable) will be compared before and after the intervention.
Measured: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Feb 2026
- Study start11 Aug 2025
- Primary completion31 Dec 2027 (estimated)
- Study completion31 Dec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (12)Papers the sponsor has linked to this study.
- Other trials for Obesity & OverweightStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- This is a single-center, prospective, longitudinal, randomized controlled trial with two parallel groups (intervention and control). Participants will enter the study during the fourth postoperative week and will be assessed at baseline and at week 7. Both groups will receive exercise programs designed according to the FITT principle (Frequency, Intensity, Time, and Type of exercise). The intervention group will complete a structured, semi-supervised concurrent exercise program combining aerobic and resistance training with planned progression of exercise intensity and training volume. The control group will receive the usual institutional metabolic rehabilitation program at Clínica BUPA Santiago, including supervised continuous aerobic exercise, targeted muscle strengthening, and stretching according to the standard clinical protocol.
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 87 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Universidad Autónoma de Chile
- Sponsor type
- University, hospital or other
- Collaborators
- Clinica Bupa Santiago
- Responsible party
- Principal investigator, María José Pabst, Universidad Autónoma de Chile
- Investigators
- María José Pabst Pérez, MSc, Principal investigator, Universidad Autónoma de ChileTomás Vergara Soria, Kinesiólogo, Principal investigator, Clínica BUPA SantiagoSebastian Barrios Valenzuela, Kinesiólogo, Study chair, Clínica BUPA SantiagoLuis Astete, MSc, Study chair, Universidad Autónoma de ChileNicolas Arancibia Ramirez, Kinesiólogo, Study chair, Clinica AlemanaErika Troncoso, MsC, Study chair, Clinica las CondesRosario Alonso Domínguez, PhD., Study director, Universidad de Salamanca. EspañaMaría de la Luz Tocino, PhD., Study director, University of Salamanca
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07423780
- Sponsor's protocol ID
- CEC CBS /4-2026
- Acronym
- BAR-EX
- Status last verified
- Sep 2026
- First submitted
- 14 Nov 2025
- Last updated
- 25 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data (IPD) will not be publicly shared to protect patient confidentiality. Only aggregated and anonymized results will be disseminated through scientific publications or presentations.
Publications
Otto-Yanez M, Torres-Castro R, Barros-Poblete M, Barros M, Valencia C, Campos A, Jadue L, Puppo H, Seron P, Vilaro J. One-minute sit-to-stand test: Reference values for the Chilean population. PLoS One. 2025 Jan 29;20(1):e0317594. doi: 10.1371/journal.pone.0317594. eCollection 2025.
PubMed 39879255Complicaciones a largo plazo y efectos secundarios de la cirugía bariátrica: una revisión sistemática. Journal of Negative and No Positive Results, 6(6), 582-589. https://doi.org/10.19230/jonnpr.1584
Moorehead MK, Ardelt-Gattinger E, Lechner H, Oria HE. The validation of the Moorehead-Ardelt Quality of Life Questionnaire II. Obes Surg. 2003 Oct;13(5):684-92. doi: 10.1381/096089203322509237.
PubMed 14627461Gonzalez-Molero I, Garcia Arnes JA, Dominguez Lopez M, Gallego JL. [Persistent hypoglycemia in a patient with bariatric surgery]. Med Clin (Barc). 2011 Oct 22;137(11):522-3. doi: 10.1016/j.medcli.2011.01.001. Epub 2011 Mar 10. No abstract available. Spanish.
PubMed 21396666National Institute of Diabetes and Digestive and Kidney Diseases. (2020). Efectos secundarios de la cirugía para adelgazar (bariátrica). Recuperado de https://www.niddk.nih.gov/health-information/informacion-de-la-salud/control-de-peso/cirugia-adelgazar-bariatrica/efectos-secundarios
Muñoz, R., Hernández, J., Palacio, A., Maiz, C., & Pérez, G. (2016). El ejercicio físico disminuye la pérdida de masa magra en pacientes obesos sometidos a cirugía bariátrica. Revista Chilena de Cirugía, 68(6), 303-308. https://doi.org/10.1016/j.rchic.2016.05.007
Alvero-Cruza, J. R., Correas Gómez, L., Ronconi, M., Fernández Vázquez, R., & Porta i Manzanido, J. (2011). La bioimpedancia eléctrica como método de estimación de la composición corporal, normas prácticas de utilización[Bioelectrical impedance analysis as a method of body composition
Cancino-Ramirez J, Troncoso-Ortiz EJ, Pino J, Olivares M, Escaffi MJ, Riffo A, Podesta D I, Vasquez M M, Gonzalez-Rojas L. [Exercise and physical activity in adults who underwent bariatric surgery. Consensus document]. Rev Med Chil. 2019 Nov;147(11):1468-1486. doi: 10.4067/S0034-98872019001101468. Spanish.
PubMed 32186608McIver CM, Wycherley TP, Clifton PM. MTOR signaling and ubiquitin-proteosome gene expression in the preservation of fat free mass following high protein, calorie restricted weight loss. Nutr Metab (Lond). 2012 Sep 14;9(1):83. doi: 10.1186/1743-7075-9-83.
PubMed 22974011Tamboli RA, Hossain HA, Marks PA, Eckhauser AW, Rathmacher JA, Phillips SE, Buchowski MS, Chen KY, Abumrad NN. Body composition and energy metabolism following Roux-en-Y gastric bypass surgery. Obesity (Silver Spring). 2010 Sep;18(9):1718-24. doi: 10.1038/oby.2010.89. Epub 2010 Apr 22.
PubMed 20414197Pleticosic-Ramírez Y, Mecías Calvo M, Navarro-Patón R. Efectos de programas de ejercicio físico en la composición corporal, condición física y calidad de vida de personas mayores con sobrepeso u obesidad: Una revisión sistemática effects of physical exercise programs on body composition, physical fitness and quality of life in older people with overweight or obesity: A systematic review.
Thomas-Lange J. Sobrepeso y obesidad en chile: Consideraciones para su abordaje en un contexto de inequidad social. Rev chil nutr. 2023;50(4):457. doi: 10.4067/s0717-75182023000400457.
Study at a glance
From the registry record, last updated by the sponsor on 25 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of a Concurrent Exercise Program on Muscle Quality, Body Composition, Functional Response, and Quality of Life in Individuals Undergoing Bariatric Surgery: Protocol for a Randomized Controlled Clinical Trial
- ClinicalTrials.gov ID
- NCT07423780
- Acronym / sponsor ID
- BAR-EX / CEC CBS /4-2026
- Conditions
- Obesity & Overweight, Post-bariatric Surgery
- Keywords
- Muscle quality, Body composition, Functional capacity, Therapeutic exercise, Quality of life, concurrent exercise, one-minute sit-to-stand, ectus femoris ultrasound
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 87 participants (estimated)
- Lead sponsor
- Universidad Autónoma de ChileUniversity, hospital or other
- Collaborators
- Clinica Bupa Santiago
- Study start
- 11 Aug 2025 (actual)
- Primary completion
- 31 Dec 2027 (estimated)
- Study completion
- 31 Dec 2028 (estimated)
- First posted
- 20 Feb 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study aims to evaluate the effect of a 5-week concurrent exercise program (aerobic and resistance training) on muscle quality, body composition, functional response, and quality of life in individuals undergoing bariatric surgery.
This is a single-center, prospective, longitudinal, randomized controlled clinical trial with two parallel groups: an intervention group and a control group. A total of 87 adults aged 18 to 60 years who have undergone sleeve gastrectomy or Roux-en-Y gastric bypass and have a medical indication for metabolic rehabilitation will be recruited.
The intervention group will participate in a structured, semi-supervised concurrent exercise program for 5 weeks, consisting of two in-person sessions per week (10 sessions in total), whereas the control group will continue receiving usual kinesiology care and standard clinical management according to the institutional rehabilitation protocol at Clínica BUPA Santiago. All participants will be assessed at two time points: baseline, during the fourth postoperative week, and at week 7.
The primary outcome will be the change in rectus femoris muscle quality assessed by ultrasound (echo intensity). Secondary outcomes will include body composition (bioelectrical impedance analysis), functional response (One-minute Sit-to-Stand Test), and quality of life (Moorehead-Ardelt II questionnaire).
Additionally, adherence to the exercise program in the intervention group will be assessed as the percentage of attendance at supervised exercise sessions, and its association with the magnitude of changes in study outcomes will be explored.
The findings are expected to provide clinically relevant evidence regarding the effectiveness of exercise during the early postoperative period and to contribute to the optimization of metabolic rehabilitation strategies following bariatric surgery.
Detailed description
Bariatric surgery is an effective treatment for severe obesity; however, the early postoperative period is frequently associated with loss of lean body mass, reduced muscle strength, and functional decline, which may negatively affect recovery and quality of life. Physical exercise has been proposed as a key component of metabolic rehabilitation, although evidence regarding structured concurrent exercise programs initiated early after bariatric surgery remains limited, particularly with respect to muscle quality.
The aim of this study is to evaluate the effect of a 5-week concurrent exercise program on rectus femoris muscle quality in individuals undergoing bariatric surgery, compared with a control group receiving usual kinesiology care. Secondary objectives include evaluating changes in body composition, functional response, and quality of life, as well as exploring the association between exercise adherence and the magnitude of observed changes.
This is a single-center, prospective, longitudinal, randomized controlled clinical trial with two parallel groups (intervention and control). A total of 87 adults aged 18-60 years who have undergone sleeve gastrectomy or Roux-en-Y gastric bypass at Clínica BUPA Santiago and have a medical indication for metabolic rehabilitation will be recruited. Participants will undergo baseline assessment during the fourth postoperative week and will then be randomly allocated in a 1:1 ratio to the intervention or control group using a sequence generated and administered by an individual independent of the assessors and treating physical therapists.
The intervention group will participate in a structured, semi-supervised 5-week concurrent exercise program designed according to the FITT principle (Frequency, Intensity, Time, and Type of exercise). The program will combine aerobic and resistance training and will include two supervised in-person sessions per week (10 sessions in total) plus one complementary home-based session each week. Aerobic training will progress from continuous moderate-intensity exercise to interval training, whereas resistance training will progressively increase training volume for large muscle groups. Exercise intensity will be monitored using the Borg Rating of Perceived Exertion scale, and resistance loads will be individually adjusted according to each participant's clinical tolerance.
Participants allocated to the control group will continue receiving usual kinesiology care and standard clinical management according to the institutional metabolic rehabilitation protocol at Clínica BUPA Santiago. This program will also follow the FITT principle and will include two supervised sessions per week consisting of continuous aerobic exercise, targeted muscle strengthening, and static stretching, consistent with routine clinical practice, without the structured progression incorporated into the concurrent exercise program.
Following the 5-week intervention period, both groups will complete one week without supervised exercise sessions to minimize the acute effects of exercise on muscle measurements. Final assessments will be performed at week 7.
The primary outcome will be the change in rectus femoris muscle quality assessed by musculoskeletal ultrasound using echo intensity as the primary indicator. Secondary outcomes will include body composition assessed by bioelectrical impedance analysis, functional response assessed using the One-minute Sit-to-Stand Test, and quality of life assessed using the Moorehead-Ardelt II questionnaire.
Exercise adherence will be assessed exclusively in the intervention group as the percentage of attendance at supervised exercise sessions. The association between adherence and the magnitude of outcome changes will also be explored using a dose-response approach.
Statistical analyses will follow the intention-to-treat principle. The primary analysis will be performed using analysis of covariance (ANCOVA), with study group as the fixed factor and baseline values as covariates, adjusting for prespecified clinically relevant covariates when appropriate. Secondary outcomes will be analyzed using the same approach. Complementary analyses will include within- and between-group comparisons using parametric or non-parametric tests according to data distribution, estimation of effect sizes, and exploratory correlation and linear regression analyses to evaluate the association between exercise adherence and changes in study outcomes.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
- Model description
- This is a single-center, prospective, longitudinal, randomized controlled trial with two parallel groups (intervention and control). Participants will enter the study during the fourth postoperative week and will be assessed at baseline and at week 7. Both groups will receive exercise programs designed according to the FITT principle (Frequency, Intensity, Time, and Type of exercise). The intervention group will complete a structured, semi-supervised concurrent exercise program combining aerobic and resistance training with planned progression of exercise intensity and training volume. The control group will receive the usual institutional metabolic rehabilitation program at Clínica BUPA Santiago, including supervised continuous aerobic exercise, targeted muscle strengthening, and stretching according to the standard clinical protocol.
| Arm | Type | Receives |
|---|---|---|
| Concurrent Physical Exercise Program | Experimental | Behavioral: Concurrent Exercise ProgramParticipants allocated to the intervention group will complete a structured, semi-supervised concurrent exercise program during the postoperative period following bariatric surgery. Participants will enter the study during postoperative week 4 and undergo a baseline assessment before starting the intervention. The program will last 5 weeks and will include 10 supervised in-person sessions (2 sessions/week, approximately 60 minutes each) and one complementary home-based session per week. After completion of the intervention, participants will remain one week without supervised exercise sessions before the week 7 follow-up assessment. |
| Usual Metabolic Rehabilitation Program | Active comparator | Behavioral: Usual Metabolic Rehabilitation ProgramParticipants allocated to the control group will receive the usual metabolic rehabilitation program at Clínica BUPA Santiago. The rehabilitation program will follow the FITT principle (Frequency, Intensity, Time, and Type of exercise) and will include two supervised sessions per week for 5 weeks consisting of continuous aerobic exercise, targeted muscle strengthening, and stretching according to the institutional protocol. All participants will undergo baseline and week 7 assessments. |
Who may qualify
- Ages
- 18 to 60 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Adults aged 18-60 years.
- Participants eligible for the institutional PAD (Pago Asociado a Diagnóstico) bariatric surgery program with medical indication for metabolic rehabilitation.
- Undergoing sleeve gastrectomy or Roux-en-Y gastric bypass at Clínica BUPA Santiago.
- Medical indication for metabolic rehabilitation.
- Able and willing to provide written informed consent.
Key exclusion criteria (7 listed)
- Type 1 diabetes mellitus or type 2 diabetes mellitus with severe complications (including stage G4-G5 nephropathy, severe autonomic neuropathy, or high risk of exercise-related hypoglycemia).
- Severe musculoskeletal disorders limiting participation in the exercise program.
- Acute cardiovascular event within the previous 3 months or medical contraindication to supervised exercise.
- Severe cardiorespiratory disease or dyspnea at rest or with minimal exertion.
- Dependence on supplemental oxygen.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Concurrent Exercise ProgramAlso: Concurrent Physical Exercise ProgramConcurrent physical exercise program of 5 weeks combining aerobic and resistance training in individuals undergoing bariatric surgery. The program includes two supervised in-person sessions per week (10 sessions total), each lasting approximately 60 minutes, and one recommended weekly home-based session guided by a prescribed exercise plan. Aerobic exercise is performed at moderate to high intensity, monitored using the Borg Rating of Perceived Exertion scale. Resistance training targets major muscle groups and is prescribed based on an estimated one-repetition maximum (1RM), with progression in volume and intensity according to individual tolerance and safety criteria. The program begins at postoperative week 4. After completing the 5-week intervention, participants undergo a 1-week period without supervised sessions before the post-intervention assessment. | Behavioural | Concurrent Physical Exercise Program |
| Usual Metabolic Rehabilitation ProgramUsual institutional metabolic rehabilitation program at Clínica BUPA Santiago based on the FITT principle (Frequency, Intensity, Time, and Type of exercise). The program includes supervised continuous aerobic exercise, targeted muscle strengthening, and stretching delivered twice weekly for 5 weeks according to the institutional clinical protocol. | Behavioural | Usual Metabolic Rehabilitation Program |
Primary outcome
Change in rectus femoris muscle quality (echo intensity; grayscale units 0-255)
Time frame: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Muscle quality will be assessed by ultrasound as echo intensity (mean grayscale value, 0-255) within a standardized region of interest, analyzed using ImageJ, at baseline and post-intervention. Change will be calculated as Δ = post - pre.
11 secondary outcomes
Change in percent body fat (%)
Time frame: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Change in fat mass (kg)
Time frame: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Change in skeletal muscle mass (kg)
Time frame: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Change in 1-minute Sit-to-Stand performance (1min-STST)
Time frame: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Adherence to the exercise program (supervised in-clinic sessions)
Time frame: During the 5-week intervention period (calculated at the end of the program based on attendance to the 10 supervised sessions).
Change in visceral fat area (cm²)
Time frame: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Change in basal metabolic rate (kcal/day)
Time frame: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Change in rectus femoris muscle thickness (cm)
Time frame: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Change in rectus femoris cross-sectional area (cm²)
Time frame: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Change in intramuscular fat infiltration assessed by ultrasound echo intensity (grayscale units 0-255)
Time frame: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of intervention and 1 week of rest).
Change in quality of life assessed by the Moorehead-Ardelt II questionnaire
Time frame: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 25 Sep 2026.
- Background: PubMed 39879255Otto-Yanez M, Torres-Castro R, Barros-Poblete M, Barros M, Valencia C, Campos A, Jadue L, Puppo H, Seron P, Vilaro J. One-minute sit-to-stand test: Reference values for the Chilean population. PLoS One. 2025 Jan 29;20(1):e0317594. doi: 10.1371/journal.pone.0317594. eCollection 2025.
- BackgroundComplicaciones a largo plazo y efectos secundarios de la cirugía bariátrica: una revisión sistemática. Journal of Negative and No Positive Results, 6(6), 582-589. https://doi.org/10.19230/jonnpr.1584
- Results publication: PubMed 14627461Moorehead MK, Ardelt-Gattinger E, Lechner H, Oria HE. The validation of the Moorehead-Ardelt Quality of Life Questionnaire II. Obes Surg. 2003 Oct;13(5):684-92. doi: 10.1381/096089203322509237.
- Results publication: PubMed 21396666Gonzalez-Molero I, Garcia Arnes JA, Dominguez Lopez M, Gallego JL. [Persistent hypoglycemia in a patient with bariatric surgery]. Med Clin (Barc). 2011 Oct 22;137(11):522-3. doi: 10.1016/j.medcli.2011.01.001. Epub 2011 Mar 10. No abstract available. Spanish.
- Results publicationNational Institute of Diabetes and Digestive and Kidney Diseases. (2020). Efectos secundarios de la cirugía para adelgazar (bariátrica). Recuperado de https://www.niddk.nih.gov/health-information/informacion-de-la-salud/control-de-peso/cirugia-adelgazar-bariatrica/efectos-secundarios
- Results publicationMuñoz, R., Hernández, J., Palacio, A., Maiz, C., & Pérez, G. (2016). El ejercicio físico disminuye la pérdida de masa magra en pacientes obesos sometidos a cirugía bariátrica. Revista Chilena de Cirugía, 68(6), 303-308. https://doi.org/10.1016/j.rchic.2016.05.007
- Results publicationAlvero-Cruza, J. R., Correas Gómez, L., Ronconi, M., Fernández Vázquez, R., & Porta i Manzanido, J. (2011). La bioimpedancia eléctrica como método de estimación de la composición corporal, normas prácticas de utilización[Bioelectrical impedance analysis as a method of body composition
- Results publication: PubMed 32186608Cancino-Ramirez J, Troncoso-Ortiz EJ, Pino J, Olivares M, Escaffi MJ, Riffo A, Podesta D I, Vasquez M M, Gonzalez-Rojas L. [Exercise and physical activity in adults who underwent bariatric surgery. Consensus document]. Rev Med Chil. 2019 Nov;147(11):1468-1486. doi: 10.4067/S0034-98872019001101468. Spanish.
- Results publication: PubMed 22974011McIver CM, Wycherley TP, Clifton PM. MTOR signaling and ubiquitin-proteosome gene expression in the preservation of fat free mass following high protein, calorie restricted weight loss. Nutr Metab (Lond). 2012 Sep 14;9(1):83. doi: 10.1186/1743-7075-9-83.
- Results publication: PubMed 20414197Tamboli RA, Hossain HA, Marks PA, Eckhauser AW, Rathmacher JA, Phillips SE, Buchowski MS, Chen KY, Abumrad NN. Body composition and energy metabolism following Roux-en-Y gastric bypass surgery. Obesity (Silver Spring). 2010 Sep;18(9):1718-24. doi: 10.1038/oby.2010.89. Epub 2010 Apr 22.
- Results publicationPleticosic-Ramírez Y, Mecías Calvo M, Navarro-Patón R. Efectos de programas de ejercicio físico en la composición corporal, condición física y calidad de vida de personas mayores con sobrepeso u obesidad: Una revisión sistemática effects of physical exercise programs on body composition, physical fitness and quality of life in older people with overweight or obesity: A systematic review.
- Results publicationThomas-Lange J. Sobrepeso y obesidad en chile: Consideraciones para su abordaje en un contexto de inequidad social. Rev chil nutr. 2023;50(4):457. doi: 10.4067/s0717-75182023000400457.
- Individual participant dataSharing planned: No. Individual participant data (IPD) will not be publicly shared to protect patient confidentiality. Only aggregated and anonymized results will be disseminated through scientific publications or presentations.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
María José Pabst Pérez, MSc principal investigator
Universidad Autónoma de Chile
Tomás Vergara Soria, Kinesiólogo principal investigator
Clínica BUPA Santiago
Sebastian Barrios Valenzuela, Kinesiólogo study chair
Clínica BUPA Santiago
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Concurrent Exercise Program and Usual Metabolic Rehabilitation Program in people with Obesity & Overweight and Post-bariatric Surgery, run by Universidad Autónoma de Chile at 1 site in Chile.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 25 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Chile. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact María José Pabst Perez, MSc (+56950023025, majose.pabst@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in rectus femoris muscle quality (echo intensity; grayscale units 0-255) (time frame: Baseline (pre-intervention) and 7 weeks after baseline (after 5 weeks of exercise and 1 week of rest).). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07423780, which also lists 12 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 25 Sep 2026.