Participants, interventions and outcomes
Study setting {9}
The study will be carried out at the Department of Physical Medicine and Rehabilitation Service in the San Juan de Dios Hospital, a public hospital in the city of Curicó, located at Chacabuco # 121 street, in the Maule region, Chile. All procedures will be conducted by at least two experienced physiotherapists and the department is strategically located to ensure that any medical emergencies can be promptly cared for. All procedures will be performed in a room with controlled temperature (22 – 24ºC) and air humidity (40 – 60%).
Eligibility criteria {10}
Inclusion criteria
Participants of either sex will be considered eligible if they are between 18 and 65 years old, have undergone bariatric surgery at the above-mentioned hospital, have been cleared for exercise, are in the final phase of operative wound healing, have been administered antithrombotics after surgery and have no plans to change their residence in the year after surgery.
Exclusion criteria
Participants with immediate postoperative complications (anastomosis or wound dehiscence) or decompensated comorbidities, who are on dialysis, or who suffer from a neuromotor disease will be excluded.
Who will take informed consent? {26a}
After receiving a list of patients scheduled for bariatric surgery from a staff member of Bariatric Surgery Service of the hospital, AHS will telephone each patient, invite them to participate, and make an individual appointment. In this, the objective of the study, inclusion and exclusion criteria, participation, risks, benefits and ethical implications will be explained. In the case that the potential participant wants to participate in the research, the informed consent will be signed in 3 copies. One for the participants, one for the researcher and one for de clinical record from the hospital.
Additional consent provisions for collection and use of participant data and biological specimens {26b}
Not applicable, this trial does not have biological specimens.
Interventions
Explanation for the choice of comparators {6b}
Participants will be randomly assigned to one of the three groups: 1) a control group (CG) that will receive standardized recommendations; 2) a moderate-intensity continuous exercise training group (MICT-G); or 3) a high-intensity interval exercise training group (HIIT-G).
Intervention description {11a}
Participants allocated to the MICT and HIIT groups will perform two weekly sessions of supervised exercise for 16 weeks. Sessions will be divided into a 3-week adaptation period and 13 weeks of formal training. All sessions will consist of:
- Join Mobility (3 minutes): head and neck, shoulder, elbow, wrist, hip, knee, ankle and trunk.
- Warm-up (7 minutes): treadmill walking at 1-2 km/h.
- Aerobic Component: MICT group: 15 minutes on a cycle ergometer at moderate intensity (40-60% of Heart Rate Reserve) or at a perceived exertion rating of 5-6 out of 10. HIIT group: 8 minutes on a cycle ergometer, including a 60-second sprint at 90% maximal heart rate followed by a 60-second rest until four sets are completed.'
- Strength training: 15 minutes of exercise in the large muscle groups with weight machines or dumbbells, including 1-2 sets of 8-10 repetitions at 50-60% of one-repetition maximum strength (1RM).
- Cool-down (5 minutes): proprioceptive neuromuscular facilitation exercises for abdominal muscles and the pelvic floor will be performed on a mat. Stretching exercises for arm, leg, and trunk muscles will be performed in three 30-second sets. Hemodynamic variables will be checked to ensure that blood pressure and heart rate values return to baseline.
Exercise Progression
Beginning with the fourth week, the aerobic load in the MICT group will be adjusted to 60% of the heart rate reserve and the duration will be adjusted to 30 min. In the HIIT group, the number of sets will be increased to 1 by week until 10 sprints. Strengthening exercises will be performed in 3 sets of 10-12 repetitions, with intensities between 60-70% 1RM. The 1RM value will be assessed at baseline and week 8.
During both training programs, heart rate, blood pressure, oxygen saturation and perceived exertion will be evaluated with the Borg CR-10 scale.
Participants allocated to the CG will be follow the indications of regular physical activity practice according to WHO (at least 150 minutes per week of moderate physical activity or at least 75 minutes of intense physical activity), will be explained by ATA. The protocol followed by all patients operated of bariatric surgery at the San Juan de Dios hospital is to receive these indications.
Criteria for discontinuing or modifying allocated interventions {11b}
Will be criteria for discontinuing: participant request, severe alteration of hemodynamic parameters during the training, participants who attend less than 85% of the training sessions, participants who were absent on evaluation days and participants from the training group who engage other regular physical exercise.
Strategies to improve adherence to interventions {11c}
Not applicable, this trial does not have strategies to improve adherence.
Relevant concomitant care permitted or prohibited during the trial {11d}
Not applicable, this trial does not have concomitant care permitted or prohibited.
Provisions for post-trial care {30}
Once the study is completed, the CG and group with less effect of the study, will be invited to carry out the training that has obtained the best effect.
Outcomes {12}
Outcomes will be assessed at four time points: 1) one week before surgery; 2) 21 days after surgery (baseline before starting the exercise program); 3) 8 weeks after the beginning of the exercise program; and 4) one week after the end of intervention.
Primary outcomes will be: 1) body composition; 2) heart rate variability; 3) six-minute walk test results and 4) perceived quality of life. Secondary outcomes include the results for: 1) maximal respiratory pressure, 2) flowmeter, 3) hand dynamometry, 4) the 30- second sit-to-stand test and 5) the basal metabolic rate.
Data collection will include sex, age, place of residence, marital status, education level, and physical activity level according to the International Physical Activity Questionnaire [29].
Body Composition
Body composition will be measured with tetrapolar bioelectrical impedance, (INBODY 270, Inbody Co. Ltd, Korea). The body fat percentage, muscle and bone mass, and basal metabolic rate will be evaluated.
Heart rate variability
R-R intervals will be recorded with a Polar V800 heart rate monitor (Polar, Oi, Finland); a sensor will be placed on the chest at the fifth intercostal space. The participant will then rest in the supine position for 10 minutes to stabilize heart rate and blood pressure. R-R intervals will be recorded under the following conditions: 1) after resting in the supine position for 10 minutes; 2) after resting in the orthostatic position for 10 minutes (active standing). The participants’ respiratory rate will be recorded throughout the test.
Heart rate variability will be analysed through spectral analysis in an autoregressive model. The spectral components will be obtained at low frequency (LF, 0.04-0.15 Hz) and high frequency (HF, 0.15-0.4 Hz) bands in absolute units (ms2). Standardized units are calculated as the ratio between LF or HF (absolute units) and the power spectral density, minus the very low frequency component (VLF, 0.003-0.04 Hz) and multiplied by 100. The LF band is modulated by the sympathetic and parasympathetic autonomic nervous system (with sympathetic predominance), the HF band is associated with cardiac vagal control, and the LF/HF ratio is calculated to assess sympathovagal balance [30].
Maximal respiratory pressures
Maximal inspiratory (MIP) and expiratory (MEP) pressure will be assessed with a respiratory pressure meter (MicroRPM, MicroMedical Ltd., Kent, UK). All measurements will be performed with the participant seated, using a 2 mm aperture mouthpiece and a nose clip to prevent air leakage. MIP will be measured from residual volume, whereas MEP will be measured from total lung capacity. Clear instructions about performing the test will be provided [31].
Flowmeter
While the patient is seated, a mini-Wright flowmeter (Clement Clarke, Mason, OH, USA), nosepiece, and disposable nozzle will be used to measure peak expiratory flow. Peak expiratory flow measurement will be based on maximum inspiration. After being instructed the use of the flowmeter, the patients will be asked to blow as hard and as long as possible [32].
Hand dynamometry
To evaluate handgrip strength, a digital dynamometer will be used (CAMRY EH101, Guangdong, China). After being instructed about the test and use of the dynamometer, the participants will perform a maximal isometric contraction for 5 seconds with each hand while standing [33].
Six-minute walk test
The six-minute walk test will be used to evaluate functional capacity. It will take place in a flat corridor with a 15-meter track. A cone will be placed at each meter to determine the beginning and ending distance. Participants will be instructed to walk back and forth as quickly as possible for 6 minutes, and the total distance covered during will be recorded. Before and after the test, blood pressure, heart rate and oxygen saturation values will be measured. Verbal encouragement will be given every minute, according to Mexican National Institute of Respiratory Disease guidelines [34].
Perceived quality of life
The Moorehead-Ardelt quality of life questionnaire II will be applied at each evaluation, and the Bariatric Analysis and Reporting Outcomes System (BAROS), which has been validated for bariatric surgery patients, will be applied at the final evaluation [35, 36].
Moorehead-Ardelt quality of life questionnaire II
This test measures quality of life in 6 dimensions: self-esteem, physical activity, social activity, work activity and sexual activity. Each dimension has 10 response options that are accompanied by images for clarification. Each answer is scored through a visual scale ranging from -0.5 (most unfavourable situation) to +0.5 (most favourable situation). The sum of all dimensions produces a global score: very good (2.1 to 3), good (1.1 to 2), fair (-1 to 1), poor (-2 to -1.1) and very poor (-3 to -2.1).
Bariatric Analysis and Reporting Outcomes System
This test measures quality of life and the benefits of bariatric surgery by incorporating the weight loss or gain percentage after surgery into the Moorehead-Ardelt questionnaire, including comorbidity resolution, reoperation and complications. While the Moorehead-Ardelt scoring is identical to that described above, the other items are scored according to dimension. Scores for the weight loss dimension (as percent of excess weight lost) were: -1 (0-24%), 0 (25-49%), 1 (50-74%), 2 (75-100%). Scores for the comorbidities dimension were: -1 (aggravated), 0 (no changes), 1 (some improvement), 2 (one major comorbidity resolved and improvement in others), 3 (all major comorbidities resolved and all others improved). Scores for the complications dimension were: deduct 0.2 points for a minor complication, deduct 1 point for a major complication, deduct 1 point for reoperation. Global scores for the instrument are the sum of all dimensions, categorized as failure (≤1), fair (>1 to 3), good (>3 to 5), very good (>5 to 7) and excellent (>7 to 9).
Thirty-second sit-to-stand test
Participants will be instructed to cross their arms over their chest and stand in front of a reinforced 44-cm-high chair that is positioned against a wall. They will then sit and stand as many times as possible in 30 seconds, and the number of repetitions will be recorded.
Participant timeline {13}
Fig. 1 show the recommended SPIRIT figure with the participant timeline.
Sample size {14}
GPower 3.1 was used to determine the sample size, assuming a power of 80% and a significance level of 5%. Calculations were based on Herring et al. [37], considering BMI and heart rate as primaries outcomes. This study compared the effects of MICT versus a control group in patients post bariatric surgery. The higher sample size was obtained for the outcome ‘heart rate’. A total of 17 participants per group were required to detect a significant decrease in the heart rate (effect size = 1.01). However, due to possible dropouts, 25 participants will be included in each group, totaling 75 volunteers.
Recruitment {15}
Participants recruitment will occur weekly. A list of patients who are scheduled to have bariatric surgery will be provided by a staff member of the San Juan de Dios, Curicó´s Hospital, Chile. Participants who are interested and meet inclusion criteria will be invited to participate in the study after signing the informed consent.
Assignment of interventions: allocation
Sequence generation {16a}
Concealment mechanism {16b}
Implementation {16c}
After baseline assessment, randomization will be performed using sealed opaque envelopes. Envelopes will contain a piece of paper containing the letters A, B or C, corresponding to the three groups of the current study. An independent researcher (i.e., not involved in the current study) will organize the envelopes in numerical order and will keep them in a safe place until baseline assessments are concluded. Then, the envelope labelled with the same number as assigned to the participants when they were included in the study will be unsealed and informed to the leading research. Participants could be assigned to one of the three groups: 1) control group, 2) moderate-intensity continuous training group and 3) high-intensity interval training group. The Figure 2 shows the study design flow chart describing all the steps of the study (Fig. 2).
Assignment of interventions: Blinding
Who will be blinded {17a}
This will be a single-blinded study where the outcome assessor (i.e., the researcher in charge of the evaluations) will have no information about the participants study group.
Procedure for unblinding if needed {17b}
Not applicable, unblinding is not permissible in this trial.
Data collection and management
Plans for assessment and collection of outcomes {18a}
The assessments will be carried out at the institution’s Physical Medicine and Rehabilitation Service, and the intervention program will be carried out in the Service’s Adult Physical Therapy Gym. All the assessments will be conducted by a trained and experienced physical therapist (outcome assessor). Prior the start of the study, was trained and familiarized with the evaluation protocol.
Plans to promote participant retention and complete follow-up {18b}
A weekly phone call will be made to CG participants, asking about their health status and the indications for this group will be reinforced, in turn a text message will be sent to remind the evaluation date and time.
Participants who are in the training groups, in each session will be asked for feedback on their health status and will be sent a text message to remind them the training schedule.
In the event that any participant misses their training or evaluation, they will immediately proceed to call to ask about the reasons for not showing up.
Data management {19}
All the information collected from this trial will always be protected and in the care of the lead research, who will assign a secure locker in his office where all documents of the investigation will be kept.
All electronic material will be duly stored and backed up in the researcher's computer equipment with a safe password.
Confidentiality {27}
In order to keep confidentiality after the assessments, the outcomes assessor will store the participants' data separately from any identifying information and coded with a unique study ID. This ID will be linked to participant identity only within an encrypted, password-protected local database running on a secure host device maintained by outcome assessor and the study supervisor.
Plans for collection, laboratory evaluation and storage of biological specimens for genetic or molecular analysis in this trial/future use {33}
Not applicable, this trial does not have biological specimens.
Statistical methods
Statistical methods for primary and secondary outcomes {20a}
Data normality will be assessed with the Shapiro-Wilk test. Variance homogeneity and sphericity will be assessed with the Levene and Mauchly tests, respectively. For the primary and secondary outcomes that meet the assumptions for the analysis of variance (ANOVA), a mixed model ANOVA with Bonferroni correction will be used to assess the interaction between Group (control group vs MICT vs HIIT) and Time (Baseline vs Post 8-week intervention vs Post 16-week intervention). Otherwise, data will be analyzed with the Wilcoxon test for within groups comparisons and the Mann-Whitney test for between groups comparisons using the Bonferroni’s correction. The significance level will be set at 5%. Cohen’s d will be calculated to determine the effect size. All analysis will be performed in SPSS 24.
Interim analyses {21b}
Not Applicable. Interim analyses will not be performed in the present study.
Methods for additional analyses (e.g. subgroup analyses) {20b}
Not Applicable. Additional analyses are not planned in the present study.
Methods in analysis to handle protocol non-adherence and any statistical methods to handle missing data {20c}
Per-protocol and intention-to-treat analysis will be performed in order to account for the possible dropouts during the study. In the per-protocol analysis, we will include only the participants who attended at least 85% of the sessions and underwent the baseline and post intervention outcome assessments. For the intention-to-treat analysis, we will consider all the participants who underwent the baseline assessments and after being assigned to one of the study groups, took part in at least one session. Missing data will be handled by multiple imputation method. Five imputed data sets will be obtained by multiple linear regression models for each variable. The final imputed value will be the arithmetic mean of the 5 data values created.
Plans to give access to the full protocol, participant level-data and statistical code {31c}
Not Applicable. Public access to the full protocol, data sets and statistical code are not planned for this trial. However, this information might be available upon a reasonable request to the corresponding author keeping participants anonymity.
Oversight and monitoring
Composition of the coordinating centre and trial steering committee {5d}
The centre is coordinated by ATA and the leading researcher AHS. The trial will be directed by the principal investigators AHS and ARZ. No additional steering committee is considered for this study. All researchers will meet weekly to discuss the research progress and possible unforeseen events.
Composition of the data monitoring committee, its role and reporting structure {21a}
No additional monitoring committee is considered for this study. The leading investigators (AHS and ARZ) will meet weekly with all the researchers involved in this study to discuss the research progress and any adverse event that arises during the procedures. Researchers are instructed to report any issue to the leading investigators immediately, who will then inform the board review committee from the San Juan de Dios, Curicó´s Hospital, and the Ethics Committee of the Universidad Católica del Maule, Talca, Chile, when appropriate.
Adverse event reporting and harms {22}
In the end of each training session and evaluations participants will be asked to report any complains and symptoms produced by the proposed activity. Outcome assessor and the lead researcher will be in charge to collect and record this information throughout the study. All complications and dropouts will be reported in the final manuscript.
Frequency and plans for auditing trial conduct {23}
The trial conduct will be continuously monitored by the leading investigators. The San Juan de Dios, Curicó´s Hospital Review Board requires monthly report to get informed about the research’s progress and the occurrence of any adverse event. No extra auditing is considered for this study, unless requested by the Hospital’s Review Board or the Ethics Committee of the Universidad Católica del Maule.
Plans for communicating important protocol amendments to relevant parties (e.g. trial participants, ethical committees) {25}
Protocol amendments need to be informed and approved by the San Juan de Dios, Curicó´s Hospital Review Board and the Ethics Committee of the Universidad Católica del Maule. Modifications will be updated at the clinicaltrials.gov by the leading investigator (AHS).
Dissemination plans {31a}
Each participant will receive a full report with the results of their assessments. By the end of the study, the leading researcher will contact all the participants to provide the final results of the trial and to deliver educative material with information about healthy lifestyle and exercise recommendation. Secondary outcomes and preliminary results will be reported in local and international conferences. The final results will be submitted to a peer‑reviewed indexed scientific journal within the 5 years after the last participant was enrolled.