"Effectiveness of Supervised and Unsupervised mHealth-based Exercise Interventions on Clinical Outcomes in Adults With Type 2 Diabetes and Obesity Within a Primary Care Context"

Effectiveness of Supervised and Unsupervised mHealth-based Exercise Interventions on Clinical Outcomes in Adults With Type 2 Diabetes and Obesity Within a Primary Care Context: a Randomized Controlled Trial Protocol

Type 2 diabetes (T2D) and obesity are two of the most common chronic conditions worldwide, and they frequently occur together. Both conditions are closely linked to physical inactivity, which is currently recognized as a major risk factor for a wide range of diseases. Although structured exercise programs have shown benefits for people living with these conditions, maintaining long-term participation remains a significant challenge. The rise of mobile health (mHealth) technologies - such as smartphone apps and wearable devices - offers a promising new way to support people in becoming and staying more physically active.

This study aims to compare the effects of two different 20-week exercise intervention programs versus standard medical care in adults aged 30 to 65 who have been diagnosed with both T2D and obesity.

Participants will be randomly assigned to one of three groups:

Group 1 (Supervised Training): Participants will attend two in-person, supervised exercise sessions per week at a local sports facility, each lasting 60 minutes. Sessions will be led by a qualified trainer and will include strength, flexibility, and functional exercises. Participants will also receive weekly motivational text messages and group health coaching.

Group 2 (Unsupervised mHealth Training): Participants will follow the same exercise plan independently using a mobile application (ActiVital), which is part of the Andalusian Physical Activity Prescription Plan (PAPEF). They will receive their weekly training schedule through the app and will also receive text messages and group health coaching.

Group 3 (Control Group): Participants will continue with their usual medical care without any structured exercise program.

All participants across the three groups will be provided with a Fitbit Charge 6 wearable device to monitor daily physical activity and health indicators.

The study's central hypothesis is that both structured supervised exercise and app-guided unsupervised exercise will lead to meaningful improvements in clinical indicators - such as blood glucose levels, glycated hemoglobin (HbA1c), blood lipids, and blood pressure - as well as in body composition, physical fitness, sleep quality, and overall quality of life, when compared to standard care alone. It is also hypothesized that the mHealth approach will show particular benefits in terms of adherence, self-management, and scalability.

A total of 126 participants will be recruited through the Primary Care Center of Osuna (Seville, Spain), with measurements taken before and after the 20-week intervention period. The study will help determine which type of exercise program is most effective and feasible for people managing both type 2 diabetes and obesity in a primary care setting.

Study Overview

• Status: Not yet recruiting
• Conditions: Obesity; Diabetes Mellitus, Type 2; Insulin Resistance; mHealth; Physical Exercise; Primary Care; Wearable Devices; Sedentary Behaviors
• Intervention / Treatment: Behavioral: Supervised Exercise Training Program; Device: Wearable Device Monitoring (Fitbit Charge 6); Behavioral: Health Coaching Sessions; Behavioral: Weekly Motivational Text Messages; Behavioral: mHealth Unsupervised Exercise Program (ActiVital App); Other: Usual Medical Care

Detailed Description

Background and Rationale

Type 2 diabetes (T2D) and obesity represent a growing global health burden, both individually and as comorbid conditions. Physical inactivity is recognized as the fourth leading cause of death worldwide and is directly implicated in the development and progression of both pathologies. While lifestyle interventions combining exercise and behavioral change have demonstrated efficacy in improving glycemic control and metabolic profile, their long-term effectiveness remains limited due to poor adherence and lack of scalability. Mobile health (mHealth) interventions - delivered via smartphones, wearable devices, and digital platforms - have emerged as a promising complementary strategy to extend the reach of structured exercise programs beyond traditional clinical settings.

Despite a growing body of evidence supporting mHealth for T2D and obesity independently, no study to date has rigorously evaluated the comparative effectiveness of supervised versus app-guided unsupervised exercise interventions in patients presenting with both conditions concurrently.

Study Design

This is a 20-week, three-arm, parallel-group randomized controlled trial (RCT) conducted at the Primary Care Center of Osuna, Seville, Spain. Exercise sessions will take place at the covered indoor facilities of the Municipal Sports Center of Osuna. The trial will compare two active intervention arms against a usual care control group.

Randomization will be performed using computer-generated block randomization (variable block sizes of 4-10) via Research Randomizer (https://www.randomizer.org), stratified by sex and baseline glycated hemoglobin (HbA1c) level. Allocation concealment will be ensured by maintaining the randomization list with a researcher not involved in outcome assessments. The allocation sequence will remain concealed until participants are formally enrolled and assigned.

External evaluators, blinded to group allocation, will conduct all pre- and post-intervention assessments.

Intervention Description

All participants across the three groups will receive a Fitbit Charge 6 wearable device for continuous monitoring of physical activity indicators, and will attend two group health coaching sessions (weeks 4 and 12) focused on lifestyle habits relevant to T2D and obesity management (diet, physical activity, sleep). All groups will also receive two weekly motivational text messages encouraging daily use of the wearable device and reminding participants of scheduled assessment appointments.

Experimental Group 1 (EG-1) - Supervised In-Person Training Participants will complete 40 supervised exercise sessions over 20 weeks (2 sessions/week, Tuesdays and Thursdays), each lasting 60 minutes, at the Municipal Sports Center of Osuna. The exercise prescription follows the guidelines of the American Diabetes Association (ADA), the American College of Sports Medicine (ACSM), and the World Health Organization (WHO) for individuals with T2D and obesity.

Each session is structured as follows:

Warm-up (10 min): joint mobility, marching in place, dynamic stretching Main block (40 min): resistance training targeting major muscle groups Cool-down (10 min): static stretching, breathing exercises, relaxation

The 20-week program is organized into four progressive phases:

Phase 1 - Adaptation (Sessions 1-8): Muscular activation and technical learning. 2-3 sets × 10-12 repetitions. Exercises: chair squat, chest press with resistance band, seated row with band, lateral raises, biceps curl, triceps extensions, knee plank.

Phase 2 - Initial Progression (Sessions 9-20): Strength-endurance development. 3 sets × 10-15 repetitions. Exercises: free squat, deadlift with resistance band, wall push-ups, glute bridge, military press, inclined row, lateral plank with knee.

Phase 3 - Intermediate Progression (Sessions 21-32): Increased load and postural control. 3-4 sets × 8-12 repetitions. Exercises: assisted lunges, double deadlift, bench chest press, kneeling row, weighted squat, calf raises, core exercises.

Phase 4 - Consolidation (Sessions 33-40): Functional circuits. 2-3 rounds per session. Circuit 1: squat + military press + plank. Circuit 2: lunges + band row + crunch. Every Minute on a Minute (EMOM) formats and progressive repetition ladders are incorporated.

During each session, heart rate (Fitbit Charge 6), Rating of Perceived Exertion (RPE), and blood oxygen saturation (pulse oximeter) will be recorded. A standard leaflet with recommendations for autonomous aerobic activity on non-training days will be provided at baseline.

Experimental Group 2 (EG-2) - Unsupervised mHealth Training Participants will follow the identical exercise program as EG-1, delivered autonomously through the ActiVital mobile application - the official digital platform of the Andalusian Physical Activity and Exercise Prescription Plan (PAPEF, 2023-2030). Participants will access their individualized weekly training plan via the app and will confirm session completion directly within the platform after each workout. Basic training and onboarding on app usage will be provided at study initiation.

Control Group (CG) Participants will continue their usual medical care as prescribed by their primary care physician, without any structured exercise intervention. They will receive the wearable device and text messages consistent with the other groups but will not receive an exercise plan.

Outcome Assessment Protocol All participants will attend two assessment visits (pre-intervention: weeks 0-1; post-intervention: weeks 20-21), each consisting of two separate appointments spaced 9 days apart.

Visit Day 1: Delivery of informed consent documentation and health questionnaires; distribution of ActiGraph GT9X Link+ accelerometers (worn on the wrist for 7 consecutive days); distribution of Fitbit Charge 6; app installation and onboarding for EG-2.

Visit Day 2 (9 days later): Blood analysis, physical fitness assessments, body composition measurements; questionnaire completion; accelerometer retrieval.

Measurement Instruments and Procedures

Clinical Variables:

Fasting blood glucose will be measured using an Accu-Chek Inform II glucometer. HbA1c, full lipid panel (total cholesterol, Low Density Lipoprotein (LDL), High Density Lipoprotein (HDL) and triglycerides), C-reactive protein (CRP), creatinine, estimated glomerular filtration rate (eGFR), and hepatic transaminase levels (GOT/GPT) will be obtained via venous blood draw following a 9-12 hour fast. Blood pressure (systolic and diastolic) will be assessed using an OMRON sphygmomanometer and Littmann stethoscope. Medication use (initiation, modification, or discontinuation) will be tracked throughout the entire 20-week period.

Body Composition:

Body mass (kg), BMI (kg/m2)(calculated from height and weight), body fat percentage, and muscle mass will be assessed via bioelectrical impedance analysis (BIA) using an InBody 770 device (Biospace Co., Ltd., Seoul, South Korea). Waist and hip circumferences will be measured using a standard anthropometric tape measure.

Physical Fitness:

Aerobic capacity: 6-Minute Walk Test (6MWT), measuring total distance covered on a regulation athletics track.

Lower limb strength: 30-second Sit-to-Stand Test (30-STS), counting full stands completed in 30 seconds with arms crossed over the chest.

Explosive lower limb power: Countermovement Jump (CMJ), measured using an optical measurement system (Optojump, Microgate S.R.L., Bolzano, Italy), recording jump height (cm), power output (W), and take-off velocity (m/s).

Functional mobility and fall risk: Timed Up and Go test (TUG), measuring time (seconds) to stand from a chair, walk 3 meters, turn, and return to seated position; and 6-Meter Walk Test, measuring gait speed (m/s) using photoelectric cells.

Resting and active heart rate: continuously monitored via the Fitbit Charge 6 wearable device.

Sleep Quality and Daily Physical Activity:

Both outcomes will be assessed using an ActiGraph GT9X Link+ accelerometer worn on the wrist for 7 consecutive days at each measurement point. Variables recorded include total sleep time, sleep efficiency, sleep latency, wake after sleep onset, sedentary time, and time spent in light, moderate, and vigorous physical activity, estimated energy expenditure (kcal), and daily step count.

Psychological Well-being and Health-Related Quality of Life:

Assessed using the SF-36 Health Survey (Short Form-36; McHorney et al., 1994), a validated generic instrument measuring eight domains: physical functioning, role-physical, bodily pain, general health, vitality, social functioning, role-emotional, and mental health. Each domain is scored 0-100, with higher scores indicating better health status.

Adherence:

In EG-1, adherence will be tracked via manual attendance records. In EG-2, session completion will be logged directly within the ActiVital app. Wearable device usage will be monitored continuously across all groups throughout the 20-week period.

Statistical Analysis A descriptive analysis of all variables will be performed using means and standard deviations (or medians and interquartile ranges for non-parametric data), and frequencies and percentages for categorical variables. Data normality will be assessed using Kolmogorov-Smirnov or Shapiro-Wilk tests.

Between-group comparisons will be conducted using ANOVA or ANCOVA with repeated measures, adjusting for relevant covariates (age, sex, baseline fitness level). Non-parametric alternatives (Kruskal-Wallis, Friedman test) will be applied where normality assumptions are not met. Intra-group pre-to-post differences will be assessed using paired t-tests or Wilcoxon signed-rank tests as appropriate. Post-hoc analyses will use the Scheffé test.

Effect size will be calculated using Cohen's d or partial eta-squared (η²), interpreted as: small (<0.25), moderate (0.25-0.40), or large (>0.40) per Cohen (1973). Pearson or Spearman correlation analyses will examine associations between improvements in clinical variables and physical activity adherence. Multiple regression models will be used to identify predictors of response to the exercise programs. Statistical significance will be set at p < 0.05. All analyses will be disaggregated by sex where possible.

Statistical analyses will be performed using SPSS v.25 (IBM, Portsmouth, UK). Data will be stored and managed through REDCap (Research Electronic Data Capture), a secure, web-based platform for research data collection, with access restricted to authorized study investigators.

Sample Size Justification Sample size was calculated using G*Power 3.1, based on an a priori ANCOVA with fixed effects. Using a large effect size (f = 0.80) for HbA1c reported in a comparable study (Yin et al., 2022), with α = 0.05, power = 95%, 3 groups, 1 covariate, and 10 numerator degrees of freedom, a minimum of 42 participants per group was determined. Accounting for an estimated 10% dropout rate, the target sample is 47 participants per group, yielding a total of 141 participants. After excluding non-eligible individuals, 126 participants will be enrolled (42 per group).

Data Management and Ethical Considerations Data will be collected and managed in accordance with the EU General Data Protection Regulation (GDPR) and applicable Spanish legislation. Personal data will be pseudonymized using a dissociation-pseudonymization process (reversible coding). Anonymized final datasets will be stored in idUS, the University of Seville's open-access repository, with unique Digital Object Identifiers (DOI). Data will be retained for 10 years following study completion, after which it will be securely destroyed.

This study has been approved by the Ethics Committee for Research of the University Hospitals Virgen Macarena-Virgen del Rocío (approval code: SICEIA-2026-000343; favourable opinion issued on 26 May 2026), in accordance with the principles of the Declaration of Helsinki and applicable Spanish biomedical research legislation (Ley 14/2007, of 3 July). All participants will provide written informed consent prior to enrolment (informed consent version V1, dated 29 January 2026).

• Study Type: Interventional
• Enrollment (Estimated): 126
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: CARLOS GOMEZ, SPORTS SCIENCES; Phone Number: 0034 650067474; Email: carlosgg@euosuna.org

Study Locations

• Spain
  • Sevilla
    • Osuna, Sevilla, Spain, 41640
      • José Manuel Jurado Castro
      • Contact: José Manuel JMJC JURADO CASTRO, DOCTOR; Phone Number: 0034 697825719; Email: josemjc@euosuna.org

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Diagnosed with both type 2 diabetes mellitus and obesity
• Aged between 30 and 65 years
• Body Mass Index (BMI) between 30 and 40 kg/m²
• Glycated hemoglobin (HbA1c) greater than 6.5% (48 mmol/mol)
• Fasting plasma or capillary blood glucose equal to or greater than 126 mg/dL (7.0 mmol/L)
• Willing and able to provide informed consent to participate in the study
• Available and willing to commit to a 20-week intervention period
• Able and willing to use a smartphone and receive text messages
• Able and willing to use a wearable device (smartwatch) and its associated mobile application

Exclusion Criteria:

• Presence of any obesity-related comorbidity requiring clinical referral, including eating disorders, pseudotumor cerebri, sleep apnea, hypoventilation syndrome, or orthopedic problems that limit physical activity
• Presence of psychiatric or medical conditions that would prevent compliance with the study protocol
• History of a cardiovascular event (myocardial infarction, stroke, heart failure episode, or revascularization procedure) in the past 6 months
• Presence of any medical condition that contraindicates participation in the proposed physical activity program
• Current use of insulin therapy
• Presence of orthopedic or other physical limitations that may interfere with the ability to exercise safely
• Currently undergoing treatment for a malignant tumor (other than non-melanoma skin cancer)
• Currently receiving treatment for, or diagnosed with, an eating disorder
• Planned bariatric or weight-loss surgery (e.g., liposuction, gastric band, gastric bypass) within the next 5 months
• Currently pregnant, given birth in the last 6 months, breastfeeding in the last 3 months, or actively planning a pregnancy in the next 5 months
• Currently enrolled in, or planning to enroll in, a weight loss program during the study period
• Lost more than 5 kilograms of body weight in the past 3 months

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Health Services Research
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Supervised In-Person Training (EG-1); Participants attend two supervised group exercise sessions per week (Tuesdays and Thursdays, 60 min/session) at the Municipal Sports Center of Osuna over 20 weeks (40 sessions total). The program follows a progressive 4-phase resistance training protocol (adaptation, initial progression, intermediate progression, and consolidation) based on ADA, ACSM, and WHO guidelines for T2D and obesity. Heart rate, RPE, and oxygen saturation are monitored each session. All participants receive a Fitbit Charge 6 wearable device, weekly motivational text messages, and two group health coaching sessions (weeks 4 and 12).	Behavioral: Supervised Exercise Training Program; Progressive 20-week resistance training program delivered in-person, twice weekly (Tuesdays and Thursdays), in 60-minute supervised group sessions at the Municipal Sports Center of Osuna. The program comprises 40 sessions organized into four phases: adaptation (sessions 1-8), initial progression (sessions 9-20), intermediate progression (sessions 21-32), and functional consolidation (sessions 33-40). Exercises target major muscle groups using bodyweight, resistance bands, and dumbbells. Session structure: 10-min warm-up, 40-min main block, 10-min cool-down. Intensity is monitored via heart rate (Fitbit Charge 6), RPE scale, and pulse oximetry. Prescribed in accordance with ADA, ACSM, and WHO guidelines for T2DM and obesity.; Device: Wearable Device Monitoring (Fitbit Charge 6); All participants across the three study arms receive a Fitbit Charge 6 consumer-grade wearable device associated with the Fitbit mobile application. The device continuously monitors physical activity indicators including resting and active heart rate, daily step count, energy expenditure, and sleep quality parameters throughout the 20-week study period. Data are accessible to participants via the Fitbit app.; Behavioral: Health Coaching Sessions; Two group health coaching sessions are delivered to all participants at weeks 4 and 12 of the intervention. Sessions focus on lifestyle habits relevant to the management of T2D and obesity, including physical activity, dietary behavior, sleep hygiene, and weight management. Coaching is conducted in person by the research team and aims to reinforce behavioral change and promote long-term adherence.; Behavioral: Weekly Motivational Text Messages; All participants receive two motivational text messages per week throughout the 20-week study period. Messages address topics related to physical activity, diet, sleep, and weight management, and serve as reminders to use the wearable device daily and attend scheduled assessment appointments.
Experimental: Unsupervised mHealth Training (EG-2); Participants follow the identical 20-week, 4-phase progressive resistance training program as EG-1, delivered autonomously via the ActiVital mobile application (Andalusian Physical Activity Prescription Plan, PAPEF 2023-2030). Participants access their weekly training plan through the app and confirm session completion within the platform. All participants receive a Fitbit Charge 6 wearable device, weekly motivational text messages, and two group health coaching sessions (weeks 4 and 12).	Device: Wearable Device Monitoring (Fitbit Charge 6); All participants across the three study arms receive a Fitbit Charge 6 consumer-grade wearable device associated with the Fitbit mobile application. The device continuously monitors physical activity indicators including resting and active heart rate, daily step count, energy expenditure, and sleep quality parameters throughout the 20-week study period. Data are accessible to participants via the Fitbit app.; Behavioral: Health Coaching Sessions; Two group health coaching sessions are delivered to all participants at weeks 4 and 12 of the intervention. Sessions focus on lifestyle habits relevant to the management of T2D and obesity, including physical activity, dietary behavior, sleep hygiene, and weight management. Coaching is conducted in person by the research team and aims to reinforce behavioral change and promote long-term adherence.; Behavioral: Weekly Motivational Text Messages; All participants receive two motivational text messages per week throughout the 20-week study period. Messages address topics related to physical activity, diet, sleep, and weight management, and serve as reminders to use the wearable device daily and attend scheduled assessment appointments.; Behavioral: mHealth Unsupervised Exercise Program (ActiVital App); Identical 20-week progressive resistance training program as Intervention 1, delivered autonomously via the ActiVital mobile application, the official digital platform of the Andalusian Physical Activity and Exercise Prescription Plan (PAPEF 2023-2030). Participants access their individualized weekly training plan through the app and log session completion within the platform after each workout. Initial onboarding and basic app training are provided at study entry.
Active Comparator: Usual Care Control Group (CG); Participants continue their standard medical care as prescribed by their primary care physician, with no structured exercise intervention. They receive a Fitbit Charge 6 wearable device for activity monitoring and two weekly text messages reminding them to use the device and attend scheduled assessments. Group health coaching sessions are provided at weeks 4 and 12, consistent with the other arms. No exercise plan is delivered.	Device: Wearable Device Monitoring (Fitbit Charge 6); All participants across the three study arms receive a Fitbit Charge 6 consumer-grade wearable device associated with the Fitbit mobile application. The device continuously monitors physical activity indicators including resting and active heart rate, daily step count, energy expenditure, and sleep quality parameters throughout the 20-week study period. Data are accessible to participants via the Fitbit app.; Behavioral: Health Coaching Sessions; Two group health coaching sessions are delivered to all participants at weeks 4 and 12 of the intervention. Sessions focus on lifestyle habits relevant to the management of T2D and obesity, including physical activity, dietary behavior, sleep hygiene, and weight management. Coaching is conducted in person by the research team and aims to reinforce behavioral change and promote long-term adherence.; Behavioral: Weekly Motivational Text Messages; All participants receive two motivational text messages per week throughout the 20-week study period. Messages address topics related to physical activity, diet, sleep, and weight management, and serve as reminders to use the wearable device daily and attend scheduled assessment appointments.; Other: Usual Medical Care; Participants in the control group continue their standard medical care as prescribed by their primary care physician at the Primary Care Center of Osuna, without any structured exercise intervention. This includes routine clinical follow-up, pharmacological treatment, and general lifestyle recommendations as per standard clinical practice for T2D and obesity.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from Baseline in Glycated Hemoglobin (HbA1c) at 20 Weeks	Glycated hemoglobin (HbA1c) reflects average blood glucose over the preceding 2-3 months and is the standard marker for long-term glycemic control in type 2 diabetes. Measured via venous blood draw after a 9-12 hour fast, analyzed in a certified laboratory. Expressed as a percentage (%). Higher values indicate poorer glycemic control. Diabetes diagnostic threshold: HbA1c ≥ 6.5% (48 mmol/mol).	Baseline (week 0) and post-intervention (week 20)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from Baseline in Fasting Blood Glucose at 20 Weeks	Fasting blood glucose measured after a minimum 8-hour fast using an Accu-Chek Inform II glucometer. Values expressed in mg/dL. Higher values indicate poorer glycemic control. Diabetes diagnostic threshold: fasting plasma glucose ≥ 126 mg/dL (7.0 mmol/L).	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in Lipid Profile (Total Cholesterol, LDL, HDL, Triglycerides) at 20 Weeks	Full lipid panel obtained via venous blood draw after a 9-12 hour fast. Includes total cholesterol, LDL, HDL, and triglycerides, all expressed in mg/dL. Lower LDL and triglycerides and higher HDL indicate a more favorable cardiovascular risk profile.	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in Resting Systolic and Diastolic Blood Pressure at 20 Weeks	Resting blood pressure measured manually using an OMRON sphygmomanometer and Littmann stethoscope after 5 minutes of seated rest. Systolic and diastolic values recorded separately in mmHg. Lower values indicate better cardiovascular health.	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in High-Sensitivity C-Reactive Protein (CRP) at 20 Weeks	Systemic inflammatory marker measured via venous blood draw, analyzed in a certified laboratory. Expressed in mg/L. Higher values indicate greater systemic inflammation and increased cardiometabolic risk in individuals with T2DM and obesity.	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in Renal Function (Creatinine and eGFR) and Hepatic Transaminases (GOT/GPT) at 20 Weeks	Renal function assessed via serum creatinine (mg/dL) and estimated glomerular filtration rate (eGFR, ml/min/1.73m²). Hepatic function via GOT and GPT transaminases (U/L). All obtained from venous blood draw. Elevated values may indicate organ dysfunction linked to metabolic disease.	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in Body Mass at 20 Weeks	Body mass assessed in kilograms (kg) via bioelectrical impedance analysis (BIA; InBody 770, Seoul, South Korea).	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in Body Mass Index (BMI) at 20 Weeks	BMI calculated as kg/m² by combining body mass (kg) and height (m) measured via bioelectrical impedance analysis (BIA; InBody 770, Seoul, South Korea). Eligible participants present BMI 30-40 kg/m². Higher values indicate greater obesity severity.	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in Body Fat Percentage at 20 Weeks	Body fat percentage (%) assessed via bioelectrical impedance analysis (BIA; InBody 770, Seoul, South Korea). Higher values are associated with worse metabolic outcomes in T2DM and obesity.	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in Skeletal Muscle Mass at 20 Weeks	Skeletal muscle mass assessed in kilograms (kg) via bioelectrical impedance analysis (BIA; InBody 770, Seoul, South Korea). Lower values are associated with worse metabolic outcomes in T2DM and obesity.	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in Waist Circumference at 20 Weeks	Waist circumference measured in centimeters (cm) using a standard anthropometric tape measure following standard anatomical landmarks. Lower values indicate reduced central adiposity and visceral fat accumulation.	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in Hip Circumference at 20 Weeks	Hip circumference measured in centimeters (cm) using a standard anthropometric tape measure following standard anatomical landmarks. Lower values indicate reduced central adiposity.	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in Waist-to-Hip Ratio at 20 Weeks	Waist-to-hip ratio calculated by dividing waist circumference (cm) by hip circumference (cm), yielding a dimensionless ratio. Lower values indicate reduced central adiposity and visceral fat accumulation.	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in Aerobic Capacity as Assessed by the 6-Minute Walk Test at 20 Weeks	Total distance (meters) walked at self-selected pace on a regulation athletics track over 6 minutes. Provides a submaximal assessment of aerobic capacity and functional endurance. Greater distance indicates better aerobic performance.	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in Lower Limb Strength as Assessed by the 30-Second Sit-to-Stand Test at 20 Weeks	Number of complete sit-to-stand repetitions from a standard chair in 30 seconds, with arms crossed over the chest. Validated measure of lower limb muscular strength and endurance. Higher scores indicate greater functional strength.	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in Jump Height as Assessed by the Countermovement Jump Test at 20 Weeks	Maximal vertical jump height (cm) performed from a standing position with a rapid knee flexion prior to take-off, hands on hips. Measured via optical system (Optojump, Microgate S.R.L., Italy). Higher values indicate greater explosive power.	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in Explosive Power as Assessed by the Countermovement Jump Test at 20 Weeks	Mechanical power output (W) during a countermovement jump performed from a standing position with a rapid knee flexion prior to take-off, hands on hips. Measured via optical system (Optojump, Microgate S.R.L., Italy). Higher values indicate greater explosive power.	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in Take-off Velocity as Assessed by the Countermovement Jump Test at 20 Weeks	Vertical take-off velocity (m/s) during a countermovement jump performed from a standing position with a rapid knee flexion prior to take-off, hands on hips. Measured via optical system (Optojump, Microgate S.R.L., Italy). Higher values indicate greater explosive power.	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in Functional Mobility as Assessed by the Timed Up and Go Test at 20 Weeks	Time (seconds) to rise from a chair, walk 3 meters, turn, return, and sit down. Shorter times indicate better functional mobility and lower fall risk. Scores >12 seconds suggest high fall risk in older or clinically compromised adults.	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in Gait Speed as Assessed by the 6-Meter Walk Test at 20 Weeks	Gait speed (m/s) measured over a 6-meter course at habitual or fast pace using photoelectric cells. Higher speeds indicate better functional capacity. Gait speed below 0.8 m/s is associated with increased risk of adverse health outcomes in adults with chronic conditions.	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in Sleep Quality and Daily Physical Activity Level as Assessed by Accelerometry at 20 Weeks	ActiGraph GT9X Link+ accelerometer worn on the wrist for 7 consecutive days. Sleep outcomes: total sleep time, efficiency, latency, and nocturnal awakenings. Physical activity outcomes: time in sedentary, light, moderate, and vigorous activity (min), energy expenditure (kcal), and step count.	Baseline (week 0) and post-intervention (week 20)
Change from Baseline in Health-Related Quality of Life as Assessed by the SF-36 Health Survey at 20 Weeks	SF-36 Health Survey (McHorney et al., 1994) measures eight domains: physical functioning, role-physical, bodily pain, general health, vitality, social functioning, role-emotional, and mental health. Each domain scored 0-100; higher scores indicate better health-related quality of life.	Baseline (week 0) and post-intervention (week 20)
Adherence to the Assigned Exercise Intervention Over 20 Weeks	GE1: percentage of 40 supervised sessions attended, tracked via manual attendance records. GE2: percentage of prescribed sessions completed, logged within the ActiVital app. All groups: percentage of days with valid Fitbit Charge 6 wearable device usage over 20 weeks.	Continuously monitored throughout the 20-week intervention period

Collaborators and Investigators

• Sponsor: Escuela Universitaria de Osuna
• Collaborators: University of Seville

Study record dates

Study Major Dates

• Study Start (Estimated): October 1, 2026
• Primary Completion (Estimated): March 30, 2027
• Study Completion (Estimated): April 1, 2027

Study Registration Dates

• First Submitted: June 22, 2026
• First Submitted That Met QC Criteria: July 2, 2026
• First Posted (Actual): July 6, 2026

Study Record Updates

• Last Update Posted (Actual): July 6, 2026
• Last Update Submitted That Met QC Criteria: July 2, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Obesity; mHealth; Diabetes Mellitus, Type 2; Physical Exercise; Wearable
• Additional Relevant MeSH Terms: Endocrine System Diseases; Nutrition Disorders; Metabolic Diseases; Overnutrition; Body Weight; Glucose Metabolism Disorders; Diabetes Mellitus; Hyperinsulinism; Overweight; Pathological Conditions, Signs and Symptoms; Behavior; Nutritional and Metabolic Diseases; Signs and Symptoms; Obesity; Diabetes Mellitus, Type 2; Insulin Resistance; Motor Activity; Sedentary Behavior
• Other Study ID Numbers: SICEIA-2026-000343

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No