This study will evaluate the effectiveness of a virtual assistant-guided exercise program to improve adherence in older adults. In a nonrandomized controlled clinical trial, the experimental group will complete a 12-week, home-based program (60-minute sessions, 3 times per week) supported by a virtual assistant (BOT). The control group will comprise community-dwelling older adults already engaged in the municipal program Enguera se saludable, which delivers an in-person exercise program of comparable frequency and duration. The primary outcome is exercise adherence, defined as the proportion of prescribed sessions completed. Secondary outcomes include muscle strength, balance, functional capacity, health-related quality of life, and the user experience and usability of the virtual assistant.

The objective of this study is to determine whether a virtual assistant-controlled, home-based exercise program can improve adherence to therapeutic exercise among older adults, compared with a conventional municipal program of similar dosage. Although exercise is effective for preserving function and quality of life during aging, adherence remains suboptimal. Virtual assistants may offer a scalable and acceptable solution to support sustained participation.

The study will employ a nonrandomized controlled clinical trial (quasi-experimental design) involving community-dwelling adults aged ≥60 years. Participants will be allocated to groups based on program pathway:

Experimental group (Virtual Assistant/BOT): a structured home-based exercise program (60 minutes per session, 3 sessions per week for 12 weeks), guided and monitored by a virtual assistant (BOT), including automated session delivery, reminders, and adherence tracking.

Control group (Municipal program): older adults already participating in Enguera se saludable, an onsite, instructor-led municipal program with equivalent frequency and duration (60 minutes, 3 times per week for 12 weeks). Attendance records from the municipal program will quantify adherence.

The primary outcome is exercise adherence, defined as the proportion of prescribed sessions completed during the 12-week period, with predefined adherence thresholds (e.g., ≥75% of sessions completed). Secondary outcomes include changes in muscle strength, balance, functional performance, and health-related quality of life. Additional measures will include user perceptions, usability, and satisfaction with the virtual assistant to evaluate acceptability and feasibility.

Given the nonrandomized design and the pre-existing enrollment of the control group, the study will incorporate the following methodological safeguards:

Baseline demographic and clinical characteristics (e.g., age, sex, comorbidities, prior activity level) will be comprehensively documented.

Baseline imbalances will be controlled through statistical adjustment (e.g., covariate adjustment, propensity score procedures, and sensitivity analyses) to reduce selection bias and confounding.

Exercise dosage (frequency, duration, and intervention length) will be matched across groups, or, when small discrepancies arise, dosage will be included as a covariate in the analyses.

This study is expected to contribute evidence regarding whether a virtual assistant-based exercise program represents a viable, effective, and acceptable alternative to conventional program delivery models for promoting active and healthy aging in community-dwelling older adults.

Inclusion Criteria:

• Adults aged 60 years or older.
• Community-dwelling individuals capable of participating in an exercise program.
• Ability to complete 60-minute exercise sessions, three times per week during the 12-week intervention.
• Experimental group (BOT Group): Participants willing to use a smartphone/tablet and interact with the virtual assistant.
• Control group (Municipal Exercise Group): Individuals already enrolled in the municipal program Enguera se saludable.
• Ability to understand the study procedures and provide written informed consent

Exclusion Criteria:

• Medical contraindications to physical exercise, as determined by clinical judgment (e.g., uncontrolled cardiovascular, respiratory, or metabolic conditions).
• Severe cognitive impairment or neurological conditions that limit the ability to follow instructions or safely perform the exercise program.
• Severe mobility limitations preventing participation in structured exercise (e.g., inability to walk independently with or without aid).
• Acute musculoskeletal injuries or recent surgeries that contraindicate exercise participation.
• Individuals currently participating in another structured exercise program that would interfere with the study interventions (other than Enguera se saludable for the control group).
• Inability or unwillingness to comply with the requirements of the study (frequency, duration, assessments).
• For the BOT group: lack of access to a device compatible with the virtual assistant or inability/unwillingness to use it.

All genders are eligible. Eligibility is based on age (≥60 years) and clinical criteria, not on sex assigned at birth or gender identity. Gender will be self-reported for descriptive and subgroup analyses (options: woman, man, non-binary, another identity, prefer not to say).

Outcome assessors and data analysts will be blinded to group allocation to prevent assessment and analysis bias, while participants and exercise instructors will remain unblinded due to the nature of the interventions.