Worldwide, the prevalence of frailty in people aged ≥60 years ranges from 7% to 24% [1]. In Latin America and the Caribbean, the prevalence of frailty ranges from 7% to 42.6% [2]. A recent study conducted in Chile found that 10.9% of individuals aged >60 years are frail, including 7.7% of men and 14.1% of women affected. The study also reported that the prevalence of frailty in Chile increases significantly with age, reaching 58% for men and 62% for women after the age of 80 years [3]. Frailty is a clinical stage with a multifactorial etiology that involves disorders of multiple interconnected physiological systems [4]. Its diagnosis is commonly based on 5 components: muscle strength, gait, exhaustion, weight loss, and chronic fatigue [5]. People who are frail have a higher risk of falls, disability, long-term care, and death [6]. Therefore, prevention and early detection have become significant challenges for public health and clinical practice [7].

The first-line therapy for managing frailty should include a multicomponent physical activity program with a resistance-based training component [8]. Recent evidence shows the efficacy of a multicomponent exercise program as a strategy to prevent [9] and reverse frailty to prefrailty. In addition, it has been seen that a multicomponent exercise program can improve physical fitness, particularly resistance and balance [10,11], and quality of life [12] in older adults with this clinical stage. Despite the many benefits of exercise, participation is low among older adults, with relatively few older adults who are frail meeting the recommendations for exercise [13,14].

In Chile, the “More Autovalent Older Adults” (Más Adulto Mayor Autovalente) program, implemented by the Ministry of Health, is one of the primary national strategies aimed at promoting and maintaining functionality and physical fitness in older adults [15]. International and national experience indicates that most of these programs are group-based aerobic exercises and the promotion of self-care. Furthermore, participation rates may fluctuate due to factors such as time, available space, weather conditions [16,17], or distance between home and the exercise location, representing a barrier for older adults to join or maintain their attendance at out-of-home programs [18]. As a result, older adults are more likely to develop sarcopenia or frailty due to the decrease in physical activity [19]. In addition, exercise instructors have a more difficult time offering individual instruction to their older adult participants when the physical activity program is carried out with large groups and heterogeneous health characteristics and may have trouble providing effective feedback relevant to their cognitive characteristics [19]. Home-based exercise alternatives have been proposed to overcome the limitations of conventional programs, such as videos, online platforms, and mobile apps [20]. However, this modality does not offer direct feedback, making it difficult for older adults to benefit fully, and the risk of injury is higher [19].

In this context, telerehabilitation has been proposed as a new intervention method to prevent or improve frailty. Telerehabilitation refers to the delivery of rehabilitation services to patients remotely, using information and communication technologies [21]. Communication between the patient and the rehabilitation professional may occur through a variety of technologies, such as the telephone and internet‐based videoconferencing [22]. Widely accepted advantages exist for the use of telerehabilitation rather than the more traditional, clinic-based service delivery model. Telerehabilitation facilitates access to rehabilitation opportunities [23], reduces health care disparities, and allows patients to receive services in the comfort and privacy of their own homes [24,25]. This model eliminates geographical barriers [26-28] and reduces both the time and out-of-pocket expenses associated with transportation. In addition, it diminishes the reliance on others for mobility or the need for adapted transportation for some older individuals who are frail [24,27,29,30]. Consequently, telerehabilitation is associated with increased session attendance and functional improvements comparable to or even superior to those achieved with in-person care [31].

Synchronous telerehabilitation (STR) involves real-time, two-way video and audio communication between the exercise instructor and participant, allowing for supervised training using high-speed telecommunications technologies. This would allow for real-time interactions between exercise instructors and older adults living in their homes [32,33]. Three international studies have evaluated the effectiveness of STR programs for older adults at high risk of falls and sarcopenia. Significant improvements were found in physical condition (leg strength measured with the chair stand test), static balance (Berg Balance Scale), and decreased sarcopenia [19,33,34]. Telerehabilitation is considered a viable alternative to traditional rehabilitation, as it reduces the use of outpatient resources and improves quality of life. However, further randomized controlled trials are required to evaluate its efficacy in older adults with chronic diseases, frailty, and sarcopenia [35-37].

To date, few studies in Chile have reported using these mobile technologies (asynchronous telerehabilitation) to support the treatment of older adults on physical fitness and functional status [38]. Nonetheless, no studies have been found examining the effects of an STR program on the physical capacity, functional status, and quality of life of older people who are frail. Few studies have rigorously examined whether patients achieve comparable benefits from in-clinic versus remote physiotherapy telerehabilitation sessions. Much of the existing research implements a hybrid model of combined home and clinic sessions rather than just remote delivery [39]. This is because the combined service delivery increases confidence in the accuracy of diagnosis and assessment of progress by providing regular opportunities for physical contact and manipulation of a patient’s extremities and joints. Regardless of whether a combined or remote-only model is used, studies comparing telerehabilitation with clinic-based physiotherapy consistently suggest that both approaches yield comparable results [39,40].

In this context, this study aims to analyze whether the effectiveness of an STR program is better than a face-to-face physical therapy (FPT) program in the primary outcomes (lower body strength and cardiorespiratory fitness) and secondary outcomes (upper limb strength, dynamic balance, static balance, number of steps, functional status, and quality of life) in older adults who are frail. We hypothesize that (1) both STR and FPT programs improve primary (lower body strength and cardiorespiratory fitness) and secondary outcomes (upper limb strength, dynamic balance, static balance, number of steps, functional status, and quality of life) in older adults who are frail and (2) STR produces equal or greater improvements compared to face-to-face programs in these outcomes.

This study is designed as a blinded (assessor and statistician), parallel-group, randomized controlled trial. The CONSORT (Consolidated Standards of Reporting Trials) guidelines for clinical trials will be followed [41,42], with reporting on social and psychological interventions [43], and the SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) guidelines for protocol studies (Multimedia Appendix 1) [44]. The clinical trial was registered on ClinicalTrials.gov (NCT06784245).

The Centro Integral del Adulto Mayor (CIAM; Comprehensive Center for Older Adults) in the city of Los Angeles, Biobío region, Chile, will be invited to participate. CIAMs aim to provide care, promotion, and support to individuals aged ≥60 years. These centers are managed by local municipalities and serve as spaces for social interaction and activities, including workshops, meetings, and medical and social care tailored to older adults. CIAM Los Angeles was selected due to its central role as the primary location where older adults from throughout the city gather. This provides access to a diverse group of older adults, including those who are frail and meet the study’s selection criteria. A collaboration agreement was created with CIAM to be able to carry out outcome measurements and the FPT program. In addition, CIAM has a space equipped with a 50-inch smart television and physical activity equipment so that a health professional can guide telerehabilitation sessions.

The sample size was calculated a priori using G*Power 3.1.9.7. A total of 52 participants in total are required (26 in each group), considering Cronbach α=.05, 1-β=.8, and effect size=0.8 (lower limb strength based on the results of a previous study) [19]. Considering the possibility of abandonment, 6 participants were added (N=58; n=29 in each group; Figure 1 [42]).

All individuals aged ≥60 years belonging to CIAM Los Angeles will be invited to participate. Research support staff will conduct recruitment in person or by telephone. To be eligible for participation, individuals must meet the following inclusion criteria: (1) both sexes aged ≥60 years, (2) older adults from the CIAM, (3) older adults diagnosed with frailty according to the modified Fried phenotype scale [5], (4) ability to stand up and walk ≥10 m without assistive devices, (5) Abbreviated Mini-Mental State Examination >13 points [45], and (6) no medical contraindication for physical exercise. In addition, older adults must have a smartphone or tablet and an internet connection at home. Computer or internet literacy is not required as an eligibility criterion. Exclusion criteria include older adults with fractures, recent acute myocardial infarction, associated cardiovascular pathology, severe acute respiratory failure, high blood pressure, uncontrolled diabetes mellitus, limitations following instructions, as well as individuals participating in another exercise program during the project (Figure 1).

The sample will be selected by quota until a size of 58 participants is reached. The selection will be random among those who meet the inclusion and exclusion criteria. Participants will be randomized by research staff using a computer-generated sequence and concealed allocation to one of the following two groups: (1) the STR group, which will receive STR, or (2) the FPT group, which will receive FPT. A simple randomization computational sequence stratified by gender, age, and frailty will be used to obtain a balance between men and women, age ranges, and severity of frailty in both groups. The randomization sequence will be concealed using sequentially numbered, opaque, sealed envelopes to ensure allocation concealment (Figure 1).

Primary outcomes (lower body strength and cardiorespiratory fitness) and secondary outcomes (upper limb strength, dynamic balance, static balance, number of steps, functional status, and quality of life) will be assessed face-to-face 2 weeks before the initiation of the intervention in both groups (Figure 2).

In addition, at that time, STR group participants will be provided with a tablet and home exercise equipment (exercise mats, resistance bands, cones, and dumbbells). If exercise materials are lost or damaged, they will be replaced. A home visit will be conducted to identify barriers to exercise and assess the most suitable location to carry out the STR sessions. One week before the intervention, there will be 2 induction sessions on the proper use of sports equipment, as well as video calls. Written and verbal instructions will be provided outlining the simple steps necessary to connect to an online meeting and facilitate participation in the STR program, as well as the proper use of the home exercise equipment. In addition to the induction sessions, asynchronous material was provided to address questions related to connectivity and the use of devices such as tablets and watches.

At the beginning of the interventions, all participants will be given a hydration kit (cotton towel and a water bottle) and a smartwatch (Fitbit Inspire 2, Google LLC) to measure continuous heart rate monitoring during exercise sessions to maintain exercise intensity, and pedometer (OMRON HJ-321, Kyoto, Japan) to record the number of daily steps each participant takes. (All the equipment that will be delivered to participants is guaranteed).

During the intervention period, nutrition guidance and exercise education will be provided to all participants once every 4 weeks. Throughout the 12-week intervention period, the participants will be encouraged to maintain the same physical activity levels and calorie intake as before participating in the study. During the education sessions, we will inform the participants to inform the support personnel holding the education sessions about any changes in physical activity levels or nutrition intake. A record will be kept of the number of sessions completed by each participant, which will serve as an indicator of adherence to the program. In addition to session attendance, retention rates (including reasons for nonattendance or withdrawal) and interactions with the technical support team will be recorded.

A postintervention assessment will be conducted after the last week of the 12-week program (Figure 2).

All data collection will be carried out in a face-to-face meeting with older adults at a care center. Technical staff will be trained to ensure an unbiased procedure. Measurements will be taken individually in a place with optimal conditions of privacy, temperature, and humidity. Evaluations will be conducted by health care professionals. The person evaluating will be different from the one performing the interventions.

The study was conducted in accordance with the Declaration of Helsinki [66] and approved by the University Santo Tomas Ethics Committee (CEC Accredited Res. No. 01-MZS, approved on May 24, 2024). Informed consent will be obtained from all participants involved in the study.

Missing data will be handled by intention-to-treat analysis (multiple imputation method) [67]. The description will be made as measures of central tendency and dispersion (continuous variables) and as percentages (categorical variables). Using the Shapiro-Wilk test, the normality of the data will be verified, and a two-step approach for transforming will be applied to the nonnormal variables [68]. Homoscedasticity will be analyzed using Levene test. A 2-way repeated measures ANOVA will be used to determine the effects of interventions. The effects of the model are the group (experimental group vs control group), the time points (before and after test), and their interaction over time (time × group). The Bonferroni post hoc test will be applied to identify statistically significant comparisons. The t test effect size will be determined using Cohen d (<0.2 insignificant; ≥0.2 and ≤0.49 small; ≥0.5 and ≤0.79 moderate; ≥0.8 large) [69]. All analyses will be performed using SPSS (version 26; IBM Corp), with a significance level of P<.05, and GraphPad Prism (version 8).

It is plausible that both an STR program and a face-to-face physiotherapy program have positive effects on the primary and secondary outcomes of the study. This hypothesis is based on evidence from systematic reviews and meta-analyses that supports how exercise-based interventions generate benefits in muscle strength, balance, cardiorespiratory fitness, quality of life, and the number of daily steps in older people [35,38,70,71].

We expect the STR program to offer results equal to or superior to those of the face-to-face physical exercise intervention, as this type of intervention has been described as an effective strategy to overcome the commonly reported barriers to access and adherence to physical exercise [24,27,29,30]. In addition, it would be of great interest to conduct a multicenter study in the future involving different cities and countries, thus confirming whether the results expected in this study could be replicated in other latitudes and social and geographical contexts. However, factors such as self-efficacy in using technological devices, motivation to practice physical activity [72], and the perception of loss of social support by not attending group sessions with people who share similar conditions [73] could interfere with the expected results of the telerehabilitation program in the intervened older adults. However, the personalized design of the program, with direct attention from a professional in charge of delivering the sessions, is expected to mitigate these limitations effectively.

While asynchronous telerehabilitation may represent a viable alternative that overcomes many of the barriers associated with in-person therapy, future clinical trials should directly compare synchronous and asynchronous modalities to determine their respective advantages and limitations. Furthermore, it is recommended that digital literacy measurement be considered, either as an inclusion criterion or as a covariate, to better understand its effect on treatment adherence and outcomes.

Implementing STR programs could represent a viable and effective alternative to in-person physical therapy for older adults who are frail. This innovative approach would not only achieve comparable or superior improvements in strength, cardiorespiratory fitness, and other functional indicators but also facilitate access to rehabilitation by overcoming geographical and logistical barriers. Telerehabilitation would allow for the personalization and optimization of therapeutic resources, improving the quality of life and independence of a vulnerable population. These potential findings would have important implications for integrating remote strategies into routine practice and for fostering future research that expands their application in clinical settings.