Acceptability of an adolescent lifestyle mHealth app: a qualitative study using focus groups and interviews

Introduction

Background

Mobile health (mHealth) apps—defined as mobile, tablet, telemonitoring, or wearable technologies used to support health and public health practice—have emerged as promising tools for promoting sustainable health behavior change among adolescents due to their accessibility, affordability, and ability to integrate into daily life (1,2). With an estimated 3.4 billion smartphone users worldwide, half of whom have downloaded at least one mHealth app (3), these technologies provide opportunities for real-time data collection, personalized feedback, and minimally burdensome engagement that can enhance care quality and support healthier lifestyles (4,5). In the United States, mobile device adoption is nearly universal, with 98% of individuals owning a mobile phone and 91% owning a smartphone, which is commonly used for social media, information seeking, and gaming (6,7). In 2018, 95% of adolescents aged 13–17 years had smartphone access (8,9). Despite this high level of access, adoption and sustained use of adolescent-focused mHealth tools remain limited: only 21% of adolescents report downloading an mHealth app, and regular use is even lower, with just 8% engaging consistently and 47% rarely or never using the apps they download (10). These patterns underscore the need to understand what makes mHealth tools acceptable, engaging, and sustainable for adolescent users.

Because adolescents’ engagement with digital health tools is shaped not only by their own preferences but also by the influence of caregivers and clinicians, designing effective mHealth interventions must incorporate the perspectives of all three groups. Caregivers and clinicians play a central role in shaping adolescents’ awareness of health behaviors, reinforcing behavior change, and endorsing or facilitating the use of supportive technologies. Thus, a comprehensive assessment of acceptability requires a framework that captures these intersecting influences.

To guide this evaluation, the present study uses the Theoretical Framework of Acceptability (TFA) (11) as its conceptual foundation. The TFA includes seven well-established domains—affective attitude, burden, ethicality, intervention coherence, opportunity costs, perceived effectiveness, and self-efficacy. Although the TFA provides a widely used and conceptually robust structure for evaluating health interventions, it was originally developed based on adult populations and was intended to be refined as it is applied to new contexts and populations (11,12). Growing evidence suggests that adolescent engagement with mHealth interventions is shaped by developmental, social, and contextual influences that may not be fully captured by the original TFA domains. For example, Chen et al. (2022) (13) demonstrated that adolescents’ assessments of health apps were influenced by additional factors such as peer norms and expectations informed by prior experiences with commercial apps, supporting the need for framework adaptation in adolescent populations. Related literature suggests that motivation-related design features including gamification, feedback, and social interaction, play an important role in enhancing adolescent engagement and shaping user experiences (14,15), which may, in turn, influence perceptions of acceptability. In addition, prior studies of adolescent mHealth interventions consistently highlight the influence of caregiver and clinician support on perceptions of credibility, adoption, and continued use, underscoring acceptability as a multi-stakeholder construct (16,17). Together, this body of literature supports extending the TFA to include intervention motivational aspects and stakeholder endorsement as adolescent-salient constructs, strengthening the framework’s developmental relevance and its applicability for evaluating mHealth interventions designed for adolescents.

Rationale and knowledge gap

This study aims to understand how adolescents, their caregivers, and clinicians assess the acceptability of CommitFit^SM and whether the app includes features that support consistent and sustained use for improving health behaviors. We used the TFA as the conceptual foundation for our analysis, given its established use in examining intervention acceptability in mHealth and behavioral research (13,18-20). However, although the TFA has been used in studies involving adolescents (13), it has not been applied to examine acceptability across interconnected stakeholders—adolescents, their caregivers, and clinicians—whose perspectives jointly shape engagement with adolescent health technologies.

Our work is distinguished from previous studies in that, by conducting two complementary phases of assessment—a prospective design phase and a retrospective post-development phase—we were able to identify additional influences on acceptability that extend beyond the original TFA domains. Specifically, we introduce two constructs—intervention motivational aspects and stakeholder endorsement—that capture critical features of adolescent engagement not fully accounted for within the existing framework. Motivational elements such as gamification, peer influence, and user expectations emerged as central to adolescents’ willingness to adopt and remain engaged with the app, while endorsement from caregivers and clinicians shaped perceptions of credibility and sustained use. These additions build on, but move beyond, the TFA’s seven domains and offer a more developmentally and contextually attuned understanding of acceptability for adolescent mHealth interventions.

While Chen et al. (2022) (13) proposed the additional domains of “peer norms” and “intervention expectations” to capture how adolescents’ social environments and comparisons to commercial apps shape acceptability, this study consolidates these concepts under the broader theme of intervention motivational aspects, as both domains intersect with gamified features (e.g., streaks, points, leaderboards), social interactions, and user expectations that drive engagement. These motivational influences, together with adolescents’ emotional responses captured in the TFA domain of affective attitude, reflect the increasing role of social exchange and gamification in adolescent digital behavior. Furthermore, because adolescents’ uptake of health apps is also shaped by the encouragement and legitimacy conveyed by caregivers and clinicians, our findings highlight stakeholder endorsement as an additional construct essential for understanding acceptability within the adolescent context. Incorporating these two expanded themes—intervention motivational aspects and stakeholder endorsement—provides a more comprehensive lens for evaluating mHealth app acceptability among adolescents and strengthens the applicability of the TFA to populations whose engagement is profoundly influenced by social dynamics and trusted adult support.

Objectives

The objective of this study is to examine how adolescents, their caregivers, and clinicians evaluate the acceptability of CommitFit^SM across the design and post‑development phases, and to assess whether the app includes features that support sustained engagement in health-promoting behaviors. To address this objective, the study focuses on two research questions: (I) how do adolescents, caregivers, and clinicians assess the acceptability of CommitFit^SM across the seven established TFA domains? (II) What additional factors, beyond the original TFA structure, influence adolescents’ willingness to engage with and consistently use a health behavior mHealth app?

Building on these questions, this study applies the TFA as its foundational framework and examines whether two additional constructs—intervention motivational aspects and stakeholder endorsement—play a meaningful role in shaping perceptions of acceptability. Prior mHealth app research has used the TFA to guide acceptability assessment during intervention design and evaluation (18-20); however, given that the framework was originally developed for adult populations and adolescent-specific acceptability frameworks remain limited, its application to adolescents warrants further examination.

By applying and extending the TFA within an adolescent mHealth context, this study addresses an important conceptual gap and offers a more developmentally attuned understanding of acceptability. Findings are intended to inform future research on adolescent mHealth design and evaluation and to guide clinical practice by identifying design features and sources of caregiver and clinician support that may enhance engagement, promote sustained health behavior change, and facilitate integration of digital health tools into adolescent care.

Methods

We conducted 6 focus groups in the design or prospective phase and interviews in the post-development or retrospective phase. In the prospective phase of the study (Study 1), adolescents, their caregivers, and clinicians were presented with a visual static prototype of CommitFit^SM. CommitFit^SM is a gamified mHealth app that allows users to choose targets related to behaviors such as eating more fruits and vegetables, drinking water, cutting back on sugary drinks, being physically active, and improving sleep. Leaderboards and locked avatar items are then used to add a competitive, game-like element to the experience (16,21). As they record their habits and reach these goals, they earn points. Participants were asked to discuss perceived acceptability of the intervention and provide feedback on the prototype. This phase captured the anticipated acceptability of the app prior to participation in the intervention. In the retrospective phase of the study, only adolescents (caregivers and clinicians were excluded) downloaded and used the CommitFit^SM app for 2 weeks. Experienced acceptability was assessed based on adolescents’ direct engagement with the app, reflecting the perspectives of the primary end users.

Focus groups were selected in the formative stage to encourage dynamic conversation in which participants could respond to one another, highlight shared expectations, and voice collective or contrasting concerns essential for shaping an intervention still in development. Stakeholders were intentionally recruited to represent the full ecosystem surrounding adolescent mHealth use: adolescents who would ultimately use the app, caregivers who influence household decision‑making and feasibility, and clinicians who could anticipate workflow implications and practical implementation needs within care settings.

By contrast, Study 2 (the post-development, retrospective phase) was designed to capture adolescents’ experience-based reflections following direct interaction with the app. Because adolescents are the primary end users, 10 participants engaged with the fully functional CommitFit^SM app for 2 weeks and then completed individual semi‑structured interviews. This format was selected to elicit personal insights, nuanced usability feedback, and authentic engagement behaviors that may not emerge in group settings. The post-development phase focused exclusively on adolescents to evaluate how well the intervention aligned with users’ lived experiences, usability needs, and motivational drivers. Caregivers and clinicians were not included in this phase because their perspectives had been incorporated during earlier formative stages aimed at refining feasibility, safety, and family‑ or clinic‑level considerations. Accordingly, Study 2 intentionally limited participation to adolescents to ensure that the final evaluation reflected a more user‑centered and experience-proximal lens on acceptability grounded in the perspectives of the population for whom the intervention was designed.

We assessed the acceptability of the app using qualitative methods and analyzed the findings using the adapted TFA. Using this two-phased analysis approach, we examined acceptability from both perspectives—anticipated and experienced—at two distinct time points: during the design phase and after the development phase. Table 1 illustrates the relationship between the original seven TFA domains and the potential users of the CommitFit^SM app.

Design

Recruitment and participants

Eligible adolescents were identified through the electronic health records (EHRs) at a family medicine and pediatric clinic within the University of Missouri Health Care system. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by Missouri Health Science Institutional Review Board at the University of Missouri (No. 2092610). Eligibility criteria required youth to be 13–16 years old, fluent in English, reading at or above a sixth‑grade level, and familiar with smartphone app use; exclusions included severe mental health conditions (except mild or well-managed anxiety or depression), intellectual disabilities, and eating disorders. Adolescents of any body mass index (BMI) were included because CommitFit^SM focuses on promoting healthy lifestyle behaviors rather than weight status. Additional participants were recruited through provider referrals from the same clinical population. Enrollment occurred on a first-come, first-served basis until targeted adolescents were enrolled, with parents or legal guardians contacted by phone or email to complete the recruitment process. Participating caregivers in the Study 1 focus groups had children between 13 and 16 years old, but they were not required to be the caregivers of the adolescents who took part in the focus groups.

Design (prospective) phase: Study 1

We conducted 6 online focus groups via Zoom^©, involving a total of 25 participants: 6 adolescents, 7 caregivers, and 12 clinicians. Each group was presented with a static prototype of CommitFit^SM. To facilitate open discussions, the focus groups were organized into subgroups of adult caregivers, adolescent females, adolescent males, and clinicians. Adolescent groups were separated by gender based on feedback indicating that such separation would encourage greater comfort and more candid responses. During this design phase, we explored participants’ anticipated acceptability of CommitFit^SM. All sessions were video and audio recorded, transcribed, and analyzed. Input from caregivers and clinicians was considered especially valuable, given their integral roles in adolescent healthcare decision-making (22-27).

Post-development (retrospective) phase: Study 2

After downloading and using the CommitFit^SM app for 2 weeks, 10 adolescents participated in interviews. To use CommitFit^SM, each of the 10 adolescents selected one health behavior to focus on from the following options: increasing fruit and vegetable intake, drinking more water, reducing sugary beverage consumption, engaging in physical activity, or improving sleep. To support engagement, the app sent daily reminders prompting users to log their progress. Upon completion of their goal period, participants were awarded points based on their consistency in logging behaviors and their average success in achieving their goals. These points contributed to a leaderboard ranking, displayed under usernames chosen during registration. To protect privacy, users were advised not to use or share real names or any personally identifying information.

This post-development phase aimed to assess the experienced acceptability of CommitFit^SM. Following app use, adolescents participated in semi-structured interviews conducted via Zoom^© to gather feedback on real-world use, engagement, and sustained interaction with the app. All interviews were video and audio recorded, transcribed verbatim, and analyzed utilizing Dedoose software.

Study 2 was conducted 6 months after Study 1, allowing time to incorporate feedback from earlier stakeholder engagement. While stakeholders, including caregivers and clinicians, were involved during the design phase to inform CommitFit^SM app features and relevance, feedback during the retrospective phase was collected exclusively from adolescents, as the overall app features are specifically tailored for use by this population.

Participants and context

Participating adolescents for the focus groups (Study 1) and interviews (Study 2) were between the ages of 13 and 16 years. Participating caregivers in the focus groups in Study 1 had children between the ages of 13 and 16 years, but were not required to be caregivers of the adolescents in the focus groups. We attempted to recruit adolescents and caregivers from diverse backgrounds, including African American families, low-income households, individuals with healthy weights, as well as those who were overweight or obese, and families residing in rural communities. We also sought to recruit equal numbers of males and females. Eligible adolescents and caregivers were invited to participate in focus groups and interviews. Consent forms were sent via email to the caregivers of adolescents who expressed interest in the study. Caregivers were required to provide informed consent electronically, both for their adolescents and for themselves. Additionally, 12 pediatric and family medicine clinicians participated in the focus group sessions during the design phase of the app. For the study, family medicine and pediatric healthcare providers affiliated with University of Missouri were invited via email to participate in focus groups. All healthcare providers who chose to participate submitted their consent via email. Participants were given the opportunity to clarify any questions about the study to confirm understanding and withdraw from the study if preferred. We compensated all participants with a $50 e-gift card from selected vendors, Walmart, Target, or Amazon, for their participation.

CommitFit^SM mHealth app

CommitFit^SM is a behavioral lifestyle mHealth application designed to support adolescent health behavior change through gamification‑based goal setting and achievement. The app was developed using a user‑centered approach with input from adolescents, caregivers, and clinical and technical experts from the University of Missouri’s School of Medicine and College of Engineering. Drawing on expertise in adolescent development, patient-clinician communication, gamification, and user‑centered design of electronic decision support tools, we created the CommitFit^SM smartphone application to motivate adolescents to set, track, and achieve health behavior goals and improve overall lifestyle behaviors (Figure 1).

Figure 1 Screenshots of CommitFitSM app: (A) dashboard, (B) goal selection page, (C) goal logging page, and (D) gamification leaderboard page. This figure was adapted from Open Access articles (16) and (21) under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/).

The CommitFit^SM application was designed to empower adolescents to independently establish health behavior goals as a means of improving lifestyle behaviors. Its development was informed by the principles of self-determination theory. The basic function of the app is to allow adolescent users to select a maximum of two of five health behavior goals, including: (I) increased physical exercise; (II) increased intake of fruits and vegetables; (III) decreased intake of sugar-sweetened beverages; (IV) increased water consumption; and (V) increased overnight sleep. These goals have been built into the app based on clinical insights and prior research on child obesity. Adolescents can choose up to two health behaviors (fruits/vegetables, water, decreased sugary beverages, physical activity, sleep) (Figure 1) and then set a goal level for each behavior and a time period to work on their goal. Participants receive daily reminders to log their health behaviors and are awarded points based on their logging activity and their average success in achieving the set goals.

Points earned within CommitFit^SM are used to rank participants on a leaderboard and displayed under the anonymous username selected during registration. In addition to its emphasis on five core health behaviors, the app incorporates a broader set of supportive features, with plans for further expansion in future iterations. Current enhancements include gamification elements such as streaks, rewards, competitions, leaderboards, and points to strengthen user engagement. Educational resources, reminders, and notifications are also integrated to encourage adolescents to set goals and maintain consistent app use. These features were endorsed by adolescents, caregivers, and clinicians during both the design (prospective) and post-development (retrospective) phases.

Future plans for CommitFit^SM also include integration with EHR, enabling real-time collection of patient-generated data for input into a provider-facing ambulatory tool. This integration will enhance in-clinic practices and support more informed clinical decision-making regarding health behaviors. Adolescents, caregivers, and clinicians expressed strong support for this feature, recognizing its potential to improve both health outcomes and workflow efficiency.

Focus group and interview guide

A semi-structured focus group and interview guide were developed to explore the acceptability of CommitFit^SM. The development of the questionnaire and interview guide followed a theory‑informed process in which items were systematically mapped to relevant constructs and refined through stakeholder input and iterative review to ensure that each question accurately captured participants’ perceptions of acceptability. Their development was further guided by prior research on childhood obesity as well as clinical experience working with adolescents with obesity (A.S.B.). To ensure relevance and clarity, the guides were reviewed by another clinician (R.J.K.) and the research team and were refined to better capture adolescents’ perspectives and experiences. This process helped ensure that the questions were developmentally appropriate and aligned with the study’s objectives. Each focus group lasted for approximately 60 minutes. Participants were presented with a static prototype of CommitFit^SM. A total of 6 focus groups with caregivers, female adolescents, male adolescents, and clinicians were conducted. The semi-structured interviews lasted for 60 minutes and began with broad questions regarding participants’ experiences using mHealth applications and their interactions with such tools. Subsequently, the questions were refined to specifically elicit feedback on the acceptability of the CommitFit^SM app and participants’ intentions for continued use (see Table 2). The focus groups and interviews were conducted online using Zoom^©, using the video function to record non-verbal reactions.

Facilitators A.S.B. and R.J.K. (clinician researchers) conducted individual interviews and focus groups, while at least two additional researchers observed and recorded each session. All recordings were later transcribed for analysis. Participants in focus groups were encouraged not only to respond to the questions but also to engage with one another, fostering deeper exploration of both individual and shared perspectives. This approach was intended to reduce the likelihood of socially desirable responses.

To enhance the credibility of the findings, a systematic strategy was employed that included prolonged engagement with the data, peer debriefing to review and discuss interpretations, and maintaining transparency among team members. Furthermore, triangulation of data from both focus groups and individual interviews strengthened the rigor and trustworthiness of the results.

Focus groups and individual interviews were used at different stages of the study to align each method with its methodological strengths and the nature of the data being elicited. During the design phase, focus groups were conducted to capture socially constructed perspectives and to leverage group interaction for idea generation, discussion, and collective reflection on app concepts. In contrast, individual semi-structured interviews were used in the post-development phase to elicit adolescents’ personal and nuanced reflections on app use, engagement, and perceived impact, which may be less likely to emerge in group settings. Separating methods by phase also minimized the potential for priming effects that could occur if group discussions influenced subsequent individual responses. By applying each qualitative method at the stage where it was most appropriate, the study achieved methodological triangulation across phases while preserving analytic clarity between socially negotiated and individually experienced dimensions of acceptability.

Data analysis

We conducted an abductive analysis grounded in the principles of the Grounded Theory approach, utilizing Dedoose^© as the qualitative data analysis platform. Abductive analysis is characterized as “a creative process of producing new hypotheses and theories based on surprising research evidence” (13) and incorporates elements of both deductive and inductive reasoning.

We selected this approach with a foundation in Grounded theory to create analytic distance from both the existing literature and our own prior experiences. This approach enabled us to remain receptive to emergent insights from the data, challenge conventional interpretations of the phenomena, and support a genuinely inductive analytic process, while facilitating an iterative movement between theory and data (11,28,29). It also encouraged re-examination of the data to identify new patterns, thereby stimulating novel ways of thinking and reinforcing the inductive process (18,19).

The analysis of the focus group and interview qualitative data was conducted in 3 phases: a team debrief, a rapid preliminary analysis immediately following each focus group, and a comprehensive final analysis of the compiled data. For the final analysis, audio recordings of the focus groups and interviews were transcribed using Microsoft 365 software and were subsequently reviewed manually by research team member PG to identify and correct any errors. This meticulous process contributed to a foundational understanding of the acceptability of CommitFit^SM among adolescents, caregivers, and clinicians.

The codebook was developed using both deductive and inductive approaches. Themes were initially organized according to the seven domains of the TFA (deductive), while novel ideas that emerged from the data were categorized into new constructs (inductive) (29). The entire research team collaborated to refine and review the themes to ensure reliability and accuracy. For example, deductive coding grouped participant quotes that reflected user-friendliness, such as “see, that was pretty straightforward to choose [a goal], how much, how long you wanted to do it” under the TFA domain of Intervention Coherence.

This abductive analytic approach also enabled the identification of acceptability-related themes that were not fully captured by the original TFA domains. In the final analytic phase, all focus group and interview transcripts were de-identified and analyzed using a combination of TFA-informed and inductive thematic analysis (30). Each researcher independently conducted blinded coding in Dedoose^©, after which the full team met regularly to compare interpretations, refine emerging themes, and ensure analytic consistency. Through iterative team discussions and reflexive analytic engagement, the research team identified coherent patterns, minimized potential bias, and strengthened the credibility and trustworthiness of the findings. Coding continued until thematic saturation and consensus were achieved, at which point the codebook was collaboratively finalized. Given the focused scope of the study and the characteristics of the target user population, the sample provided sufficient depth to generate rich and meaningful insights. The research team included pediatric clinicians, a family medicine physician, and PhD-trained researchers with expertise in adolescent health, digital intervention development, and qualitative methods. To address the potential influence of these professional perspectives on data collection and interpretation, the team engaged in reflexive discussions focused on positionality and interpretation, fostering transparency and interpretive rigor throughout the analytic process.

Data management and storage

All participant information was stored electronically on the researchers’ computers in accordance with privacy and confidentiality protocols. Computer files were password-protected, and the computers were kept in locked offices with restricted access. All identifying information was removed to ensure that individual participants could not be identified. Every effort was made to maintain data security and prevent the disclosure of participants’ identities. Data collected through the mobile app was stored anonymously on a secure external server.

Results

In Study 1 of CommitFit^SM, we recruited 7 adult caregivers (1 male, 6 females), 6 adolescents (2 males, 4 females), and 12 clinicians (5 males, 7 females) to participate in our focus groups. 10 adolescents (6 males, 4 females) participated in CommitFit^SM Study 2 (post development), adding up to a total of 35 participants for both studies (Tables 3-5). Considering the focused nature of our topic (acceptability of CommitFit^SM and adolescent mHealth apps) and our target population, this sample size was sufficient to reach saturation, as shown by the repetitive key themes with no new information generated from the data (31,32).

Adolescents ranged in demographic backgrounds, as identified from the EHR: 5 participants were overweight (BMI percentile: 85–95%), 4 participants were from a low-income household as determined by Medicaid enrollment, 1 participant was from a rural community, and 3 participants self-reported being a racial or ethnic minority. Adolescent participants ranged in age from 13 to 16 years old.

Out of the 12 healthcare clinicians who participated in the focus group sessions, 5 identified as male and 7 identified as female. All participants identified themselves as non-Hispanic or Latino and White, with 1 participant also co-identifying as American Indian or Alaska Native. 9 of the clinician participants were Doctors of Medicine (MDs), 2 were Doctors of Osteopathic Medicine (DOs), and one was a psychologist. Additionally, our focus group participants represented several subspecialities, including pediatric endocrinology, clinical informatics, developmental pediatrics, and health and clinical psychology. Most participants had more than 10 years of clinical practice experience.

Themes

Two additional themes emerged from the analysis—“intervention motivational aspects” (e.g., gamification, leaderboards, streaks, competition) and “stakeholder endorsement” in addition to the seven original TFA domains. These new themes were incorporated as extended TFA domains alongside the original constructs: affective attitude, burden, ethicality, intervention coherence, opportunity cost, perceived effectiveness, and self-efficacy (Figure 2). Numerous studies on mHealth and health applications have similarly employed TFA domains to conceptualize acceptability within intervention research (18-20).

Figure 2 Updated TFA for mHealth apps among adolescents. This figure depicts the added new domains “intervention motivational aspects” and “stakeholder endorsement” along with the seven domains of acceptability put forth by Sekhon et al. (11). mHealth, mobile health; TFA, Theoretical Framework of Acceptability.

Theme 1: affective attitude

The impression and attitude indicated by participants in the design or prospective and post-development, or retrospective phase were consistent. Adolescents responded positively to the visual design and user interface of CommitFit^SM, expressing excitement about its modern, engaging look and intuitive layout. The app’s aesthetic appeal and interactive elements contributed to a sense of ownership and motivation, reinforcing their interest in continued use. Adolescents were excited about the look and feel of CommitFit^SM.

• “Parts of the app that have the colored backgrounds that have all these fun colors…maybe the background could be like a little more color, but the greys ok because the color in front will pop it out more, so you pay more attention to the front.” [Design or prospective phase adolescents].

Another participant affirmed, “It’s pretty easy to understand.” [Design (prospective) phase, adolescents]. The same thought was supported by another adolescent. For example,

• “Easy to read and straight to the point.” [Design (prospective) phase adolescent].
• While some of the caregiver felt the visual can be more realistic “I think that it is great so far…I think the drawings are little too cartoony…everything is a little like bubbly.” [Design (prospective) phase caregiver].

They showed enthusiasm to learn and use the app and ascribed adjectives like ‘cool’, ‘useful’, and ‘good’.

• “Probably the resources and like how much information it gave you because I thought it was cool how I could go on there. And I didn’t know when we work really hard or and its super-hot outside, our bodies lose water and release heat forms. But just like a cool thing like that. nutrition facts, sleep facts, I thought that was cool. So that was useful.” [Post-development or retrospective phase, adolescent 1].
• “I feel like this is a good app. I think it was great, I would definitely use this app.” [Post-development (retrospective) phase, adolescent 1].
• “I personally think it’s pretty straightforward. Pretty simple. And you can just select it really easily and be able to set your goals really easily because I could just imagine other fitness apps being way more extreme, and who knows if I’ll ever be able to set a goal on those other apps.” [Post-development (retrospective) phase, adolescent 6].

Overall, participants expressed a positive attitude toward CommitFit^SM, highlighting its relevance, usability, and potential to support adolescent health behavior change. Their feedback reflected strong engagement with the app’s features and confidence in its value as a supportive tool.

Theme 2: burden

Participants commented that CommitFit^SM was easy to use and admired the plain and simple look of the app. Several participants noted that CommitFit^SM encouraged them to become more physically active, helping them shift away from sedentary habits. The app’s structured routines made it easier to engage in activities that were previously perceived as challenging, reducing the psychological burden often associated with behavior change.

• “Because whenever you do something for so long, it’s kind of just gets in a routine. So just sitting down, it just kind of feels like for me, it just feels kind of weird. So, getting up and moving around and being more active feels more fun. [giving up sitting idle].” [Post- (retrospective) development phase, adolescent].
• “I don’t think we enabled notifications and also I just got that one email every day that reminded us, but you did better at remembering to do it. Sometimes after dinner, we go upstairs to bed to text and say yes. I used to forget until I like literally to hit the bed. I’m just like, Oh, crap. And I was like, gotta eat three more vegetable. 5 to 3 servings and 9 hours of sleep. You better put that in right now. That’s a lot. Oh, [CommitFit^SM] would tell you later to log in. But I would usually forget until I hit them, so, like, oh, crap. I need a message.” [Post- (retrospective) development phase, adolescent].

Participants’ perceptions of burden remained largely consistent across the study phases. There were no substantial differences between their views during the design phase and those expressed in the post-development or retrospective phase. Overall, participants continued to perceive the level of effort and time required to engage with the app as manageable and appropriate.

Theme 3: ethicality

Participants explicitly noted that health apps have the potential to both encourage unethical behaviors and reinforce positive personal values. Several adolescents acknowledged that while gamified features can be motivating, they may also foster excessive competitiveness. Some participants admitted that, in an effort to win or maintain their status on leaderboards, users might be tempted to engage in dishonest behaviors—such as falsifying data or exaggerating progress. At the same time, others emphasized that these apps can also promote integrity, self-discipline, and alignment with one’s personal health goals when used responsibly.

• “I personally know some very competitive people and if you tell them anything like, hey, I bet you I win at ping pong and they’re like Oh no, I suck at ping pong, but let’s go, I’ll beat you anyways and then people are like really competitive with them.” [Design (prospective) phase, adolescent].
• “It’s also like different, cause people could lie…trying to find a way to keep it.” [Design (prospective) phase, adolescent].

One of the caregivers who was also a clinician commented:

• “From the pediatrician side, all teenagers lie to me and tell me how much they exercise.” [Design (prospective) phase, caregiver].

While another caregiver showed confidence about the integrity of adolescents stating:

• “To complete this as far as the integrity of the kids. I don’t think kids that are going to commit to this we have to worry about there [integrity] because they they’re already committed to bettering themselves.” [Design (prospective) phase, caregiver].

The same thought was echoed by adolescents in the post development or retrospective phase. Participants accepted the importance of health care and self-management, but recognized that it depends on the individual who is using the app.

• “I think if for adolescents especially the more it’s only in their control and not parents—being able to add things. Better now, if an adult wants to use it, that’s different, you know.” [Design (prospective) phase, clinician].

While other participants expressed personal value as important when self-monitoring as it impacts the person individually.

• “I know a couple of [friends] it’s a win win win…cheating is like if she did it, like cheating yourself.” [Being dishonest in logging goals to get points; post-development (retrospective) phase, adolescent].

Another adolescent echoed the same thought.

• “I believe in just being honest. Being honest or just giving stuff because you’re not really hurting anybody else. It’s just kind of a personal. But I just feel like if I ever did do this, I would have personally felt really, really weird. So, it’s not, like, really bad.” [Post-development (retrospective) phase, adolescent].

One adolescent mentioned how CommitFit^SM could help him keep up with his own goal.

• “I was thinking when I got in the water in aggregate throughout the day, that was okay. So then when I do, it kind of motivates me because I have to drink the water and then the more water, I drink more.” [Post-development (retrospective) phase, adolescent].

Participants’ conceptualizations of ethicality remained consistent across both phases of the study. Their understanding of what constitutes ethical versus unethical behavior in the context of mHealth app use did not significantly change from the design phase to the post-development phase.

Theme 4: intervention coherence

Clinicians enthusiastically emphasized the importance of allowing users to set customizable and individualized goals within the app. They noted that flexibility in goal setting is essential to ensure that each adolescent’s unique needs, abilities, and health priorities are addressed. Clinicians highlighted that tailored goals not only make the app more relevant and engaging but also enhance motivation and the likelihood of achieving meaningful behavior change.

• “How we can make goals if they’re too broad, then I think it’s harder for them to kind of achieve them or we don’t stick with them. Those types of things, so we try to make specific goals that they can.” [Design (prospective) phase, clinician].

Adolescents also pointed out that frequent reminders could become overwhelming. While they appreciated occasional prompts to stay engaged or meet goals, excessive notifications were described as intrusive and stressful. For example, one participant said,

• “They [reminders] kind of got annoying because if you stayed in bed all day then you would just know that like at the end of the night you didn’t do anything like it told you.” [Design (prospective) phase, adolescent].

Some participants also suggested expanding the resource page to include practical content such as exercise routines, healthy recipes, and wellness tips. They proposed that these resources could be linked to credible external websites to provide users with additional, up-to-date information and support for maintaining healthy habits. Participants felt that such features would make the app more useful and engaging for everyday lifestyle management.

• “I think recipes is a good idea or just like snacks…like healthy snacks that you can grab. Most healthy snacks that you could come just put like a couple of like name brands or stuff because when my mom goes grocery shopping then we could just like go and look for that healthy snacks because I snack a lot so normally the snack.” [Design (prospective) phase, adolescent].

This perspective was echoed by several caregivers.

• “Giving them [adolescents] options to snack ideas and exercising tips and healthy choices… they can think about what they’re going to eat and make a healthy choice… so it can become easier.” [Design (prospective) phase, caregiver].

Adolescents highlighted the importance of the resource page in CommitFit^SM.

• “I really like the resources page. I thought it was pretty helpful. Like if I didn’t know how to reach my goal. Gave me, tips how to do it.” [Post-development (retrospective) phase, adolescent].

Participants were able to clearly describe how CommitFit^SM functions, demonstrating their understanding of its key features. They explained that the app allows users to set personalized health goals, log their daily progress, and monitor achievements over time. This familiarity indicates that the app’s interface and navigation were intuitive, enabling users to engage meaningfully with its goal-setting and tracking components.

• “[I] can figure out how to use [the app].” [Design (prospective) phase, adolescent].

After exploring the static prototype of CommitFit^SM and interacting with it for 2 weeks, participants shared their experiences and feedback.

• “I thought it was pretty easy to use. Just pretty plain and simple.” [Post-development (retrospective) phase, adolescent].

Responses to questions about intervention coherence remained largely consistent across study phases. Participants demonstrated a similar understanding of CommitFit^SM’s purpose, structure, and intended outcomes during both the design (prospective) and post-development (retrospective) phases. This consistency suggests that the app’s core objectives and functions were clearly communicated and maintained throughout the development process.

Theme 5: opportunity costs

Opportunity cost was not a major concern among participants. Caregivers, in particular, expressed strong support for CommitFit^SM, emphasizing that screen time devoted to health-promoting activities was far more valuable than time spent on video games or other entertainment apps. Several caregivers viewed the app as a positive trade-off, encouraging its use as a healthier alternative. One caregiver specifically noted that it would be preferable for adolescents to give up video gaming in favor of using CommitFit^SM to develop and maintain positive health behaviors.

• “So don’t sit there and stare at Minecraft, YouTube videos for three hours…this is more of a quality time and this app [CommitFit^SM] is productive.” [Design (prospective) phase, caregiver].

Occasionally, adolescents noted that CommitFit^SM would need to be versatile and engaging to maintain their interest. They expressed concern that if the app was too limited in functionality or repetitive, they might feel they were “missing out” on other apps or activities they typically enjoy.

• “Tik Tok it’s really addicting, and I really like music and I think that it has to like if you’re going to make like an app, it should like relate to everyone.” [For them to use; design (prospective) phase, adolescent].

Clinicians pointed out:

• “Helping kids to identify how reducing social media time in particular is beneficial to mental health.” [Design (prospective) phase, clinicians].

Another clinician supported the fact and commented:

• “I think by encouraging the physical activity that’s encouraging them to get off their phone.” [Design (prospective) phase, clinicians].

One adolescent expressed a clear preference for using the app as a tool to support healthier choices. She stated that she would rather engage with CommitFit^SM to improve her health behaviors than continue with habits she recognized as unhealthy. This perspective highlights the acceptability and motivational potential of the app, suggesting that it can encourage adolescents to consciously replace detrimental behaviors with positive, health-promoting actions.

• “That’s a probably. I would stick with it. Like if I wasn’t using that app, it just becomes such a bad habit. I probably won’t drink any soda or any sugar beverage.” [Post-development (retrospective) phase, adolescent].

Theme 6: perceived effectiveness

All participants’ evaluation of the potential effectiveness of CommitFit^SM collectively affirmed that the app could support adolescents in improving their health behaviors. Their feedback highlighted a shared belief in the app’s relevance and utility for promoting positive lifestyle changes. Many adolescents expressed that:

• “It helps you like pass away all the soda and the stuff like the snacks and stuff, giving you specific tips on what to do, to eat healthy and stuff.” [Design (prospective) phase, adolescent].

Several clinicians stated that CommitFit^SM would be a helpful tool to improve health behavior among adolescents:

• “Setting goals and tracking and so it’s going to be really, really helpful from a behavioral standpoint.” [Design (prospective) phase, clinician].

Caregivers highlighted:

• “From [CommitFit^SM] you can send a screenshot…. it can come into the electronic medical record and from there [clinician] can see it….it is the physician has involvement and is not just a 120-minute time slot involvement but involvement over the long range.” [Design (prospective) phase, caregiver].

Clinicians expressed enthusiasm about the planned integration of CommitFit^SM with EHR, noting that such functionality could potentially reduce their administrative burden and streamline care coordination:

• “Well, my feeling was that this is ideally going to be the actual real data that right now we’re getting as a general gestalt when they walk in of the previous amount of time, and this is markedly more useful.” [Design (prospective) phase, clinician].

Adolescents commented:

“I only get like three points one day because I drink soda and I didn’t have any fruits and vegetables and then I like ditch. So, and then the next day I was like, okay, can I have any that. And I woke up and I ate an orange.” [Post-development (retrospective) phase, adolescent].

CommitFit^SM appeared to enhance self-awareness among adolescents by encouraging them to actively reflect on their health behaviors and daily routines. Through goal setting, progress tracking, and regular feedback, participants became more conscious of their habits, recognizing areas where they could make improvements. Several adolescents reported that the app helped them notice patterns in their behavior, such as dietary choices, which they had previously overlooked, fostering a sense of accountability and personal insight.

• “If you go over to a friend’s house, everybody’s having a soda. You’re just like, oh, I want a soda. And then the next day, I had a soda yesterday with my friend. I’ll drink water today. That’s good. Or if you like, that’s coming in the future. You’re like, okay, I’m going to go to a birthday party that day. So today I’m going to have this business kind of like plan your week out.” [Post-development (retrospective) phase, adolescent].

Adolescents articulated that CommitFit^SM triggered them to opt for healthy choices rather than unhealthy ones:

• “It probably started getting it, especially school times when I packed my lunch. So, if I were like, okay, let’s do some fruit and vegetables. So, I’d throw like an orange or like a banana…And orange never really comes to mind when you think, especially if you like, go to the pantry and you got like Cheez-Its or goldfish or something that sounds better than an orange, but okay.” [Post-development (retrospective) phase, adolescent].
• “Personally, feel a lot better about myself cause I usually would just have, like, one serving each day or like, two. But I am now starting to get like three or even four servings.” [Post-development (retrospective) phase, adolescent].

Perceived effectiveness of CommitFit^SM remained consistent throughout both phases of the study for all participants. Participants expressed similar beliefs about the app’s ability to support behavior change, achieve health goals, and provide meaningful feedback during both the design (prospective) phase and the post-development (retrospective) phase. This stability suggests that participants’ confidence in the app’s potential impact was well-established early on and was maintained after extended interaction with the functional app.

Theme 7: self-efficacy

Adolescents expressed a high level of confidence in their ability to use CommitFit^SM, indicating that the app was intuitive and accessible. Many participants felt comfortable navigating its features, such as setting goals, logging progress, and tracking, without difficulty. Some adolescents went further, stating that they would be likely to use the app on a regular basis, suggesting not only ease of use but also perceived relevance and personal value in supporting their health behaviors. This combination of confidence and intended regular use points to strong potential for sustained engagement with the app, for example:

• “[I] would most likely use this app every day. Well, maybe not every day, but every other day.” [Design (prospective) phase, adolescent].

Adolescents also voiced that they liked CommitFit^SM and it was fun to use.

• “I like that, cause it kind of made me think like I can’t forget to get my activity. So, I could catalog my activity and stuff like that. Actually, like this app is kind of fun.” [Design (prospective) phase, adolescent].

Caregivers also showed confidence that tracking their progress would be encouraging.

• “[Tracking health behaviors] maybe like water intake, because being hydrated is important.” [Design (prospective) phase, caregiver].

Another adolescent supported that tracking would be motivating and keep them going.

• “...weekly [tracking], just seeing that you’re making even the tiniest bit of progress is probably a good thing.” [Design (prospective) phase, adolescent].

Clinicians also confirmed that tracking would be beneficial.

• “I think kids are going to want to see progress as much as possible so that they don’t get frustrated. So anyway, that we can maximize the visual. Then able to visualize that they’re improving. I think it’s important.” [Design (prospective) phase, clinician].

Adolescents were able to comprehend how to set and log goals in CommitFit^SM and reach their selected goals.

• “I thought it was pretty easy to use. Just pretty plain and simple.” [Post-development (retrospective) phase, adolescent].

Adolescents demonstrated confidence in their ability to independently navigate CommitFit^SM, including selecting and setting goals without requiring assistance from parents, caregivers, or peers. They reported feeling capable of understanding the app’s features, identifying which health behaviors to target, and tailoring goals to their own preferences and abilities. This self-efficacy suggests that the app is intuitive and user-friendly, empowering adolescents to take ownership of their health behaviors and engage proactively with the intervention.

• “See that was pretty straightforward to choose how much, how long you wanted to do it.” [Post-development (retrospective) phase, adolescent].

New theme 1: intervention motivational aspects

This study identified an emergent theme highlighting the importance of motivational features, such as gamification (e.g., avatars, streaks, points, leaderboards), in mHealth applications. Participants emphasized that these features are critical for fostering both initial acceptance and sustained engagement among adolescents. Both adolescents and caregivers expressed enthusiasm and interest when introduced to the gamification elements incorporated in CommitFit^SM.

• They echoed that “Leaderboard, I guess that’s the first thing that kind of stuck out to me.” [Design (prospective) phase, adolescent].

Caregiver highlighted that “I like the little avatars. Those are cute.” [Design (prospective) phase, caregiver].

Many clinicians supported healthy competition to achieve goals like:

• “I like that and then they could compete against each other just on like the number of fruits and vegetables that they tried or something like that. I will say so... I’m excited to see if that goes over well or not.” [Design phase prospective phase, clinician].
• Adolescents affirmed, “I thought the little character guy [avatar] was pretty funny. I like the gear store. It was pretty good. She’s got gray pants and the blue hair. I showed my mom. We had a good gig.” [Post-development (retrospective) phase, adolescent].

Healthy competition was identified as a motivating factor by many adolescents.

• “I think I can tell you that the challenge is I felt really effective.” [Post-development (retrospective) phase: adolescent].
• “I think adding the challenges...with your friends and staff and that would be really fun.” [Post-development (retrospective) phase, adolescent]
• “And the other thing is, it’s more like a fun competition because you don’t know the other people and they’re kind of just mystery people.” [Post-development (retrospective) phase, adolescent].
• “I like the point system and how it can compete with other people because it motivates you to do better and to remember to log.” [Post-development (retrospective) phase, adolescent].

New theme 2: stakeholder endorsement

The second emergent theme related to adolescents’ use of CommitFit^SM for lifestyle improvement was identified during the design or prospective phase. When discussing adolescent engagement with the app, many caregivers and clinicians emphasized the need for a health application like CommitFit^SM that could motivate and facilitate healthier behaviors among adolescents. Stakeholder endorsement of adolescent mHealth applications is critical, as it can influence both acceptability and sustained use. Caregivers also expressed enthusiasm about the potential for parental oversight within the app.

• “That’s a safety thing, and also privacy. I am constantly checking like his social media. I think that there needs to be a setting where the parents have to or have the ability to check. Just sort of the term parental oversight.” [Design (prospective) phase, caregiver].

Clinicians expressed strong support for CommitFit^SM, noting its potential to serve as a common platform for communication with patients and, potentially, caregivers. A well-designed, tailored health application such as CommitFit^SM—focused on improving adolescent health behaviors and integrated with EHR—would not only enable adolescents to log their goals but also allow clinicians to track real-time data, thereby enhancing efficiency during clinic visits.

• “I personally think I would use it when I did the growth chart.” [Design (prospective) phase, clinician].
• Another clinician added, “I think as long as it comes up in real time, like when you’re accessing their chart…I think that would be the most helpful because you’re just not relying on your memory. You’re looking back at old notes. It’s something that’s quickly and easily seen and accessible.” [Design (prospective) phase, clinician].

Similar acknowledgments were heard from caregivers and one caregiver who is also a clinician stated,

• “If somehow people who enrolled in this app and they couldn’t get together with their physician, I could call and say, hey [NAME], I need an update from your son on his weight… if th’re’s anything else that comes up, there are lines of communication.” [Design (prospective) phase, caregiver].

The two additional themes identified in this study are particularly relevant for fostering acceptance and sustaining adolescent engagement and motivation in using CommitFit^SM. Motivational factors such as gamification and endorsement from key stakeholders play a critical role, as adolescents are often influenced by caregivers and healthcare providers when making health-related decisions (27,29,31,32). Consequently, it is essential to capture stakeholders’ perceptions regarding adolescents’ use of mHealth applications.

Discussion

Key findings

Qualitative data from focus groups and interviews with adolescents, caregivers, and clinicians—who were presented with either a static prototype or, in the case of adolescents in the post-development (Phase 2) study only, a functional version of the mHealth application were analyzed using the seven domains of the TFA: affective attitude, burden, ethicality, intervention coherence, opportunity cost, perceived effectiveness, and self-efficacy. In addition to these established domains, two themes emerged from the data: intervention motivational aspects and stakeholder endorsement, resulting in a nine-domain framework of acceptability that more fully captures adolescent-specific drivers of engagement and sustained use.

Across both study phases, adolescents expressed strong enthusiasm for the overall look and feel of CommitFit^SM, describing the design as engaging and well aligned with their age group. This positive affective response was closely linked to perceptions of low burden; adolescents reported that the app integrated easily into daily routines and did not feel intrusive or taxing. Establishing consistent routines through app use made activities that had previously been perceived as difficult feel more manageable, suggesting that habit formation reduced perceived effort and supported sustained engagement. These findings underscore the interdependence of affective attitude and burden in shaping adolescent acceptability.

Ethicality emerged as a nuanced domain. Adolescents recognized that mHealth apps can reinforce positive health values but also cautioned that competitive features, if overly emphasized, could promote dishonest behaviors. This reflects adolescents’ awareness of social pressures and performance norms within digital environments and highlights that ethicality is not inherent to specific features but shaped by how those features are designed and framed. These observations suggest that social and competitive elements must be implemented carefully to balance motivation with fairness and psychological safety.

Differences across stakeholder groups were most evident within the domain of intervention coherence. Clinicians emphasized the importance of goal customization and personalization to support individual progress and maintain clinical relevance, whereas adolescents expressed concern that excessive reminders could become overwhelming and lead to disengagement. These differing perspectives reflect stakeholders’ distinct priorities: clinicians focus on adherence and progress monitoring, while adolescents value autonomy and minimal intrusion. Participants also requested expanded practical resources—such as exercise guides and healthy recipes—to help link app activities with meaningful health outcomes. Opportunity cost was not a major concern; caregivers viewed CommitFit^SM as “quality screen time” and preferable to entertainment-based digital activities.

Perceived effectiveness and self-efficacy emerged as central determinants of acceptability across all groups. Participants emphasized that sustained engagement depends on adolescents believing the app can support meaningful behavior change and feeling confident in their ability to use it successfully. Acceptability ultimately hinged on whether CommitFit^SM could plausibly improve health behaviors and whether adolescents felt capable of engaging with the app over time, with opportunity costs viewed as minimal relative to these benefits.

Integrating these findings with broader mHealth and motivational literature highlights two determinants that extend beyond the original seven TFA domains. Intervention motivational aspects, including gamification elements such as avatars, streaks, points, and leaderboards, supported engagement by reinforcing autonomy, competence, and relatedness. Stakeholder endorsement emerged as a second driver of acceptability. Encouragement and legitimization from caregivers and clinicians validated app use, reduced perceived costs, and reinforced adherence. This endorsement operated through several mechanisms: signaling trustworthiness, normalizing continued use within daily routines and clinical encounters, and supporting problem‑solving around goal adjustment or notification preferences. Caregivers and clinicians played complementary roles, with caregivers acting as gatekeepers and co‑regulators of routines and screen time, and clinicians serving as validators who aligned app use with care plans, offered personalized guidance, and reinforced clinical relevance. Clinician endorsement, in particular, emerged as critical for clinical implementation by supporting alignment with existing workflows and strengthening CommitFit^SM’s credibility as a health intervention, including the potential for future EHR integration.

For adolescents navigating multiple layers of authority, such endorsement is a pivotal lever for both initial uptake and sustained engagement.

Together, these findings suggest concrete design priorities for adolescent mHealth interventions: customizable goal-setting, and reminder frequency to preserve autonomy; motivational feedback mechanisms such as progress tracking and gamification to reinforce engagement; ethically designed social features that avoid excessive competition; and readily accessible practical resources that link app use with meaningful health outcomes. Incorporating visible caregiver and clinician endorsement further strengthens credibility and supports sustained use within both home and clinical contexts.

The consistency of acceptability perceptions across the design and post-development phases suggests early alignment between stakeholder expectations and adolescents’ lived experiences of app use. This finding underscores the value of prospective acceptability assessment during the design phase as a foundation for later experienced acceptability and sustained engagement. However, consistency in perceived acceptability does not guarantee long-term adherence or behavior change, highlighting the need for future research to incorporate objective usage analytics and longitudinal follow-up to examine engagement trajectories and their relationship to health outcomes.

This study differs from prior work by employing a two-stage assessment of acceptability—first during the design phase and again in the post-development phase—and by incorporating perspectives from adolescents, caregivers, and clinicians. Evaluating adolescent mHealth interventions using the seven TFA domains together with the two additional domains identified here advances a nine-domain framework of acceptability that more fully explains adolescent-specific drivers of sustained use. Adolescents prioritized motivational design and socially safe engagement; caregivers emphasized ease of use and trustworthy content; and clinicians focused on personalization and clinical integration. Applying this expanded framework during both design and post-development phases offers actionable guidance for developing developmentally appropriate, clinically relevant mHealth interventions capable of supporting sustained engagement and long-term health behavior change among adolescents.

Strengths and limitations

A key strength of this study is its multi-phase, multi-stakeholder qualitative design, which enabled the collection of rich, triangulated insights from adolescents, caregivers, and clinicians across both the design and post-development phases of CommitFit^SM. Conducting multiple focus groups and interviews allowed for the capture of diverse perspectives and nuanced feedback, strengthening the credibility, depth, and robustness of the findings. Including caregivers and clinicians—stakeholder groups often absent in adolescent mHealth research—provided essential context regarding real-world feasibility, family dynamics, and clinical workflow considerations. The consistency of themes across phases further enhances the transferability of the results, demonstrating that user impressions remained stable across time, context, and level of app maturity.

Although this study has several notable strengths, several limitations must also be recognized. First, reliance on self-reported data in the post-development phase limited the ability to directly link acceptability to actual usage patterns or behavioral outcomes; future work should incorporate in-app analytics (e.g., session frequency, feature engagement) and, when feasible, objective health indicators aligned with CommitFit^SM’s behavioral targets. Second, focus groups carry a risk of conformity or groupthink. Although same-gender groups were used to promote comfort, maintaining individual interviews, as done in the post-development phase, remains essential for surfacing divergent or dissenting views. Third, as with most qualitative research, the sample size limits generalizability; larger and more diverse cohorts, including adolescents from under-resourced and rural settings, are needed to assess the consistency and equity of effects. Finally, while participants expressed interest in future EHR integration to support shared decision-making, such integration will require careful evaluation of workflow burden, privacy safeguards, and usability to avoid unintended clinical or documentation risks.

Comparison with similar research

Our findings contribute to a growing body of evidence supporting the importance of social and motivational factors in mHealth adoption. For instance, Kenny et al. (33) conducted related research among adults and identified social interaction as one of the key determinants of mHealth use. Social interaction could influence the ethicality domain of the TFA, for example, team-based competitions may foster collaboration but could also lead to ethical concerns such as dishonesty or an excessive focus on winning, which would be counterproductive to the purpose of the app.

Although recent studies have highlighted the potential harm of social media use among adolescents, emerging evidence also suggests that information exchange among peers with similar health conditions can empower adolescents to better manage their own health (34). The significance of these social interactions is further supported by prior research (24,25), which suggests that connecting with peers fosters a sense of community, belonging, and emotional support among users. Within the context of the TFA, these dynamics are closely related to the domain of opportunity costs, as participation in supportive peer networks may be perceived as a beneficial trade-off relative to other uses of time and resources.

Similarly, our findings align with motivational elements identified in previous adolescent-focused mHealth studies. A 2017 study by Chan et al. (10) found that features such as rewards, customization, and competition promote sustained engagement with health apps among adolescents. These motivational features correspond with our additional domain, intervention motivational aspects. Specifically, gamification elements such as rewards, avatars, points, and leaderboards serve as effective strategies to encourage adolescents to remain engaged with mHealth interventions. Furthermore, our findings correspond closely with motivational factors previously identified by adolescent health researchers examining mHealth interventions (33,35,36).

In this study, we found that motivational aspects of the intervention, particularly gamification, play a critical role in the acceptance and sustained use of mHealth applications. While one prior study (37) concluded that gamification features do not significantly influence user ratings in app reviews, other research such as Miller et al. (2016), Chan et al. (2017), and Primack et al. (2012) demonstrates that self-managed gamified apps often incorporate novel challenges (3,10,38), which foster self-motivation among adolescents and encourage continued engagement with the app (39). Moreover, although complex app designs with conflicting priorities have been identified as barriers to mHealth adoption (10), our findings suggest that well-aligned priorities that facilitate social interaction through healthy competition can mitigate these barriers, enhancing user engagement and promoting sustainable health behaviors.

Explanations of findings

Qualitative findings from our study indicate that the seven TFA domains were relevant for assessing the acceptability of CommitFit^SM among adolescents, caregivers, and clinicians, providing insight into how these stakeholders perceive the acceptability of mHealth applications. Although the TFA was originally developed based on adult healthcare interventions, our findings support its applicability for evaluating adolescent mHealth apps. At the same time, this study extends the original conceptualization of acceptability by introducing two additional domains—intervention motivational aspects and stakeholder endorsement—which underscore the importance of motivation and social context for sustained use among adolescents. Notably, responses across the seven original TFA domains remained consistent from the design (prospective) phase to the post-development (retrospective) phase, supporting the robustness of the framework across stages of app development. Further research is warranted to test this expanded framework and examine its utility for evaluating adolescent mHealth interventions.

Motivational features within the additional domain of “intervention motivational aspects” highlight the importance of designing mHealth applications that actively engage adolescents. Gamification elements, such as rewards, avatars, points, and leaderboards, leverage adolescents’ tendencies toward play, competition, and achievement by providing immediate feedback and reinforcing positive behaviors. By making the experience interactive and enjoyable, these features can enhance engagement, support sustained use, and promote adherence to behavioral goals over time.

Perceived health benefits represent a critical facet of acceptability and closely align with the perceived effectiveness domain. Participants indicated that interactions with the CommitFit^SM app could positively influence health behaviors and lifestyle, particularly when the app is supported by caregivers and accessible to clinicians through integration with clinical systems. Prior evidence suggests that mHealth applications linked to EHR systems can facilitate shared decisionmaking among adolescents, caregivers, and healthcare providers (24,34). Direct data export from CommitFit^SM to the EHR could enable clinicians to review app-generated information and provide timely, personalized feedback to enhance care quality. At the same time, although EHR tools may improve provider satisfaction, concerns regarding patient safety have been associated with poor EHR usability (25-27,37). When implemented thoughtfully, integrating CommitFit^SM with EHR systems has the potential to strengthen clinician-adolescent relationships and promote collaborative care.

“Stakeholder endorsement” emerged as an important determinant of acceptability by shaping which mHealth app features caregivers and clinicians support and recommend for sustained use among adolescents. Such endorsement can increase adolescents’ confidence in the intervention, promote consistent engagement, and foster trust among adolescents, caregivers, and clinicians, reinforcing collaborative efforts to support positive health behaviors.

Implications and actions needed

Our findings support the use of the TFA for evaluating adolescent mHealth interventions while also demonstrating the need to expand the framework to include two additional domain‑level constructs: intervention motivational aspects and stakeholder endorsement. Although these nine domains were examined in the context of CommitFit^SM, they represent broader dimensions of acceptability that are likely relevant across adolescent mHealth applications. These domains should be systematically considered during the development of adolescent‑focused mHealth interventions. This includes designing appropriate and engaging interfaces; incorporating motivational features such as gamification; minimizing user burden through ease of use; addressing ethical considerations; enabling personalization and goal‑setting; providing high‑quality support resources; acknowledging opportunity costs; strengthening perceived effectiveness; enhancing self‑efficacy; and securing caregiver and clinician endorsement. Iterative, multi‑stage evaluation across development phases is critical for refining app features and ensuring alignment with adolescents’ evolving needs. Integrating these acceptability considerations early and consistently can help ensure that adolescent mHealth apps are engaging, feasible, ethically sound, and capable of supporting sustained health behavior change. In particular, fostering motivation and securing strong endorsement from caregivers and clinicians are likely to be central to long‑term acceptability and continued use of CommitFit^SM and similar interventions.

Future research should evaluate and validate the expanded nine‑domain framework by examining whether the additional constructs predict sustained engagement and behavior change beyond the original TFA domains. Further work should also explore moderators such as age, gender, rurality, and caregiver involvement that may influence the salience of specific domains; assess implementation strategies that operationalize stakeholder endorsement (e.g., clinician scripts, caregiver onboarding); and examine equity impacts to ensure the framework is responsive to diverse adolescent populations and clinical settings. Such efforts will strengthen the framework’s relevance and utility for guiding the design and implementation of effective adolescent mHealth solutions.

Conclusions

Acceptability of adolescent mHealth apps is multidimensional and socially embedded. For CommitFit^SM, sustained use was more likely when the app supported adaptive and achievable goals, delivered clear progress feedback through motivational features that resonate with adolescents, and received active endorsement from caregivers and clinicians. These insights move beyond broad developmental principles to offer concrete guidance on what to build, how to implement interventions within care contexts, and how to evaluate them over time. Applying the expanded nine‑domain approach during both design and evaluation can strengthen the engagement, credibility, and clinical viability of adolescent mHealth interventions.

Qualitative feedback from adolescents, caregivers, and clinicians underscores the relevance of all nine acceptability domains—seven from the original TFA and two added domains—which were consistently endorsed across both the design (prospective) and post-development (retrospective) phases of CommitFit^SM. These domains appear particularly salient during initial app exposure, shaping first impressions, and early engagement. Future research should examine more diverse adolescent populations to assess the generalizability of these findings and use qualitative, quantitative, or mixed‑methods approaches to validate the expanded framework and further elucidate motivational processes underlying adoption and sustained use. As adolescent mHealth continues to evolve, ongoing research will be essential to ensure that interventions are not only effective, but also acceptable, trusted, and used sustainably in real‑world settings.

Acknowledgments

A part of this work was presented in poster format at the North American Primary Care Research Group (NAPCRG) 2023 conference.

Footnote

Data Sharing Statement: Available at https://mhealth.amegroups.com/article/view/10.21037/mhealth-2025-76/dss

Peer Review File: Available at https://mhealth.amegroups.com/article/view/10.21037/mhealth-2025-76/prf

Funding: The research reported in this publication was supported by the University of Missouri Coulter Biomedical Accelerator. The content is solely the responsibility of the authors and does not necessarily represent the official views of the University of Missouri Coulter Biomedical Accelerator or the University of Missouri. This work was made possible with support from Washington University in St. Louis Center for Diabetes Translation Research (Grant P30DK092950 from the National Institute of Diabetes and Digestive and Kidney Diseases). The content is solely the responsibility of the authors and does not necessarily represent the official views of the Center for Diabetes Translation Research or the National Institute of Diabetes and Digestive and Kidney Diseases.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://mhealth.amegroups.com/article/view/10.21037/mhealth-2025-76/coif). K.T.B. is supported by an NIH T32 Alcohol Training Grant through the National Institute on Alcohol Abuse and Alcoholism (NIAAA) in the United States (No. T32AA013526). The other authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by Missouri Health Science Institutional Review Board at the University of Missouri (No. 2092610), and informed consent was obtained from all individual participants and legal guardians.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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