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Abstract

Background: School-based health promotion is a key public health strategy to reduce disease burden and health inequalities. School-based interventions with local evidence of effectiveness need to be scaled up to maximize their benefits. A Project Promoting healthy Living for Everyone in Schools (APPLE Schools) is a health promoting school (HPS) intervention that targets schools in disadvantaged settings and has been shown to be effective in promoting children's healthy lifestyle behaviors and reducing health inequalities. To support its scale-up, we aimed to identify core functions (basic purposes driving intervention's effectiveness) and forms (specific content and delivery strategies implemented to achieve core functions). Method: We extracted 5,301 action items from 191 annual action plans written between 2011 and 2021 in 70 APPLE Schools. We followed an implementation science approach and used supervised machine learning algorithms to classify 2,683 unique action items into intervention activities and implementation strategies. Core functions were drawn from theoretical frameworks; forms were identified through thematic analysis. Results: We identified 55 forms and mapped them to 17 core functions of intervention activities and implementation strategies. The most common core functions of intervention activities were enablement (96%), modeling (66%), and education (54%); the most common core functions of implementation strategies were relational and organizational support context (86%), partnerships and networking (84%), student participation (78%), and professional development and learning (73%). The remaining core functions were identified in <50% of the schools. Forms included a broad range of activities, with a greater variety of those that addressed the most common core functions. Conclusions: We created matrices of core functions and forms of intervention activities and implementation strategies to inform the successful scale-up of APPLE Schools, an effective and cost-effective HPS intervention. These matrices can be used as a guide to improving existing HPS interventions and scaling them up to new settings.

Plain Language Summary

Health Promotion in Schools: Identifying Key Elements of a Successful School Intervention to Support Its Expansion into More Schools Across Canada

Children living in disadvantaged communities are disproportionately impacted by lack of access to opportunities for physical activity and nutritious food, and so are at highest risk of childhood obesity and chronic diseases later in life. Effective interventions to reduce the risk for chronic disease in vulnerable children exist but they need to be expanded to reach more children. A school-based program called A Project Promoting healthy Living for Everyone in Schools (APPLE Schools) delivers a very successful intervention to encourage healthy living and mental health to vulnerable kids from disadvantaged communities. It currently operates in more than 100 schools in western Canada (Alberta, British Columbia, Manitoba, and Northwest Territories). The program plans to expand nationally to reach more vulnerable children. To do this, we need to understand which program elements make it successful.

From annual action plans developed by 70 APPLE Schools between 2011 and 2021, we extracted health promotion activities and strategies that support these activities. Overall, we identified a comprehensive list of 17 essential components of the APPLE Schools program. In addition, we identified 55 specific activities that—if put in place—will ensure a successful expansion of this program into new schools across Canada. The most common core functions were helping students make healthy choices (enablement), showing positive examples (modeling), and teaching (education). The most common forms included building supportive school environments, forming partnerships, engaging students in delivering health promoting activities, and providing staff training. This work can also benefit other schools that can use this resource to guide their health promotion efforts to improve healthy living among their students.

Keywords

adaptation implementation evidence-based intervention health promoting school intervention complex interventions core functions and forms

Introduction

School-based interventions that foster healthy lifestyle behaviors and mental wellness from a young age are a critical public health strategy to reduce the chronic disease burden (Fung et al., 2012). Schools are also the ideal setting for delivering health promotion interventions that tackle health inequalities (Vander Ploeg, Maximova, et al., 2014). Therefore, school-based health promotion interventions with local evidence of effectiveness need to be scaled up to maximize their benefits. The World Health Organization advocates for health promoting schools (HPS) interventions to be implemented in each school, given their demonstrated effectiveness in improving children's health and well-being and academic outcomes, as well as cost-effectiveness and high return on investment (World Health Organization and the United Nations Educational, Scientific and Cultural Organization, 2021).

However, HPS interventions might be difficult to implement, sustain, and adapt to new contexts (Craig et al., 2008). Unlike discrete school-based interventions (e.g., installing water fountains or hydration stations or extending a physical activity break by 10 min), HPS interventions are complex: they include a wide range of intersectoral, multistakeholder, and multicomponent actions (or intervention activities) that aim to improve lifestyle behaviors and health of students and school staff, with most of these actions requiring at least several approaches (or implementation strategies) to adopt, integrate, and sustain them (Domitrovich et al., 2008; McIsaac et al., 2017; Moore et al., 2017; Ozer, 2006). Moreover, HPS intervention activities and implementation strategies must be tailored to each school's unique context, existing assets, and other contextual determinants of HPS implementation outcomes. A well-documented example of a successful HPS intervention currently operating in more than 100 elementary schools in several provinces and territories across Canada is A Project Promoting healthy Living for Everyone in Schools (APPLE Schools), an innovative, not-for-profit HPS intervention targeting elementary schools in socioeconomically disadvantaged settings.

APPLE Schools is internationally recognized as an evidence-based best practice for school health by the National Institute of Health/National Cancer Institute (National Cancer Institute, 2020), and as one of the world's 100 most innovative and inspiring education projects by a global nongovernmental organization HundrED (HundrED, 2019). In a series of quasi-experimental, pre–post trials with a parallel nonequivalent control group, the APPLE Schools intervention has been shown to be effective, with APPLE Schools students developing better nutrition habits, becoming 35% more physically active in/outside of school and 40% more likely to have a healthy weight (Bastian et al., 2015; Maximova et al., 2015; Roberts et al., 2016; Tran et al., 2014; Vander Ploeg et al., 2012; Vander Ploeg, McGavock, et al., 2014). The evidence also documents reductions in health inequalities: while all students benefit from the intervention, those most in need (i.e., most disadvantaged) benefit the most (Bastian et al., 2015; Vander Ploeg, Maximova, et al., 2014). Over 2 years, school averages of student lifestyle behaviors improved to approximate provincial levels (Bastian et al., 2015; Vander Ploeg, Maximova, et al., 2014). Moreover, this intervention was shown to be cost-effective (Ekwaru et al., 2017), with an astounding return on investment of 860% (i.e., every $1 invested avoids $8.6 in future direct and indirect costs associated with chronic diseases; Ekwaru et al., 2021).

APPLE Schools was inspired by and modeled after the grassroots initiative called Annapolis Valley Health Promoting Schools (AVHPS), implemented in Nova Scotia in 1997 (Veugelers & Fitzgerald, 2005). The efforts to transfer the AVHPS intervention to schools in Alberta were informed by multiple training sessions, with the AVHPS team sharing experience implementing the intervention in Nova Scotia and thoughts on tailoring it to the Albertan context (Fung et al., 2012). Since its launch in 2008 in 10 schools in Alberta, this research evidence enabled APPLE Schools to scale up its operations to over 100 schools in Canada, now serving more than 33,000 children annually. Efforts are underway to scale it up to 200 schools in disadvantaged settings in the coming years and reach over 60,000 students annually.

To support these efforts and ensure implementation fidelity, which is crucial to maximizing the intervention's effectiveness and sustainability in new contexts, it is imperative to discern core functions (i.e., basic purposes, mechanisms and theoretical principles that fundamentally define the intervention and drive its effectiveness) and forms (i.e., specific content and delivery strategies implemented to achieve core functions; Jolles et al., 2019) of APPLE Schools intervention activities and implementation strategies. Indeed, clearly outlining which elements should be retained (i.e., core functions) and which ones can be tailored to the local context and needs (i.e., forms) is recognized as one of the essential determinants of a successful scale-up (Gesell et al., 2021; Hawe et al., 2004). This approach is particularly suited for the APPLE Schools intervention, shown to produce differential effect across schools and students (with disadvantaged schools and students benefiting the most) and requiring tailoring of its intervention activities and implementation strategies to each school's unique context. To our knowledge, only a few studies attempted to specify core functions and forms of complex interventions (Byng et al., 2008; Fianu et al., 2017; Hill et al., 2020; Jolles et al., 2019; Kirk et al., 2021; McNeal et al., 2022; Villeval et al., 2016, 2019; Wahlen et al., 2022), but they focused predominantly on healthcare interventions in clinical settings. Only one (Villeval et al., 2019) aimed to unpack the core functions and forms of a school-based health promotion intervention targeting nutrition and physical activity education. Further, none of the studies identified core functions and forms of both interventional aspects—intervention activities and implementation strategies. In this study, we aimed to build matrices of core functions and forms of APPLE Schools’ intervention activities and implementation strategies to inform the transfer of this intervention to schools across other Canadian provinces and territories.

Methods

The APPLE Schools Intervention

Grounded in the HPS approach, APPLE Schools aims to promote healthy lifestyle behaviors and mental health and well-being by transforming the culture of school communities to one where “the healthy choice is the easy choice” (Fung et al., 2012). APPLE Schools implements the HPS approach by delivering harmonized actions on four distinct but interrelated pillars (i.e., social and physical environment; teaching and learning; policy; and partnerships and services) to help school communities build capacity and students to take greater ownership of their own health (Pan-Canadian Joint Consortium for School Health, 2016). Recognizing the unique context in which each school functions, the APPLE Schools intervention is tailored to each school's needs and priorities. As such, there is no predetermined set of intervention activities and implementation strategies to be found in every APPLE School (which would be the case if the intervention followed a one-size-fits-all approach, previously shown to be largely ineffective in producing the desired effect, Powell et al., 2017).

To tailor the intervention to each school's needs and facilitate implementation, APPLE Schools places a school health facilitator (SHF) in each school who works closely with students, families, school staff, local business and community partners to collaboratively identify health promotion goals and implement health promotion activities. SHFs provide hands-on, full-time support over the first 2–3 years, after which a volunteer teacher mentored through APPLE Schools’ central office and called a school health champion (SHC) becomes the key person to maintain the HPS culture in the school.

Analytical Approach

To develop matrices of core functions and forms of APPLE Schools intervention activities and implementation strategies, the analytical approach included the following steps: (a) extracting all activities documented in APPLE Schools annual action plans; (b) classifying extracted activities into intervention activities and implementation strategies using manual and machine learning (ML) approaches; (c) mapping intervention activities and implementation strategies onto two sets of theory-informed core functions; and (d) grouping intervention activities and implementation strategies within each core function into forms using thematic analysis.

Extracting Activities From APPLE Schools Annual Action Plans

Between 2011 and 2021, APPLE Schools was operating in 70 schools. The SHFs and SHCs in these schools, under the guidance of APPLE Schools mentors, prepared a total of 555 annual action plans, which documented goals, objectives, and what and how health promotion-related activities were implemented. Action plans, particularly in the early years, did not follow a structured format; therefore, their organization and richness of captured information vary between schools. To prioritize action plans most likely to yield rich information, we rated them according to the level of detail provided, readability and comprehension, and whether they had been updated throughout the school year. The total score ranged from 0 to 3, with higher scores indicating better quality and richness of action plans (see Supplemental Material 1). Those rated lower than 3 (n = 364) were excluded (see Figure 1).

Figure 1.

Flowchart of Data Collection.

From the 191 action plans with a total score of three, 5,301 activities were extracted using a data extraction form, pilot-tested by two researchers (JK and BM). For each activity, the form captured the following information: goals and objectives, name (e.g., Smoothie Day, Taste Testing, Hoop Dance), how and by whom it was delivered (e.g., “Teacher brought her own fruit [crab apples] from her own garden”), whether students were involved in planning and delivery (e.g., “Student leaders planted and tend to flowers and vegetables [in the school garden]”), frequency of delivery (e.g., throughout the year, once a year, every month, every day), when it was delivered (e.g., throughout school year, fall, winter, spring), target audience (e.g., all grades, specific grades, school staff), as well as details about any adaptations made and justification for these changes (e.g., “Changes for the few months of cold weather: The student leaders will go to assigned classes and have the students participate in ‘Just Dance’ [indoors, as opposed to going to an outdoor playground]”). To obtain a sample of unique activities for analysis, repeat activities in the same school and activities that were planned but not delivered were excluded (n = 2618).

Classifying Activities into Intervention Activities and Implementation Strategies

The large number of unique activities retained for analyses (n = 2683) required employment of supervised ML methods, commonly used in sentiment analysis research (Geethangili & Suresh, 2022; Nasteski, 2017; Osisanwo et al., 2017), to maximize the efficiency and utility of all data available (as opposed to manually coding and analyzing only a subset of activities). First, JK and BM labeled (or manually classified) a subset of 1200 (45%) randomly selected activities as either intervention activities (i.e., what was implemented) or implementation strategies (i.e., how—or using which strategies or techniques—intervention activities were implemented). Of these 1,200 manually classified activities, a subset of 600 activities, along with the labels assigned by JK and BM, was used to train two ML algorithms to recognize text patterns associated with intervention activities and implementation strategies. Since ML algorithms require text to be processed and simplified, text of each activity was tokenized: phrases were split into individual words, which were reduced to their root stem (e.g., “running” was reduced to its root stem “run”) to enable cross-comparison across activities. Word vectors for each activity were created using the Term Frequency-Inverse Document Frequency approach, which considers the frequency of each word within each activity against its frequency in the entire sample of activities (for a detailed explanation of this approach, see Geethangili & Suresh, 2022; Li & Ou, 2021). Once the text was processed, ML algorithms used the k-Nearest Neighbors algorithm with k = 5 and Euclidean distance measures to classify activities according to the most common category among each activity's five nearest neighbors in the labeled training set (Dey et al., 2016).

Two ML algorithms (one trained to predict the likelihood of each activity being classified as an intervention activity and another one trained to predict the likelihood of each activity being classified as an implementation strategy) were applied to the remaining 600 activities within the training set, but no labels assigned by researchers were provided. ML classification of each activity as an intervention activity vs. implementation strategy was validated against labels assigned by researchers (JK, BM) in order to verify each algorithm's predictive performance (Stevens et al., 2020). ML models attained class precision and recall >80% for true positives, which was deemed sufficient to proceed, given that the subsequent two steps (i.e., mapping intervention activities and implementation strategies to their core functions and grouping activities into forms) involved analyses done by the researchers. The remaining unlabeled 1,483 activities were classified by ML algorithms only. ML models were ran using RapidMiner version 10.1 (rapidminer.com).

Of 2,683 extracted activities, 300 contained information pertaining to intervention activities and implementation strategies. For example, one of the extracted activities was “Spring Walk Day: [date]. Grade 3 students planned and implemented the event. We wore the T-shirts from [local community organization - blinded] and ended the walk with the Zumba party.”). This activity contains information on both the “what” (i.e., Spring Walk Day, Zumba party) and the “how” (i.e., the intervention activity was planned and implemented by Grade 3 students); therefore, the first part was classified as an intervention activity, and the second part—as an implementation strategy. The majority of extracted activities were labeled as intervention activities (n = 2,066), and fewer than half were labeled as implementation strategies (n = 1,217).

Mapping Intervention Activities and Implementation Strategies onto Their Core Functions

Nearly one-third of activities classified in the previous step as intervention activities (n = 685) and implementation strategies (n = 405) were randomly selected for mapping onto core functions. Core functions of intervention activities were drawn from the Behavior Change Wheel (BCW; Michie et al., 2011), considering a comprehensive range of interventions it captures and its appreciation of the broader social and physical contexts within which individual behavioral change occurs. Core functions of implementation strategies were drawn from the implementation components of HPS outlined by Rowling and Samdal (2011; see Table 1). JD and CH mapped intervention activities and implementation strategies to their core functions: in 60% and 82% of cases, intervention activities and implementation strategies were assigned by JD and CH to the same core function, respectively. Disagreements were discussed and resolved by the two reviewers.

Table 1.

Framework for Mapping Forms onto Core Functions of APPLE Schools Intervention Activities and Implementation Strategies.

Intervention components	Core functions	Definitions
Intervention activities (i.e., what is planned and implemented; related to the end goal of the intervention)	Education	Increasing knowledge or understanding of healthy lifestyle behaviors.
	Persuasion	Using communication strategies to stimulate positive changes in lifestyle behaviors.
	Incentivization	Using rewards to induce positive changes in lifestyle behaviors.
	Coercion	Creating expectations of cost associated with unhealthy lifestyle behaviors.
	Training	Imparting skills required to engage in a healthy lifestyle.
	Restriction	Using policies to reduce or eliminate the opportunity to engage in unhealthy lifestyle behaviors.
	Environmental restructuring	Altering the physical or social context.
	Modeling	Providing an example of engaging in healthy lifestyle behaviors.
	Enablement	Reducing barriers to engaging in healthy lifestyle behaviors.
Implementation strategies (i.e., how the intervention is implemented and the change strategies [or integration strategies] to overcome the barriers to implementation and ensure that the intervention becomes part of the routine)	Preparing and planning for school development	"Early focus and emphasis on alignment processes that can stimulate readiness and commitment for change among all relevant stakeholders” (Samdal & Rowling, 2011) can include coordination committees representative of all stakeholders’ perspectives, and following an intervention theory-based planning model (Rowling & Samdal, 2011).
	Policy and institutional anchoring	"Initiative or actions in [a] school policy document; […] clarifying goals of the intervention approach and matching them with the overall goals and visions of the school” (Samdal & Rowling, 2011) can include school and district level policies (Rowling & Samdal, 2011).
	Professional development and learning	Opportunities to gain “knowledge, attitudes, skills, aspirations and [change] behaviours” for staff (Samdal & Rowling, 2011) can include professional development which is formal, decided upon by people from above in a top down approach, and focuses mainly on knowledge and competency development. Can also include professional learning which is more informal and can be done via school based conversations, observing and being coached, mentoring, analyzing and planning individually, and group work (Rowling & Samdal, 2011).
	Leadership and management practices	Leadership to “stimulate readiness and motivation for change, provide role modelling and support for staff”; Management to “put in place practices and structures that can facilitate organisational development and change” (Samdal & Rowling, 2011) can include distributed leadership and combinations of leaders at multiple levels that work together (Rowling & Samdal, 2011).
	Relational and organizational support context	"Support structures, strategies and practices which facilitate smooth and efficient implementation of activities, [and] organisational structures [including] timetabling, physical environment and fiscal resources” (Samdal & Rowling, 2011) can include improved relationships between teachers, students, and parents, and improvements to the physical environment and organizational structures (Rowling & Samdal, 2011).
	Student participation	Student “contributions are sought and valued” which “further enhances their relatedness to teachers and fellow students and [K] their connectedness to school.” Students are empowered “to achieve learning goals and develop self-reliance in their thinking” and “develop skills important for current and future civic engagement” (Samdal & Rowling, 2011) can include consulting students but also providing training and opportunities for student leadership and active participation (Rowling & Samdal, 2011).
	Partnerships and networking	"Intersectoral collaboration between health and education ensures efficient use of resources and competence.” “Involvement of the stakeholders in the school (students, teachers, parents and local community) [with] mutual commitment towards common goals” (Samdal & Rowling, 2011) can include networking with other schools, parent engagement, and linking with local agencies, parents and other community resources (Rowling & Samdal, 2011).
	Sustainability	"Actions to facilitate sustainability include monitoring performance […] and evaluating progress” (Samdal & Rowling, 2011) can include long-term anchoring of the initiative in policy plan, ongoing resources for professional development, and monitoring performance of agreed actions and evaluating progress (Rowling & Samdal, 2011).

Note. APPLE Schools = A Project Promoting healthy Living for Everyone Schools.

Grouping Intervention Activities and Implementation Strategies into Forms Within Their Core Functions

To our knowledge, there are no established frameworks that would capture forms of intervention activities. Regarding the forms of implementation strategies, the School Implementation Strategies, Translating ERIC Resources (SISTER) framework (Cook et al., 2019) outlines implementation strategies in school-based interventions. However, most SISTER implementation strategies occur outside of the inner setting and/or pertain to the exploration and preparation phases of intervention implementation (see Aarons et al., 2011), which are unlikely to be captured in APPLE Schools action plans. Therefore, we relied on a reflexive thematic analysis (Braun & Clarke, 2019), positioned within a constructive perspective, to help identify forms for intervention activities and implementation strategies documented in APPLE Schools action plans. First, JK read all activities included in action plans during data extraction and generated initial descriptive codes for activities within each function. JK and JD discussed and modified these codes, and generated overarching themes, which were continuously revised. To quantify the frequency of core functions in 70 APPLE Schools, we calculated the proportion of schools that documented each function in their action plans.

Results

In thematic analysis, we identified 55 forms across 17 core functions of intervention activities and implementation strategies (see Tables 2 and 3, respectively). Both matrices include core functions, the proportion of schools that addressed each function, their forms, and activity examples with direct quotes from action plans. For intervention activities, we also captured the target of each form: physical activity, healthy eating, mental health, school connectedness, staff health and wellbeing, physical environment, family and community involvement, and cultural connection.

Table 2.

Forms and Functions Matrix of APPLE Schools Intervention Activities.

Core function (% of schools that have documented each core function)	Form	Target	Activity examples
Education (54%)	Educating students about physical activity and sedentary behavior	Physical activity	“Creating and promoting monthly themes relating to health and wellness. […] Had various classroom activities for teachers based on health and physical activity monthly campaigns since October 2010.” (School 40, 2011–2012)
	Educating students about healthy eating habits and food science	Healthy eating	“Registered Dietician from Alberta Health Services presented to Gr. 5 and 6 classes [about] reading and understanding nutrition labels to assist in making healthier snack choices. [The dietitian] left lesson plans for teachers to use as needed in class.” (School 58, 2013–2014)
	Educating students about mental health and well-being in class	Mental health	“A nursing student came in to talk with the grade 3 students about healthy stresses and negative stresses and how to decrease [negative] stress in our lives.” (School 68, 2016–2017)
	Educating parents and families about health promotion	Family and community involvement	“Information booths to be [set up] at events where parents will be present outside of school hours” (e.g., parent-teacher nights). Presented table on “How to pack a healthy lunch” at parent-teacher night with taste tests of healthy snack ideas.” (School 20, 2011–2012)
Persuasion (42%)	Encouraging students to be more active outside of school hours	Physical activity	“Walk to School Week. […] Students were encouraged to walk to school this week over the announcements.” (School 61, 2014–2015)
Persuasion (42%)	Using school displays to promote health education and send positive messages	Physical environment	“Positive messaging throughout the school. We have positive inclusive messages throughout the school (big focus on the bathrooms).” (School 20, 2019–2020)
Incentivization (12%)	Organizing challenges to encourage friendly competition and promote a healthy lifestyle	Staff health and well-being	“Hydration Station Staff Challenge: We had a staff challenge for 1 week for staff to drink 9–12 cups of water per day. Staff members had a tracking sheet to track their water intake. We had 11 staff members participate and in total drank 586 cups of water [that] week!” (School 33, 2020–2021)
Incentivization (12%)	Fostering staff wellness and a sense of belonging by showing appreciation for their work	Staff health and well-being	“Recognizing exceptional and beyond work from staff at [school]. Mugs and bags are given. Staff [members] leaving us get going away gifts and praises.” (School 12, 2018–2019)
Coercion (0%)	N/A	N/A	N/A
Training (40%)	Teaching students cooking and food preparation skills	Healthy eating	“Some students are participating in hands-on cooking experiences (pizza/salad/smoothie parties) to teach about healthy eating, reading, counting, and measuring. The food preparation activities also reinforce following directions and adult/peer interactions.” (School 48, 2018–2019)
	Providing hands-on gardening experiences	Healthy eating	“Have partnered up with the Grade 4/5 students in Room 6 to support their science unit on plant growth and development. They have painted planters and will be growing herbs, vegetables, and plants to display around the library for a healthy environment and will later be enjoyed during our healthy snack program.” (School 9, 2014–2015)
	Teaching students about different cultures to reinforce the principles of equity, diversity, and inclusion	Cultural connection	“Each grade will be given a different country to bring food from, students will pay $1 and choose 4 food items that were brought in. This activity will be supported by our Cultural Diversity teachers who can follow up on the different cultures/countries in their class.” (School 15, 2016–2017)
Restriction (27%)	Replacing unhealthy foods served at special events with healthier options	Healthy eating	“Serve whole wheat buns and a side of veggies on Hotdog Day.” (School 19, 2019–2020)
Environmental restructuring (31%)	Ensuring the availability of equipment that promotes physical activity	Physical environment	“Recess Activity Bins: equipment purchased from Sportfactor and unveiled to students for their use.” (School 3, 2012–2013)
Environmental restructuring (31%)	Introducing new elements of the physical environment that promote healthy eating	Physical environment	“APPLE School additional funding […] has helped out the school [by providing]: 1) soda streams for each class to help with having carbonated water to deter the students from bringing pop; 2) baking supplies, i.e., pans, liners, mixers, ninja, spatulas; 3) ice machine for staff room so everyone could have cold water staff and students; 4) fresh fruit and vegetables.” (School 26, 2018–2019)
Modeling (66%)	Exposing students to alternate ways of being physically active	Physical activity	“Zumba Fitness Class. […] Introducing the students and staff to a way fitness can be fun and different than they usually do.” (School 32, 2016–2017)
Modeling (66%)	Exposing students to new healthy foods through taste testing	Healthy eating	“SHF has been introducing choose most often foods to staff and students through nutritious taste tests. Going forward, on a monthly basis, the SHF will do a Taste Test centered on the holiday/event of the month.” (School 12, 2016–2017)
Enablement (96%)	Organizing dedicated days for students to be physically active	Physical activity	“Wellness Wednesday. […] Had over 200 students [attending] yoga, dance, outdoor hike, volleyball, art, and music [activities].” (School 11, 2019–2020)
	Integrating physical activity breaks during regular class time and school-wide events	Physical activity	“The [DPA] bins include quick daily activities that can enable classrooms to get active when there is no scheduled gym class.” (School 6, 2012–2013)
	Providing opportunities for organized extracurricular sports	Physical activity	“Division 1 Soccer Club is running on Mondays, and Division 2 Soccer Club is running on Wednesdays.” (School 6, 2012–2013)
	Providing opportunities for student-led physical activity	Physical activity	“Recruit students to be Playground Activity Leaders (PALS). […] PALs are playing games during indoor recesses with younger kids.” (School 34, 2013–2014)
	Offering students healthy food during school hours	Healthy eating	“Ensure all children have access to nutritious foods through the Breakfast Program. [Staff] run the Breakfast Program from Pre-K to Grade 6, serving cereal, milk, oatmeal or a cereal bar.” (School 12, 2016–2017)
	Providing health promotion activities and programming focused on mental health and well-being during school-wide events	Mental health	“Hats on for Mental Health. […] Students and staff wore hats for Google Meet meetings that day. Teachers read age-appropriate stories about mental health/emotions.” (School 42, 2019–2020)
	Offering activities and school-wide events that foster the sense of belonging	School connectedness	“First day of school, students, parents/guardians, staff, Elders, and leadership attend to greet everyone with a celebration. Healthy snacks and drinks are provided.” (School 2, 2019–2020)
	Organizing health promotion activities for staff	Staff health and well-being	“Staff Lunch Club. Healthy foods are prepared and supported. It reminds staff of [to be selected] ‘most often’ food choices and supports our APPLE Schools initiatives. It provides positive role modeling.” (School 9, 2014–2015)
	Inviting families to participate in school activities	Family and community involvement	“Family fitness nights. Families and students who attend events will be asked to become involved in the APPLE Core committee. SHF will engage parents at the event to collect their input on HPS initiatives.” (School 33, 2014–2015)
	Partnering with organizations to deliver school activities	Family and community involvement	“Create opportunities for school staff to utilize community organizations for health and physical education needs. Students participate and learn hip-hop dance with the Third Street Beat and then perform. Edmonton Eskimos, Oil Kings come and speak to children about the importance of being healthy, exercising and staying in school.” (School 40, 2011–2012)
	Encouraging students to connect with their own culture	Cultural connection	“Provide opportunities for the Elders to work with and teach the students, staff, parents and community about Cree culture (beading, tipi making). […] Elder [name removed] teaches the students about smudge bags, regalia, and tells them the Cree name for the items. Elder [name removed] teaches the students about proper behaviours and rules, […] set up large tipis for school events [and] is also in charge of making hand drums in the fall.” (School 12, 2016–2017)

Note. APPLE Schools =A Project Promoting healthy Living for Everyone Schools; HPS: health promoting schools; DPA: daily physical activity; PALs: playground activity leaders; SHF: school health facilitator.

Table 3.

Forms and Functions Matrix of APPLE Schools Implementation Strategies.

Core functions (% of schools that have documented each core function)	Forms	Activity examples
Preparing and planning for school development (34%)	Setting up a coordination committee	“Start a School Wellness Committee to discuss health initiatives in the school and suggestions for a School Health Policy, [with the] first meeting [happening] in October and [then] every two months. Composed of staff members.” (School 35, 2014–2015)
	Developing health promotion materials (e.g., documents, plans) for staff to follow throughout the school year	“Whole School Physical Education Plan: teachers are provided with a Physical Education binder and [receive] weekly reminders of what units to cover in physical education. New resources are regularly provided.” (School 73, 2012–2013)
	Allocating time during staff and committee meetings to brainstorm new and reflect on existing health promotion activities	“Staff Collaboration & Planning. This time was used to create and prepare activities for staff [and] students in relation to APPLE school guidelines.” (School 20, 2019–2020)
Policy and institutional anchoring (33%)	Developing new and revising existing school policies	“Introduce the concept of school policy in the staff meetings at the beginning of the year. Discuss what to include in the policy and where teachers struggle with implementing a policy. Initial discussions – September 2014, including what worked well last year, what needs improvement, and any new ideas.” (School 35, 2014–2015)
	Informing the school community about school policies and enforcing them	“Implement the Alberta Health and Wellness Nutrition Guidelines for schools. Review and assess the [school] nutrition policy annually. Hand out a one-pager nutrition policy for parents and increase enforcement of the rules around celebrations and birthdays. […] Policy was reviewed in June 2011 [and] now includes policy on foods available on field trips.” (School 46, 2011–2012)
	Documenting provincial guidelines and health promotion goals in the action plan	“Provide nutritious food programs that meet the Alberta Nutrition Guidelines for Children and Youth […]. All menus have been improved to include only choose most often (75%) and choose sometimes (25%) foods to students.” (School 57, 2011–2012)
Professional development and learning (73%)	Equipping staff with resources and health promotion practices to apply in class	“[SHF] has given lots of resources (sensory/calming) to the classroom teachers (K-4 to Grade 6) to have on hand. […] SHF participated in the Preschool Roundup. SHF had a table with sensory items such as homemade play dough, rubbery goop, rice and ice, spaghetti worms, and shaving cream. There was also lots of information on calming and breathing techniques. [School] is looking forward to the calming DPA bin from APPLE Schools in the fall, so we can make more and put them in the tipis in the classrooms.” (School 12, 2016–2017)
	Providing formal training on health topics	“Mental Health therapist […] presented information to staff on how to identify concerns and assist families/children with services should they require support. We have initiated support for 2 children. Families are pleased with the support, and there has been a positive improvement in the children's behaviour.” (School 9, 2014–2015)
	Modeling of health promotion activities by APPLE Schools mentors and/or SHFs/SHCs	“School health mentor has come […] to provide PD on how to use the DPA bins and has been in different classes showcasing some activities.” (School 18, 2019–2020)
Leadership and management practice (41%)	Fostering champions (SHF, SHC) to drive APPLE Schools’ implementation	“SHCs […] are always readily available to support staff, students, and parents in providing APPLE Schools-friendly ideas both inside the classrooms and out. The two of them are extremely helpful and resourceful. They also share/forward APPLE emails to the entire staff.” (School 9, 2014–2015)
	Providing incentives for staff to implement APPLE Schools and improve their own lifestyle behaviors	“Add healthy snacks and lunches to staff PLCs and PD days. The SHF will prepare the meals and snacks for the staff after the items are brought to school. The principal also ordered in a lunch for the staff another time which was a great success and a nice way to socialize and enjoy some downtime.” (School 26, 2016–2017)
	Establishing and supporting the distributed leadership model by engaging school community members	“Staff, [school administration], students, parents, and community members will be gathered together twice a year to meet as a Health Committee.” (School 25, 2012–2013)
Relational and organizational support context (86%)	Improving the social environment through school-wide campaigns that focus on the socio-emotional health of school community members	“Introduce calming techniques and social skill instruction through the evidence-based program [called] Supporting Positive Behaviour in Alberta Schools. […] SHF went into grades 6 & 8 classrooms to discuss stress (positive & negative), the effects of stress and coping techniques. The classrooms have received lots of calming/soothing equipment.” (School 12, 2016–2017)
	Showing appreciation for school staff	“[SHC] provided a little journal for all staff as a random act of kindness to recognize all the hard work and challenges that staff are overcoming [during the COVID-19 pandemic] year.” (School 42, 2020–2021)
	Incorporating health-promotion messages into the physical environment	“Hall of Health: Update the walls of the ramp leading into the gym with information about healthy eating and active living. Run poster contests (prize: free hot lunch) throughout the year with topics on healthy eating (October) and how the students stay active (May). Students can read the posters on the wall during recess.” (School 35, 2013–2014)
	Purchasing and rotating equipment to ensure it reaches the maximum number of students	“Traveling Fun Fitness Circuits. Due to the availability of the gym, some classes do not have gym each day. The decision was that the circuits rotate to a new day each month. e.g., October- Monday; November- Tuesdays etc.” (School 3, 2013–2014)
Partnerships and networking (84%)	Engaging families and community members in school activities	“Promote and organize events [for] families to participate in […] (family fitness challenges, Family Fun Run, activity night teasers, family dances, etc.).” (School 77, 2012–2013)
	Involving parent volunteers in the delivery of health promotion activities	“Parents volunteered to assist with Taste Test to work on creating sustainability.” (School 42, 2015–2016)
	Connecting with struggling families to address financial barriers to students’ participation in health promotion activities	“Ensure that no students are unable to participate in activities due to financial barriers.” (School 8, 2012–2013)
	Developing partnerships with profit and nonprofit organizations to enable the delivery of health promotion activities	“Collaborate with local community leagues, junior highs and high schools, and organizations to participate in school events and provide leadership examples for the [school] community. Continue to collaborate with community organizations such as River Valley Programming, U of A Ringette, and use buddy systems within the school to promote leadership for all (student leadership collaboration opportunities).” (School 46, 2011–2012)
Student participation (78%)	Organizing and managing student leadership teams that deliver student-led health promotion activities	“The PALs initiative started in October 2014. Some of the grade 5/6 students completed a half day of training in which they learned how to teach and lead a game; how to promote and model appropriate play; how to communicate effectively; and how to use the DPA bins. The PALs [initiative] has now grown to about 20 members that promote positive play and physical activity by providing classrooms with a weekly opportunity to play a game in the gym. They also run indoor recess, going to each classroom to lead a fun energizer or DPA bin.” (School 9, 2014–2015)
	Seeking and providing opportunities for students’ leadership training	“Took 26 students to the Spark, Ignite, Kindle, Catch Fire conference [and] 4 students to the Extraordinary Leaders Conference in Niagara Falls. Took 21 students to the Calgary WE Day (October 26, 2016). Took 8 students to the What Do You Do with an Idea conference in Bonnyville. These conferences are the “spark” used to “ignite” our students.” (School 15, 2016–2017)
	Incorporating students’ input into health promotion activities	“Girls Club: students meet at the library [to engage in] activities students wish for. Taking care of nails, learning clean hygiene, building peer support.” (School 2, 2019–2020)
	Encouraging students to take on responsibilities in health promotion activities	“Students are given the opportunity to lead school-wide assemblies. The students are given an opportunity to teach the school about one of the seven habits.” (School 9, 2014–2015)
Sustainability (48%)	Surveying the school community to gather feedback on existing programming or guidelines	“Survey school community with regards to guidelines. […] Feedback gathered will be considered in September just prior to the full implementation of the Healthy School Guidelines.” (School 72, 2012–2013)
	Participating in research projects that collect data and report on various student outcomes	“The REAL Kids evaluation was a success again this year. Students enjoyed using the pedometers.” (School 71, 2012–2013)
	Using external/validated tools to formally evaluate the school	“Healthy Assessment Tool for Schools (HATS) has the potential to identify programs and practices, assess needs and provide direction for schools to positively influence health behaviours related to physical activity, healthy eating and mental wellbeing.” (School 71, 2012–2013)
	Holding regular meetings to review the action plan and school activities	“Continue to hold APPLE Core Team meetings twice a year to monitor and reflect upon action plan and review Real Kids research results.” (School 77, 2012–2013)

Note. APPLE Schools =A Project Promoting healthy Living for Everyone Schools; PAC: parent activity council; PLC: professional learning communities; PLF: professional learning Fridays; PRISM: professionals respecting and supporting individual sexual minorities; WITS: walk away, ignore, talk it out, seek help.

Core Functions and Forms of Intervention Activities

The most commonly addressed core functions were enablement (96%), modeling (66%), and education (54%), while others were addressed in fewer than half of the schools: persuasion (42%), training (40%), environmental restructuring (31%), restriction (27%), and incentivization (12%). None of the implemented forms were mapped to the coercion function.

Enablement was fulfilled not only by almost all APPLE Schools but also through a greater variety of forms, compared to other functions. The forms were implemented to benefit different members of school communities (e.g., students, families, school staff) and aimed at all but one target (forms related to the physical environment were mapped to environmental restructuring). The education function was fulfilled by staff-led activities aimed at educating students about healthy lifestyle behaviors and mental health and well-being. Efforts were also made to educate families about health promotion to ensure consistency of health promotion messages between the school and home settings. Two related functions of modeling and training were addressed by exposing students to new foods through taste testing and alternative ways of staying physically active, and through teaching students cooking and food preparation skills and providing hands-on gardening experiences, respectively. Importantly, targeted activities to reinforce the principles of equity, diversity, inclusion, and accessibility (EDIA; e.g., asking students to bring traditional dishes) have also been documented, particularly in recent years when the EDIA principles became an integral part of school curricula. The rest of the functions (i.e., restriction, incentivization, environmental restructuring, and persuasion) were addressed by a limited number of forms.

Core Functions and Forms of Implementation Strategies

The following four core functions of implementation strategies were addressed in most schools: relational and organizational support context (86%), partnerships and networking (84%), student participation (78%), and professional development and learning (73%), while others were addressed in fewer than half of the schools (range: 33–48%).

Fostering champions in schools—SHFs or SHCs, depending on the school's stage in APPLE Schools—was central to ensuring the leadership function. SHFs and SHCs were the driving force behind implementing most of the forms mapped to this and other core functions. Another crucial implementation strategy was setting up coordination committees that varied in composition (e.g., staff, students, parents) and met on a regular basis to review schools’ action plans, discuss funding and activities, and map existing assets (preparing and planning). School relational and organizational support context was addressed through forms aimed at improving the social and physical environments. Anchoring the HPS principles in school (policy and institutional anchoring) was done through developing new and revising existing school policies (i.e., formal policies), often with the input of various stakeholders, and informing school community members about these policies to facilitate adherence to them. In the absence of formal school policies, some schools used provincial/territorial guidelines to inform their health promotion activities. Forms addressing the partnerships and networking function centered around engaging parents as participants and/or partners in delivering health promotion activities and developing new or strengthening existing partnerships with community organizations. Some schools formed student leadership teams (e.g., Student Wellness Action Team, Physical Activity Leaders), comprised of students with formal leadership training, to oversee forms mapped to student participation and encourage students to play an active role in the planning and delivery of health promotion activities. To increase school staff's competency in delivering health promotion activities and fulfill the professional development and learning function, staff were provided with resources on health-related topics and given opportunities to participate in formal training or witness APPLE Schools mentors and/or SHFs/SHCs delivering health promotion activities. Finally, gathering feedback on existing programming and/or guidelines, collecting data on various student outcomes, and formally evaluating the school's HPS-related outcomes were often used to address the sustainability function. Data emerging from these activities were often shared with the broader school community.

Discussion

While specifying matrices of core functions and forms of various interventions is becoming more common in implementation science and practice (Byng et al., 2008; Fianu et al., 2017; Hill et al., 2020; Jolles et al., 2019; Kirk et al., 2021; McNeal et al., 2022; Villeval et al., 2016, 2019; Wahlen et al., 2022), there is a lack of studies that would also attempt to disentangle the “what” and “how to” aspects of interventions. This study aimed to close this gap by leveraging over 10 years of health promotion activities, delivered and recorded in 555 annual action plans in 70 APPLE Schools, to derive a list of 17 core functions and 55 forms of specific actions that comprise the APPLE Schools intervention (“what” or intervention activities) and techniques used to bring about its implementation outcomes (“how to” or implementation strategies). Below, we discuss study's results and their practical implications, its strengths and limitations, and reflect on the methodological approach we employed and directions for future research.

While keeping in mind that the number of core functions was predetermined by the theoretical frameworks chosen to guide this study, only a few core functions of intervention activities (i.e., enablement, modeling, education) and implementation strategies (i.e., relational and organizational support context, partnerships and networking, student participation, and professional development and learning) were documented in more than half of the schools. A wide range of forms was implemented to fulfill core functions, with a greater number and variety of forms mapped to these most commonly documented core functions.

The core function of intervention activities that stands out in that it was addressed almost universally (in 64 out of 67 schools) was enablement, with most of its forms aiming to improve student physical activity and healthy eating. This finding aligns with the philosophy (i.e., “making the healthy choice the easy choice”) and historical emphasis of the HPS approach on promoting “healthy eating and active living” (Veugelers & Schwartz, 2010). Albeit to a lesser degree, modeling and education functions were also commonly addressed. Forms implemented to fulfill the modeling function reflected continuous efforts of APPLE Schools SHFs and SHCs to introduce new foods (e.g., Taste Testing) and activities (e.g., Zumba fitness classes) to complement traditional health education approaches and make these activities more accessible to those students who might not get exposed to them outside of school. These activities often required establishing new or tapping into existing partnerships with community organizations. The finding that the education function was commonly implemented is consistent with the results reported by Villeval et al. (2019) and is to be expected since its forms may be easier for school staff to integrate into the school curriculum which already has health education as an essential component.

The aforementioned core functions require concurrent systemic changes to the school's physical environment (Bartelink et al., 2022; Leger et al., 2007), which is why one of the HPS pillars in the original framework is “the school physical environment” (World Health Organization, 1996). Changes to the school building, grounds, spaces, and equipment serve as tangible expressions of the broader organizational support context (Guldager et al., 2018). However, modifying the physical environment requires considerable financial investments, which might not be readily available in APPLE Schools, most of which are located in socioeconomically deprived areas. This could explain why environmental restructuring was one of the rarely documented core functions. Others included restriction and incentivization, reported in 27% and 12% of schools, respectively, with no forms falling under the coercion function.

It is worth noting that most of the forms of intervention activities were aimed at the student body. The lack of documented forms targeting staff health and lifestyle behaviors could be due to students often being perceived as the main (and sometimes the sole) target audience in school-based health promotion interventions. Nevertheless, staff wellbeing is essential to the effectiveness of the HPS interventions. Therefore, designing and implementing forms that target lifestyle behaviors of school community members other than students would support creating a positive social environment that promotes the social, emotional, cognitive, and physical wellbeing of students (Braun et al., 2020; Granziera et al., 2023). Finally, involving families in school-based health promotion activities, whether as participants or active deliverers, is crucial to ensuring consistent health promotion messages in the school and home settings but is challenging due to parents grappling with competing priorities. This calls for schools and school-based health promotion initiatives to actively devise new strategies or adapt existing ones (Centers for Disease Control and Prevention, 2019a, 2019b) to engage family and community in HPS and sustain their involvement.

Similarly to core functions of intervention activities, core functions of implementation strategies addressed in most schools were those commonly emphasized as crucial to the successful HPS implementation (e.g., relational and organizational support context, partnerships and networking, student participation, professional development and learning). Ideally, all core functions of implementation strategies should be addressed as they serve as key enablers of intervention activities and major determinants of intervention's implementation outcomes. While some interventions may be successfully delivered by using only one implementation strategy (e.g., providing training on new guidelines), complex interventions such as APPLE Schools often require multifaceted implementation strategies, and each implementation strategy can be viewed as an intervention on its own (Proctor et al., 2013). Therefore, our finding that fewer extracted activities were classified as implementation strategies compared to intervention activities (n = 1217 vs. 2066)—which could in part explain why they were mapped onto fewer core functions—should not be interpreted as implementation strategies receiving less attention than intervention activities during the APPLE Schools implementation. APPLE Schools is an established intervention that encompasses activities across all intervention phases (i.e., exploration, adoption/preparation, implementation, sustainment, Aarons et al., 2011), but since school-specific action plans are written and used during the implementation and sustainment phases, they do not fully capture activities delivered by the APPLE Schools central office during the first two phases.

For example, implementation strategies related to planning were documented in 34% of schools. Notwithstanding, preparing and reviewing the action plan itself is an act of planning, and APPLE Schools mentors meet with SHFs and SHCs to review their action plan at least twice during the school year to encourage schools to plan, adapt, and improve their health promotion programming. This underscores the importance of relying on multiple sources of information (e.g., in-depth interviews with APPLE Schools mentors, SHFs/SHCs, school administrators) in order to capture the full breadth of implementation strategies. More work is needed to document a comprehensive set of implementation strategies, identify the ones that APPLE Schools SHFs and SHCs perceive to be the most feasible and effective, and, similar to Moore et al. (2021), map them onto the SISTER framework (Cook et al., 2019), which covers implementation strategies across all four intervention stages.

In addition, specifying each implementation strategy according to the prerequisites outlined by Proctor et al. (2013; i.e., in terms of the actor, action, action target, temporality, dose, and implementation outcome affected; and providing justification for a specific strategy and detailed guide on how to use each strategy and keep track of its utilization) would increase the practical value of this work. For example, the implementation strategy “Developing new and revising existing school policies” could be further refined by specifying that it is APPLE Schools central office, in collaboration with school divisions, (actors) that should develop new and revise school policies (action). This strategy should be directed at school staff to improve their knowledge of school policies (target). This is an ongoing implementation strategy, since policies should be revised on an ongoing basis (temporality and dose), which aims at ensuring the intervention's sustainability (implementation outcome). Systems thinking and complex adaptive systems provide the theoretical justification for this implementation strategy, as altering school policies was shown to foster a culture that promotes healthy behaviors, supports mental well-being, and encourages physical activity (Rosas, 2017).

However, specifying implementation strategies according to prerequisites outlined in Proctor et al. (2013) was not feasible in this study since the list of implementation strategies was derived from activities documented in action plans. Indeed, the process of specifying each strategy might benefit from a consensus-building process (e.g., Delphi), which merits a separate study. Future research could also link all implementation strategies to barriers and facilitators to the implementation and sustainment of HPS interventions (e.g., using the CFIR 2.0 framework, Damschroder et al., 2022) to understand which implementation determinants are particularly vital to implementation success (Larson & Cook, 2023).

Strengths and Limitations

There are several considerable strengths of this study. First, we used an inventory of 191 action plans, completed for a large number of APPLE Schools in socioeconomically deprived areas in both urban and rural settings. This comprehensive inventory of action plans yielded rich data of more than 2,000 unique activities, which we used to derive a list of 55 forms of intervention activities and implementation strategies and mapped them onto their theory-informed core functions. Another strength is that this study further advances the approach taken by Villeval et al. (2019) by teasing apart APPLE Schools’ intervention activities and implementation strategies. Moreover, this study demonstrates how manual text classification can be successfully supplemented by ML methods. In our experience, supervised ML algorithms achieved high class precision and recall (>80%) in identifying the “what” and “how to” aspects of the APPLE Schools intervention. The application of ML methods in public health and health promotion research remains limited despite becoming increasingly common in healthcare research (Tricco et al., 2023). This study demonstrates that supervised ML algorithms can help tease apart complex aspects of interventions and therefore have a place in the toolbox of implementation scientists. Moreover, since the commencement of this study, artificial intelligence (AI) technology has been introduced and can serve as a powerful tool that could be leveraged by implementation scientists (Trinkley et al., 2024).

Several limitations are worth noting. Given that the APPLE Schools intervention has evolved since its inception in 2008, some of the recently introduced intervention activities might be underrepresented. For example, there were fewer than expected forms targeting mental health and wellbeing, school connectedness, and cultural connection. In response to worrisome trends in mental health and well-being of children and adolescents (Gohari et al., 2024) and a well-recognized need to foster connectedness within communities to battle social isolation and loneliness (Statistics Canada, 2021), APPLE Schools’ programming was enhanced in 2017 to include mental health and well-being as one of its priority areas (Annual Reports—APPLE Schools, n.d.). Therefore, we expect activities related to mental health and well-being to become more consistently documented in the coming years.

In addition, action plans written in the early years of the APPLE Schools intervention did not have a predetermined structure as to what information should be captured and at what level of detail. To circumvent this limitation, we classified action plans in terms of the comprehensiveness of data that could be extracted from them and limited data extraction to action plans deemed “high quality” (i.e., complete and well-written). Finally, while there is no existing framework that outlines the core functions of HPS interventions, we utilized the BCW framework given the comprehensive list of interventions it offers and its explicit acknowledgement that individual behavior changes occur within a complex context and arise from combinations of different components of the behavior system. Results of this study may inform the refinement of existing frameworks and development of new frameworks that are better aligned with the HPS approach.

Given the holistic and complex nature of HPS interventions, which require the coordinated implementation of multiple interrelated activities across several pillars, we did not attempt to isolate the individual contributions of specific forms or core functions to producing implementation and/or intervention outcomes. Liu et al. (2019), in their systematic review and meta-analysis of school-based obesity prevention interventions, found that individual components of multicomponent interventions may demonstrate limited effectiveness when assessed in isolation, despite the overall intervention being effective. This phenomenon may be explained by mechanisms such as accumulation, amplification, facilitation, cascade, or convergence (Weiner et al., 2012), through which individual components interact synergistically to produce implementation and/or intervention outcomes.

Nonetheless, several forms and core functions of intervention activities and implementation strategies identified in this study—when delivered as stand-alone, single-component interventions—have been previously shown to improve children's lifestyle behaviors. For example, Jacob et al. (2021) showed that health promotion education (aligned with the education function in this article) resulted in a shift toward healthier body mass index levels in adolescents aged 10–19 years. Bikomeye et al. (2021) found that schoolyard greening (an example of the environmental restructuring function) positively influenced children's physical activity and mood. Likewise, Wang et al. (2025) demonstrated that providing opportunities for physical activity through daily physical education, structured outdoor play, and access to sports facilities (an example of the enablement function) increased adolescent physical activity levels. We acknowledge that identifying high-impact forms and/or core functions might help refine the HPS approach. However, effects of individual forms and/or core functions need to be considered in the context of other components that comprise the HPS interventions and—through various mechanisms of actions—produce implementation and intervention outcomes.

Conclusion

In this study, we developed matrices of core functions and forms for documented intervention activities and implementation strategies of the successful HPS intervention called APPLE Schools. These matrices provide a roadmap for scaling up this intervention to new settings and can serve as a useful resource for school administrators and school health practitioners working on implementing HPS interventions in schools. Current work is underway to identify systematic and proactive cultural adaptations made to APPLE Schools intervention activities and implementation strategies over the years. These adaptations will further help improve the fit of the APPLE Schools intervention for racially and ethnically diverse disadvantaged communities during scale-up. Additionally, this work informs the development of AI-powered tools that can provide schools with tailored, real-time support for effective implementation and sustainment of HPS interventions.

Supplemental Material

sj-docx-1-irp-10.1177_26334895251385936 - Supplemental material for Intervention Activities and Implementation Strategies for School-Based Health Promotion: Identifying Core Functions and Forms to Facilitate Scale-up of an Effective Intervention

Supplemental material, sj-docx-1-irp-10.1177_26334895251385936 for Intervention Activities and Implementation Strategies for School-Based Health Promotion: Identifying Core Functions and Forms to Facilitate Scale-up of an Effective Intervention by Julia Dabravolskaj, Jodi Kalubi, Julia Moore, Boshra A. Mandour, Camila Honorato, Paul J. Veugelers and Katerina Maximova in Implementation Research and Practice

Footnotes

List of Abbreviations

Acknowledgements

The authors also like to thank APPLE Schools for sharing their action plans to facilitate this research.

ORCID iDs

Julia Dabravolskaj

Jodi Kalubi

Julia Moore

Boshra A. Mandour

Camila Honorato

Paul J. Veugelers

Katerina Maximova

Ethical Consideration

Not applicable.

Consent to Participate

Not applicable.

Consent for Publication

Not applicable.

Authors’ Contributions

JK, JD, JM, KM, and PJV designed the project and data analysis plan. JK led the analyses, and BAM, CH, and JD assisted with coding and thematic analyses. All authors discussed the results and contributed to interpretation. JD and JK lead the drafting and revising of the manuscript, with KM and PJV providing critical feedback. All authors read and approved the final manuscript.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

Declaration of Conflicting Interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Data Availability

The datasets used and/or analyzed during the current study are not available as supplementary file due to their volume but are available from the corresponding author on reasonable request.

Supplemental Material

Supplemental material for this article is available online.

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