Introduction

The importance of actively promoting the implementation process of health promotion interventions has long been widely recognized [1]. Effective interventions can only have the intended impact in the target population if they are sufficiently and appropriately implemented by intermediate users in practice [2,3,4]. Similar to the development of interventions, promotion of the implementation process of interventions requires a planned approach. Several phases can be distinguished in this implementation process, namely promotion of the decision to adopt the intervention, actual implementation or use, sustainability, scaling up (to a larger group of users), and de-implementation (where the intervention is ineffective) [5,6,7,8,9]. The literature has identified many types of strategies that can often be combined to achieve the implementation goals of the different implementation phases, for example, financial strategies (such as subsidy for use), education (training of users), cooperation (a consortium of stakeholders), evaluation and monitoring (monitoring of use), or participation (close involvement of the target group) [10, 11]. Strategies are selected based on identified modifiable and important determinants of the implementation process in the specific implementation context. These may include many different and interacting determinants that may be related to characteristics of the intervention (e.g., too complex to use), the intermediate user (low self-efficacy towards use), the organization of the intermediate user (inadequate facilitation of the intermediate user), and the socio-political context (school closure during the corona pandemic) [12, 13].

While descriptions of the process of intervention development are widely available in the literature, this is less the case for the process of promoting implementation. After a brief explanation of the Power Food (Dutch: Krachtvoer) program, the purpose of this article is to describe how the implementation process of this program has been and is being promoted and reflect on the key perceived success factors and challenges of our approach. Input for the reflection are available visitor data from the program website and discussions during various regular project meetings during the process.

Krachtvoer

Krachtvoer is a Dutch classroom educational program taught by teachers to first and second graders of prevocational secondary schools (aged 12 to 14 years). The goal is to help students make lasting healthy lifestyle choices. The main themes are fruit, drinking, and healthy snacks. The program consists of 13 modules of 30–45 minutes each, part of which can be chosen “to taste” by the teacher, thereby responding to the needs of a class. The minimal version comprises eight lessons over a period of several weeks. Krachtvoer was developed systematically based on available theoretical and empirical knowledge and has a phased approach. Successive modules offer the steps necessary to achieve lasting behavioral change: from attention and enthusiasm for the topic of healthy eating and being aware of one’s own food choices, through identifying and improving the behavioral determinants that may be a barrier to change for the target group itself, to formulating personal goals, and to finally making, regularly evaluating, and adjusting action plans.

In Krachtvoer, students are actively engaged in their own nutrition. This is reflected in the many active and varied learning methods, such as worksheet assignments, photo assignments, environmental scans, food preparation, tasting, quizzes, and interactive games. Krachtvoer can be used by schools to start, intensify, or broaden the Healthy School Approach and obtain the nutrition theme certificate of the Dutch Healthy School Program (Gezondeschool.nl).

Krachtvoer was launched in 2002. In two projects granted by the Netherlands Organization for Health Research and Development (ZonMw) (1998–2002 and 2006–2010), of which Maastricht University in Maastricht, the Netherlands was the project leader, first and second (hard copy) versions of Krachtvoer were developed and implemented in schools, and evaluation and implementation studies were conducted [14, 15]. This resulted in a “Good evidence of effectiveness” recognition by the Dutch National Institute for Public Health and the Environment (RIVM) in 2015. From the start, cooperation with various research and practice partners has been established. Around 2015, a cooperation with educational organization Yuverta (then CITAVERDE), and thus with the educational domain, was also established. Starting in 2017, the two organizations worked towards developing an updated version of Krachtvoer by using an intensive co-creation approach with users and an intersectoral network of national partners [16].

Krachtvoer has been available on the Krachtvoer.nu website since the summer of 2019 and was rerecognized by the National Institute for Public Health and the Environment by the end of 2021. The website acts as a broad support program for use. After signing up on the website once, teachers have access to the teaching materials, including teacher manuals, lesson plans, worksheets, and ready-to-use interactive whiteboard (digibord) presentations with short videos, interactive quizzes, and instructions for assignments. Teachers can find step-by-step support on the website to get started with Krachtvoer, and each module includes a range of support options, such as substantive background information on for example types of fats, or tips for interacting with students. In addition, possibilities for program expansions are offered, for example with regard to other lifestyle behaviors.

The target group of users of Krachtvoer are teachers at over 450 school institutions, where over 300,000 prevocational first- and second-grade students are educated (https://ocwincijfers.nl).

Implementation strategies

Tab. 1 summarizes the key determinants identified in the implementation context of Krachtvoer and the implementation strategies that respond to barriers of implementation. The determinants were identified and selected based on previous research on the implementation of Krachtvoer [17], information gathered from stakeholders during the co-creation approach [16], and the literature (e.g. [3, 6, 12, 13, 18,19,20,21,22,23,24]).

Table 1 Overview of key determinants and implementation strategies by implementation phase
Full size table

Decision to adopt

Since various perceptions may influence the decision to adopt Krachtvoer and these perceptions may differ among potential users, a website information page using a question-and-answer format was chosen. Potential users can immediately click on the information button that is relevant to them. The page is located after the homepage and before the required user log-in. The questions touch on identified questions and considerations users may have during their decision-making process. For example, the page provides information about the purpose, target audience, and content. However, it also explains that the program can be fitted into the existing curriculum and aligned with the Dutch core objectives of education and that the Healthy School Thematic Certificate in Nutrition can be obtained through use. It is emphasized that Krachtvoer is suitable for the target group because of its active working methods, that students and teachers are involved in (further) development of the program, and that research results not only show the program is effective, but that students find the Krachtvoer lessons more fun, interesting, and easier than lessons based on conventional methods. There is also a focus on the ease of use and easy availability of all materials after one-time (free) registration. Finally, the expertise of the team of program developers is explained, and it is mentioned that the phased approach of Krachtvoer is scientifically based and the program is recognized by the National Institute for Public Health and the Environment.

Testimonials in the form of quotes from teachers and students about their experiences with Krachtvoer support the information. A roadmap visualizes the program phases to achieve behavior change. The website also offers a preview option that allows teachers to see and try out one of the modules before signing up. To make the information even more accessible, a short introductory video has been placed on the homepage that addresses the key points of the information page.

Actual use

The overarching strategy deployed to promote actual use is the co-creation approach [16]. This is a joint initiative between Maastricht University’s health promotion experts and Yuverta’s practice professionals, who collaborate intensively within a project team. Four Yuverta prevocational school sites were the primary cooperation partners and implementation sites during an initial co-creation phase, facilitating direct connections with students, teachers, parents, and support staff and joint learning about use. At the national level, the process is supported by an intersectoral group of partner organizations (Dutch Nutrition Centre, Dutch Youth Institute, TNO Netherlands Organization of applied Scientific Research, Fontys University of Applied Sciences School of Sport Studies, Schools for Health Consultancy, and the developers of earlier versions of Krachtvoer affiliated with their current organizations ResCon and Maastricht University). The Healthy School Program stakeholders also join the partner meetings.

Through continuous so-called micro-process cycles of using (i.e., implementing (parts of) the intervention), measuring, evaluating, and adapting, Krachtvoer is continuously being developed based on information gathered from all stakeholders. Action-oriented research, in which information is collected from all those involved by means of, for example, interviews and observations, thus serves as the “engine” for the co-creation. The resulting adjustments are always aimed at making sure Krachtvoer’s content, layout, and technology meet the wishes and needs of users as much as possible with regard to similar program and user characteristics that often play a role in the adoption decision, such as ease of use and self-efficacy, but now as they are actually experienced. It also involves adjustments to make Krachtvoer as compatible as possible with the ever-changing context within and around the school setting, such as curriculum innovation, developments around Healthy School, and new lifestyle guidelines.

A second overarching strategy for promoting actual use is the website user support program. The specific strategies within this support program include both support for implementation fidelity (use as intended by the developers) and for adaptation to one’s own unique context in a way that maintains the effective principles [5]. To specifically support implementation fidelity, clear handling instructions are provided in the module manuals. In addition, particular lesson components, such as explanations of when one eats enough fruit, are offered as “ready-made” knowledge videos or worksheets. Conducting the lessons in the intended order and without skipping parts is supported with lesson plans, but the interactive whiteboard presentations especially guide the teacher through the lesson. To specifically support adaptive use, teachers can choose from a selection of the offered modules according to their students’ needs. They are supported in their choice by the roadmap. In addition, within program sections, teachers are offered alternatives for action, for example, there is the possibility of using printed worksheets instead of digital ones. During corona times, the interactive games were offered as “online learning snacks,” which teachers could use as educational breaks during home schooling.

Each module comprises a listing of “training” opportunities. Examples include a multicultural food glossary and information and reading tips on conversation techniques for talking to students about their health. A range of program expansion opportunities to, for example, other Healthy School initiatives offers teachers opportunities to adapt the intervention to their own context but is also aimed at supporting the implementation of Krachtvoer as part of the Healthy School Approach. Some program-wide manuals are aimed at converting the intention to use into the actual use of Krachtvoer. These include a step-by-step plan for teachers to prepare the use of Krachtvoer within their organization.

Sustainability

Different forms of sustainability are distinguished in the literature [25]. We limit ourselves to describing the strategies that were used to promote that 1) Krachtvoer is not used once but permanently by schools for ever new year groups and classes, and 2) Krachtvoer remains available as a program for all schools. In short, with regard to the first form of sustainability, it can be said that the co-creation approach and the support program are the most important strategies for this as well since important determinants of use also influence the decision to continue using the intervention.

Specifically for sustainability, the support program contains a section aimed at supporting a pioneering role within the school and drafting or including Krachtvoer in an internal policy plan. A checklist is provided to both build support within the school and organize practical aspects regarding sustainability, such as budget, available space, and personnel. A reference to the checklist of the Healthy School Approach and a so-called flywheel for the Healthy School Approach, which is integrated into the expansion offer, support the framing of Krachtvoer within a broader Healthy School Approach.

The co-creation approach is also the overarching strategy for the second form of sustainability. After the first intensive co-creation phase, a ten-year plan for nationwide use has been developed, to which all parties involved have committed themselves. The intention is that Krachtvoer can continue to be used by schools until 2030 and that continuous development will be possible so that the intervention continues to match the constantly changing context in and around schools. The plan includes agreements on, among other things, hosting the website and a quality control and improvement system based on monitoring and evaluation of use. Maastricht University and Yuverta are jointly taking the lead in this plan. Not only does this ensure a continuous link with practice, but a direct opportunity for further development of the program in practice is also maintained. Maastricht University is committed to quality assurance of the program, which includes initiating and supervising research into use and evaluation by students. The plan also identifies the joint task of finding sources of funding to implement the plan. This has since resulted in a so-called Implementation Impulse grant from the Netherlands Organization for Health Research and Development [26] and a so-called Next Step Implementation grant from the Maastricht University Medical Centre+ [27].

Making the intervention available online touches on both forms of sustainability. For schools, it makes use more accessible, especially repeated use, since materials do not have to be ordered over and over again. For the developers, it simplifies in many ways (such as financially and logistically) the continuous development and dissemination of Krachtvoer and thus the feasibility of sustaining the intervention. In addition, offering the program for free is an implementation strategy that enables schools to sustain the program, as implementation of interventions is often done with the help of external and temporary grants.

Scaling up

The previously discussed sustainability of Krachtvoer and the promotion of low-threshold use are important conditions for scaling up, i.e., rolling out the intervention to more and more schools and regions. To scale up use to as many as possible of the more than 450 school institutions in the Netherlands that offer prevocational education, the ten-year plan for nationwide use includes a dissemination plan. Core to the plan is that dissemination will use existing networks, agencies, and channels in both the education and health domains as much as possible. The partner network assists the project team in identifying these.

Different scaling-up levels are distinguished. After the initial “pilot implementation” at four school sites of, at the time, educational organization CITAVERDE in the province of Limburg, part of the strategy focuses on scaling up to the other school sites of this organization. The 2021 merger of CITAVERDE with two other educational organizations to form educational organization Yuverta—with 27 prevocational school sites in the south and middle of the country and the Randstad conurbation—will be used for this purpose. Part of the strategies focus on further dissemination in Limburg through the Maastricht University and Yuverta networks.

For scaling up to the national level, the main focus is on the connection with and dissemination through the national Healthy School Program [28], for which the (re-)recognition of Krachtvoer as an intervention with good indications of effectiveness is important. In addition, dissemination activities focus on visibility and information on websites of various organizations and platforms, news items are actively posted at stakeholder organizations and on social media, and we attend meetings to network and give presentations. For such meetings, dissemination materials have been developed that have the Krachtvoer look and feel, such as flyers. At the international level, efforts are being made to disseminate the ideas of Krachtvoer, including through the Schools for Health in Europe Network Foundation (https://schoolsforhealth.org/).

The project team meets at least three times a year to evaluate dissemination activities, based in part on monitoring data on new registrations, and to prepare for new dissemination opportunities that arise. Evaluation of the scale-up strategies also takes place during partner meetings. This way, scaling-up plans can also be constantly adapted to the dynamic implementation context. Finally, scaling up is facilitated by Yuverta creating working hours for the implementation of the dissemination plan and investing in competency development for the purpose of dissemination, for example by participating in the National Institute for Public Health and the Environment’s course My Intervention in the Market.

De-implementation

De-implementation of Krachtvoer, that is, reducing or stopping implementation, may be important if the intervention is implemented in a context where it is ineffective, inappropriate, or harmful [7]. This implementation phase is not included in Tab. 1 because there is not yet a planned approach to investigating the need for de-implementation and actually promoting de-implementation. The Krachtvoer website does include a disclaimer that the program was developed for, and evaluated in, prevocational students. If the program is implemented in other target groups, it cannot be assumed that the program will have the expected effect.

Visitor data for 2019–2022

During the 2019–2020 school year, the first year the website was available, the website had 1762 unique visitors and 2849 visits, while there were 3227 unique visitors and 4848 visits in 2020–2021 and 2546 unique visitors and 3797 visits in 2021–2022. The bounce rate, which is the percentage of visits aborted within a second, was around 36% in the first two years and around 33% in the third year. In all school years, the percentage of visitors who revisited the website hovered around 17%. About two-thirds of visitors visited more than one page during a visit, an average of 4 to 5. The pages of the first three modules were visited five times more often than those of the other modules. The website was visited from all over the Netherlands but mostly from Limburg and the Randstad. Each year, the website was, relatively speaking, most frequently visited in December and March. During (summer) holidays, there was a minimal number of visitors.

By July 1, 2022, 631 people were signed up as user, compared with 418 in July 2021 and 243 in July 2020. Over all years, the most sign-ups, relatively speaking, were seen in the spring. The 631 signed-up users represent 204 schools, 137 of which offer prevocational education. In three-quarters of the cases, there is one signed-up user per school. The remaining signed-up users who are employed by an educational institution work, for example, at an elementary school, a secondary school where prevocational education is not offered, or a vocational school. Other signed-up users are working, for example, as dieticians or coaches or are employed by a Public Health Service. During the third school year, about two-thirds (n = 420) of all signed-up users logged in, of whom 36% (n = 230) logged in at least twice. Of this latter group, 89% are employed by an educational institution. When signing up, enrollees most often indicated they intended to use Krachtvoer for prevocational level 1 students (the most basic level) (n = 392), followed by level 2 students (n = 315), level 4 students (n = 268), and finally level 3 students (n = 206). Intentional use among second graders (n = 458) was mentioned slightly more often than use among first graders (n = 391). Intentional use by non-intended education and grade levels was also reported (n = 27), such as use in senior general secondary education or upper elementary school.

Reflection

The purpose of this article was to describe the planned process of promoting the implementation of Krachtvoer and, based in part on visitor data from the Krachtvoer website, to reflect on the approach.

To promote the implementation of Krachtvoer, a combination of almost all types of implementation strategies mentioned in the literature has been employed [11]. A combination of implementation strategies that span the different implementation phases and drive support, education/training, cooperation, finance, participation, monitoring/evaluation, infrastructure, and adaptations to make the program appropriate to the implementation context is also considered most effective in the literature [10, 29, 30]. The planned approach helped us arrive at this complete set of implementation strategies by not overlooking key phases, determinants, or possible types of implementation strategies.

The basic idea of the planned approach is that each strategy within the complex process of promoting implementation serves its own purpose and thereby adds value. Nevertheless, especially the project team’s leading role characterized by the cooperation between the education/practice domain and health/research domain, the co-creation with users, and the intersectoral cooperation with national partners are perceived by us as essential. This allows for a continuous fit of both the intervention and the package of implementation strategies with the implementation context.

Major challenges lie in monitoring and evaluation research. The importance of these is evident, but due to lack of manpower and time, the (continuous) implementation of these strategies is still far from optimal. The visitor data we can currently report give some indication of the interest in Krachtvoer but say little about the adoption and the actual use and sustainability of Krachtvoer, both in terms of quantity and quality, and the contribution of the implementation strategies deployed to furthering the various implementation goals. This has also resulted in little feedback from implementation practices since 2019 for improvements to the intervention and implementation strategies. In addition, the visitor data are difficult to interpret with regard to the evaluation of implementation strategies because of the corona pandemic. Nevertheless, some developments in the visitor data are positive, namely the continuous growth in enrolled users and the lower bounce rate in the third school year. After three years, the signed-in users represent 16.5% of all secondary schools in the Netherlands where Krachtvoer can be offered, whereas before the corona pandemic, 10% in two years was the target. The user data also provide indications that Krachtvoer may be used in target groups other than the intended target group. Without better monitoring and evaluation, it is not possible to say whether this is undesirable and strategies should be employed for de-implementation.

The lack of structural financial support for sustaining and scaling up the intervention and the structural implementation of the implementation strategies is perceived as the main challenge and even frustration. This now always depends on short-term grants to deploy manpower and the “voluntary” commitment of many stakeholders. We are fortunate that stakeholders, in their time between subsidized project periods, want to continue their commitment to quality sustainability and improvement and dissemination actions (guided by monitoring and evaluation), in addition to their regular work. However, the downside risk is high and keeping the returns of previous temporary subsidies accessible to practitioners is thus not evident. A national (funding) policy in the Netherlands to support the sustainability of proven effective and well-implementable health promotion interventions is sorely missed.

We realize that the above identification of the success factors and challenges of our approach is based on our own experiences and not on systematically collected and analyzed data. Nevertheless, we hope that our description of the process of promoting the implementation process and our reflection on it will be of value to others trying to promote the implementation of interventions in the Dutch setting and will also provide input to policy makers on the barriers encountered in practice.