Sporting programs for inactive population groups: factors influencing their long-term sustainability in the organized sports setting

The organized sports sector has received increased interest as a setting to stimulate physical activity among inactive target groups. To reach many inactive people and to obtain population health benefits, it is important that effective sporting programs are sustained over a long period of time. This study identified the factors influencing the long-term sustainability of these kind of sporting programs located within local sports clubs. Fourteen sporting programs in the Netherlands aimed at increasing physical activity levels of inactive population groups and funded within the National Action Plan for Sport and Exercise (NAPSE) were the focus of this study. The programs were developed by ten National Sports Federations (NSFs) and implemented by different sports clubs in the Netherlands within a three-year funded implementation period (2008-2011). This research consisted of face-to-face interviews with the program coordinators of the NSFs (n=14) and telephone interviews with representatives of sports clubs that provided the programs (n=17 continued the program, n=11 discontinued the program) six and a half years after the funding period ended (November 2017-March 2018). A sustainability framework with five pre-specified main themes (i.e. program design, implementation, trainer/coach, organizational setting, broader community environment) guided data collection and (deductive) thematic analysis. Ten of the fourteen NAPSE funded sporting programs were sustained at the level of the NSFs. Most factors facilitating (+) and impeding (-) the long-term sustainability of the programs were mentioned by both NSFs and sports clubs, like program adaptation (+) and a lack of program financing (-). Program evaluation (+) and high program costs (-) were


Abstract Background
The organized sports sector has received increased interest as a setting to stimulate physical activity among inactive target groups. To reach many inactive people and to obtain population health benefits, it is important that effective sporting programs are sustained over a long period of time. This study identified the factors influencing the longterm sustainability of these kind of sporting programs located within local sports clubs.

Methods
Fourteen sporting programs in the Netherlands aimed at increasing physical activity levels of inactive population groups and funded within the National Action Plan for Sport and Exercise (NAPSE) were the focus of this study. The programs were developed by ten National Sports Federations (NSFs) and implemented by different sports clubs in the Netherlands within a three-year funded implementation period (2008)(2009)(2010)(2011). This research consisted of face-to-face interviews with the program coordinators of the NSFs (n=14) and telephone interviews with representatives of sports clubs that provided the programs (n=17 continued the program, n=11 discontinued the program) six and a half years after the funding period ended (November 2017-March 2018). A sustainability framework with five pre-specified main themes (i.e. program design, implementation, trainer/coach, organizational setting, broader community environment) guided data collection and (deductive) thematic analysis.

Results
Ten of the fourteen NAPSE funded sporting programs were sustained at the level of the NSFs. Most factors facilitating (+) and impeding (-) the long-term sustainability of the programs were mentioned by both NSFs and sports clubs, like program adaptation (+) and a lack of program financing (-). Program evaluation (+) and high program costs (-) were examples of factors that were more important to NSFs, while factors related to human resources (e.g. lack of volunteers (-)) or the sports club nature (e.g. social aspect in program design (+)) were more important to sports clubs. The factors were summarized in the form of a checklist.

Conclusions
This study adds to the knowledge base concerning the long-term sustainability of sporting programs aimed at inactive people in the organized sport setting. The results can be used to develop strategies to promote long-term sustainability of these kind of programs and inform funding guidelines.

Background
Participation in regular physical activity has positive effects on physical, mental and social health, both for children and adults [1][2][3][4]. Nonetheless, 53% of the Dutch population of 4 years and older is not sufficiently active to receive these benefits [5]. People who are insufficiently active are at increased risk for chronic diseases and mortality, especially those who are completely inactive [4,6]. There is therefore a need for initiatives to promote physical activity among inactive target groups. In this regard, a settings-based approach to health promotion has been advocated by the World Health Organization [7]. A setting is the place or social context in which people engage in daily activities in which policy, environmental, organizational, interpersonal and personal factors interact to affect health and well-being. The settings-based approach has an ecological perspective and highlights the importance of the whole system of the setting, rather than just individual responsibility, when stimulating healthy behaviors [8][9][10].
Next to settings such as schools and workplaces, the organized sports sector has received increased interest by policy makers, health professionals and sport practitioners as a setting to stimulate physical activity among inactive target groups [11][12][13][14][15][16]. Sports clubs have great potential to reach many people due to their wide reach into community and the social and informal nature of participation [15,17]. Furthermore, participation in sport at a sports club can contribute significantly to physical activity levels for health benefits [18]. Therefore, attracting inactive target groups to sports clubs seems a promising strategy to increase population levels of physical activity. In Australia, for instance, State Sporting Organizations were funded to implement health promotion policies and practices in their associated sports clubs to create healthy and welcoming environments as a means to increase participation in sport by inactive target groups [12,14]. Also, the development of cross-sectoral (including partnerships between health organizations, local governments and sports clubs) sporting programs for people who were not currently active and who were on low incomes was stimulated [11,19]. In the Dutch context, ten National Sports Federations (NSFs) received financial resources within the National Action Plan for Sport and Exercise (NAPSE) to develop sporting programs adapted to the needs and abilities of inactive people [16]. These activities had to be incorporated within the regular activities of their associated sports clubs. A total of fourteen sporting programs were developed and implemented within a three-year funded implementation period (2008)(2009)(2010)(2011). Examples included a six-week cycling program for inactive adults and weekly hockey for (inactive) seniors played on a small field with soft sticks and soft balls. There is evidence that these sporting programs are effective in attracting insufficiently active people and increasing their physical activity levels, but it seems a challenge to reach large numbers of the least active ones [20][21][22]. To reach many inactive people and to obtain population health benefits, it is important that effective programs are sustained over a long period of time [13]. However, many health promotion programs are discontinued after initial funding ends [23].
Different frameworks have been created to support in the development of sustainable health promotion programs in health care, school and community settings [24][25][26][27][28][29]. There is limited research, however, concerning the sustainability of health promotion programs implemented in the organized sports setting. One study examined factors influencing the sustainability of a funded health promotion program within sport and recreation organizations [19]. Sustainability of the health program was, for example, facilitated when the program aligned with the core values and activities of the sport organization, supportive partnerships were available and training opportunities were provided to staff.
Conversely, a lack of funding opportunities was an important factor impeding sustainability of the health program. Another study, investigating the implementation period of the aforementioned NAPSE sporting programs, also found that a lack of financial resources after the funding period hindered continuation of programs, while integration of the program in the sport organization's long-term policy facilitated program sustainability [16]. Both studies were performed directly after the funding period ended and it is not known whether programs were actually sustained over time. Furthermore, research questions were not directly examined at the level of sports clubs, but only representatives of regional and national sport organizations (i.e. Regional Sports Assemblies and NSFs) were questioned. The focus of sports clubs is mainly on providing sport activities and running competitions and they mostly rely on volunteers. Consequently, they may experience other challenges than (sport) organizations that rely on professionals or paid staff in sustaining these kind of programs [11,16]. Therefore, the aim of this study was to examine factors influencing the long-term sustainability of the fourteen Dutch NAPSE sporting programs, considering both the perspectives of the NSFs and sports clubs, to identify similarities and differences between these two groups.

Definitions and framework
In the scientific literature there is little consensus on the definition of sustainability [23,28,29]. In this study, sustainability is defined as the continuation of a program or program activities within an organization after an initial funding period [19,28]. There is also no consensus about how long programs or activities should be continued after an initial funding period to be called 'sustained', but a period of at least two years is frequently mentioned [23,29]. In the current study, the focus is on factors influencing the long-term sustainability of programs, i.e. a timespan of six and a half years after the funding period ended.
The sustainability framework of Shediac-Rizkallah & Bone (1998) guided data collection and (deductive) thematic analysis [28]. This theoretical framework suggests that potential factors influencing sustainability of health promotion programs can be grouped in four main themes: 1) program design factors; 2) implementation factors; 3) factors within the organizational setting (in this study, the organizational setting of the NSF and sports club) and 4) factors in de broader community environment. Accordingly, the theoretical framework was complemented with other (more recent) sustainability studies [16,19,[23][24][25][26][27][29][30][31][32]. This was done by organizing the identified factors from these studies under the four main themes. However, two studies also revealed different factors related to the actual user or implementer of a program [23,25]. In this study, this corresponded with the trainer or coach of the sports club. Therefore, these factors were included in our framework under a new and fifth main theme of factors, namely 'trainer/coach' (see also Additional file 1 -Theoretical framework of factors).

Sample
This study included the 14 NAPSE sporting programs that were developed by ten Dutch NSFs and implemented by different sports clubs in the Netherlands (period June 2008-June 2011). For more information about the funded implementation period, we refer to a previous article [16]. The programs varied with regard to sport type, content, duration and target group. A description of the original programs can be found in Table 1. This research consisted of face-to-face interviews with the program coordinators of the NSFs and telephone interviews with representatives of sports clubs that provided the programs.
The program coordinators of the NSFs (n=14), who also participated in the research concerning the implementation period [16], were invited to participate in this study by email. In case a program coordinator did not respond, a general email was send to the NSF to get in contact with the former or current program coordinator or a representative of the NSF that was well-informed about the sporting program. In addition, the participating NSFs were asked to provide the email addresses of four sports clubs that started the program between 2008-2011: 1) two sports clubs that continued the program and; 2) two sports clubs that discontinued the program. In case a sports club agreed to participate, the NSF provided the email address of the sports club (i.e. of the local coordinator or trainer of the program) to the researchers. Subsequently, the sports club was invited to participate in the research by email. < Insert Table 1 here > Procedures A total of 14 face-to-face interviews of 60-90 minutes duration were conducted with former (n=6) and current (n=8) program coordinators of the NSFs between November 2017 and March 2018. In addition, telephone interviews were conducted with representatives of sports clubs. In case the NSF had stopped the program or no current program coordinator was present, it was more difficult to retrieve participating or nonparticipating sports clubs. In general, sports clubs that discontinued the program were harder to retrieve by the NSFs. Therefore, not all NSFs provided enough contact details of sports clubs and for two NAPSE sporting programs (a program that was continued by the NSF and a program that was discontinued by the NSF) no email addresses of sports clubs were provided. Consequently, a total of 28 telephone interviews of 45-60 minutes duration were conducted with representatives of sports clubs (n=17 continued the program, n=11 discontinued the program; see also Additional file 2 -Number of interviews with sports clubs) between January 2018 and March 2018. The semi-structured interviews were performed by two researchers (LO, MK) independent of each other. The first two interviews were conducted by both researchers so that interviewing was done in a comparable manner. All interviews were recorded with a digital voice recorder and transcribed verbatim.
The interview questions were framed on the five pre-specified main themes of the sustainability framework. In addition, background information about the respondent, NSF/sports club and sporting program were obtained.
The representatives of the NSFs and sports clubs were informed about the background and aims of the study through email (written) and before the start of the interview (verbally).
In addition, they were informed that participation was voluntary, all collected information would be kept strictly confidential and only anonymized data would be published. All respondents provided informed consent for their participation as well as consent for their interviews to be recorded and transcribed verbatim. Participants were not exposed to procedures, nor were they obligated to follow certain behavioral rules. Therefore, in accordance with the Dutch Medical Research Involving Human Subjects Act (WMO), medical ethics committee's approval was not necessary for conducting this study [33]. cross-checked coding of a random selection of the transcripts (19% of transcripts) and all evolving (sub)themes. In case of disagreement, the results were discussed between both researchers and codes (subthemes) were refined. After that, the coding of all transcripts was once again checked by the first researcher (LO) in the same way and order as described previously. The results of the NSFs and sports clubs were compared to identify the key (sub)themes or factors important for the long-term sustainability of a sporting program aimed at inactive people in the organized sports setting and to summarize similarities and differences between the two groups (i.e. NSFs and sports clubs). For this purpose, we compared the two groups with respect to the meaning and interpretation of (sub)themes, the frequency and prominence of (sub)themes (number of respondents mentioning a theme), and specific examples provided to support or explain a particular (sub)theme. Finally, the findings were shared and discussed with the research team for feedback and comment. However, this did not result in any changes in coding or (sub)themes per group.

Results
Respondent characteristics are presented in Table 2. Although there were some changes in (local) coordinators after the funding period, most representatives of NSFs and sports clubs were involved in the sporting program for multiple years. Representatives of sports clubs were mainly the trainers that provided the program to participants. Furthermore, a diverse sample of sports clubs was represented, including sports clubs of different sizes and from all regions in the Netherlands (see also Table 2). Sports clubs that discontinued programs had provided the programs for an average of three years (range 1-8 years; not in Table).
< Insert Table 2 here >   Table 3 describes continuation of and changes made to the sporting programs after the funding period by the NSFs. Six and a half years after the funding period ended, ten of the fourteen NAPSE funded sporting programs were sustained at the level of the NSFs, but one program without direct involvement of sports clubs. Previously, people could participate in this program on an individual basis or at a sports club, but the NSF only continued the individual training option. Many sports clubs, however, still provided their own training programs for inactive people or people novice to the sport. For eight of the sustained programs, a NSF program coordinator was present and nine NSFs still provided support (e.g. materials, advice) to their associated sports clubs to run the programs. During the years, some changes were made in target group (n=6 programs) and/or content (n=9 programs) of the programs. The other four NAPSE funded sporting programs were directly stopped at the level of the NSF after the funding period. However, one program was still offered by sports clubs without involvement of the NSF. For another program, coordination of the NSF was not necessary anymore, because sports clubs (and event organizations) could run the program on their own. < Insert Table 3 here > The sustained programs varied widely with regard to the number of activities offered per year, their actual reach and the number of participants becoming a member of a sports club/the NSF (see Table 4). When there was no NSF program coordinator or a program was completely stopped at the level of the NSF (but not at the level of sports clubs), this information was often unknown. < Insert Table 4 here > Key factors influencing the long-term sustainability of sporting programs aimed at inactive population groups In Table 5, the key facilitating (+) and impeding factors (-) influencing the long-term sustainability of the sporting programs are presented per main theme. Inductively added factors are presented in bold. Most factors were mentioned by both NSFs and sports clubs (n=17, e.g. Program design: program adaptation (+)). However, some factors were more important to NSFs (n=5, e.g. Implementation: program evaluation (+)) or sports clubs (n=9, e.g. Program design: social aspect (+)). The results are described in more detail below under the five main themes -program design, implementation, trainer/coach, organizational setting NSF/sports club and broader community environment. Since the impeding factors were often the inverse of the facilitating factors, they are not always explained separately.

Program design
There were different program design factors important for the long-term sustainability of the programs. First, sustained programs aligned with the target group's needs as they provided opportunities for inactive people to become more physically active in a proper way. For inactive people, the threshold to participate in the sport in general or at a sports club in particular may often be too high. NSFs and sports clubs reported they still provide the sporting programs so that this target group can become acquainted with the sport in an easy and appropriate way without getting injuries. Afterwards, they are experienced enough to continue the sport in a beginner's group at the club: "You have people something to offer. You can guide people, who have to start from zero.
In the past, it was sometimes difficult. These people had to start in a group at the club for which they were not ready. Then they quit, because they are always the ones that are the slowest of the group. Now, they can start slowly, build it up gradually and later continue in a beginner's group at the club." (Sports club, continued program) Second, the social opportunities provided during the program (e.g. drinking coffee/thee before, during or after training, going to and participating in a sport event together), the acquired social relationships and having fun during participation were main reasons for sport participants to keep attending the programs (according to trainers) and also for trainers to stay motivated themselves. This resulted in continuation of activities by (trainers of) sports clubs.
Another program design factor enhancing programs' long-term sustainability was program adaptation. During the years, sporting programs were adapted (i.e. with regard to content or organizational aspects) both by NSFs and sports clubs, to constantly meet the needs of the target group and the sports clubs. Changes were also made to programs due to the availability of new knowledge or technologies (e.g. using a running app instead of a training schedule per email), new partnerships (e.g. changing program name in sponsor name) and sometimes decreased financial resources (e.g. providing less training sessions in schools). Mostly, only minor adaptations were made (see also Finally, high program costs (e.g. due to the use of expensive program materials, intensive guidance of participants or the need to rent a specific (sports) accommodation), which could not be financed from participant fees alone and for which external financial resources were needed, resulted in discontinuation of programs by NSFs.

Implementation
Key implementation factors influencing the long-term sustainability of programs are described below.It should be noted that these factors were not only important during the three-year funded implementation period but also thereafter.First, the NSFs (i.e. national or regional trainer courses) and sports clubs (e.g. trainers transmitting knowledge and skills to other trainers) provided trainer courses specific for the sporting programs on a regular basis (i.e. once or multiple times a year). These were very important for sustaining the programs: they provided trainers of sports clubs with the necessary skills to guide the inactive target group and assured sufficient (professional) trainers were available.
Another implementation factor facilitating the long-term sustainability of programs was their effectiveness. When a program showed positive effects with participants, like participants learning the sport and becoming more physically active, NSFs and sports clubs were more likely to continue it. Also, partners and sponsors were more willing to contribute (and keep contributing) to effective programs: Programs were also continued by NSFs and sports clubs due to the acquired benefits, such as more people becoming familiar with the sport or sports club, a better image of the sport, attracting new target groups, more participants, new club members and people who are willing to do club volunteer tasks. However, programs were stopped when they did not align with the organization's core values and activities and program benefits were absent: "We are not the right organization to do something with this target group. The program has no advantages for us. It even has no societal advantages." (NSF, discontinued program) Sustained programs secured their financial resources which included internal financial resources, participant/membership fees and in some cases sponsorship fees. Financial resources were not only used to run the programs, but also to educate trainers, to promote the program, to buy (sport) materials and to further develop the program. On the other hand, a lack of program financing, sometimes in combination with high program costs (see Program design factors), was an important reason for NSFs and sports clubs to discontinue programs.
Most NSFs still supported sports clubs in different ways, for example, by providing them with knowledge and advice, (promotional) materials, financial resources and training and education opportunities (see also Table 3). Promoting the sporting programs nationally and supporting clubs with organizational aspects were other examples of NSF support to clubs. This saved sports clubs a lot of time and made it possible for them to focus mainly on the sport activities and guidance of participants. A lack of support of the NSF to sports clubs resulted in discontinuation of programs by some sports clubs: "First, the NSF had three club advisors, but they left due to cut downs. After that, we were not approached anymore to implement the program. The club advisors always helped us.
They made the connections with municipalities and schools. We implemented the program multiple times, but now we have stopped. I think because we are not approached anymore." (Sports club, discontinued program) The remaining organizational factors influencing long-term sustainability were related to human resources. Having one or more persons in the organization responsible for coordinating the program within the organization facilitated the long-term sustainability of programs. These persons focused, for instance, on promotion of the program, recruitment of clubs or participants, the recruitment of trainers and all kinds of other organizational aspects. On the level of the NSF, this was the employed NSF program coordinator, sometimes assisted by other NSF employees. Sports clubs relied on one or more enthusiastic committed trainers or volunteers: Programs were less sustainable when there was no coordinator present. Also, continuation of programs was threatened when the current coordinator would leave. For sports clubs, this was mainly due to their reliance on and often a lack of volunteers: "Well, I am doing this now for the third or fourth year. One day, I will look around to see whether someone could take over my task. When there is no one who wants to do this, this could impede continuation of the program. It is common in volunteering that people want to help and support, but it is sometimes difficult to find a real coordinator or leader." (Sports club, continued program) Finally, as described previously, the availability of (enough) professional trainers at sports clubs enhanced sport experiences of (inactive) participants and, therefore, continuation of programs (see also factors related to Implementation and Trainer/coach).

Broader community environment
Several factors in the broader community environment were reported that influenced the long-term sustainability of programs. First, long-term partnerships were important for sustaining programs, both at the national and local level. NSFs collaborated, for instance, with (sport) event organizers, municipalities, sport stores and other commercial organizations (e.g. from food and drink industry). Local sports clubs collaborated amongst others with schools, municipalities, organizations for elderly people, sport stores, health professionals (e.g. a physiotherapist) and other sports clubs. Partners promoted the programs, facilitated in recruitment of inactive participants, provided financial, material or human resources and shared their expertise or facilities. Brand awareness, more participants (e.g. for sport events), attracting new customers (e.g. for sport stores) and contributing to more healthy or physically active people were examples of benefits for partner organizations.
Furthermore, the popularity of a sport in general or of the sporting program in particular also facilitated it's long-term sustainability according to the NSFs: "Many people do the sport and the sport is still growing enormously. We facilitate people to practice it with this program. We show people that practicing the sport in a safe and appropriate manner is important to us." (NSF, continued program) Finally, competing programs or sport activities threatened continuation of sporting programs, especially at the sports club level:

Results in the ecological perspective
Considering the ecological perspective of the settings-based approach to health promotion [8][9][10], an ecological model is used to summarize the results. In Figure 1 This study identified factors influencing the long-term sustainability of the fourteen Dutch NAPSE sporting programs aimed at inactive people, taking into account both the views of the NSFs and sports clubs. It is positive that ten of the fourteen NAPSE sporting programs were continued by the NSFs (and their associated sports clubs) six and half years after the funding period ended. Programs were sustained in different ways, for instance, with and without coordination or support of the NSF, continuing all or a part of the activities and with varying reach into the community.
Although financial resources were important to sustain programs, there were many other influencing factors, such as program adaptation and program effectiveness. Most factors were mentioned both by NSFs and sports clubs, but some factors were more related to the specific context of these organizations, i.e. a professional-led organization vs. a mostly voluntary-based organization (see also Table 5).
Furthermore, the long-term sustainability of a sporting program is a continuous process, which starts at program development and continues through program implementation and continuation (after a funding period) phases. Therefore, early and active planning is needed to create the conditions that enhance the long-term sustainability of programs.
This requires formulating sustainability objectives (e.g. what is to be sustained, how, by whom and when) and developing and implementing strategies specifically to enhance sustainability. In this regard, the checklist in Figure 1 can be helpful. Furthermore, monitoring and evaluating sustainability objectives and strategies through time and at all levels of the organized sports setting is important to make adjustments when necessary.
As mentioned previously, program adaptation was an important factor facilitating longterm sustainability. Changes to programs were made to align the program with the needs of the inactive target group and sports clubs, but changes were also made due to new knowledge, new partnerships and decreased financial resources. In the literature, program adaptation is also identified as an important factor for program sustainability and it was a pre-specified factor in our framework [23,27,29]. However, changing or removing essential components of programs could lead to non-desired outcomes [29,38]. Therefore, it is important to identify the core elements of the programs that are critical for the achievement of desired outcomes (i.e. increasing physical activity levels of inactive people) and to further study how program adaptation influences these outcomes.
Finally, it was difficult to recruit large numbers of the least active people. It is important to keep attracting inactive people by promoting the sporting programs in a fun and nonthreatening manner, using promotion channels that are appropriate to the target group [20]. Some NSFs and sports clubs collaborated with organizations (e.g. elderly organizations) or health professionals (e.g. a physiotherapist) to recruit inactive people.
However, others did not have the knowledge or resources to get in contact with this target group. By sharing knowledge and good practices between NSFs and sports clubs on how to recruit and engage inactive people, participant numbers can be increased. This will contribute to the long-term sustainability of these kind of programs.

Comparison of factors with other studies
To our knowledge, this is the first study that examined factors influencing the long-term sustainability of sporting programs aimed at inactive target groups and implemented in the organized sports setting. Some of the retrieved sustainability factors are comparable to those found in the study concerning the implementation period of the NAPSE programs [16] and the research about the sustainability of a health promotion program within sport and recreation organizations [19]. For example, alignment of the program with the sport organization's mission and activities, the availability of financial resources, the provision of training and education opportunities and supportive partnerships. Presumably, these are the basic factors or conditions for continuation of sporting programs, both in the short-and longer-term. The same is true when comparing the results with our theoretical framework, which was based on sustainability research of health promotion programs in a diverse range of settings (e.g. healthcare setting, schools, communities) [16,19,[23][24][25][26][27][28][29][30][31][32].
This implies there are generic factors influencing the long-term sustainability of a health promotion program independent of the setting in which it is implemented. However, this study also identified new factors (i.e. the inductively added factors), especially those that were related to the (organizational) setting of sports clubs (e.g. dependence on volunteers) and the specific aim of the NAPSE programs (e.g. program alignment with needs inactive target group). Sports clubs are largely run by volunteers and the sports clubs setting is, therefore, quite different from the more professional led NSF setting and the other studied settings (e.g. health care setting, schools, communities). Securing human resources (e.g. availability of professional trainers, committed leader) is, therefore, one of their most important challenges when continuing program activities over a long period of time. Also, the social and fun aspects of participation are inherent to the sports club nature and are important aspects to include in program design. It is important that all these factors are taken into account, in particular when the NSF is the developer of the program and receiver of the funding and sports clubs are responsible for implementation and continuation of activities. In this regard, the support that NSFs provided to sports clubs (e.g. the provision of training and education opportunities, knowledge and advice, (promotional) materials) facilitated long-term sustainability of programs at sports clubs. Furthermore, this highlights again that it is important to take into account the particular (implementation) context of a program when considering its long-term sustainability [39, 40].

Practical implications
Overall, the results of this study can aid policy makers, sport practitioners and health professionals in the development of strategies to promote long-term sustainability of health promotion programs in general and physical activity promotion programs in particular located within the organized sports setting. As mentioned previously, the checklist in Figure 1 can be used as guidance for this purpose. The checklist can also be helpful in formulating funding guidelines by funding bodies, so that program developers and implementers pay greater attention to the long-term sustainability of their program from the start and integrate sustainability goals and evaluation of these goals in their plans. Program developers and implementers should, for example, elaborate on how they will consider the needs of the inactive target group and how they are going to secure financial resources for the program after the funding period. In this way, the long-term sustainability of these kind of programs will be enhanced.

Strengths and limitations of the study
Factors influencing the long-term sustainability were assessed six and a half years after the funding period ended and both the views of NSFs and sports clubs were examined. In addition, a diverse sample of sporting programs and sporting organizations were included in this study, making results generalizable to different sports and sport settings. These are strengths of this study. However, there are also some limitations. Sports clubs that discontinued programs were harder to find and were less represented in this study (n=11) in comparison with sports clubs that continued programs (n=17). Also, at the level of the NSF there were fewer programs stopped (n=4) than continued (n=10). This may have resulted in more insight into facilitating factors of long-term sustainability than impeding factors. Moreover, we did not examine possible interactions between influencing factors.
For instance, the availability of supportive partnerships (factor Broader community environment) could lead to the availability of more financial resources (factor Organizational setting NSF/sports club) or the recruitment of larger numbers of inactive people (Implementation/continuation factor). In future studies, the possible interaction between factors should be further explored.

Conclusions
This study adds to the knowledge base concerning the long-term sustainability of sporting programs aimed at inactive people in the organized sport setting. The key factors facilitating and impeding the long-term sustainability of programs were identified. The results of this study can be used by policy makers, sport practitioners and health professionals in the development of strategies to promote long-term sustainability of these kind of sporting programs located within this setting. Furthermore, the results can be used to guide funding guidelines. In future research, it is important to identify the core elements of programs that are critical for the achievement of desired outcomes and to further study how program adaptation influences these outcomes. Future research should also take into account possible interactions between the different influencing factors. This will further contribute to our understanding of how the long-term sustainability of physical activity promotion programs in particular and health promotion programs in general, can be improved in this setting.

List Of Abbreviations
NAPSE: National Action Plan for Sport and Exercise; NSF: National Sports Federation.

Ethics approval and consent to participate
The representatives of the NSFs and sports clubs were informed about the background and aims of the study through email (written) and before the start of the interview (verbally).
In addition, they were informed that participation was voluntary, all collected information would be kept strictly confidential and only anonymized data would be published. They were free to ask questions about the research and could contact the researcher for questions by email or telephone. Written informed consent for participation in the study was obtained from the NSFs (at the interview location) and sports clubs (through email).
Participants were not exposed to procedures, nor were they obligated to follow certain behavioral rules.

Availability of data and materials
The datasets generated and analyzed during the current study are not publicly available to preserve the privacy of participants but are available from the corresponding author on reasonable request.   N.A.=Not applicable; NSF=National Sports Federation. * Unknown, due to lack of central coordination by the NSF and/or absence of a NSF program coordinator. ** Unknown, because at the level of the NSF the program has stopped completely. Table 5: Key factors influencing long-term sustainability of sporting programs aimed at inactive target groups*