Introduction

University education must be capable of providing an answer to the formative needs of the future professionals of Physical Activity (PA), Sport, and Physical Education (PE). This education must provide concrete knowledge about this field of study such as healthy habits, physical fitness, body expression, sports and games as well as the competences required to intervene in the different contexts where they will be able to develop their professional activity ( ^{SIEDENTOP, 2002} ). By the time their education is completed, students must be able to program, implement, and assess specific proposals of PA. Furthermore, this education must help them adapt to different environments, e.g., sports, educational, leisure, and health, and enable them to fulfill the specific aims that need to be developed in each one. This education also needs to work to accommodate the current challenges and social needs, developing high quality PA practices for different groups: children, adolescents, adults, people with disabilities, people at risk of social exclusion, women’s groups, the elderly, etc.

In order to do this, from their initial education different methodological strategies are sought to cover the largest part of this diversity of formative necessity, to enable them to obtain a profound and lasting learning. Among these methodologies, Service-Learning (SL) has had a strong impetus during the last few years ( ^{LOUGH, 2018} ). Service learning’s theoretical and practical foundation stems from experiential education and constructivism, framing SL as the opportunity for students to apply the knowledge that they have learned in the classroom within community contexts both for community engagement and experiential learning ( ^{FURCO; NORVELL, 2019} ). SL in a university context is defined as “integrating academic material, relevant community-based service activities, and critical reflection in a reciprocal partnership that engages students, faculty/staff, and community members to achieve academic, civic, and personal learning objectives as well as to achieve public purposes” ( ^{BRINGLE; CLAYTON, 2012} , p. 105).

In the university context its use is becoming more widespread as it has been shown to be beneficial for the students. Generally, the benefits of SL can be grouped into six different categories: (a) academic development (the typical learning of the field of study, grades, cognitive abilities); (b) social competences (interpersonal skills, social relationships, leadership); (c) cultural and civic competences (an understanding of the diversity of ethnic and other groups, the transformation of ideas and beliefs, and the importance of social responsibility); (d) personal development (self-esteem, self-recognition, motivation, empowerment, self-efficacy); (e) a professional perspective (confirming the choices made or opening new professional ways); and (f) ethical considerations (GARDNER; EMORY, 2018; ^{HÉBERT; HAUF, 2015} ; ^{WALKER, 2020} ).

The other aspect that characterizes SL is the service provided to the community in the context of disadvantage or vulnerability. SL projects must be designed for a specific need identified in the community which otherwise would not be covered. After running the projects, both the accomplishment of these goals and the impact of the program on the receivers must be assessed ( ^{TRYON; STOECKER, 2008} ). With regard to the organizations, research has shown benefits in relation to cultural exchange, economic advantages, and the transfer of knowledge and productivity ( ^{HARRINGTON, 2014} ). Regarding the direct receivers, the changes and improvements are as diverse as the service received.

After considering the importance of this methodology, this research has sought to systematically revise the existing evidence about the effect that implementing SL proposals in the context of PA, PE and Sport has had on the different agents involved.

Methods

Inclusion criteria

A set of inclusion criteria was established to select papers for this systematic review. Every piece of research had to meet the following criteria:

To extract information, a table with studies’ data was used. All the information can be found in Table 2 . Such table includes details of the author, the year, the country, the recipients of the service, the duration of the SL project (in weeks and hours in order to determine for how long it was implemented), the methodology used, the instruments employed in the research, the origin of the information included in the research, i.e., the participants, which aspect of SL had been researched, i.e., learning, service, learning + service, and finally, the main results. These elements were chosen because of their importance in SL projects. The service’s receptors show on which population the interventions in PA and sport had been carried out, and those that had not covered; the duration of the SL project is directly related to the university students’ learning and the possible service results; the methodology together with the instruments used will indicate which were the most widely used in this research and what useful innovations could be made in this area; elucidating where the information of the research had been collected from will help us to ascertain whether the perspective of all the agents involved had been taken into account, or if it was limited to partial information; which aspects of the SL had been researched will help us to ascertain whether only a part of the project, or the project in its entirety was valued (usually, the learning of university students); finally, the results will indicate the main conclusions associated with the impact that SL had on the different aspects researched.

Results

Search results

Figure 1 displays the process used to select the articles included in the systematic review. The initial search found 284 entries. After a first review, 110 duplicate researches were removed, and the 174 remaining articles were analyzed based on their abstracts and titles. After this analysis, 89 researches were eliminated because they were irrelevant to the topic. The remaining 85 articles were assessed by examining the full text, which resulted in the elimination of 60 articles that did not meet some of the inclusion criteria. Finally, 25 articles were deemed relevant to the investigation and were included in the systematic review. All the information can be found on Table 2 .

Source: Author.

Figure 1 Papers selection process 

Characteristics of the intervention programs

Type of research

Results obtained

Finally, this section presents the results obtained from the research. These results have been divided between the research assessing the effects of SL on the university students’ learning and the one focusing on the benefits arising from the service or the assessment of the implemented program.

Discussion

The current review summarizes all the studies on university SL and PE, PA, or sport conducted from 2008 through 2018 that met the proposed inclusion criteria. This review has shown the increase in interest for SL in proposals of PA over the past few years by means of a variety of interventions with regard to population, duration, type of research, the instruments used to gather information, and the aspects envisaged. This will allow to advance and broaden the horizons in the research into SL, addressing all aspects that have not been investigated so far.

The contexts of intervention have stood out for placing their focus on the school-age population, barely assessing how SL proposals could work with adults or the elderly. However, the students from PA and sport degrees must acquire the competences required to also be able to work with these population groups, where interests, types and methods of intervention are different from those with children and youngsters. Moreover, there is a huge amount of research where recipients are people with functional diversity or in the context of poverty or limited resources. The research conducted by ^{Lleixà and Ríos (2015)} is the only one that approaches an intervention with a population group with different characteristics, namely, prisoners in a mental health unit. There are many potential groups that could be considered for these proposals: women at risk of social exclusion, the elderly, homeless people, different ethnic groups, immigrants, or other risk groups who suffer some type of illness (diabetes, cancer, etc.), but they have not yet been taken into account. This restricts the development of the students’ academic and social competences, as well as the possibilities of the service recipients to participate in PA.

Additionally, 68% of the studies reviewed did not include any information about the total number of hours invested in the service. Those providing this piece of information showed a great diversity in the length of the interventions. This makes it difficult to assess how the time factor influences the results found. Obviously, one would expect to see differences in achievement levels in the goals of the proposal between interventions of 60 hours, compared with a practice of only 5 hours.

In the research methodology, there was a predominance of data triangulation using different instruments: 52 % employed three or more instruments, although not through the triangulation of the perspective of all the agents. Out of studies reviewed, only two of them collected information from all the agents involved in the SL project ( ^{GALVAN; PARKER, 2011} ; ^{LLEIXÀ; RÍOS, 2015} ). Only one aimed to assess learning, service and the program. This is a clear limitation of the research and is fostered by the characteristics of the methodology itself, as the requirement to cover a social need and provide an answer to its objectives necessitates the participation of all the recipients and entities playing a key role in globally assessing the efficiency of this methodology ( ^{BLOUIN; PERRY, 2009} ). SL cannot be limited to only assessing the effects of its use on students, because it is as important to know if the objectives are met, if the detected social need is coped with, and to assess the program implemented ( ^{TRYON; STOECKER, 2008} ). In order to achieve this, systematic and objective assessment of these needs is necessary.

The systematic review performed here has revealed that SL can be a helpful methodology for university students’ learning and personal development. SL also contributes to improving students’ communication skills because they must coordinate their work alongside the other agents. It also favors a change in the perceptions and preconceived ideas towards vulnerable groups, or those at risk of social exclusion. Finally, SL also helps reaffirm or open new professional ways of working. This opinion also is in accordance with other university SL studies conducted in different contexts ( ^{HÉBERT; HAUF, 2015} ).

The strength of this review lies in the large number of research papers reached out, as well as in the depth of approach into the most important elements used to assess results obtained in SL research in the contexts of PA, PE, and sport. An additional strength is the inclusion of articles published both in Spanish and English, allowing a wider vision of SL at an international level and showing the differences in the projects that are implemented in the different regions. However, the results of this study are limited as a result of inclusion criteria established in its methodology, since other proposals were left out as they simply described the implementation of SL. Furthermore, it is impossible to clearly compare the results obtained by the different studies due to the diversity of methods and techniques used to collect information, as well as the particular characteristics of the SL programs which have prevented our ability to draw strong conclusions about their results.

Future research must delve deeper into the aspects not addressed more accurately until now, such as: (1) the specificity of the knowledge in the field, i.e., particular competences mainly about the knowledge of content, (2) to assess in more detail the competences of intervention in context, (3) the changes in civic and social competences, i.e., short- and long-term, (4) the specific competences of intervention on groups with special characteristics, such as disabilities, and the ability to organize specific tasks adapted to their needs, (5) and finally, the effects that the programs have on the groups depending on the objectives established, for example, an improvement in PA levels, healthy habits, active engagement of leisure time, improvement of self-esteem, socialization, etc. In addition to this it is necessary to devise a stronger path of research capable of ‘controlling’ the different aspects of an intervention such as its duration, and the groups, and employing instruments more consistently.

Conclusion

University SL in the context of PA, PE and sport have shown numerous benefits for students on the academic, social and work level; and it also demonstrated that recipients were able to maximize the benefits of practicing PA by improving their health and motor functions. As revealed by this study, the potential of the SL methodology as a formative proposal suggests expanding its use in the university context, increasing the variety of projects developed in this area, and implementing the service with other groups with more diverse physical activity proposals. Future research should also be expanded to address the perspective of all the agents involved in the projects and include a more rigorous explanation of the characteristics of the projects that allow to clarify the real impact of the results obtained.