The purpose of this explorative study was to identify determinants of physical activity and sedentary behaviour in Belgian university students. Furthermore we collected ideas and recommendations in order to facilitate the development of tailored intervention programs aiming to increase physical activity and decrease sedentary behaviours in university students. Similar to Story’s framework  combining Bandura’s Social Cognitive Theory  with Sallis’ ecological model  explaining health behaviour, we identified four major levels of determinants: individual, social environment, physical environment and macro environment. In turn, these determinant levels were found to be influenced by some university specific characteristics.
Many psychological factors such as perceived enjoyment, self-discipline, values, norms and beliefs, and time management were found to influence physical activity and sedentary behaviour at the same time. In Keating’s review  ‘having fun’ has been addressed as one of the primary reasons for college students to participate in physical activity or enrol in elective physical activity courses. With regard to time management, previous US studies using focus group discussions revealed that students feel like they lack time to be physically active [37-39]. Students spend a lot of time on study related sedentary activities (e.g. sitting in class, studying, or sitting in front of their computer for academic purposes), which makes it difficult to be physically active [37,38]. To counter time constraints, participants in the present study suggested to incorporate ‘sports time’ as part of their curriculum. With regard to time spent seated in classes, previous research has shown that taking a five minute walking break every hour could yield beneficial weight control or weight loss results . Hence, it should be the task of university policy makers to integrate sufficient break-time during prolonged classes. Moreover, class schedules can be arranged in such a way that students have to relocate by foot or by bike between classes.
Due to the lack of interest in physical activity students often replace time they should ideally spend on physical activity with sedentary activities. On the other hand, when students are very physically active throughout a certain part of the day, physical fatigue might cause them to be more sedentary during the rest of the day. Although relaxation was not mentioned to be a reason to be physically active, students felt they rather needed to engage in sedentary activities (such as TV watching) to clear their heads. This might indicate that university students still choose sedentary over physical activities in terms of relaxation and recreation. Hence, physical activity promoters and policy makers are challenged to convince students to engage in physical activities for relaxation purposes. Finally, students revealed that there is an absorbing quality to some sedentary activities, such as spending time on social media. Therefore, the compulsive nature of certain sedentary behaviours, such as computer use (incl. social media access), should be taken into account with regard to intervention efforts.
Concerning future interventions, the present study’s findings support LaCaille’s  suggestion to strengthen students’ self-regulation skills (e.g. self-discipline, time management) around exercise as part of the transition from secondary school to university. McArthur and colleagues  showed that self-management strategies were strongly associated with physical activity level. Moreover, our results suggest that the same self-regulation skills should be addressed when aiming to decrease sedentary behaviour during this transition period. A randomised trial in college students showed that a 30-minute single session of one-on-one motivational interviewing (including discussing perceived benefits and barriers, personalised feedback, goal setting and strategies for increasing physical activity levels) increased moderate and vigorous physical activity levels after one month . Although no long-term effects were evaluated, a single session intervention as such may be more appealing to college students and easier to implement on college campuses in comparison to more intensive models . Maybe even more appealing to college students is the use of smartphone applications. Recent research in primary care patients showed that combined goal setting with an assisting smartphone application (based on self-monitoring and personalised feedback) significantly increased the amount of steps per day in comparison to a goal setting non-application control group . Moreover, Bond and colleagues  showed that prompting small physical activity breaks after excessive sedentary time through a smartphone application increased physical activity and decreased sedentary time in overweight and obese individuals. To the best of our knowledge, no intervention efforts have been made so far to decrease sedentary behaviour in a university or college student population. Future (smartphone-based) experimental studies should investigate if similar motivational and behaviour change techniques are also effective in decreasing the amount of time university students spend in sedentary mode.
Although at the interpersonal level focus group literature in US university students only mentioned social support from friends to be influencing physical activity [37,39], the present study demonstrated that the social environment influencing students’ physical activity also included parental control, modelling and peer pressure. At the same time, these factors were found to influence students’ sedentary behaviour as well. The fact that previous US studies did not find parental influences on students’ physical activity behaviour might be explained by the longer home-university distances, forcing US university students to reside away from home more often than Belgian students, resulting in less parental influences.
In accordance with previous US research investigating determinants of physical activity , current study results showed that university students are very susceptible to monetary costs. Moreover, results revealed that price can be a barrier to participate in healthy exercise behaviour, but at the same time be an enabler to choose other non-active or sedentary (like TV viewing) behaviour. Therefore, students proposed to make (on-campus) sports activities cheaper and/or more flexible which would lower the barriers of participation, resulting in opting for more physical and less sedentary activities.
Availability and accessibility of sports lessons and facilities as well as TV or computer were found to influence university students’ physical and sedentary activities. Despite the abundantly available on-campus sports facilities (at our university), participants of the present study did not automatically engage in more physical activities and/or less sedentary time. In Keating’s review  it was concluded that the influence of campus exercise or fitness facilities on university students’ physical activity behaviours was still unclear. The same review also revealed that research on the impact of campus size and overall physical layout and structure on physical activity has been neglected so far . Hence, experimental research investigating the relative importance of physical environmental factors on physical activity, but also on sedentary behaviour in university students is needed. The abovementioned might also indicate that physical activity and sedentary behaviour in university students is not only influenced by the physical environment, but also the social environment and individual factors at the same time. The continuous interaction between determinant levels suggests that intervention strategies using multilevel approaches may be most effective .
University specific characteristics
Some student characteristics (e.g. residency, exams, etc.) seemed to be moderating relationships between determinants and physical activity and sedentary behaviour. For example, living in a student residence might affect the strength of the relation between modelling and physical activity and/or sedentary behaviour. Students may experience less parental modelling but more peer modelling when residing away from home and vice versa.
Physical (in)activity versus sedentary behaviour
Despite the introduction given on sedentary behaviour and its distinction from inactivity, it was hard to keep participants focused on sedentary behaviour as such. When asking them which factors influenced their sedentary behaviour, participants tended to deviate and talk about physically inactive behaviour instead. Therefore, the moderator had to be very alert and redirect discussions when necessary. Consequently, suggestions for interventions mainly focus on strategies to be more physically active, whereas little to no specific recommendations were made to target actual sedentary behaviour. This means that ‘sedentary behaviour’ is still a relatively unknown concept among university students, indicating that researchers along with policy makers still need to work on familiarising students with this concept and its association with overall health.
Although previous studies have shown that physical inactivity should be investigated independently from sedentary behaviour [5,15], many factors in the present study were found to influence physical activity and sedentary behaviour simultaneously. Students also believed that the lack of physical activity may increase the likelihood of spending more time in sedentary mode, suggesting an undeniable connection between both behaviours. Previous research in college students showed that computer use for men and television watching for women were negatively correlated with exercise and physical activity [16,17]. In accordance, Owen et al.  highlighted that sedentary behaviour can coexist with but also compete with physical activity. Therefore, as students suggested, intervention efforts aiming to increase university students’ physical activity might decrease time spent sedentary as well. It should be mentioned, however, that a recent review and meta-analysis of controlled trials in adults found that interventions aiming to promote physical activity (with no sedentary behaviour component) were least effective in reducing sedentary behaviour, compared to those studies that specifically targeted sedentary behaviour . Thus, a component focusing on reducing sedentary behaviour may be needed to generate meaningful reductions in sedentary time .
Strengths and limitations
This study adds important evidence to the limited literature investigating determinants of sedentary behaviour in university students and in general. Moreover, this is the first study collecting ideas and recommendations to increase physical activity and decrease sedentary behaviours in university students. This should facilitate the development of effective and tailored intervention programs aiming to improve physical activity and sedentary behaviour simultaneously. Secondly, as highlighted by Rouse et al. , sedentary behaviour is multifaceted and should not be limited to television viewing. Hence, participants of the present study were given a priori information on sedentary behaviour, making sure not only determinants of TV viewing but also other sedentary behaviours (e.g. computer use, studying, socialising) were explored. Finally, the research team chose focus group discussions over e.g. in-depth interviews, because the dynamic group interactions allowed us to get better insight into the mechanisms behind university students’ eating behaviours . On the other hand, the group setting might have intimidated some participants which, in turn, might have limited a greater sharing of their thoughts.
Our study has some limitations as well. Although we might expect that behavioural differences according to gender may be found [28,46], we chose to use mixed-gender focus groups including students of different study years and disciplines, allowing us to create greater diversity of opinion within each focus group. Secondly, participants were recruited using snowball sampling, which is a purposive nonprobability approach that is often used in qualitative research, especially when the study is explorative in nature. This approach allowed us to generate rich and lively discussions, which may not happen in a more random collection of participants . Using subjects who know one another may be a limitation to the generalizability of the findings beyond the group assessed. However, the purpose of this study was to generate a rich understanding of participants’ experiences and beliefs [47,48] and not to generalize results . Finally, no quantification was used because the issue raised most frequently is not necessarily the most important, even when it is raised by a larger number of people . In other words, each idea or opinion should be equally appreciated. Hence, future quantitative studies, using a larger representative sample, should determine the importance and value of each determinant, making differentiation according to gender or other student characteristics, as well as generalization possible.