With the vigorous development of positive psychology, well-being has been paid more and more attention by researchers, and education is no exception. The Future of Education and Skills: Education 2030, published by the Organization for Economic Cooperation and Development (OECD), clearly expresses that education should be committed to creating a better and better life for individuals and improving the overall well-being index of society (OECD, 2018). Therefore, the lack of well-being has become a prominent problem faced by students at present. As far as college students are concerned, they are in a special stage of transition from late youth to early adulthood. They not only need to deal with changes in external environment and academic tasks, but also face challenges in personal growth such as self-exploration and self-regulation. At the same time, in the new era of China's social recovery development and modernization transformation, college students are facing increasing pressure of social competition and survival, and it becomes more difficult to obtain happiness. On the whole, Chinese college students' evaluation of current happiness is lower than their expectation of future happiness (Xiaoyuan et al., 2021). There is no doubt that well-being plays an important positive role in individual growth and development. Individuals with higher well-being levels generally experience higher self-efficacy (Yuchang et al., 2020) and exhibit more prosocial behaviors (Tian et al., 2019). For college students, higher well-being is often accompanied by positive campus adaptation and better academic achievement (Coninck et al., 2019). Therefore, how to improve the well-being of college students has become the focus of many researchers.
SWB is an overall evaluation of an individual's living conditions based on his own standards, which mainly includes emotional experience and life satisfaction and reflects an individual's social function and adaptation state (Feng et al., 2021). Through literature review, it is found that existing studies have explored some risk factors and promotive factors affecting college students' SWB around individual factors (such as self-esteem and neurotic personality) and environmental factors (such as social support and negative interpersonal relationship events). In recent years, among the many factors affecting the SWB of college students, physical exercise, which is closely related to our physical and mental health, has been gradually paid attention to by researchers. A large amount of evidence, especially meta-analysis, supports the effect of physical exercise in promoting mental health. Specifically, on the one hand, the physical exercise group has lower scores in various psychological problems and symptoms than the non-physical exercise group, that is, they are healthier (Dongdong et al., 2021; Jiankun et al., 2021); on the other hand, some studies support the view that physical exercise has therapeutic effects on mental illness (Rebar et al., 2015). In addition, other studies have confirmed that factors such as the frequency of physical exercise, type of exercise, degree of enjoyment of physical exercise and EA also have a positive impact on mental health (Yinhai et al., 2022). EA will bring significant and lasting positive effects on individual SWB (Zhongkai et al., 2007). Therefore, this study focuses on the influencing factor of EA, and intends to explain the relationship and internal mechanism between EA and SWB of college students by constructing a chain mediation model, in order to provide some empirical evidence for improving the SWB of college students and promoting their mental health.
Exercise Adherence and Subjective Well-being
In the discussion of influencing factors of SWB of college students, EA is a positive factor that can not be ignored. EA refers to an individual's behavioral tendency to adherence, consistency or effort during physical exercise (Shen et al., 2016). In addition to the external behavioral characteristics such as the long-term nature and regularity of exercise behavior, it should also include the internal psychological characteristics of maintaining behavior, such as the positive emotional experience to motivate oneself to persist and the degree of effort to overcome difficulties. Previous studies focused on the relationship between physical exercise and SWB, and researchers (Hao et al., 2022; Chao et al. 2022; Yong et al., 2021) provides direct evidence of physical exercise's influence on SWB through empirical research. Research shows that physical exercise can significantly positively predict SWB, and the higher the degree of physical exercise participation, the stronger SWB will be. However, there is limited research on how EA affects SWB. Some people have proposed that EA is one of the factors to measure the impact of physical exercise on SWB, but as for the factors of EA, there is still a lack of operational definition and sufficient explanation. However, it is not difficult to find from other studies (Ying et al., 2004) that the psychological effects of physical exercise only show up when physical exercise lasts for a period of time. Although some studies have proved that EA can positively predict SWB and preliminarily reveal the correlation between EA and SWB, there is still a lack of necessary empirical research on how EA affects SWB. So, we put forward the following hypothesis:
Hypothesis 1
EA would positively predict SWB among the Chinese college students.
Mediating Effect of Mindfulness
In recent years, a large amount of evidence, especially meta-analysis, has shown a close relationship between mindfulness and SWB (Junfang et al., 2021). Mindfulness refers to the process of focusing attention on something at the moment and treating various physical and mental activities with a curious, open and receptive attitude (Menggui et al., 2018), which includes two forms of trait mindfulness and state mindfulness. Trait mindfulness refers to individual differences in inclination and willingness to perceive and maintain attention in the present event or experience. In contrast to state mindfulness, which emphasizes intra-individual changes (such as those achieved through meditation), trait mindfulness focuses on the individual's baseline linear or average level of mindfulness in daily life (Brown et al., 2003; Siegling et al., 2014). Mindfulness has been shown to be associated with many positive psychological outcomes, such as higher SWB, lower stress responses, and fewer negative emotions (JenHo et al., 2015; Shiyu et al., 2018), and as an intervention, mindfulness training can significantly improve the well-being of clinical patients and healthy people (Wei et al., 2013), and can also effectively improve individual negative emotions (Shuting et al., 2019). Therefore, we conclude that mindfulness can improve SWB of college students. In addition, studies have found that physical exercise is significantly positively correlated with mindfulness (Qingpeng et al., 2022), and physical exercise can significantly positively predict mindfulness (Wei, 2021a). Wei (2021a) research shows that only 1–2 times a week or more of physical exercise can significantly improve the level of trait mindfulness; while 3–5 times a week of physical exercise has the best effect. If the interval between two physical exercises is too long, the mindfulness effect produced by the short-term exercise cannot be accumulated, and the trait mindfulness effect will not be enhanced. Therefore, appropriate exercise frequency is a necessary condition for the accumulation of mindfulness effect, and it is also a key factor for physical exercise to enhance trait mindfulness effect. Wei (2020) combined previous studies and speculated that trait mindfulness may have a mediating role between physical exercise and psychological factors such as emotion, cognition, and self-esteem. Here, the second hypothesis was raised:
Hypothesis 2
Mindfulness would play a mediating role between EA and SWB.
Mediating Effect of Personal Growth Initiative
Robitscheck et al. (2012) believe that PGI is a metacognitive concept, a set of highly malleable skillsets that guide individuals to actively make positive changes in cognition, behavior, attitude, emotion, motivation, etc. The core feature is conscious, proactive self-improvement. The structure of PGI consists of four parts: preparation for change (identifying opportunities for personal growth), planning (developing strategies for self-improvement), utilizing resources (seeking external support or assistance to achieve personal growth) and positive behavior (taking effective self-actualization actions). Preparation for change and planning constitute the cognitive dimension of PGI, while utilizing resources and positive behavior constitute the behavioral dimension of PGI. As for the relationship between PGI and SWB, some studies have found that there is a significant positive correlation between PGI and SWB, and having meaning of life plays a partial mediating role between them (Freitas et al., 2018). Robitschek et al.(2009) proposed a multidimensional model of mental health, focus on psychological well-being (self-acceptance, positive relationship, life purpose, control environment and autonomy), emotional well-being(life satisfaction, positive emotions and well-being) and social well-being(social belonging, social contribution, social realization and social integration) three levels, and PGI is a significant predictor of multidimensional model of mental health, it was positively correlated with life satisfaction and positive emotion.The Personal Growth Initiative Scale-II (PGIS-II) applied to Chinese college students found that the four dimensions of personal growth initiative were significantly positively correlated with life satisfaction, and significantly negatively correlated with inferiority complex, social sensitivity, internet addiction, depression and hostility. When predicting life satisfaction, planning and resource utilization have significant predictive effects, but have no explanatory effect on preparation for change and active behavior (Hongfei et al., 2014). Therefore, we conclude that PGI can improve SWB. In addition, exercise psychology believes that physical exercise has many positive psychological effects. However, it is not clear how physical exercise has an active effect on PGI. Some studies suggest that the factors affecting personal growth include demographic variables, family environment, social support, cognitive restructuring, recreational activities, and social culture. Among them, the internal factors of the family and the external environment of the family have an important impact on personal growth. The external environment of the family refers to various cultural, political, entertainment, sports, religious and other communication activities between the family and other systems (such as schools, communities, churches, etc.), participating in these activities will provide individuals with more opportunities for growth and promote their better growth (Whittaker et al., 2001). Recreation is one of the important functions of sports. Chun et al., (2010) studies have shown that recreational activities can promote individual post-traumatic growth in various ways, such as building bonds with others. Here we put forward the third hypothesis:
Hypothesis 3
PGI would play a mediating role between EA and SWB.
Chain Mediating Effect of mindfulness and Personal Growth Initiative
Studies have shown that there is a significant positive correlation between mindfulness and PGI (Loo et al., 2014; Yimeng et al., 2022), indicating that they may play a chain intermediary effect between EA and SWB. Individuals with mindful traits are more willing to actively seek opportunities for growth (David et al., 2007), more receptive to open experience, and more able to constantly reflect and transcend from open experience. "Attentional awareness" and "open acceptance attitude" are the core components of mindfulness (Norris et al., 2018). Like self-reflection, mindfulness with this feature is more inclined to "enjoy life" and will not repeatedly experience past autobiographical memory situations. It is non-critical observation and awareness of the present moment (Ardelt, 2003). While PGI requires individuals to be clearly aware of the time when they are ready for change (Robitschek et al., 2009), and to actively seek and use external resources. The "awareness" and "openness" of mindfulness just provide the conditions for PGI to grow. Here, the four hypothesis was raised:
Hypothesis 4
Mindfulness and PGI would play a chain mediating role between EA and SWB.
The Present Study
In conclusion, there is a positive correlation between EA and SWB of college students. The higher the degree of EA, the stronger the SWB. Therefore, hypothesis 1 is proposed: EA would positively predict SWB among the Chinese college students. There is a significant positive correlation between mindfulness and SWB, and there is a significant positive correlation between EA and mindfulness. Therefore, hypothesis 2 is proposed: Mindfulness would play an intermediary role in the relationship between EA and SWB. There is a significant positive correlation between PGI and SWB, and there is a significant positive correlation between EA and PGI. Therefore, hypothesis 3 is proposed: PGI would play a mediating role between EA and SWB. There is a significant positive correlation between mindfulness and PGI. Therefore, hypothesis 4 is proposed: Mindfulness and PGI would play a chain mediating role between EA and SWB. Based on this, this study took EA as the independent variable, SWB as the dependent variable, and mindfulness and PGI as the mediating variables to construct a chain mediation model (Fig. 1). This study further deepens and expands previous studies, which has theoretical value and research significance. It is not only helpful to understand the relationship between EA and SWB, but also helpful to understand "how" EA affects SWB and enrich the research on SWB. This study focuses on whether mindfulness and PGI play a chain mediating role between EA and SWB, and explains how EA affects SWB, which is of great significance for improving and intervening SWB of college students.