Peers provide multi-dimensional support, laying a solid emotional and behavioral foundation for adolescents' participation in physical exercise. On the emotional level, companionship, encouragement, and affirmation from peers are key drivers for initiating and sustaining exercise behaviors [“My friends' cheers kept me going when I felt like stopping during long-distance running” (Silva et al., 2014)]. This positive emotional interaction effectively enhances individuals' exercise motivation and psychological resilience. On the behavioral level, immediate, concrete assistance and co-participation directly translate into higher exercise frequency and intensity [“Having classmates to play badminton with made me go to the court significantly more often each week” (Gao, 2013)]. Research further indicates that high-quality sports friendships, characterized by high trust, shared sports interests, and reliable mutual assistance, are significantly positively correlated with long-term participation in adolescent physical activity [“We are not just partners on the court; we also exchange tips and insights privately. This kind of friendship makes me love the sport even more” (Xu, 2021)]. Moreover, good peer relationships can effectively buffer feelings of frustration during exercise, providing a stable psychological support environment for sustained participation [“Even if we lose a match, teammates don't blame each other but summarize it together. This makes me dare to push myself next time” (Wang and Ye, 2021)].

Positive team interaction is a key contextual factor sustaining adolescent participation in physical exercise, while the resulting peer acceptance and group belonging are core drivers for long-term engagement. In team sports, shared goals and collaborative processes significantly enhance cohesion among members [“To win the class basketball game, we practiced tactics together after school. It felt like we were united, striving for the same goal” (Ingrell et al., 2019)]. This close interaction not only increases the enjoyment of the sport itself but also provides individuals with a strong sense of identity and value within the group [“Being a member of the school team makes me proud and demands higher standards from myself” (Zhang, 2023)]. Studies show that when adolescents feel accepted and needed within a sports team, their intrinsic motivation and willingness to persist in exercise significantly increase [“In the track and field team, no one looks down on others for running slowly. We encourage each other, making me feel this is my ‘home'. I want to stay even when it's tough” (Xu, 2021)]. Therefore, constructing a supportive and inclusive team environment is crucial for transforming external social attraction into adolescents' enduring internal drive for participation.

Good peer relationships are not only the cornerstone of positive interactions but also possess the important function of effectively resolving conflicts and maintaining team stability, thereby providing a safe and stable social environment for adolescents' sustained participation in physical exercise. In team collaboration and competitive confrontations, disagreements, competitive friction, or blame for mistakes are inevitable. At such times, peer relationships built on mutual trust and respect can transform potential destructive conflicts into opportunities for deepening relationships through positive communication, perspective-taking, and timely forgiveness [“We almost argued over a bad pass during the game, but we talked it out right after, and now we understand each other's positioning habits better” (Zhao, 2021)]. This effective conflict management mechanism significantly reduces the risk of sports withdrawal or dropout due to interpersonal friction [“I wanted to quit before because I found a teammate too domineering, but after we all talked it out, now we get along and cooperate much more naturally” (Wang, 2024)]. Therefore, fostering adolescents' conflict resolution skills in sports contexts is a key link in maintaining team cohesion and ensuring the sustainability of their sports participation.

In the social learning process of adolescent physical exercise, the role of peers as “behavioral models” exerts an irreplaceable influence. Social learning theory emphasizes that individuals acquire new behavioral patterns by observing and imitating others, a mechanism particularly evident in adolescent physical exercise (Xiang, 2005). First, peers' physical activity level becomes a key predictor of an individual's activity level. Multiple longitudinal studies confirm that adolescents unconsciously absorb their peers' exercise habits, gradually adjusting their own level of engagement (Quan and Lu, 2020). Second, the demonstration effect of peers plays a unique role in the acquisition of complex motor skills. Compared to traditional teacher demonstrations, peer demonstrations are more referential due to the proximity of ability levels. Motor skill learning theory suggests that learners are more inclined to imitate peers whose abilities are similar but slightly superior, a phenomenon Vygotsky termed the optimal learning space within the “zone of proximal development” (Iserbyt et al., 2011). In an experimental study on tennis forehand teaching, students in the peer demonstration group performed significantly better in skill retention tests than the control group receiving only teacher demonstration (Iserbyt et al., 2011). Furthermore, peer assistance creates high-quality informal learning environments. By observing peers' successful movements, analyzing their mistakes, and listening to their experience sharing, individuals can quickly form correct mental representations of movements and effectively avoid common errors (Wang et al., 2018). This “proximal demonstration” and immediate feedback mechanism based on peers significantly reduces the cognitive load of skill learning and accelerates the internalization and automatization process of motor skills. It is noteworthy that the effectiveness of peer modeling is moderated by various factors. Research shows that the model's ability level, the quality of the relationship with the observer, and the authenticity of the demonstration context all influence the effect of observational learning (Mean and Kof, 2023). When the model is perceived as a “similar other” and has a close relationship with the observer, their demonstration often elicits stronger motivation to imitate and more lasting behavioral change.

In the social environment of adolescent physical exercise, the “motivational climate” collectively created by the peer group has a profound impact on individuals' participation motivation. Achievement goal theory distinguishes between two basic types: “task-involving” and “ego-involving.” Among these, the task-involving climate created by peers is confirmed to be a key socio-psychological factor in stimulating and maintaining adolescents' intrinsic motivation (Jõesaar et al., 2012). A task-involving climate is characterized by an emphasis on effort, improvement, cooperation, and skill mastery. In this climate, peers focus more on personal ability improvement than mere outcome comparison, and individuals perceive success as stemming from their own effort and progress, providing fertile ground for cultivating intrinsic motivation [“In our team, as long as you give your all on the court, even if we lose in the end, everyone will applaud you. We care more about whether we did better today than yesterday” (Ingrell et al., 2019)]. This collective value defining success as effort and progress effectively reduces fear of failure and enhances individuals' sense of autonomy and enjoyment in participation. In contrast, an ego-involving climate created by peers may undermine intrinsic motivation. When the peer group overemphasizes competition, social comparison, and an “outcome-only” focus (where only winning or being the best is recognized), it significantly increases psychological pressure and anxiety among adolescents. Especially for individuals with temporarily lower skill levels, this climate can easily lead to self-doubt and reduced interest in participation (Cox and Ullrich-French, 2010). A student in a qualitative interview admitted: “If the team only cares about who runs the fastest or scores the most, someone like me with a weaker foundation feels a lot of pressure, even afraid to train” (Wang and Ye, 2021). The task-involving climate promotes intrinsic motivation through several psychological mechanisms. First, by emphasizing effort and improvement, it helps individuals establish a controllable attribution for success, believing that they can improve their ability and succeed through their own efforts, which directly enhances their sense of behavioral autonomy (Jõesaar et al., 2012). Second, by encouraging cooperation and mutual assistance, it satisfies adolescents' need for belonging, providing them with stronger social connection and emotional support within the team (Ingrell et al., 2019). Third, by focusing on the learning process and personal progress, it effectively enhances the sense of skill mastery and enjoyable experience in sports (Mean and Kof, 2023).

In the socialization process of adolescent physical exercise, peer comparison and competition constitute a complex and powerful influencing mechanism. Moderate social comparison can effectively stimulate competitive awareness and performance improvement. When adolescents observe the excellent performance or progress of peers, especially those of similar ability, it often triggers a competitive mindset of “not wanting to fall behind,” leading them to invest more effort to prove their own capability. An experimental study found that in a physical fitness test, the boys' group told to “compete against the class average” performed significantly better in the standing long jump than the control group instructed to “compete only against their own previous performance” (Wang et al., 2022). This moderate upward comparison can serve as an external driver in specific contexts, prompting individuals to step out of their comfort zone. However, the effects of peer comparison show significant gender differences. Multiple empirical studies indicate that male groups generally respond more positively to peer comparisons based on direct competition, and their sports performance shows greater improvement as a result (Quan and Lu, 2020; Zhang, 2021). This difference may be related to the differential socialization of gender roles early on, where society often encourages males more to demonstrate competence in competitive situations. A large-sample survey showed that, after controlling for other variables, having more opposite-sex peers (potentially triggering stronger competition and display motivation) had a significantly greater effect on increasing boys' physical exercise time than girls' (Quan and Lu, 2020). It is noteworthy that peer comparison has a clear “double-edged sword” effect. When comparison becomes excessive or the environment overemphasizes “winner-takes-all,” its positive effects quickly diminish and can even turn negative. For adolescents with lower skill levels or insufficient self-confidence, persistent unfavorable comparisons can easily induce anxiety, frustration, and “learned helplessness,” ultimately leading to decreased motivation for sports participation and withdrawal behavior (Wang and Ye, 2021). Therefore, the key lies in guiding adolescents toward constructive social comparison—focusing on peers' strategies and effort processes for learning, rather than merely comparing outcomes.

In the psychological mechanisms through which peers influence adolescent physical exercise, self-efficacy and enjoyment of exercise serve as key mediating variables, translating external social support into individuals' enduring internal willingness and behavior. According to social cognitive theory, individual behavior is not only influenced by the environment but is also regulated by their beliefs about their own capabilities (i.e., self-efficacy), and peer support is an important source for shaping these beliefs. (1) Peer support is a key pathway to enhancing sports self-efficacy. When adolescents receive encouragement, positive feedback, or even concrete assistance from peers during physical exercise, they are more inclined to believe that they also possess the ability to complete specific sports tasks. A structural equation modeling study targeting high school students confirmed that peer support not only had a direct effect on physical activity level but also produced a significant indirect effect through self-efficacy (indirect effect value = 0.14, p < 0.01; Silva et al., 2014). A student who successfully completed their first 5-km run with peer encouragement shared: “Every time I wanted to give up, my friend would shout beside me, ‘You can do it, you're almost there.' Hearing those words, I really felt I could run a little further” (Xu, 2021). (2) Enjoyment of exercise is the internal lubricant sustaining participation behavior. Peer support and positive interaction can significantly enhance the inherent fun of the physical exercise process. This enjoyment stems not only from the dopamine release during exercise itself but also from the social pleasure and sense of belonging gained in shared activities. When physical exercise is closely associated with positive emotional experiences (such as the joy of cooperating with friends, the satisfaction of being accepted by the team), individuals' intrinsic motivation is greatly stimulated. Research indicates that in team sports, the quality of peer relationships can positively predict enjoyment of exercise, which in turn significantly influences future participation intention (β = 0.32, p < 0.001; Gao, 2013). (3) There is a synergistic enhancement effect between self-efficacy and enjoyment. On one hand, higher self-efficacy prompts individuals to be more willing to try and persist, thereby increasing opportunities for successful experiences and exercise enjoyment. On the other hand, strong enjoyment of exercise reinforces individuals' positive evaluation of their own abilities, further enhancing their self-efficacy. Together, these form a positive psychological feedback loop, allowing the long-term benefits of peer support to be sustained.

Among the psychological drivers of adolescent physical exercise, identity and the need for group integration constitute a deep-seated socio-psychological mechanism. This mechanism is particularly evident in specific groups (such as migrant children, transfer students, or those with weak foundational sports skills), becoming an important force driving their participation in physical exercise. (1) The need for group integration is the initial motivation triggering peer effects. For adolescents facing challenges in adapting to their social environment, participating in peer-led physical activities is an effective strategy for social integration. A panel study focusing on migrant children found that a strong need for group integration was a significant reason for the inverted U-shaped curve distribution of peer effects on their sports participation (β = 0.24, p < 0.01; Ye et al., 2024). In a qualitative interview, a junior high student who had moved to the city with their parents admitted: “When I first transferred schools, I didn't know anything. Going to play basketball with classmates was the quickest way to make friends. Even though my skills were poor at first, I kept going so I wouldn't be left out” (Zhao, 2021). This indicates that in this context, physical exercise transcends its singular function of fitness, becoming a social passport to group membership. (2) Peer relationships indirectly promote sports participation by influencing self-esteem levels. Social identity theory posits that individuals derive self-worth from their group membership. When adolescents are accepted and recognized within a sports group, their overall self-esteem level increases significantly. A study on multicultural adolescents confirmed that peer relationships fully mediated the relationship between self-esteem and group acceptance (effect size = 0.36, p < 0.001; Lee et al., 2022). This self-esteem, reinforced through peer relationships, subsequently translates into more positive attitudes toward sports participation and higher participation frequency. (3) The formation of identity exhibits dynamic developmental characteristics. As individuals deepen their participation in the sports group, their identity undergoes a transition from “instrumental identity” (participating to integrate) to “substantive identity” (participating out of passion). This transition process significantly enhances the stability and sustainability of sports participation. Research found that high school students who participated continuously in sports clubs for over a year had significantly higher levels of identity than short-term participants (t = 3.42, p < 0.01; Zhang, 2023).

In adolescent development research, non-cognitive abilities (such as perseverance, cooperative spirit, responsibility, and emotional regulation skills) have been proven to be important literacies influencing long-term individual development. This study found that peer effects play a key mediating role between physical exercise and the development of non-cognitive abilities, forming a self-reinforcing positive feedback loop. Physical exercise provides an authentic context for the development of non-cognitive abilities. Aspects such as rule adherence, coping with wins and losses, and cooperative coordination in team sports create a natural setting for cultivating perseverance and cooperative spirit. A structural equation modeling study involving 6,067 adolescents showed that peer effects partially mediated the relationship between physical exercise and non-cognitive abilities, with an effect share of 24.5% (Li et al., 2024b). This indicates that physical exercise not only directly promotes the development of non-cognitive abilities but also produces an indirect reinforcing effect through the social mechanism of peer interaction. On one hand, peer interaction is a key mechanism for cultivating specific non-cognitive abilities. In team sports situations, adolescents internalize character traits by observing specific behaviors of peers, such as persistence in the face of setbacks (“Seeing my teammate keep playing after getting injured taught me not to give up easily”) and tolerance during conflicts (“The captain never blames teammates for mistakes but encourages us to do better next time”). This process of observational learning and situational modeling makes abstract qualities like “perseverance” and “cooperation” concrete and learnable. On the other hand, non-cognitive abilities and peer effects form a bidirectional enhancement loop. Individuals with higher non-cognitive abilities find it easier to establish good peer relationships, thereby gaining more opportunities to participate in collective sports activities; rich peer sports interactions further promote the development of their non-cognitive abilities. This finding was verified in a longitudinal study: baseline cooperative ability significantly predicted peer acceptance 1 year later (β = 0.18), and peer acceptance in turn predicted the improvement of non-cognitive abilities (β = 0.26; Mean and Kof, 2023).

In the systematic application of peer effects to educational practice, structured intervention models demonstrate significant advantages. Numerous studies show that well-designed intervention strategies such as cooperative learning, peer tutoring, and peer education are more effective than traditional teacher-centered instructional models in enhancing students' motor skills, social abilities, and participation motivation. First, cooperative learning enhances comprehensive competencies by building positive interdependence. In this model, group members are assigned shared learning goals and clear role divisions, where each individual's success is closely linked to the team's overall performance. A physical education teaching experiment with sixth graders found that students in the cooperative learning situation showed significant improvement not only in social skills and preference for group cooperation (p < 0.01) but also mastered motor skills faster than the control group receiving traditional instruction (Goudas and Magotsiou, 2009). Second, peer tutoring creates a low-threat, high-feedback learning environment. Having peers of similar or slightly higher ability act as tutors can effectively reduce learners' anxiety and provide more timely and comprehensible movement corrections and psychological support. In a tennis skill teaching study, the group using task cards combined with peer teaching achieved skill acquisition effects almost as effective as the teacher-centered model, while better achieving the dual goals of social and motor skill development (Iserbyt et al., 2011). This supports the social constructivist view that knowledge (including motor skills) is constructed more effectively through collaboration and dialogue with peers. Third, peer education utilizes the power of role models to guide behavior and transmit values. When healthy, positive behavioral patterns are demonstrated and advocated by peers rather than authority figures, they are often more persuasive and influential. A “peer education” intervention experiment targeting urban primary school students confirmed that this model not only significantly improved students' sports friendship quality but also effectively enhanced their social adaptation skills (Li, 2013). This suggests that peer education can reach deep-seated attitudes and beliefs that are difficult to influence through traditional instruction. However, the key to the success of structured interventions lies in systematic design. Effective intervention is not simply about grouping students; it requires careful design of task structure, reward mechanisms, and individual accountability. For example, in reciprocal peer tutoring, clear role switching and role definition were proven crucial for improving skill retention (Iserbyt et al., 2010). These design elements work together to ensure the active engagement of every participant, avoid “free-riding,” and thus maximize the educational benefits of peer interaction.

While actively leveraging peer effects, it is essential to clearly identify and systematically mitigate their potential negative risks. Research shows that negative peer relationships and unbalanced social comparisons, if not effectively addressed, can significantly undermine adolescents' motivation for exercise and even harm their mental health. First, negative peer relationships, such as conflict, exclusion, or betrayal within a team, are significant risk factors leading to the discontinuation of adolescent sports participation. A survey of junior high school students showed that students who experienced peer conflict (e.g., being blamed by teammates, isolated within the team) had a 2.3 times higher risk of dropping out of sports activities in the subsequent month compared to those who did not (OR = 2.3, p < 0.01; Zhao, 2021). In a qualitative interview, a student who had quit the school basketball team admitted: “There were always a few people in the team who formed cliques. If you made a mistake, they would look at you with that kind of expression. Later, I felt too much pressure and didn't want to go anymore” (Wang, 2024). The psychological burden caused by such negative social experiences often outweighs the enjoyment derived from the sport itself. Second, over-reliance on peer comparison can turn into a harmful stressor. When the team atmosphere overemphasizes individual ranking and ability competition rather than effort and improvement, it can easily trigger anxiety and fear of failure, especially among adolescents with lower skill levels. A study on the motivational climate of physical education classes found that students in an ego-involving climate (overemphasis on winning and outperforming others) had significantly lower levels of intrinsic motivation than those in a task-involving climate (emphasis on effort and improvement; t = 4.32, p < 0.001; Cox and Ullrich-French, 2010). Third, group heterogeneity may lead to the marginalization of specific individuals. In mixed-ability groups, if the activity design and teacher guidance fail to fully consider individual differences, students with lower skill levels may be unintentionally excluded from the core interaction circle due to their inability to meet the group's skill requirements. An observational study on inclusive physical education classes found that although peer-mediated support increased the activity time of students with severe multiple disabilities, their level of social interaction remained low (Klavina and Block, 2008). This suggests that simply placing students together is insufficient; proactive strategies are needed to foster positive interactions. To effectively mitigate these risks, educational practice should focus on: (1) Strengthening monitoring and guidance of peer relationships, promptly identifying and mediating conflicts; (2) Guiding students to establish a healthy view of competition, emphasizing self-improvement over social comparison; (3) Adopting differentiated grouping strategies and providing multi-level task design to ensure that every student can find their place and value in the group.

The effects of peer influence are not uniform; they exhibit significant heterogeneity across different groups and contexts. Therefore, educational interventions must adopt differentiated guidance strategies based on individual characteristics and specific situations to maximize positive effects while avoiding potential risks. First, the strength of peer effects shows clear gender differences. Multiple studies consistently indicate that male adolescents are generally more susceptible to peer influence in physical exercise. A large-sample regression analysis showed that the peer effects coefficient for boys (β = 0.62) was significantly higher than that for girls (β = 0.41), and the presence of opposite-sex friends had a significantly greater effect on increasing boys' exercise time than girls' (Quan and Lu, 2020). This suggests that in practical applications, interventions for boys could more effectively leverage peer modeling and competitive mechanisms, while for girls, more emphasis might be placed on cooperative and supportive peer relationships. Second, the influence of peer effects varies across different family backgrounds. A study on migrant children found that the strength of peer effects on their sports participation showed an inverted U-shaped curve, influenced by migration distance and duration (Ye et al., 2024). This indicates that for groups with a strong need for social integration, peer effects can serve as a powerful lever for promoting sports participation. Similarly, research on children from multi-child families revealed that sibling physical activity level significantly influenced individual exercise frequency (β = 0.085) and time (β = 0.208), with notable heterogeneity by gender, birth order, birth interval, and athletic ability (Guozhang et al., 2025). This suggests that family-based peer interventions should also consider these structural factors. Third, the effectiveness of peer effects is moderated by individual personality traits and social status. Students with higher self-esteem or social competence can better leverage the positive aspects of peer relationships, while those with lower self-esteem or social anxiety may be more vulnerable to negative peer influences. A study on multicultural adolescents found that self-esteem indirectly promoted multicultural acceptance through peer relationships, but this mediating effect was not significant for students with high social withdrawal tendencies (Lee et al., 2022). This reminds us that for students with specific personality traits, direct peer interventions may not be sufficient, and additional psychological support may be needed. Therefore, differentiated guidance strategies should include: (1) Gender-specific intervention approaches, designing peer activity content that aligns with the social interaction preferences of different genders; (2) Family background considerations, tailoring peer support systems to the specific needs of groups like migrant children; (3) Personality trait matching, providing additional social skill training for students with social interaction difficulties to help them better integrate into peer groups.