1. Introduction and Literature Review
The psychology of sustainability and sustainable development which is relatively a new research of Sustainability Science is centered on the psychological approach in the constructional processes of sustainability and sustainable development, and it unveils psychological factors which are sustainable for individuals and also facilitate their well-being in different environments such as personal, social, and organizational environments [
1]. Specifically, based on the psychology of sustainability and sustainable development perspective in organizations [
2], fostering a healthy team environment can lead to healthy and successful outcomes as well as well-being in team members. As Di Fabio and Rosen stated “opening the black box of psychological processes“ leads to sustainable development [
1], understanding the psychological processes of the team dynamic is essential to ultimately produce optimal outcomes and promote sustainability in teams.
Team communication is critical for sharing information, processing decision-making, providing solutions for problems, resolving team conflicts, and establishing interactional patterns [
3,
4]. In sports, effective instruction through clear communication facilitates athletes’ skill development, confidence improvement, motivation, and satisfaction [
5]. Especially, effective communication between team members (i.e., coaches and athletes, as well as between athletes) enhances team coordination and, in turn, team success [
6,
7]. Communication is also considered a way to build foundations between individuals by sharing thoughts and emotions and to develop a rapport between coaches and athletes [
8]. Effective (or positive) communication is, for example, that coaches use athlete-supportive, encouraging, and motivating verbal and non-verbal languages while communicating with athletes, whereas ineffective (or negative) communication is that coaches use intimidating, criticizing, yelling, and ignoring/disrespectful languages [
5]. Therefore, coaches’ interaction and effective communication between coaches and athletes influences athletes’ development, performance, behaviors, psychological and emotional well-being, motivation, and sport persistence [
9,
10,
11,
12]. Given the open flow of communication in a close relationship, a co-oriented view can be created between coaches and athletes [
13].
The formation of a close relationship based on trust and respect between the coach and athletes is essential for effective communication in order to lead to compatible coach–athlete partnerships [
14]. The nature and quality of the relationship established between coaches and athletes affects athletes’ physical and psychological development, well-being, skill development, and athletic performance [
15,
16,
17]. The relationship quality is also associated with athletes’ perceived training and performance satisfaction, physical self-concept, motivation, and passion [
18,
19,
20,
21]. Various conceptual models of the coach–athlete relationship were developed and examined [
9,
22]. As aforementioned, the open flow of communication results in co-orientation that represents coaches’ and athletes’ shared perspectives such as goals, values, and beliefs [
23]. Shared knowledge and understanding made coaches and athletes appropriately work for each other’s needs, aspirations, and problems [
15,
22]. Communication enables coaches and athletes to develop co-orientation [
24]. Although the original definition of co-orientation focused on relationship members’ perceptual consensus [
25], co-orientation is closely related to effective communication, and previous research on the relationship between communication and successful performance showed similar results [
26]. When coaches effectively communicated with athletes, athletes tried to achieve their goals [
27]. Even though communication is the critical factor influencing athletes and team performance, as these studies illustrated, research examining the relationship between communication between team members and the coach–athlete relationship has been insufficient. Therefore, our first hypothesis was the following:
Hypothesis 1. Communication has a positive effect on coach–athlete relationship.
In relation to communication and coach–athlete relationship, shared trust between team members and team efficacy have been known as factors that help to maximize team function, motivation, and persistence in teams [
28,
29,
30]. Team efficacy is shared confidence within a team to successfully accomplish collective tasks [
31], and it is also considered individual perceptions in a team toward the team’s capabilities [
32]. Team efficacy is a crucial factor that influences team success [
33,
34]; research on team efficacy has been rare and limited in the sport psychology discipline. Team performance (achievement) especially can be enhanced by strengthening communication, cohesion, and skill usage. Successful experience also has a positive influence on team efficacy [
35,
36]. Additionally, communication is known to be a critical factor in predicting team efficacy between athletes and coaches [
37]. Positive communication during competitions contributed to increased team performance [
38]; whereas, negative communication was an obstruction for teams [
39]. Moreover, the coach–athlete relationship as a psychological construct reflects social interpersonal nature and interaction within sport teams [
40], and the quality of the coach–athlete relationship is directly and indirectly linked to collective efficacy [
40,
41,
42]. The coach–athlete relationship is how athletes perceive their relationship with their coaches. As an antecedent of team efficacy within sport teams [
35], Jowett et al. [
40], for example, found that athletes’ perception on the relationship with their coaches positively influenced team efficacy. Therefore, we hypothesized as follows:
Hypothesis 2. Communication has a positive effect on team efficacy.
Hypothesis 3. Coach–athlete relationship has a positive effect on team efficacy.
In competitive sport situations, athletes often experience negative emotions (e.g., anxiety, frustration, and anger) which hinder optimal performance and team success. Recently, aggression has been the focus of attention because of its ability to influence the mental and physical health of athletes. Aggression that consists of anger and aggressiveness (i.e., aggressive behavior) can even cause critical issues such as serious injuries which may terminate athletes’ careers [
43,
44,
45]. The aggressiveness appearing in adolescence tends to lead to school maladjustment such as low academic achievement or dropout and predicts the involvement of antisocial behavior or crime in adulthood [
46]. Sport psychologists and sociologists have examined the concept of aggression and the relationship between aggression and other related factors (antecedents and consequences). In early research, aggression was defined as behaviors with intentions to harm another person physically and psychologically [
47,
48]. In addition, athletes’ aggression was defined as intentional behaviors aiming to harm opponents physically and psychologically whether it was socially acceptable or not [
49]. To explain aggressive behaviors more clearly, various personal, emotional, and social variables also need to be studied together [
50,
51,
52]. Studies showed male athletes experienced greater competitiveness and less empathy than female athletes, and thus male athletes generally scored higher on aggression than female athletes scored [
53,
54]; however, Keeler [
55] reported there were no significant gender effects on aggression after controlling for basic demographic variables. Effective communication between coaches and athletes in competitive sports significantly influenced athlete aggressive behaviors during games [
56]. For example, coaches’ verbal aggressiveness was negatively related to athletes’ intrinsic motivation, effort, and competence, and positively associated with anxiety [
57]. In line with social learning theory [
58], previous research indicated that athletes learned aggression from observation and indirect experiences from aggressive behaviors of coaches and peer athletes [
59]. Young athletes also learned aggression through observing and modeling adult athletes who achieved their goals by aggressive behaviors [
60]. Intriguingly, athletes in team sports (especially physical interactional sports such as rugby and soccer) showed a more aggressive disposition compared to athletes in individual sports [
61]. In this perspective, immoral team environment and coaches’ behaviors may influence aggressive behavior in athletes [
62]. Hodge and Ronsdale [
63] reported that athletes who had good relationships with their coach showed less antisocial behavior and more social behavior. Aggression is a team problem as well as an individual problem [
64]. Another study illustrated that aggression was an important factor for the belief of team efficacy [
65]. Furthermore, the potential aggression of athletes in team sports influenced their emotions, team environment, and performance negatively, and consequently, it could intimidate positive values and functions of sports [
66]. While team efficacy is one of the important antecedent factors influencing the aggression of athletes, in many studies, the relationship between team efficacy and aggressive behavior has not been examined empirically. Therefore, we hypothesized as follows:
Hypothesis 4. Communication has a negative effect on aggression.
Hypothesis 5. Coach–athlete relationship has a negative effect on aggression.
Hypothesis 6. Team efficacy has a negative effect on aggression.
Importantly, researchers [
67,
68,
69,
70,
71] have reported effective communication is one of the key factors to build strong social cohesion (i.e., interpersonal relationship) between coaches and athletes and between athletes and athletes, increase collective efficacy, help athletes regulate their negative emotions and behaviors such as anxiety and aggression, and finally contribute to team success and sustainability. Identifying factors related to aggression is essential to manage the various aggressive behaviors in sports situations and prevent athletes from serious injuries. However, only limited research has been conducted to examine the relationships among the variables, and no study has tested the variables simultaneously. Thus, the primary purpose of this study was simultaneously to investigate how team communication, team efficacy, and coach–athlete relationship influence aggression in order to reveal fundamental information for decreasing athletes’ aggression level. The hypothesis of the current study is as follows:
Hypothesis 7. Communication has an indirect effect on aggression mediated by coach–athlete relationship and team efficacy.
4. Discussion
The research results related to team sports indicated that effective communication has a positive influence on performance and competition results by improving the quality of the coach–athlete relationship and team efficacy and by decreasing aggression. In addition, recent coach–athlete relationship studies focused first on relational approaches in which coaches and athletes perceived themselves mutually in a friendly way, and second on the psychological influences of coach–athlete relationship. However, these studies suffer some limitations because they only considered an individual approach without group processes. Therefore, this study examined the effect of communication on aggression, with the coach–athlete relationship and team efficacy as mediating factors.
First, communication had a significant positive association with coach–athlete relationship (Hypothesis 1). This finding is consistent with previous studies that indicated the importance of communication on building and maintaining the quality relationship between coaches and athletes [
8,
9,
13,
14,
22,
23,
24,
25]. This finding is also well supported by the four stages of the linear group development theory, which states that a team goes through four stages to be an ideal team and that subjective and open communication is a key that can resolve conflicts, replace hostility with solidarity and cooperation, and stabilize interpersonal relationships [
53]. Carron et al. [
28] reported that team communication is necessary for the development of team structure and team maintenance. Furthermore, they suggested that decision-making, goal-setting, cooperation, team building, position, leadership, and conflicts in the team are also related to team communication [
28]. Athletes especially perceived the evaluation of coaches and the effects of training differently depending on the communication style of the coaches. In other words, athletes prefer coaches who talk comfortably with consideration for the athletes while communicating. It also makes athletes believe that their training is more effective.
Second, communication had a significant positive relation to team efficacy (Hypothesis 2). This finding supports the previous research finding that effective communication among team members increased self-efficacy and collective efficacy and in turn performance [
78]. The critical factors of team success are team communication, team cohesion, and skill enhancement [
32]; thus, team outcomes can be improved or decreased by these factors. If team members do not communicate well within the team, the team members will not be cohesive and cooperative emotionally. As explained by the shared mental model [
79,
80], the result of effective verbal and non-verbal communication enables team members to build strong shared trust on performance ability and team work, anticipate one another’s behaviors, and coordinate their actions. Therefore, team members, including athletes, should communicate with each other consistently and effectively for team cohesion, team efficacy, and consequently team performance.
The coach–athlete relationship had a positive influence on team efficacy (Hypothesis 4). Recent studies on the coach–athlete relationship [
40,
81] emphasized on the two-way communication with a relational perspective. In team sports, trust between team members should be shared to achieve team goals. In addition, the coach–athlete relationship is important, as well as building trust between athletes during training and competition. With a qualitatively facilitated coach–athlete relationship, team members can have strong team cohesion and team efficacy. In the sport field, coaches and athletes are strongly emphasized to interact consistently. The coach–athlete relationship is an important factor that determines team cohesion, team efficacy, and team success (team performance). According to Jowett et al. [
38], the interpersonal factor was divided into the coach–athlete relationship and team cohesion. Additionally, they reported that the coach–athlete relationship had more influence on team efficacy than team cohesion.
Team efficacy had a negative influence on aggression (Hypothesis 6), whereas coach–athlete relationship was not significantly associated with aggression (Hypothesis 5). Both findings were consistent with previous research showing there was insignificant association with the relationship between teacher–student relationship and aggression but significant association with the relationship between student–student relationship and aggression [
82]. In previous studies [
76,
83], team efficacy was influenced by significant others such as coaches, team captain, and leading players. We can easily observe and experience the situation that athletes in sports team are trying to become cohesive by shouting “We are one team, and we can do it.” In this situation, the cohesion of the team increased. Therefore, aggressive behaviors during games decrease when players understand the importance of team cohesion and have fewer negative conflicts with other players.
Lastly, communication had a significant indirect effect on aggression mediated by coach–athlete relationship and team efficacy supporting Hypothesis 7. This study emphasized the importance of communication between coaches and athletes as the main factor and coach–athlete relationship and team efficacy as the mediating factors that control aggression in athletes. As Hypothesis 4 as well as Hypothesis 7, we expected to have partial mediation effects. That is, communication would have a direct association with aggression and an indirect association with aggression through coach–athlete relationship and team efficacy; however, communication was not significantly associated with aggression. The meaningful pathway that was found confirmed indications that effective communication enhanced the quality of the coach–athlete relationship, team efficacy, and consequently decreased athletes’ aggression. This supports previous research which found that fostering sustainable social environment decreased aggression [
82].
There are several limitations to generalize the current findings. First, this study used a cross-sectional design to collect the data to examine the mediation effects of coach–athlete relationship and team efficacy on the relationship between communication and team efficacy. Because the data were collected only once, the results cannot provide clear causal relationships among variables in this study. Although aggression is generally considered more of a personality trait, it is possible that athletes may have higher levels of aggression during season than off season. Thus, a longitudinal approach to examine the relationship between communication and aggression with mediating variables should be conducted in future research. Second, this study did not analyze the data by sex (e.g., male vs. female), age (e.g., middle school, high school, and college), or sport types (e.g., collision type vs. contact type vs. non-contact type sports) because of the small sample size per group for the invariance test. For example, males from general psychology are usually more aggressive than females, but that is not always true. The results of the gender effects in a specific sport context are still equivocal. Therefore, future research should have enough sample size per group for the invariance test in order to find effects of moderating variables on the relationship between communication and aggression.