Physical inactivity and a sedentary lifestyle have been major health issues due to their incremental disadvantages to one’s wellbeing. This has been made worse by the recent COVID-19 crisis, which imposed home quarantines and restrictions on public activities and gatherings. Staying and working at home increases screen time and deskbound activity, resulting in decreased physical activity levels ^[1]. Moreover, it is common that physical activity declines at a high rate in adolescence and young adulthood ^[2][3]. Rowland ^[2] explained that the reasons for one’s declined physical activity can be intrinsic and biologically driven as “the result of a fall in central drive as well as other biological factors, such as decreasing skeletal muscle mass in older years” (p. 3). Besides biological and intrinsic barriers, extrinsic factors affecting physical activity levels are also influential. These extrinsic factors often navigate people away from physical activity in real-world situations. This is particularly true for females who are further stressed out by social pressure ^[2]. Additionally, convenient lifestyles and technological advancement indirectly encourage sedentary behaviours among young adults. Activities related to commuting, working and leisure involve significantly less physical activity now than before.

The positive and negative impacts of physical activity and inactivity are incremental in nature. “It has been recognised that most diseases affected by exercise are a result of life-long processes, surfacing clinically in older adult years” ^[2] (p. 2). A systematic review of longitudinal studies for the years 1996 to 2011 concluded a correlation between sedentary behaviour with a high risk of mortality in later ages, including those related to CVR, hypertension, symptomatic gallstone, site-specific cancers (ovarian, endometrial and colon), diabetes and even mental disorders ^[4]. A consistent relationship between sedentary behaviour during adolescence and weight gain or obesity in adulthood was also identified. Correspondingly, a sedentary lifestyle during adolescence would increase cardiometabolic risk in adulthood and vice versa ^[5].

Furthermore, a sedentary lifestyle can also lead to anxiety and depression ^[6][7]; when the level of physical activity falls, depressive symptoms experienced by a person increase ^[8]. Conversely, being physically active improves one’s mental health by reducing depressive symptoms. Being physically active during adolescence could also lower the risk of having depression symptoms throughout adulthood, up to the age of 62 ^[9]. This has given rise to recent research interest in health promotion and the wellbeing of employees at work, influenced by mental and physical health factors ^[10].

Based on self-determination theory (SDT), motivation, also referred to as ‘the why of behaviour’, serves as why an individual performs an activity ^[11][12][13]. In day-to-day life, identifying the motivations of one’s action or behaviour is never straightforward; it is often caused by a combination of multiple inseparable motives operating as one entity. Motivations differ in their degree or level (how much motivation) and orientation (what type of motivation) a person exhibits. In the most basic SDT categorisation, motivation is divided into extrinsic motives and intrinsic motives. These two classifications of motives have been used in many psychological studies exploring ‘the why’ of various actions and behavioural intentions, including those about exercise intention. For instance, there are studies on physical activity and its motivations via self-determination theory ^[13], intrinsic versus extrinsic motivation in sport by Vallerand and Losier ^[11], extrinsic motivations in exercise adherence by Ednie and Stibor ^[14] and studies that incorporate a variety of motivational items that can be categorised into intrinsic or extrinsic motives ^[15][16][17]. The theory of the social comparison process, also known as social comparison theory, was established and developed by Leon Festinger ^[18]. In developing this theory, Festinger posited that a person chooses someone who has similar abilities or opinions for the purpose of comparison. Self-evaluation and social comparison naturally lead to a discrepancy in opinion and level of ability and cause pressure among members of a social group to reduce this difference. In the theory of the social comparison process, movements towards uniformity of abilities would be adequate by influencing members whose performance is lower and changing their value to be in line with their superior’s ability and, thus, increase their motivations to ‘drive upward’ ^[18][19]. Upwards comparison requires role models or agents to provide hope and inspiration who are often persuasive ^[19][20][21]. This new upwards direction led to the formulation of the new concepts of social comparison, including self-enhancement and self-improvement, which are significantly linked to assimilation to the upwards target. Assimilation has been previously studied under the idea that one could obtain the same upper status of the upwards target by psychological closeness, leading to the identification of the comparison target ^[20]. In social identity theory, ‘the self is reflexive. It can take itself as an object and categorise, classify, or name itself in particular ways concerning other social categories or classifications’ ^[22] (p. 224). In facilitating the social categorisation process, the social comparison process is prominent, especially for grouping those similar to the self as the in-group and those who are different from the self as the out-group. This process results in accentuating the perceived similarity among the in-group members and the perceived differences among the out-group members ^[22][23]. When a person defines themselves according to the social identity of a particular group, they attempt to align their behaviour with the group members’ behaviours ^[24]. In other words, self-categorisation or identification with a particular social group verifies one’s identity by looking similar to other members in the group and perceiving traits from the group’s perspective. Moreover, it also depersonalises an individual’s self-perception as one embodiment of the in-group prototype ^[22]. It assimilates “ones’ attitudes, feelings and behaviours to the in-group prototype” ^[23] (p. 187). Through depersonalisation, the in-group members develop the values of cohesiveness, inclusiveness, altruism and collectiveness, resulting in improved self-esteem and self-worth ^[22][25]. In sports psychology, social identity treats features of the sporting context as elements that can be integrated into one’s sense of self and turn them into a sport-related behaviour ^[26]. For instance, the members of a specific fitness group and fitness trainers mutually verify the features of ‘regular exercise’ and ‘healthy diet’ ^[27][28] and foster togetherness and belongingness among its members, and this often becomes the benchmark of their social identity and their prototype. When the newbies conform to the prototype and successfully verify their social identities, they are accepted as a part of this fitness social group, enhancing their self-esteem and leading to identification and assimilation of the group’s social identity as their one integral and communal identity ^[25]. Once the in-group identification is achieved, each member develops strong attraction, greater commitment and loyalty to the group ^[22]. Since identification fortifies an intragroup’s prototypicality, it would also concurringly support the influence possessed by the most prototypical member. As members cognitively and behaviourally follow the group’s prototype, they would automatically agree and comply with the verbal messages conveyed by the most prototypical member, creating a status-based differentiation between a leader and their followers ^[23]. Therefore, given that a ‘fit body’ is a prototype in the fitness group, a fitness trainer who is the most prototypical member (a member who has the fittest physique) is viewed as a leader who has the most influence on their group’s members.

2.1. Appearance and Weight Management Motives to Exercise

For the identification to happen, a gym-goers’ motivation to exercise must also be considered. Extrinsic motives to exercise refer to exercising motives that are driven by external reward and influence. They are generally described in terms of their fundamental characteristics subject to external and separable outcomes, whether a tangible reward, avoidance of punishment, avoidance of feelings of guilt/shame, attainment of recognition/approval or any combination of these characteristics ^[13]. Extrinsic motives to exercise are widely identified as the most common motives for novice exercisers or newbies ^[29]; they are also referred to as the most compelling motives for initiating exercise ^[30]. Among those extrinsic motives to exercise, health and appearance-related goals are repeatedly rated as the highest two ^{[14][15][16][17]}. Health has been used as an alibi and endorsement for appearance and weight management goals ^[27][31]. “A notion of health/fitness … was about maintaining a balance of food and exercise to achieve a slim body shape” ^[32] (p. 711). A physically fit and attractive fitness trainer is also perceived to be in their best health by gym-goers ^[33]. Due to the misleading association of health goal to weight management motive, in this discussiontudy, health motive is excluded, leaving only two motives, i.e., appearance and weight management motives. In addition, the inclusion of appearance and weight management motives in this research is because these two motives are “central to personal trainers’ construction of the service that they offer to their clients” ^[27] (p. 27).  Furthermore, prior research into exercise motivation suggests that gym-goers who are motivated by appearance and weight management goals are more subjected to self-objectification and have relatively low body satisfaction, body esteem and self-esteem, especially for women ^[28][34][35]. According to self-determination theory (SDT), appearance and weight management motives are categorised under external regulation and introjected regulation, the two most minor self-determined forms of extrinsic motivation. In an effort to improve their self-esteem and find a remedy for self-disapproval, appearance- and weight management-driven gym-goers were then predicted to socially compare and identify with a physically attractive fitness trainer and then persuade them to sign up for an exercise program offered. 

2.2. Gender Influencing Gym-Goers’ Preferences over Appearance and Weight Management Motives

Gender-specific characteristics could affect people’s behaviour, daily activities and relationships, including those within the physical activity domain. In the history of sports psychology, extrinsic exercise motives, especially those related to motives in appearance enhancement, attractiveness boost and health maintenance, have been associated with women ^[34][36]. A study of college students’ motivation for physical activity identified that college women had “greater concerns regarding their body weight than men” ^[15] (p. 93). Women with higher body mass index (BMI) would exercise to lose weight ^[37]. Polman ^[38] also supported the finding that women’s body composition affected their satisfaction, making them prefer weight management as their top exercise motivation. Women are 2.4 times more likely than men to choose appearance goals as their exercise motive ^[30]. As for men, they are more likely to view physical activity as a means to pursue ego-related outcomes, such as their show of mastery and competence. “Men reported higher levels of motivation … for a challenge, competition, social recognition, and strength and endurance” ^[15] (p. 54). Similarly, Ednie ^[14] found that men’s higher ratings on their exercise motives are enjoyment, challenge, competition and social motives. Women’s appearance and weight management motives are related to what society and culture perceive as a beauty standard—women’s beauty is equal to a slim and slender figure. Society and culture pressure young women to be overly concerned about their body size and weight. Moreover, “females are highly influenced by others, including society, and their gym participation is due to pressure as opposed to desire” ^[34] (p. 13). Similarly, Anić et al. ^[37] found that women influenced by appearance and weight management motives are significantly influenced by sociocultural pressure as well as appearance idealisation ^[37]. Women tend to be more motivated by appearance and weight management motives, often because of their high motivation, low perceived competence, low task orientation and low incremental beliefs ^[39]. As a result, they resort to external stimulation such as fitness trainers’ physical attractiveness as their motivation to exercise ^[29][40]. Hypothetically, given that women would be more motivated by appearance and weight management motives, they would be more possibly convinced to sign up for an exercise program offered. 

2.3. Age Influencing Gym-Goers’ Preferences over Appearance and Weight Management Motives

When it comes to exercise motivation, various prior studies have focused on exercise adherence besides exercise intention ^{[11][13][14][15][41]}. It was found from preliminary research that young adults appreciate and value physical attractiveness substantially more than middle-aged adults and elderly adults. Thus, they are more motivated by appearance and weight management goals as ways to enhance their own physical attractiveness. Furthermore, Caglar et al. ^[17] found that motives related to appearance are one of the most important motives for exercise among participants aged 21 to 24-years-old. In line with this, Kilpatrick et al. ^[15] also discovered that among the top three motives of college students for physical activity, appearance and weight management motives dominated them. In the study of Brunet and Sabiston ^[41], a significant positive correlation was also found between introjected regulation and physical activity for young adults, reflecting on the body image concerns and self-imposed pressure in obtaining or maintaining a desired physical appearance among young adults. The elderly care more about their health, mental wellbeing and extending their lives ^[30][42] than their appearance and physical attractiveness. This motivational pattern related to the elderly is also supported by a qualitative study by Rotwein ^[43]. The study found that people above 40 years old would strive to improve their quality of life and stay healthy. Appearance objectives such as losing weight and becoming toned are no longer their main focuses. Theoretically, young adults are more motivated by appearance and weight management motives and, hence, could be easily persuaded to sign up for an exercise program offered. 

2.4. Self-Identification with Physically Attractive Fitness Trainers

A great physique of a trainer is a reflection of the professionalism and their projection as a good role model and exemplar ^[28]. In a fitness group, a great physique of a physically attractive trainer represents their quality as the most prototypical member who has an influential impact on other members. This is because members of a particular fitness centre would attempt to conform to this prototype of a fit physique. This justification is also supported by prior studies that found that gym-goers’ preferred body type is often similar to their instructor’s figure, indicating they wish to have a physique similar to their instructor’s body ^{[29][40][43][44]}. Gym-goers’ identification with a physically attractive fitness trainer begins with socially comparing themselves with a physically attractive trainer. The social comparison process in the fitness environment is related to evaluating ability that would instigate self-improvement motive; this comparison process is also known as an upwards comparison. In the study on social comparison among fitness app users, upwards fitness comparison with higher performers elevates users’ self-efficacy and motivation to exercise, ultimately resulting in their participation in physical activity ^[45]. An alterable state of one’s appearance would cause a temporary improvement in self-perception, self-esteem ^[46] and self-efficacy ^[45]. In other words, if gym-goers believe that they could improve their appearance to compete with their physically attractive fitness trainer, the comparison can be uplifting, and their reaction to the comparison would not be negative. “The more easily improved a body part is perceived to be, the less likely a comparer is to feel negatively as a result of the comparison” ^[46] (p. 61). After comparing themselves with a physically attractive trainer, gym-goers would identify with the trainer as their idol and role model. Identification is motivated by the disinhibitory effect, whereby gym-goers repeat a similar action or exercise regime given by a fitness trainer expecting that they can have an attractive physique and fitness appearance of the trainer. Interestingly, social comparison to a superior other, including a physically attractive fitness trainer, evokes self-inferiority and self-dissatisfaction. Exposing gym-goers to a physically attractive fitness trainer as the attractive model would lower their self-image and evoke a feeling of dissatisfaction while simultaneously presenting the product (exercise program offered) as a relief or remedy from those negative emotions ^[47]. Self-inferiority and dissatisfaction, triggered by social comparison to a physically attractive fitness trainer, are more likely to be gym-goers driven by appearance and weight management motives. Gym-goers’ incentives for seeking a trainer often originated from the negative force due to their frustration because they failed to attain their desired physique or fitness appearance ^[44]. Through this identification process, gym-goers who are driven by appearance and weight management motives could be convinced to sign up for an exercise program, leading to their exercise intention.