Despite overwhelming evidence of the health benefits related to regular exercise participation [1
], the majority of U.S. adults do not meet physical activity guidelines [3
]. The World Health Organization [5
] and US Department of Health and Human Services [6
] recommends adults engage in aerobic activity for at least 150 min at moderate intensity or 75 min at vigorous intensity each week, in addition to incorporating resistance training on at least two days of every week. Many adults cite a lack of time and enjoyment as primary barriers to engaging in consistent and effective exercise routines [7
]. A potential solution that provides fitness and health improvements in less time per week than current guidelines is a relatively new method called high-intensity functional training (HIFT) [8
]. HIFT is a “training style [or program] that incorporates functional, multimodal movements, performed at relatively high intensity, and is designed to improve parameters of general physical fitness and performance” [9
Studies comparing HIFT-style workouts to repetitive aerobic exercises (e.g., jogging, using an elliptical machine) found HIFT elicits greater lean muscle mass, thereby improving cardiovascular endurance, strength, and flexibility [10
]. Further physical benefits of HIFT include improvements in maximal oxygen consumption [11
], decreases in body fat [11
], as well as improvements in bone mineral content [13
]. In addition to physical health benefits, investigators have reported higher levels of enjoyment among group-based HIFT participants than those engaged in more traditional resistance training programs [8
], which facilitates initiation and adherence to exercise [9
]. Based on its associated health benefits compared to traditional aerobic exercise, coupled with a reduction in time required to achieve these benefits, HIFT could be an ideal exercise modality to promote among US adults.
Most studies investigating HIFT have involved CrossFit workouts [8
], which use group-based HIFT to combine aerobic and resistance exercises that focus on functional (multi-joint) movements within a group-exercise environment. CrossFit members participate in a “workout of the day” (WOD) in a class-based format, where coaches explain the WOD and attend to participants throughout the workout, with opportunities to modify or scale exercises accordingly to fitness and skill level [16
]. Previous research suggests group-exercise environments are often more effective in delivering health benefits, such as enhanced mental health [17
], improved sense of community and belonging [15
], and greater enjoyment and adherence to exercise [19
] when compared to independent exercise. Studies show similar effects among CrossFit participants, with evidence that CrossFit can be a supportive social environment for its members, providing them social capital and support that facilitates physical and mental health benefits [15
]. For example, a recent qualitative study on CrossFit members and coaches showed people who are initially intimidated by CrossFit-style workouts overcome their initial fears and develop greater enjoyment of HIFT over time, in large part due to the supportive social environment and ability to self-select their intensity during workouts [19
According to previous research, a key factor related to someone’s affinity for, and ultimately enjoyment of, HIFT is a preference for and tolerance of high-intensity exercise [22
]. According to Ekkekakis and Petruzzello [24
], preference for exercise intensity is defined as a “predisposition to select a particular level of exercise intensity when given the opportunity (e.g., when engaging in self-selected or unsupervised exercise),” while tolerance of exercise intensity is defined as “a trait that influences one’s ability to continue exercising at an imposed level of intensity beyond the point at which the activity becomes uncomfortable or unpleasant” (p. 354). In other words, tolerance for exercise intensity relates to a type of resilience when engaging in HIFT, while preference is representative of an individual’s choice to stay above an intensity threshold [25
Most research concerning the preference for and tolerance of high-intensity exercise has been conducted on independent exercisers [22
]. In these studies, preference and tolerance are described as dispositions that go unchanged despite someone engaging in more exercise or experiencing fitness improvements. For example, Hall and colleagues studied 42 firefighters involved in a six-week training program. At the end of the program, despite reporting improved fitness scores (e.g., 1-min repetitions of pushups and sit-ups, 1.5 mile run time), preference and tolerance scores did not increase significantly among the firefighters, supporting the notion that preference and tolerance scores are a stable disposition [27
]. However, there is some evidence that suggests self-selecting intensity levels during workouts can improve tolerance levels for exercisers [28
], revealing the possibility that environmental factors (e.g., self-selecting intensity) may work to optimize a person’s preference and tolerance.
The association between the social environment and preference and tolerance remains unstudied, with the potential for preference and tolerance scores to drive social connections created within CrossFit networks, along with the possibility for social connections to influence someone’s preference and tolerance scores. Specifically, we aim to explore the possibility of social selection, social influence, and social context relative to preference and tolerance scores. Social selection eludes to the propensity for people to connect with others they are similar to on a given trait or characteristic [31
], indicating a characteristic (e.g., preference and tolerance) ultimately prompts the social connection between two people, and therefore serves to drive social connections. Contrarily, social influence suggests people become more like their social ties over time, meaning the social connection prompts changes in the outcome or characteristic so that two people become more alike [33
]. Finally, social context refers to the simultaneous development of similar characteristics due to the influence of the shared environment [32
]. Given the evidence that the social environment of group-based HIFT programs yields similar outcomes for participants as preference and tolerance (i.e., enjoyment, adherence) [10
], we wondered if the preference and tolerance scores of CrossFit participants might be associated with social selection, social influence, and/or social context.
Therefore, the purpose of this study was to assess the social environment of CrossFit relative to preference and tolerance scores among members. Specifically, we tested whether preference and tolerance scores were associated with the presence of social ties within CrossFit networks, as well as whether preference and tolerance scores of one’s social ties correlate with their own preference and tolerance scores. Thus, we answered two major research questions in this study:
Do the preference and tolerance scores of a person’s social connections relate to their own preference and tolerance scores after controlling for other factors including demographic information, duration of time as a CrossFit member, weekly class attendance rates, depressive symptoms, personality, and sense of community variables (i.e., is there evidence of social influence on preference and tolerance scores among CrossFit members)?
What individual and social factors, including preference and tolerance scores, are associated with social connections present within CrossFit networks?
The purpose of this study was to explore the social environment of CrossFit relative to preference and tolerance scores among members. After conducting social network analyses on three gyms, we provide evidence that the preference and tolerance scores of individuals relate to the preference and tolerance scores of their social connections, suggesting the possibility of social influence. Further, we found preference and tolerance scores were important in explaining the social connections present within CrossFit gyms in varying ways.
4.1. Social Environment → Preference and Tolerance
This is the first study (to our knowledge) suggesting a relationship between the social environment (e.g., social connections, sense of community) and preference and tolerance scores among exercisers. While our findings are cross-sectional and would need follow-up data to provide more concrete evidence, we did find network effects related to preference and tolerance scores in all three gyms. These network effects could be due to social selection, social influence, and/or social context. In this case, social selection could result in people naturally connecting with CrossFit members who scored similarly on the PRETIE-Q. Contrarily, people’s preference and tolerance scores could be socially influenced by those of their peers, and therefore a person’s preference and tolerance scores adjust to mirror that of their social connections. Finally, as athletes are exposed to similar HIFT workouts, coaching, and social support within their social context, they could develop connections with others and build preference and tolerance for the workouts at the same time, resulting in similar preference and tolerance scores across ties within the network.
Previous literature defines and assumes preference and tolerance are fixed/stable traits [23
], and therefore lend more support to the social selection hypothesis over social influence or social context, given the latter two assume the ability to develop preference and tolerance over time. However, the LNAMS in this study, which measures preference and tolerance as dependent variables, provides evidence for the possibility of social and contextual influence on preference and tolerance scores [54
]. One explanation could be that even though preference and tolerance are dispositional characteristics, where certain people are predisposed to higher preference for and tolerance of high-intensity exercise than others, social and environmental factors create opportunities to express or manifest preference and tolerance differently than someone’s predisposition—sometimes referred to as intraindividual variability
]. Research by William Fleeson [61
] shows that the manifestation of personality traits, notably the Big Five (i.e., extraversion, agreeableness, conscientiousness, emotional stability, and openness to experiences), are contingent on situational factors, and that the intraindividual variability related to personality traits adjusts from situation to situation. For example, people might display more extraversion when connected to more extroverted people, or when immersed in a more social type situation. Though extraversion is a personality trait, the manifestation, or expression, of that trait becomes malleable given the situation [60
]. Given most of the evidence that supports preference and tolerance as a stable trait has been conducted within an individual- versus group-exercise environment (e.g., running on a treadmill), it could be that someone in the CrossFit/group training environment (i.e., situation) might experience and express preference and tolerance differently than when exercising individually, particularly as someone connects with those who have higher preference and tolerance scores. These findings support other research that shows group-based exercise modalities, including yoga, bootcamp group workouts, and indoor cycling, can be more beneficial to a person’s health than individual/solo exercise due to the social environment available [17
]. Longitudinal research is needed to further parse the impact and relative importance of social influence, social context, and social selection.
In addition to network effects, sense of community variables were related to preference and tolerance scores, providing further evidence for the role of the social environment in explaining preference and tolerance. Specifically, administrative consideration and common interests were two SOC factors related to preference and/or tolerance in two gyms. Administrative consideration refers to the care, support, and intentionality displayed from coaches to members within CrossFit [52
]. Receiving this direct care and support, particularly in a HIFT-style workout, might help a person develop a stronger preference and tolerance for this type of exercise. Common interests describe commonality and belonging among CrossFit members. The relationship between common interests and preference and tolerance may support the selection hypothesis from above, in that, preference and tolerance may be a common value, or an interest shared between people, driving them to connect and relate.
The only demographic/background and personality trait variable related to preference and tolerance scores across multiple gyms was conscientiousness. Conscientiousness is defined as the tendency for an individual to follow socially prescribed norms for impulse control, to be goal-directed, to be planful, to delay gratification, and to follow norms and rules [65
]. Conscientiousness has been linked to longevity [66
], exercise behaviors [67
], and overall better health [65
], notably due to a person’s tendency toward achievement and order [66
]. Research has also associated grit, or the perseverance and passion for long-term goals [68
] with both conscientiousness and high-intensity exercise [69
], which could be aspects of both preference and tolerance.
4.2. Preference and Tolerance → Social Connections
Exponential random graph models (ERGMs) using preference and tolerance scores as independent variables suggest preference and tolerance could be related to increased odds of social connections present within CrossFit networks. Specifically, people with similar tolerance scores (i.e., homophily based on tolerance) were more likely to connect in gyms 1 and 3. Additionally, tolerance scores were negatively related to incoming ties in all three gyms, meaning people with higher tolerance scores were less likely to be nominated in this study. These results support the social selection hypothesis as a likely reason for tolerance homophily, given the higher likelihood of two people with similar tolerance scores having a connection (i.e., selecting one another due to shared tolerance levels), while also having a lower likelihood of receiving many nominations, thus limiting their potential influence on others due to a smaller in-degree [70
]. Qualitative studies indicate people have a tendency to be intimidated by CrossFit and high-intensity exercise, especially when they are newer to HIFT [15
]. This could explain why those who demonstrate higher tolerance might receive less social connections—they could be intimidating due to their ability to tolerate higher intensity workouts.
While homophily based on tolerance was positively correlated with social ties across multiple gyms, the direction of the relationship between homophily based on preference and social ties varied from gym to gym. In Gym 1, having similar preference scores was negatively correlated with social connections, meaning people who scored similarly on the preference items of the PRETIE-Q were less likely to connect within this particular gym. Contrarily, in Gym 3, having similar preference scores was modestly related to a tie existing. Similarly, preference scores were positively related to outgoing ties in Gym 1 (i.e., people who had higher preference scores were more likely to nominate others in Gym 1), but negatively related to outgoing ties in Gym 3. Once again, the direction of the relationship between preference and social ties is inconsistent across gyms. Given the LNAMs reported earlier demonstrated consistent network effects related to preference scores when treated as the dependent variable, but the ERGMs were inconsistent in providing evidence of a relationship between preference as an independent variable and social connections, it could be more likely network effects related to preference are based on social and contextual influence, rather than selection [32
], where social ties/the social environment prompt changes in the characteristic, rather than the characteristic prompting the creation of the social tie.
Overall, these findings suggest tolerance may have a more stable association with social connections across gyms, particularly as a possible driver behind social connections within CrossFit networks. Preference scores had more varied effects from network to network, and therefore may not be as prominent in driving social connections within CrossFit gyms. Additional research is needed to determine if preference and tolerance have similar associations with social connections as they did in this study.
In addition to preference and tolerance, structural variables, background/demographic variables, and SOC variables all helped explain the odds of social connections existing within multiple gyms. Structurally, reciprocity and transitivity were both associated with the presence of ties in all three gym networks. This suggests social connections created within CrossFit tend to be mutual (versus unidirectional), and members tend to have “friends in common” with their social ties, which often results in a highly clustered network with dense communities of people within the network. Reciprocity and transitivity both indicate a cohesive and strongly bonded network that could aid in long-term adherence to CrossFit [72
Demographically, gender and age were related to the presence of ties in multiple gyms. Similar to previous literature, gender homophily was associated with social connections in gyms 2 and 3, meaning people of the same gender were more likely to connect with one another at CrossFit [74
]. Like preference, age was also related to tie presence, but the direction of the relationship varied from gym to gym. In Gym 1, older participants were more likely to be connected with other members in their network, whereas in Gym 3, younger participants were more likely to be connected with others in their network, although the effect size is quite small in Gym 3. In Gym 1, it is possible that since the mean age is 25 years, some of the central people in the network (e.g., coaches, long-standing members), might be older, and therefore have more established connections in the network. Similarly, in Gym 3, where the mean age is slightly older (approximately 33 years), coaches and other central players may actually be younger than most members, driving the modest effect of age on social connections in this gym.
In all three gyms, having been a member of CrossFit for longer resulted in a larger likelihood of having social connections within the network. This makes sense, in that those who have been involved in the program longer have had an increased opportunity to make and sustain connections over time. Furthermore, those who have been members longer likely take leadership roles and are therefore connected with other members more readily based on their central position in the network [37
]. The number of classes attended per week was also related to more social connections in two gyms (Gym 1 and 2), suggesting the more consistently someone attends classes, the more connected they are within their network. Thus, in addition to experiencing improved physical and mental health from more consistent class participation [76
], members may also bolster social connections and social capital through regular class participation [21
All five personality traits were related to the presence of ties in Gyms 1 and 3. Specifically, conscientiousness was negatively related to social ties; agreeableness, emotional stability, and openness to experiences were positively related to social ties; and extraversion positively related to social ties in Gym 3 and negatively related to Gym 1. This is unsurprising given personality largely influences the way people connect and interact with one another [46
Finally, SOC variables including administrative consideration, equity in administrative decisions, leadership opportunities, and social spaces all positively related to social connections present within CrossFit networks. Sense of community broadly describes the ways a person feels belonging and support as a member of a larger group [51
], and therefore should be associated with someone’s connections they make within that network. These findings provide a rationale for CrossFit coaches and administrators to prioritize building a sense of community for their members, notably through administrative consideration, equity of administrative decisions, leadership opportunities, and social spaces. These efforts could result in more social connectivity among members, which often result in longer-term adherence, better physical and mental health benefits, and overall a greater enjoyment in the program [9
While this is the first study to suggest the possibility of social influence on preference for and tolerance of high-intensity exercise, the cross-sectional design limits our ability to draw concrete conclusions. Similarly, despite inviting all members from each gym to participate, those who did choose to participate could bias the findings of our study. Each network we measured had missing data, and while we were confident our response rate was high enough to draw accurate conclusions from the represented network [41
], it is possible that key members of the network, or important social ties, were left out. Similarly, people who might have joined CrossFit but left prior to data collection may not compare to those who remained members. These people who left might not benefit from the social environment the same ways as our sample participants did. Finally, the psychometric properties of the PRETIE-Q did not lend itself to retaining the original 16 items in our sample, and the TIPI only presented a moderate internal consistency. Future research may wish to investigate a shortened and revised version of this measure for use in varied exercise contexts. Additionally, future research employing longitudinal and/or experimental designs would better determine if preference and tolerance really do manifest differently in group settings as compared to independent exercise situations.