3.1. Sample Selection and Data Sources
The research data for this study were collected from the professional exercise community KEEP (
https://www.gotokeep.com/, accessed on 4 August 2023) and the chat histories of users in a WeChat group associated with the app. This online community primarily aims to pursue a healthy lifestyle through exercise, encourage, learn from, and motivate each other, and promote scientific exercise and regular exercises to prevent or alleviate health issues such as obesity, hypertension, and fatty liver. The WeChat group of community members has two main characteristics: maintaining activity and cultivating habits. Activity refers to the hundreds of daily chat messages exchanged within the group, including casual conversations, knowledge sharing, Q&A, and seeking assistance, while consistently maintaining a relatively high level of activity. Cultivating habits stems from the shared goal of mutual encouragement for exercise within the group. Group members utilize methods such as screenshots, smartwatches, exercise apps, and mini programs to share their progress in the group.
This study selected a total of 8800 chat records (excluding emojis and symbol messages) generated by 150 members of the community from 17 March 2018 to 15 April 2018, spanning a period of 30 days. The chat records were analyzed and categorized, and based on user interaction behaviors, a social network was constructed (as shown in
Figure 3). The study aimed to explore the network structure, node attributes, and the impact of chat content on users’ exercise behaviors. To achieve this, a social capital model was constructed and empirical analysis was conducted to examine the effects of social capital and irrelevant topics on users’ exercise behaviors, in line with the formulated hypotheses.
3.2. Encoding Process
This study employed content analysis to examine the chat records, involving statistical word frequency analysis and content categorization. The content was divided into semantically similar and quantifiable subcategories. Following Zhou Junjie’s social support behavior coding (SSBC) framework [
43], the chat content of the group users was classified into six types: informational support, emotional support, off-topic discussions, instrumental support, esteem support, and network support. Given the specific characteristics of the WeChat group under investigation, this research categorized the text content into four subcategories based on user-initiated topics: check-ins, irrelevant topics, common topics, and self-disclosure.
Among these, common topics encompassed three types of support behaviors from the SSBC framework: network support, informational support, and instrumental support, emphasizing their relevance to the group theme. Network support referred to shared interests and concerns related to physical exercise. Informational support involved knowledge sharing, specifically providing information related to scientific exercise, equipment selection, healthy diets, and other knowledge content relevant to the group theme. Instrumental support referred to guiding problem solving, such as how to use mini-programs for check-ins. This study considered expressions of care, encouragement, and supervision as indicators of emotional support reflected in the variable of reciprocity, while expressions of respect and trust toward others were seen as indicators of esteem support, reflecting the variable of trust.
In this study, the data underwent a preprocessing step where the conversations were segmented into different fragments based on their occurrence time and topic. Conversations that had no response for more than thirty minutes were considered ended. An example of the coding scheme can be found in
Table 1.
Based on the above classification method, a total of 730 conversations initiated by 137 participants were identified and recorded, as presented in
Table 2. In this study, the act of “check-in“ is considered the dependent variable, reflecting users’ exercise behaviors. It would be beneficial for the authors to further explore and discuss the relationship between offline exercise behavior and the dynamics of online group chat.
Understanding how users’ offline exercise behaviors correspond to their engagement in an online group chat can provide valuable insights into the influence of social interactions on exercise habits. By analyzing the content and patterns of conversations within the online health community, the authors could potentially uncover correlations between participants’ exercise routines, their participation in group discussions, and the supportive nature of the community. Furthermore, investigating the impact of the online group chat on users’ exercise behaviors can shed light on the motivational aspect of social support within the community. The discussions and interactions within the group may play a role in encouraging individuals to adhere to their exercise goals and maintain a consistent fitness routine. Thus, delving into the interplay between offline and online exercise behaviors can offer a comprehensive understanding of how social capital formed in online communities may influence users’ self-exercise and self-health management.
By addressing the relationship between offline exercise habits and the dynamics of the online group chat, the authors can enhance the relevance and applicability of their findings, potentially uncovering valuable implications for promoting exercise engagement and fostering a supportive virtual environment within the health community.
3.3. Data Processing Based on UCINET Social Network Analysis Method
Social networks can be classified into directed and undirected networks, and a comprehensive social network includes various structures, such as dyadic relationships, triadic relationships, subgroups, and positions. The interactions among members within a WeChat group are considered a type of directed network. Each member is represented by a node, and the connections established through interactions are represented by edges. Therefore, the interactions among members can be visualized as shown in
Figure 4.
We converted the dataset into a matrix format for social network analysis, as shown in
Table 3. The valid data of our WeChat group comprise 137 people. The meaning of A–D in
Table 3 is not to label these 137 users as A–D, but the name of the user, i.e., user A, user B, user C, user D, as an example for demonstration: the rows represent the sender of the conversation, and the columns represent the recipients of the conversation. Consider number “2” in the fifth column of the second row, for example; it means that user A has sent two messages to user D. The number “3” in the first column and the fifth row means that user D has sent three messages to user A. From this, the number of replies between users can be counted, and thus the independent variable can be calculated. We generated the social network graph of the community, depicted in
Figure 5, where larger nodes indicate higher centrality.
The directed social relationship network graph depicted in
Figure 4 illustrates the connections between nodes with specific directions. Outdegree refers to the number of outward connections a node has with other nodes, while indegree represents the number of inward connections a node receives from other nodes. The “outdegree” metric reflects an individual’s sociability, indicating the extent to which they pay attention to others. Individuals with higher outdegree tend to exhibit greater information output within the group, such as sharing knowledge, expressing opinions, or engaging in social interactions. Consequently, individuals with higher outdegree demonstrate a higher level of authority. Conversely, “indegree” signifies the degree to which an individual receives replies or receives recognition in the form of being “liked”, indicating their reception of information from others.
Furthermore, the members within the social relationship network graph can be categorized into cohesive subgroups based on their level of closeness and the direction of their interaction. Cliques, which are fundamental concepts in UCINET social network analysis, represent cohesive subgroups where the distance between any two nodes within a clique is equal to or less than
and we set
= 2. Based on the records of each member in the WeChat group, we adopted UCINET software and built the social network diagram as shown in
Figure 5 (different numbers represent different member). The number in each circle represents a WeChat member and the size of the circle represents the closeness of the member. The larger the circle, the stronger the closeness and the greater the influence.
Based on the existing studies [
44,
45,
46], we put up our way of calculation mode. In this study, the dependent variable, user’s exercise continuity, is represented by the “number of check-ins” made by the users. It is calculated as the total number of check-ins by user
in the group within a certain period, denoted as
.
3.3.1. Structural Capital: Centrality Owned, Centrality Accessed, Centrality Betweenness
We chose to use “outdegree” to measure centrality owned (Li et al., 2016). In this paper, the centrality of point
is set as
, and the outdegree of
is
. If point
replies to point
for
times, then
. If point
replies to point
for
times, then
. Therefore, we obtain:
Centrality accessed is represented by the “indegree” of the point, where the centrality accessed of point
is defined as
, the indegree of
is defined as
. All other factors being equal, points with higher centrality owned in the network are more likely to have higher centrality accessed due to their greater number of direct connections. In order to eliminate the interference caused by centrality owned, this study considers the frequency and proportion of interactions for different nodes and introduces a weight factor, denoted as
.
The betweenness centrality measures the extent to which a node serves as a bridge or intermediary between other nodes in terms of their connections. Nodes with high betweenness centrality may not have a high number of direct connections themselves but play a crucial role in controlling the flow of information and resources between other nodes in the network. These nodes have more pathways to access useful information and social support and tend to utilize community resources more frequently. In this study, the betweenness centrality is calculated using UCINET social network analysis software, and it is represented as
.
Here, is the probability that is on the path between points and , is the number of paths that exist between and , and denotes the number of paths that exist between points and k that pass through point .
3.3.2. Relationship Capital: Reciprocity and Trust
In this study, trust is measured based on whether users engage in self-disclosure behaviors within the group. If a user has exhibited self-disclosure behaviors in the community by posting selfies, disclosing personal health data, or describing their physical condition, it is considered an indication of trust and reliance on other members of the community. This study takes trust into account. However, if a user has engaged in self-disclosure behaviors on other publicly accessible social media platforms, the user’s self-disclosure behaviors within the group may not necessarily stem from trust. In reference to users’ activities on their individual accounts in the KEEP platform during the same period, trust is represented as
. User
‘s self-disclosure behaviors within the target WeChat group are represented as
, and the user’s self-disclosure behaviors in KEEP are represented as
,
and
, which are binary variables. We referred to users’ personal account activities on the KEEP app during the same period and set trust as
TRUi. The self-disclosure behavior of user i in the target WeChat group is represented by
, while the self-disclosure behavior in the KEEP app is represented by
. Both
and
are binary variables, with 0 indicating no self-disclosure and 1 indicating self-disclosure. If user
i make self-disclosure both in WeChat and KEEP, then
equals to 0 and indicates self-disclosure, and vice versa. Therefore, the relationship can be expressed as follows:
In this study, the concept of cliques is used to measure reciprocity. Cliques are fundamental concepts of cohesive subgroups in UCINET social network analysis. In a binary-directed relationship network, the relationships among members within a clique are reciprocal and exclusive, meaning that adding any other member would alter its nature. The number of cliques a member belongs to reflects the level of reciprocity within the overall network. Let us assume that user
belongs to n cliques, represented as
. Reciprocity (
) can be expressed as follows:
3.3.3. Cognitive Capital: Common Topics
Cognitive capital refers to the shared topics and vocabulary that are generated and used within a collective. In this study, the concept of shared group topics is used to represent cognitive capital, and it is denoted as . represents the number of times a user participates in or initiates shared topics within the group.
3.3.4. Irrelevant Topic
Many users perceive online communities as spaces for making friends and for relaxation, resulting in a significant number of irrelevant topics. In this study, the variable of irrelevant topics is included in the model as both an independent variable and a moderating variable. It is denoted as , representing the number of times a user initiates or participates in discussions on irrelevant topics.