This study is qualitative research applying Strauss and Corbin’s [25] grounded theory approach to deeply explore and describe the process of physical activity experiences among middle-aged women undergoing the menopausal transition. In addition, the study was described in accordance with the SRQR (Standards for Reporting Qualitative Research) guidelines [26].

In this study, the participants were middle-aged women experiencing menopausal symptoms, the most characteristic phenomena during the menopausal transition. Purposeful sampling was applied to recruit participants suitable for the research aim. The specific inclusion criteria were women aged 45–60 years who recognized discomfort caused by one or more menopausal symptoms and who had consistently engaged in regular exercise for at least 12 weeks, with a minimum frequency of twice a week and at least 50 minutes per session. Women currently receiving hormone therapy were excluded in order to focus solely on physical activity experiences. Recruitment was conducted among members enrolled in the group exercise program at J Fitness Center in Seoul, following the guidance of the fitness center manager. First, a mobile recruitment notice was distributed to members. Applicants were screened for eligibility, and written consent was obtained from those selected before data collection began. The sample size was determined by theoretical saturation, defined as the point at which no new concepts emerged. Data collection and analysis proceeded simultaneously through in-depth interviews and participant observation, with theoretical sampling guided by the constant comparison method. Initially, interviews were conducted with nine middle-aged women who met the criteria and reported discomfort due to menopausal symptoms while participating in physical activity. After preliminary analysis, two additional participants were selected who had experienced significant personal life changes through physical activity, in order to clarify emerging concepts. Subsequently, in comparing and analyzing participant characteristics, two more women with experiences of deep immersion in physical activity were added. Theoretical saturation was judged to have been reached with a total of 13 participants. Therefore, the final study sample consisted of 13 middle-aged women.

Data collection was conducted over a 10-month period from September 2022 to June 2023. The primary method involved in-depth interviews, complemented by direct participant observation during physical activity programs to strengthen the accuracy of content analysis. Semi-structured interview protocols guided the process, and a standardized procedure was applied for all participants. To incorporate prior analysis into subsequent sessions, an interval of at least one week was maintained between interviews. Each participant underwent one main interview lasting 90 to 150 minutes (average 120 minutes), conducted face-to-face in a private and quiet café or, at the request of two participants (participants 2 and 4), in an empty office within the center. Following these initial sessions, additional follow-up interviews were conducted as needed—two participants participated in one supplementary 10-minute interview each, either by telephone or immediately after physical activity at the center. Throughout all interviews, field notes were used to record atmosphere, attitudes, and postures, which were incorporated into data analysis. Key questions included: “What was the most difficult aspect of the menopausal transition, and what is your current situation?” “What physical activity are you currently practicing, and what motivated you to start?” “How have those around you reacted to your physical activity?” “What helped you practice physical activity?” “What emotions did you feel while performing physical activity?” “What changes have you experienced compared to before starting physical activity?” and “How has the experience of physical activity impacted your life?” Participants were informed about their rights, confidentiality, and data protection policies before participation. With consent, interviews were audio-recorded using a portable recorder and transcribed by the author. Pseudonyms were used during transcription to ensure anonymity. Draft transcripts were sent to each participant individually via mobile file to verify accuracy, and no revisions were required. As compensation, all participants received 20,000 won in cash as a transportation allowance after completing their interviews.

In this study, data were analyzed using Strauss and Corbin’s [25] grounded theory method. Analysis was performed concurrently with data collection, with ongoing efforts to maintain theoretical sensitivity. Theoretical sampling, constant comparison, memos, and diagrams were utilized, and analysis followed three stages of coding. In the first stage, open coding, the collected data were comparatively analyzed to derive concepts and categories. Interview transcripts were examined line by line, with meaningful statements underlined and concepts derived through continuous questioning and comparison. Derived concepts were compared in multiple directions, applying theoretical comparison to develop category attributes and dimensions. Similar concepts were integrated into subcategories, which were further abstracted into higher-level categories. In the second stage, axial coding, the categories identified in open coding were connected using a paradigm model to analyze their structure. The central phenomenon was identified by repeatedly questioning participants’ main concerns. Causal and contextual conditions leading to the central phenomenon were examined, as well as the strategies participants used to resolve it, the intervening conditions influencing those strategies, and the resulting consequences. The process model was further elaborated by analyzing the strategic stages over time under contextual and intervening conditions. In the third stage, selective coding, the overall situation was described in narrative form, and the core category—the central theme of the study—was derived through ongoing questioning and reflection. Relationships between categories were identified in relation to the core category. Finally, after examining both micro and macro perspectives, a situational model was constructed to integrate all elements into a comprehensive explanation.

This study endeavored to ensure the rigor of qualitative research in accordance with the criteria proposed by Guba and Lincoln [27]. To secure truth value, the authors directly participated in physical activity programs with the participants, closely observed them, conducted in-depth and brief interviews, utilized field notes, and applied a member-check process. To establish applicability, sufficient data were collected until theoretical saturation was reached, and two middle-aged women who were consistently engaged in physical activity—selected arbitrarily from the authors’ acquaintances—were asked to reflect on their experiences, thereby confirming whether the meaning of the findings could be conveyed beyond the immediate study context. To maintain consistency, the study was conducted within the established framework of data collection and analysis, with all processes described in detail to allow replication by other researchers; in addition, the results were reviewed by a doctor of nursing and a physical activity expert to check data consistency. Finally, to ensure neutrality, the researchers engaged in continuous bracketing and reflective practice, avoided leading questions during interviews, and recorded the interview content verbatim in order to capture and understand participants’ experiences from their own perspectives.

The first author completed doctoral coursework in qualitative research methods, nursing theory development, and women’s health nursing, and gained experience presenting and demonstrating physical activity programs through a nursing intervention class. Training to develop qualitative research skills included conducting a preliminary study using in-depth interviews and grounded theory. The author also published a qualitative study on the physical activity experiences of perimenopausal women in a nursing journal. During this study, the author participated in physical activity programs alongside participants from beginning to end, engaging in the same activities to ensure accurate collection and analysis of research data.

The total number of participants in this study was 13, with an age range of 50–59 years and a mean age of 54.5 years (Table 1). Menopausal status was classified according to the menopause stages proposed by SWAN (the Study of Women’s Health Across the Nation) [1]: 3 participants were in early perimenopause, exhibiting menstrual cycle changes; three participants were in late perimenopause, experiencing amenorrhea for 3–11 months; and seven participants were in postmenopause, with amenorrhea for 12 months or longer. Their mean age at menopause was 50.7 years. Participants engaged in physical activity at least three times per week, each session lasting 50 minutes or more. The average duration of maintaining physical activity was 3.4 years, ranging from 4 months to 10 years. For participants involved in two or more activities, the calculation was based on the longest-maintained activity. Most participants engaged in physical activity primarily through group exercise programs, though they were also free to participate individually in equipment-based activities within the center, without restrictions on time or frequency. Regarding marital status, one participant was single, two were divorced, and the remainder were married. Among the 13 women, one had diabetes, one had a breast cyst, and two had osteoporosis.

Through open coding, 74 concepts were derived from the data and subsequently abstracted into 28 subcategories and 13 categories (Table 2). The core category was identified as “continuing my new daily life while improving my body and mind.” During axial coding, relationships among categories were examined, and a paradigm model was constructed (Figure 1).

In this study, the process of participants’ physical activity experiences was delineated into four stages, which were presented in a process model (Figure 2) and further illustrated through simple physical movements in a situation model (Figure 3). The first stage, the awareness phase, involves recognizing the abrupt bodily changes associated with menopause and realizing the necessity of physical activity. The second stage, the strategy formulation phase, entails preparing countermeasures and devising strategies to overcome unstable life conditions. The third stage, the management maintenance phase, consists of applying various strategies while sustaining continuous management of daily life. The final stage, the adaptation phase, represents the point at which participants regain stability both physically and mentally through physical activity and thereby adapt to new life changes.

Based on an analysis of the recurring patterns centered on the core category, four distinct types were identified regarding how participants regained physical and mental stability to resume daily life. The first type (the settling type) is satisfaction-oriented, characterized by being generally content with the positive changes achieved through physical activity while remaining settled into daily routines. The second type (the obligation type) is practice-oriented, marked by consistent and diligent engagement in physical activity carried out with a sense of duty. The third type (the obsession type) is enthusiasm-oriented, defined by excessive preoccupation with physical activity accompanied by persistent craving. The fourth type (the growth type) is achievement-oriented, characterized by proactive engagement in challenges and continuous personal growth.