**Background:** Health promotion emerged as a unifying concept in the 1980s, emphasizing that health requires not only basic resources but also supportive environments and opportunities for healthy choices. Municipal public policies for sport and leisure can catalyze healthy lifestyles by guaranteeing access to regular physical activity. This study analyzed a gymnastics program offered by the Department of Sports and Leisure (SEL) of Valinhos, São Paulo, Brazil, which has operated uninterruptedly since the mid-1980s—approximately 30 years—despite changes in municipal management. The program serves female residents aged 18-59 (with continuation allowed beyond 60), requiring a medical certificate. Classes occur twice weekly for one hour at public locations in each neighborhood, including localized, functional, aerobic, circuit, stretching, and flexibility exercises, plus thematic classes, walks, and social events.
**Methods:** This case study used mixed methods. The quantitative component employed the Portuguese version of the WHOQOL-bref questionnaire, consisting of 26 questions covering physical, psychological, social relations, and environment domains plus two general quality of life questions. The minimum required sample was 204 participants (calculated from 800 total students, 5% margin of error, 90% confidence level). After accounting for exclusions, 239 women aged 35-74 participated. The qualitative component used focus groups in two classes selected by inverse socioeconomic criteria (Neighborhood A, less privileged; Neighborhood B, more privileged), with 20 randomly selected students aged 44-65. A pre-established script covered personal history, reasons for joining and staying, program strengths/weaknesses, and quality of life. Sessions were recorded and transcribed. WHOQOL-bref scores were calculated using a validated Microsoft Excel tool, and focus group data underwent content analysis following Bardin's method.
**Key Results:** WHOQOL-bref scores (scale 0-20) showed the highest averages in the physical domain (16.00) and quality of life self-assessment (15.91), and the lowest in the environment domain (13.87). The general average was 15.23. Neighborhood B (socioeconomically favored) scored higher overall (15.51) than Neighborhood A (14.84). In descending order, domain scores for all students were: physical, QoL self-assessment, social relations, psychological, environment. The greatest response amplitude was in social relations; the smallest in psychological domain.
Regarding reasons for joining (adhesion): In Neighborhood A, the main reasons were medical advice (5 students) and invitation from members (4 students). In Neighborhood B, the main reason was invitation from members (4 students), with only one joining due to medical advice.
Regarding reasons for staying (adherence): In Neighborhood A, the most cited reasons were enjoyment of participating in the group (5 students), having fun during classes (5 students), and the possibility of leaving home (4 students). In Neighborhood B, the most cited reasons were liking the teacher (7 students), enjoying participating in classes (6 students), liking the group (5 students), and liking the friendships (4 students). In both groups, no results related to aesthetics or weight loss were reported. The main reason for long-term adherence was understanding the gym class as a sociability space—a moment of meeting, exchanges, and interpersonal relationships.
For Neighborhood A students, the group represented "family"; for Neighborhood B, it represented a "moment of sociability." Both groups reported that classes positively influenced quality of life through psychological and social benefits. The main strength reported by Neighborhood A was that the class was addressed to them; by Neighborhood B, it was the teacher's professionalism. The main weakness in both groups was the desire for more class days per week.
**Clinical Implications:** This study demonstrates that public policies providing group physical activity can improve health through social and psychological mechanisms, not just biological ones. The finding that sociability—not aesthetics or weight loss—was the primary driver of long-term adherence suggests that program design should prioritize group cohesion, social connection, and enjoyment. The socioeconomic gradient in quality of life scores (Neighborhood B: 15.51 vs. Neighborhood A: 14.84) confirms that social determinants of health influence outcomes even within a structured program. The authors recommend that physical activity be characterized as a health care strategy from a biopsychosocial perspective, and that undergraduate and postgraduate education in physical education incorporate this framework. The program's 30-year uninterrupted existence despite political changes suggests that community-embedded, neighborhood-based delivery (eliminating transport barriers) and strong teacher-student relationships are key sustainability factors. Limitations include the all-female sample, lack of a control group, and no comparison between newer and longer-term participants.