Objective: This study examined the effects of a 12-week aerobic-resistance circuit training programme on pulmonary function in female security personnel, focusing on forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow rate (PEFR), and pulse oxygen saturation (SpO2).
Methods: A total of 40 participants were randomly assigned into experimental (n = 20) and control (n = 20) groups. A pre-test post-test quasi-experimental design was adopted for this study. The experimental group participated in circuit training sessions (3 times per week, 45–60 minutes per session) for 12 weeks, while the control group maintained their usual activity levels. Spirometry tests measured FVC, FEV1, and PEFR, while SpO2 was recorded using a pulse oximeter. ANCOVA was used to analyze differences between groups, with statistical significance set at p < 0.05. Results: The experimental group showed significant improvements in FVC (p = 0.008, η² = 0.174), FEV1 (p = 0.010, η² = 0.165), and PEFR (p = 0.017, η² = 0.143). However, SpO2 remained unchanged (p = 0.718, η² = 0.004). Conclusion: A 12-week aerobic-resistance circuit training programme significantly improved FVC, FEV1, and PEFR, suggesting that aerobic-resistance training enhances lung capacity and respiratory endurance in female security personnel. These findings underscore the importance of circuit training in occupational fitness programmes and support its integration into professional training regimens.