Biomechanical Associations of Breathing Techniques in Postpartum Recovery: Effects on Diaphragm Function, Abdominal Pressure Regulation, Pelvic Floor Health, and Core Stability

Background: Postpartum diaphragm and pelvic floor dysfunction commonly co-occur, impairing abdominal mechanics and pelvic stability. Coordinated core muscle activity is crucial for recovery. Structured breathing may enhance this synergy, but supporting evidence remains limited. Objective: To evaluate the association between structured breathing combined with pelvic floor muscle training (PFMT) and postpartum biomechanical function. Methods: This retrospective study included 82 postpartum women (June 2023–June 2025) assigned to a combined group (breathing + PFMT, n=41) or control group (PFMT only, n=41). Propensity score matching balanced baseline characteristics. Outcomes assessed diaphragmatic function, abdominal pressure regulation, pelvic floor strength and coordination, and core stability. Inter-group comparisons, correlation, and regression analyses were conducted. Results: Baseline variables were comparable after matching. The combined group showed greater improvements in diaphragmatic excursion (1.2 vs. 0.3 cm, p<0.001) and abdominal breathing adoption (51.5% vs. 18.2%, p=0.015). Abdominal pressure maintenance and ΔP improved significantly (p ≤ 0.003). Pelvic floor contraction pressure increased more substantially (16.7 vs. 4.3 cmH2O, p < 0.001), with better coordination (82.9% vs. 51.2%, p<0.01). Core stability and diastasis recti recovery were superior (p < 0.05). Diaphragmatic gains correlated with pressure, pelvic, and core outcomes (all p < 0.001). Conclusion: Structured breathing combined with PFMT is associated with enhanced postpartum diaphragmatic, pelvic, and core recovery, suggesting synergistic biomechanical effects.