Additive Effects of Core Stabilization Added to Postural Correction and Diaphragmatic Breathing on Craniovertebral Angle and Pulmonary Function in Adults with Forward Head Posture: A Randomized Controlled Trial

Purpose: This study compared a 4-week corrective exercise program-adding active core stabilization to a shared postural-correction and diaphragmatic breathing component-with a stretching program using the same component, on craniovertebral angle (CVA) and pulmonary function in adults with forward head posture (FHP) and an inefficient breathing pattern.Maximal voluntary ventilation (MVV) was the primary outcome; CVA, Tiffeneau index, FVC, FEV1, MIP, and MEP were secondary outcomes.Methods: Thirty-six adults were randomized 1:1 to a corrective exercise or stretching group (n= 18 each), performing 30-minute, homebased sessions three times weekly for four weeks after one in-person supervised session, with subsequent sessions guided by a standardized instructional video.CVA was measured by photogrammetry, and six pulmonary indices were assessed by digital spirometry pre-and post-intervention; Time× Group interactions were analyzed via mixed ANOVAs with Bonferroni correction.Results: CVA, FVC, FEV1, MIP, and MEP showed no significant Time× Group interaction (all p≥ 0.10); the four pulmonary indices improved over time in both groups (p< 0.05), whereas CVA showed no significant change over time.The Tiffeneau index showed a nominally significant interaction (p= 0.043) that did not survive correction, reflecting baseline differences.MVV, the primary outcome, showed a significant interaction (F = 11.56,p = 0.002) surviving correction, with a larger within-group improvement in the corrective exercise group (d= 1.64) than the stretching group (d= 0.50; between-group d= 1.13).Change scores were not correlated among CVA, Tiffeneau index, and MVV.Conclusion: A short-term program adding core stabilization to shared postural-correction and diaphragmatic breathing produced a robust MVV improvement beyond stretching alone, without significant CVA change; general pulmonary function improved similarly in both groups.Functional respiratory gains may occur independently of postural realignment in adults with FHP.