Background: Forward head posture (FHP) causes changes in the strengths and rigidities of cervical muscles.
Objective: The aim of this study was to investigate correlations between FHP and respiratory functions and the muscle activities of respiratory accessory muscles in young adults in their 20s.
Methods: A volunteer sample of 33 healthy young adults participated in this study. Craniovertebral angle (CVA), cranial rotational angle (CRA), vital capacity (VC), forced vital capacity (FVC), forced expiratory volume at 1 second (FEV1), peak expiratory flow (PEF), maximal voluntary ventilation (MVV), and sternocleidomastoid (SCM) and upper trapezius activity ratios were measured.
Results: Significant positive correlations were found between CVA and VC, FVC, FEV1, PEF, and MVV, and a significant negative correlation was found between CVA and SCM activity ratio. Significant negative correlations existed between CRA and VC and FVC, and significant positive correlations between CRA and SCM and upper trapezius activity ratios.
Conclusion: FHP may act to lower respiratory functions, and thus, the maintenance of correct head posture is required to prevent such functional reductions.
Keywords: Forward head posture; respiratory accessory muscle activity; respiratory function.