The hidden cost of slouching : exploring scapulohumeral rhythm changes in forward-headed students

BACKGROUND: Forward head posture (FHP) may alter shoulder biomechanics through changes in neuromuscular control and scapular positioning; however, its relationship with scapulohumeral rhythm (SHR) remains unclear in asymptomatic individuals. To examine the association between FHP and SHR during shoulder abduction and compare SHR across abduction ranges. METHODS: A cross-sectional study was conducted among 207 college-going young adults (18-25 years). FHP was assessed using the craniovertebral angle (CVA) via a validated smartphone application. Participants were categorized into FHP (CVA <44°) and normal posture groups. Scapular upward rotation was measured using a modified digital inclinometer, and SHR was calculated as the ratio of glenohumeral motion to scapular rotation across 0-90° abduction. Spearman's correlation analysis was performed. RESULTS: < 0.05). CONCLUSION: FHP is associated with altered SHR, particularly in early and mid abduction. These findings support incorporating cervical and scapular assessment within a regional interdependence framework.