RESUMEN
PURPOSE: A slouching posture during smartphone usage increases gravitational loadings on the cervical spine, which may lead to neck pain and degeneration. The objective of the present study was to investigate the head, neck and trunk angles in different smartphone-usage postures, as well as the posture-correction effects and comfort scores of three neck collars. METHODS: This was a prospective cohort study in which 41 healthy young subjects aged 18-25 were recruited. The head, neck and trunk angles were measured in all participants during a neutral position and three smartphone-using postures, including sitting with and without back support and standing. The postural correction and comfort scores of three collars (Aspen Vista, Sport-aid and our customized 3D printed collars) were compared. RESULTS: Smartphone use increased the head and neck flexion angles in all postures, and sitting without back support showed the greatest head and neck flexion angles. The posture-correcting effect of the customized collar was better than the Aspen Vista and Sport-aid collars. In addition, the customized collar was more comfortable to wear than the other two collars in most contact areas. CONCLUSION: Smartphone use increased both the head and neck flexion in different postures, and the proposed customized 3D-printed cervical collar significantly reduced the head and neck angles. These slides can be retrieved under Electronic Supplementary Material.