Video analysis of sagittal spinal posture in healthy young and older adults.

OBJECTIVE Changes in posture are of concern because of their association with pain or impaired physical function. Previous studies that have used computer-aided video motion analysis systems to measure posture have been compromised by the use of problematic models of skin marker placement. This study aimed to quantify and compare sagittal spinal posture in standing and sitting between young and older adults using a two-dimensional PEAK Motus system and a revised skin marker model. METHODS Twenty-four healthy young adults and 22 healthy older adults volunteered for this study. The angles of the upper and lower cervical spine, thoracic spine, lumbar spine as well as the orientations of the head, neck, and pelvic plane with respect to an external reference were measured in the standing and sitting positions. RESULTS Compared to young adults, healthy older adults demonstrated a forward head posture, with increased lower cervical spine flexion and increased upper cervical extension in both positions. Older adults also sat with significantly increased thoracic kyphosis and decreased lumbar spine flexion. CONCLUSION The angular relationship between adjacent spinal regions in the sagittal plane can be objectively quantified using image-based analysis. The concept that the anteroposterior tilt of the pelvis in standing dictates the lumbar and thoracic curves was supported by the correlations between these adjacent regions in both age groups. The model of skin marker placement used in this study can have a broader application as a clinical tool for image-based postural assessment.