A revised model of skin marker placement with the two-dimensional (2D) PEAK Motus system was used to investigate the effect of aging on sagittal range of spinal motion. Twenty-four healthy young adults and twenty-two healthy older adults were videotaped while performing the movements of flexion and extension in each spinal region--cervical, thoracic and lumbar spine. Alternative movement tests that may allow a greater range of motion (ROM) for thoracic extension and lumbar flexion were also investigated. Older adults demonstrated significantly decreased flexion/extension ranges in the cervical, thoracic and lumbar spine. The movement of cat-stretch in the all-fours position allowed greater thoracic extension, and the movement of toe-touch in standing permitted greater lumbar flexion. This study provides reference data for sagittal ranges of spinal motion in healthy young and older adults as measured by a 2D imaged-based system. The sagittal model of skin marker placement used in this study can have a broader application for ROM measurement in the clinical setting using a digital camera and freely downloadable software.