ABSTRACT
In assessing risks related to working posture, pictures of postures are taken from various directions, which can be a source of observation error. Joint postures of the neck, low back, knee, shoulder, and elbow were taken from 7 different viewing angles and 19 observers estimated joint angles after observing the pictures in 2-dimensional display. In general, it is strongly recommended to maintain the viewing angle within 40 degrees from the sagittal plane, while taking pictures of postures from the behind the individual is least recommended. In order to identify and assess risk factors of work-related musculoskeletal disorders, observational methods have been widely used in industry. They neither interfere with job process nor require expensive equipment, while being relatively reliable. The joint postures for angle estimation were; flexion of the neck, low back, knee, shoulder and elbow, and the extension of the neck, low back and shoulder. They are the main motions at each joint in the sagittal plane.
