The influence of the viewing angle on neck-load during work with video display units

Ergonomic measures have been found to reduce load-related trouble from the neck-and-shoulders during visual display unit (VDU) work. An important question is the height at which the screen should be placed to give the lowest possible load. Should it be placed at eye-level or below? The aim of the present study was to investigate whether there was any difference in external loading moments of force about the C7-T1 segment when the VDU-operators had a viewing angle of 20 degrees below the horizontal plane as compared to 3 degrees above the horizontal. Eight secretaries were videofilmed in the sagittal plane in the two work postures during simulated work. The loading moment was calculated from the film. It was significantly lower at viewing angle 3 degrees above the horizontal than at 20 degrees below the horizontal, both at the beginning (1.3 vs 2.2 nm) and at the end (1.4 vs 2.1 nm) of the film sequences (p < 0.05).