Evaluation of Physical Load Due to Neck and Body Bending Posture when Wearing Head-Mounted Display

Abstract

In the field of manufacturing, the user of a head-mounted display (HMD) often assumes a posture where the neck and body are bent forward or outward to view three-dimensional computer graphics under augmented reality or mixed reality environment. The purpose of this study was to clarify properties of the neck and body bending posture when wearing a HMD, and to evaluate the effects of the HMD and viewpoint positions on the musculoskeletal load. The research participants included six males and five females. In the experiment, each participant was instructed to gaze at a point on a sagittal plane while in a sitting position. The body joints angles and electromyography (EMG) were measured to compare the effects for the cases with and without the HMD and for different viewpoint positions. The results of the experiment showed that the lateral bending angle of the neck with the HMD was smaller than that without the HMD, whereas the lateral bending and rotation of the trunk were larger. These results suggest that a strategy involving a shift in posture was used to counteract the load produced by the mass of the HMD through increasing the trunk muscle activity more than that for the neck muscles.