Analysis of reduction effect of the cervical spine load in the presence of the headrest which can be attached to the assist device for upward work

In this paper, effectiveness of the headrest which can be attached to the assist device for upward work was investigated based on the static and dynamic analyses. In the static analysis, the cervical spine load model was proposed and static strain on the cervical spine was evaluated. As a result, the moment around C2/C3 disc and the compressive force and shear force on C2/C3 disc were reduced in the presence of the headrest. The dynamic analysis was conducted using the musculoskeletal model analysis software AnyBody Modeling System (AnyBody). First, arm lowering movement was created using the code of AnyBody. Then, dynamic strain on the cervical spine was analyzed for the created movement. As a result, activity of the sternocleidomastoid muscle, the compressive force and shear force on C2/C3 disc under wearing the assist device with the headrest were reduced as compared with those under wearing the assist device without the headrest. Therefore, usefulness of the headrest for reducing the burden on the neck during the upward work was verified.