[Purpose] The purpose of this study was to examine the influence of the cervical flexion angle when using a smart phone on muscle fatigue of the cervical erector spinae (CES) and upper trapezius (UT). [Subjects] This study recruited 12 healthy adults. [Methods] Each subject sat on a chair, with his/her back against the wall and held a smart phone with both hands. Fatigue of the neck and shoulde...
