Effect of neck flexion angles on neck muscle activity among smartphone users with and without neck pain.

This study examined the differences in neck muscle activity at various neck flexion angles in smartphone users with and without neck pain. Forty-four participants performed texting tasks for 1 min and 30 s. Neck muscle activity and pain in the neck were measured at different neck flexion angles. There was a difference in neck muscle activity for each of the neck flexion angles; the Cervical Erector Spinae (CES) muscle activity increased while the Upper Trapezius (UT) muscle activity decreased when at increased neck flexion angles. At neck flexion angle of 0°-15°, the activity of both CES and UT muscles were acceptably low. Smartphone users with neck pain had slightly higher muscle activity levels than smartphone users without neck pain. In conclusion, smartphone users should consider adopting neck flexion angles between 0 and 15 degrees during smartphone use as there is an association between this neck flexion angle range and reduced CES muscle activity. This study demonstrated that both smartphone users with and without neck pain should try to keep their neck flexion angle between 0° and 15° when using their smartphone. This would reduce neck muscle activity and the risk of developing neck disorders associated with smartphone use.