Effect of postural angle on back muscle activities in aging female workers performing computer tasks

[Purpose] This study investigated the effects of postural angle on back muscle activityduring a computer task in aging women. [Subjects] Seventeen women ≥50 years oldparticipated. [Methods] The participants were instructed to perform computer-related tasksfor 20 minutes on a workstation that simulated typical office working conditions. Backposture was measured from the measured trunk and pelvic angles. Electromyographyactivities were recorded simultaneously from the cervical erector spinae, longissimus, andmultifidus muscles. [Results] The lowest mean percentages of maximum voluntary contractionfor the cervical erector spinae and longissimus muscles were obtained when the upper trunkand pelvic angles were between 0° to −5° from the sagittal plane. The back muscleactivities increased as the upper trunk and pelvic angles exceeded 0°. Statisticalanalysis showed significant correlations between upper trunk angle and cervical erectorspinae and longissimus muscle activities. Similarly, pelvic angle was significantlycorrelated with cervical erector spinae and multifidus muscle activities. [Conclusion] Aneutral back posture minimizes muscle activities in aging women performing computertasks.Key words: Postural angle, Muscle activity, Aging