Electromyography comparison of normal chair-desk system and assistant chair-desk system on fatigue

Abstract

[Purpose] This study was designed to test the effects of the Assistant Chair-Desk System (ACDS), which can reduce the forward tilt of the neck and trunk and the level of fatigue during long lasting study in the sitting position. [Subjects] Fourteen middle school students and 14 college students of mixed gender participated in this study. [Methods] Fatigue level, the trapezius muscle, and the forward tilt angle of the head and trunk as well as distance factors were assessed before after using a normal chair-desk system (NCDS) and the ACDS for 120 minutes. [Results] There was an interaction effect in the angle and length of the neck from the sitting posture changes after 2 hours of studying using the NCDS and ACDS. There were also significant differences in the fatigue levels, hip joint angles and the lengths from the head according to the main effects of the chair-systems. [Conclusion] The studying position while using the ACDS was determined to prevent significant fatigue levels of the muscle and body, provide support to the head, by limiting the forward movement of the neck, and prevent forward tilt of the neck and trunk, by enabling the target point and gaze to be closer to the horizontal direction.

The influence of seat height, trunk inclination and hip posture on the activity of the superior trapezius and longissimus

“…Previous studies have addressed the influence of body posture and seat characteristics on muscle activity 1 , 11 , 12 ) . The study by Kamil and Dawal 13 ) demonstrated that there is a correlation between postural angle (trunk and pelvic angles) and the activity of the erector spinae, multifidus and cervical erector spinae muscles.…”