The effect of tablet use on trunk posture while sitting.

Abstract

The use of tablet during the office work is on the rise, but the biomechanical response of tablet use under various sitting postures is not well understood. This study quantitatively measured changes in trunk kinematics under three sitting conditions (raised leg, neutral leg, and lowered leg) while using a tablet. Fifteen participants were asked to sit on a chair with three different postures while staring at a handheld tablet or gazing straight ahead with a bare hand, and the head flexion, lumbar flexion and trunk inclination were captured with electrical goniometers. The results revealed significantly less lumbar flexion (12.8%) and trunk inclination (28.0%) while using the tablet compared to the empty hand condition (p < 0.001), but at a significant cost of increased head flexion (90.8%; p < 0.001). Further, while using the tablet, participants showed less head flexion in the raised leg condition (p < 0.001) than in the others (9.7% and 7.5%, respectively), but larger trunk inclination and lumbar flexion were required (p < 0.001 in both). Collectively, the lower extremity sitting posture significantly changed the way to observe the tablet by adopting more head flexion in neutral and lowered leg conditions or more trunk flexion in raised leg condition.