Effects of Performing Augmented Reality Tasks on Postural Sway While on a Ladder

Abstract

The use of augmented reality (AR) is growing in industrial occupational settings such as within the construction industry [1, 2]. Falls off ladders are already a major source of workplace injuries [3], and any adverse effects of AR on balance while working on a ladder could exacerbate the risk of falling. Therefore, the purpose of this study was to investigate the effects of viewing and interacting with AR on balance during simulated construction tasks while on a ladder. The four tasks investigated involved: (1) a reading task with AR input, (2) an assembly task requiring AR input, (3), an assembly task with verbal input, and (4) a button poking task with virtual AR buttons. We also investigated screen-relative and world-relative AR presentation styles across the relevant AR-support tasks. Balance was assessed by measuring mean speed of postural sway of the center of pressure with increases in speed suggesting a greater risk of falling. Regarding the tasks, results indicated postural sway was greater during the assembly task with verbal input (6.39 cm/s; p<0.05), the assembly task with AR input (6.33 cm/s; p<0.05), and the button poking task with AR input (7.35 cm/s; p<0.05) as compared to the reading task with AR input (2.90 cm/s). Additionally, postural sway increased more during the button poking task with AR input as compared to the assembly task with AR input. Regarding the two presentation styles, postural sway with a world-relative AR display (9.27 cm/s) was greater than a screen-relative AR display (4.95 cm/s) during the poking task with AR input (p < 0.05), but did not differ between presentation styles during the other tasks (p > 0.05). Our results suggest that care must be taken when designing AR applications for applications that are to be used on ladders or other environments where postural stability is of great importance, as the task to be completed and the presentation style can affect a worker's balance. Further research into user interface presentations styles interaction techniques and tasks involving AR menu navigation is warranted.