RESUMO
BACKGROUND: Motion platforms and driving simulators have been shown to contribute to motion sickness and a short-term increase in standing postural sway. However, no studies to date have investigated how the motion of a passenger vehicle and the performance of a task during a drive on a closed test track affects post-drive standing balance. RESEARCH QUESTIONS: What are the effects of (1) a continuous, scripted drive on a closed test track, and (2) the performance of a handheld tablet-based task during the scripted drive, on post-drive standing balance? METHODS: Fifty adults (23 males, 27 females; 40.0 ± 20.6 yr) rode in the front passenger seat of a midsized sedan on a scripted drive. Participants were assigned to one of the acceleration levels (Low, Moderate) and completed both Task and No-Task test conditions, involving a visual-based task on a handheld tablet device. Before and after each scripted drive, participants completed two standing balance exercises: 1) feet tandem, eyes open, on firm support, and 2) feet together, eyes closed, on foam support. An inertial measurement unit (IMU) captured estimates of postural trunk sway. Root-mean-square (RMS) of angular position and velocity in the anteroposterior (A/P) and mediolateral (M/L) directions, and elliptical fit and path length of sway trajectory were computed. A nonparametric analysis was performed on the balance metrics. RESULTS: Exposure to a scripted drive in a vehicle affected participants' postural sway, especially after using a handheld device during the drive. M/L RMS sway velocity and path length increased for both exercises following the scripted drive with task. Additionally, M/L RMS sway increased for the more challenging balance exercise, during which participants stood with feet together on foam support with eyes closed. SIGNIFICANCE: This study is the first to explore balance following a scripted drive on a closed test track. Changes in post-drive balance introduces potential risks to vehicle passengers; concurrent performance of a task on a handheld device further increases the likelihood that post-drive balance will be negatively affected.