The effects of a moving environment on postural control and task performance during manual materials handling, visual tracking and arithmetic tasks

The purpose of this study was to evaluate the performance of cognitive tasks and manual materials handling in a moving environment. Specifically, we were interested in how task performance, postural control and lower limb muscle activation changed when tasks were performed in motion compared to no motion conditions. The motion trials were performed on a MOOG 2000E that created a 5-degree of freedom simulated environment. The tasks examined were a lifting task, a mental arithmetic task and a visual tracking task. Results of this experiment indicated that two outcome measures of a visual tracking task (time to task completion and performance errors) were negatively affected by motion, while arithmetic task performance was unaffected. Additionally, postural control was not affected by the presence of motion in the two cognitive tasks. Lifting was the only task where postural control appeared to be negatively affected as participants exhibited significant increases in lower limb muscle activation and non-significant increases in number of steps taken. The significant increase in time to completion and errors suggest that workers performing visual tracking type tasks in an offshore environment may be more prone to committing human factors errors. Furthermore, the results suggest that the risk of falls and injury due to loss of balance may be highest in workers regularly performing lifting tasks as this was the only instance where task performance in a moving environment negatively impacted postural control. These findings were attributed to greater demands placed on the postural control system when lifting during the motion condition. This study provides ergonomists with a resource they can use to better appreciate the risks associated with performance of job related tasks in a moving environment.