Volitional Running and Tone Counting: The Impact of Cognitive Load on Running Over Natural Terrain

OCCUPATIONAL APPLICATIONS Many occupations, including those of emergency responders and military personnel, require the person to maintain volitional control of movement speed while simultaneously engaging in cognitive tasks. In the present study, runners who ran over uneven and even natural terrain slowed their running speed when confronted with increased cognitive load. Runners had impaired cognitive task performance only when the cognitive load was high and they were running over uneven terrain. While more research is warranted, the present findings indicate that willed running or movement speed reduces with increasing cognitive load. The addition of cognitive load to people who have to cover terrain may impair their speed. In occupational settings requiring both movement and cognitive tasks, the interacting effect of these tasks needs to be carefully considered. For example, where speed is important any additional cognitive load should be reduced or eliminated if possible. TECHNICAL ABSTRACT Background: Many occupations require movement over natural terrain while the person is simultaneously performing cognitive tasks (communication, navigations, etc.), yet there is little known about how cognitive load impacts movement over natural (not artificial) terrain. Purpose: The present study was designed to examine the impact of cognitive load on volitionally controlled running speed over natural terrain. Method: We examined the performance of runners on even and uneven terrain in a dual running and tone-counting working memory task. The tone counting task was performed at both a low and a high workload. Participants performed the tone-counting tasks both while running and while seated. In addition, they ran without a cognitive task load. Results: Counting accuracy significantly decreased during the dual task trials only for the high workload task and only for the uneven terrain runners. For both terrain groups there was a linear trend observed; run distance decreased as cognitive load increased. Reports of workload, task-focus and feelings of being spent after running all increased with increased cognitive load regardless of terrain. Conclusion: These findings have important theoretical and practical implications, particularly where natural running is coupled with complex cognitive tasks.