Changes in brain activity induced by the N-back task are related to improved dual-task performance.

Dual-task performance often influences athletic competition results. Previous studies have suggested that cognitive tasks might improve dual-task performance. However, the factors that contribute to the manner in which cognitive tasks improve dual-task performance remain unknown. This study aimed to examine whether changes in brain activity induced by cognitive tasks are associated with improvement in dual-task performance. Nineteen young healthy adults performed an N-back and a reaction task on different days. A dual-task was constructed by combining a force-control and a calculation task. In the force-control task, participants adjusted their knee extension force according to target waves. In the calculation task, participants were required to subtract and respond to auditory stimuli delivered via earphones. We evaluated dual-task performance before and after performing each cognitive task. Additionally, we measured cerebral hemodynamic activity using near-infrared spectroscopy during the performance of each cognitive task. As a result, performing the N-back task improved performance in the force-control task under the dual-task setup. Furthermore, increase in oxyhemoglobin in a part of the right dorsolateral prefrontal cortex during the N-back task was positively correlated with improved force control during the subsequent dual-task. Cognitive tasks can be easily performed in a clinical field. Thus, cognitive tasks could be incorporated in traditional physical training. Future research should investigate whether the present findings can translate to improving performance in athletic competitions.