Mental fatigue induced by prolonged motor imagery increases perception of effort and the activity of motor areas

Recent literature suggests that when prolonged, motor imagery (MI) induces mental fatigue and negatively impacts subsequent physical exercise. The aim of this study was to confirm possibility with neurophysiological self-reported measures. Thirteen participants performed 200 imagined isometric knee extension contractions (Prolonged MI condition) or watched a documentary (Control condition), then 150 actual extensions. Electroencephalography continuously recorded obtain motor-related cortical potential amplitude at Cz electrode (MRCP, index area activity) for each contraction. Electromyography the vastus lateralis muscle as well perceived effort required perform prolonged MI, watch documentary, were measured. During level, imagine MRCP increased over time. increase in significantly correlated amplitude. exercise, significant condition × time interaction revealed greater compared control condition, specific alteration EMG RMS muscle. These alterations observed presence during contractions, combined those suggest may impair command contractions. While effect on clear future studies should tailor exercise minimize exercise-induced decrease force production capacity its confounding effects fatigue.