Introduction A handgrip manipulation has been reported to produce varied behavioural aftereffects which are dependent on which hand had been used for the contractions. Most notably, Beckmann et al (2013) reported a protective effect of left hand-grip over the skill failure in athletes performing under stress. These effects had been proposed to result from the induction of asymmetric activity of the cortical hemispheres, with greater activity over the hemisphere contralateral to the hand used. But the effects after contractions are finished had not been directly assessed. Method We first assessed the cortical state after handgrip execution through electroencephalography (EEG). Twenty participants executed 45 seconds of dynamic handgrip exercise with each hand, and their EEG alpha band and its asymmetry ratio before and after contractions were contrasted. In a second experiment, we tested the behavioural effect of such induced state over performance in a 2D table tennis videogame with stress induction. In the task, participants controlled both paddles and had to keep the ball in movement for as long as possible. This task was carried with and without stress induction, performance and EEG signatures were assessed. Results In the first experiment, it was found that left hand contractions produced an elevation of alpha amplitudes over the whole scalp while right contractions produced a much smaller enhancement. No effects changes in alpha asymmetry were observed. In the second experiment, although stress-induction was not significant, it was noticed that greater alpha amplitudes at rest before the task correlated with better performance. Discussion It is proposed that dynamic handgrip produces a generalized enhancement of alpha amplitudes. Based on the second experiment, such induction might aid sportive performance and protect from the effects of stress, but a direct proof including both EEG and effective stress induction is still missing.     «

Introduction A handgrip manipulation has been reported to produce varied behavioural aftereffects which are dependent on which hand had been used for the contractions. Most notably, Beckmann et al (2013) reported a protective effect of left hand-grip over the skill failure in athletes performing under stress. These effects had been proposed to result from the induction of asymmetric activity of the cortical hemispheres, with greater activity over the hemisphere contralateral to the hand used. B...     »