There are several electrical brain waves, although researchers still do not fully agree on the exact frequency range and functions of the brain waves. In this study, four of these bands were quantified: the delta band (ranging between 2 to 4 Hz), theta band (ranging between 4 and 8 Hz), alpha band (ranging between 8 and 12 Hz), and beta band (ranging between 12 and 30 Hz) [20 ]. Of the four, (1) delta is the slowest frequency band with the highest power and associates with sleep states and memory consolidation; (2) the theta band is related to a state of drowsiness, network coordination, and episodic memory; (3) the alpha band is responsible for cognitive performance, selective attention, and consolidation of new motor sequences, and (4) beta is the faster frequency band with the lower power, which relates to sensorimotor association, motor imagery, and autonomous nervous system regulation [21 (link)].
The EEG technique is already seen as a robust biomarker for several medical conditions [22 (link)], although in the sports domain, due to the environment in which the measures are taken, it is still too early to define reliable biomarkers precisely [21 (link)]. Nevertheless, research in clinical [23 (link)] and sports [24 (link)] domains reported results in relative amplitude, a measure that seeks to present the contribution of oscillations in the different frequency ranges.
During the experiment, the participants performed the physical exercise task in a room where intermittent noise was allowed to maintain the ecology of the task [25 (link)]. A 32-channel Epoc Flex system (EPOC Flex Control Box from Emotiv, San Francisco, CA, USA) with various electrode placements within a traditional head cap was used. It was already validated against a Neuroscan device, but for event-related potentials (ERP), changes in alpha signatures, and steady-state visual-evoked potentials [26 (link)]. The EEG signals were recorded according to the international 10–20 system (Fp1, Fp2, F7, F3, Fz, F4, F8, T9, C5, C1, C2, C6, T10, T7, C3, Cz, C4, T8, P5, P1, P2, P6, P7, P3, Pz, P4, P8, O9, O1, Oz, O2, O10), with a sampling frequency of 128 Hz. The reference was the average of the left and right mastoids and the signals were recorded by EmotivPro (Emotiv Premium License, San Francisco, USA). During the task, EEG activity was recorded from all 32 channels. The circuit impedance was kept below 5 kΩ for all electrodes before the sessions. Participants were asked to sit comfortably in the leg press, the head remaining as still as possible, and to avoid excessive blinking.
The EEG technique is already seen as a robust biomarker for several medical conditions [22 (link)], although in the sports domain, due to the environment in which the measures are taken, it is still too early to define reliable biomarkers precisely [21 (link)]. Nevertheless, research in clinical [23 (link)] and sports [24 (link)] domains reported results in relative amplitude, a measure that seeks to present the contribution of oscillations in the different frequency ranges.
During the experiment, the participants performed the physical exercise task in a room where intermittent noise was allowed to maintain the ecology of the task [25 (link)]. A 32-channel Epoc Flex system (EPOC Flex Control Box from Emotiv, San Francisco, CA, USA) with various electrode placements within a traditional head cap was used. It was already validated against a Neuroscan device, but for event-related potentials (ERP), changes in alpha signatures, and steady-state visual-evoked potentials [26 (link)]. The EEG signals were recorded according to the international 10–20 system (Fp1, Fp2, F7, F3, Fz, F4, F8, T9, C5, C1, C2, C6, T10, T7, C3, Cz, C4, T8, P5, P1, P2, P6, P7, P3, Pz, P4, P8, O9, O1, Oz, O2, O10), with a sampling frequency of 128 Hz. The reference was the average of the left and right mastoids and the signals were recorded by EmotivPro (Emotiv Premium License, San Francisco, USA). During the task, EEG activity was recorded from all 32 channels. The circuit impedance was kept below 5 kΩ for all electrodes before the sessions. Participants were asked to sit comfortably in the leg press, the head remaining as still as possible, and to avoid excessive blinking.
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