Moein Koohestani,Ali Sharifnezhad,Ali  Abbasi,Amir-Homayoun  Javadi,Alli  Gokeler,
Brain Activation During Maximum Concentric and Eccentric Knee Extension Muscle Contractions
Journal of Brain and Nerves
2020
2733-2284
http://dx.doi.org/10.31487/j.JBN.2020.01.05
https://www.sciencerepository.org/brain-activation-during-maximum-concentric-and-eccentric-knee-extension_JBN-2020-1-105 
Abstract: Purpose: In spite of mounting evidence indicating that concentric and eccentric knee extensor muscle
contractions might have special nervous system control strategies, the differentiation of brain frequencies
between concentric and eccentric movements and how the motor cortex programs this contraction has been
less studied. In this study, the brain and muscle activation differences during maximum concentric and
eccentric contractions were compared.
Methods: Nine healthy volunteers performed 20 maximum eccentric and 20 maximum concentric knee
extensor contractions. Electroencephalography (EEG) signals from sensorimotor-related cortical areas were
recorded simultaneous with the electromyography (EMG) of the knee extensor muscles. In the spectral
analysis the performance related power values were calculated for Theta (4-7 Hz) and Alpha (7-12 Hz).
Results: The time-domain results revealed, longer time and greater cortical activity is required for the
preparation of an eccentric contraction. For the eccentric task, the cortical activity was greater, but the EMG
was lower in comparison to the concentric task values. Statistical analysis showed significant higher and
lower Theta and Alpha power in both types of contractions compared to the resting state, respectively.
Conclusion: These findings suggest that increased Theta power is associated with task complexity and
focused attention and decreased Alpha power values with increased information processing in the
somatosensory cortex.Keywords: Electroencephalography (EEG), electromyography (EMG), alpha power, theta power, eccentric contraction