BackgroundThe purpose of this study was to investigate the changes in the Power Spectrum Density (PSD) of the electroencephalography (EEG) in common sensorimotor balance training tasks of varying difficulty. Sensorimotor balance exercises including alteration of vision, base of support or surface compliance are used to improve postural control. These exercises are presumed to induce supraspinal adaptation, however, there were no studies that investigated the power changes of the cortical activity in these static balance tasks. Our objective was to provide evidence in the cortical involvement with the static balance tasks frequently used in sensorimotor training.Material/MethodsPostural sway and EEG changes of alpha, beta and sigma wave bands were measured in seventeen participants during eight balance tasks of varying difficulty with eyes open and closed, feet in tandem or apart and on foam or a firm surface.ResultsThe power of beta and sigma bands increased significantly at the parietal and central area of the brain in tasks with eyes open together with one sensory factor (base of support or surface compliance) or two sensory factors (base of support and surface compliance) altered, and in task with three sensory factors (vision, base of support and surface compliance) altered from the control task.ConclusionsThis study demonstrated the cortical involvement in the sensorimotor balance tasks, suggesting that these exercises may induce cortical adaptation for postural control. The results support subcortical control with increased task difficulty and the increase in cortical processing when task became extremely challenging.

Aims: This study examined how vision, base of support (BOS) and surface compliance affected postural sway and electromyography (EMG) activity of hip and ankle muscles during eight balance training tasks in young adults. Methods: Postural sway and EMG activity of gluteus maximus (GMAX), gluteus medius (GMED), tibialis anterior (TA), and medial gastrocnemius (GAST) were measured during eight balance tasks with eyes open or closed, feet in tandem or apart, and on foam or a firm surface. Results: Postural sway and EMG activity of hip and ankle muscles were significantly affected by the alteration of vision, surface compliance or BOS during eight balance tasks (P<0.05). There was more postural sway when the number of sensory factors altered in the balance tasks increased. GMED and TA EMG activity increased significantly in tasks with tandem standing; GMAX was recruited significantly only when vision was excluded in tasks with tandem standing; and GAST EMG activity was significantly higher in tasks on the foam and in tandem standing. Conclusions: Balance exercises may be progressed according to the rank of the task’s difficulty by increasing the number of sensory factors altered in a balance task. There was significant recruitment of hip and ankle muscles in the balance tasks indicating the importance of these muscles in postural control.