The aim of this study was to investigate the effects of different stance positions on real-time conscious movement processing, postural stability, and muscle efficiency under challenging balance environment in older adults.
Sixty-seven community-dwelling older adults were included in this preliminary analysis after the midterm period of data collection. Participants were invited to complete a series of standing balance trials. The trials involved participants standing in three different positions (two trials for each position) on a foam surface: wide-base standing (WBF), narrow-base standing (NBF), and tandem-base standing (TBF). Real-time conscious movement processing (indicated by electroencephalography (EEG) T3-Fz coherence), postural stability (indicated by the total sway path of sternum, shoulder, and pelvis measured by the motion capture system), and muscle efficiency (indicated by the co-contraction index of lower limb muscles measured by the electromyography (EMG)) were compared among the three standing positions using the mixed analysis of variances (ANOVA).
EEG T3-Fz coherence was significantly higher in TBF compared to NBF (p0.05). Sway paths of sternum, shoulder, and pelvis were significantly larger in TBF and NBF compared to WBF (ps0.05). Significantly higher co-contractions of shank and thigh were observed under TBF compared to NBF, and NBF compared to WBF (ps0.05).
Real-time conscious movement processing increased as a function of standing balance difficulty. Performance outcomes indicate that postural stability and muscle efficiency reduced as stance positions became more challenging. Taken together, this preliminary analysis highlights that older adults are susceptible to inducing environment- or stress- related conscious movement processing during postural balance in conjunction with poorer postural stability and muscle efficiency. Further analysis (e.g., sub-group analysis on older adults with high and low trait conscious movement processing propensities) is warranted when data collection will be completed.
As previous research has demonstrated the beneficial effect of an external focus manipulation that reduced real-time conscious movement processing under a challenging walking environment (but not in level-ground) in older adults, our findings provided a solid foundation for future psychomotor interventions in geriatric rehabilitation that target mitigating the negative effects of conscious movement processing during demanding balance scenarios.
conscious movement processing
standing balance
