Shaking Stimulation Enhances Postural Stability in Older Adults with Comparative Effects of 5- and 10-Minute Protocols and Underlying Mechanisms

Shaking stimulation has emerged as a novel non-pharmacological strategy for improving postural stability in older adults, primarily through activation of deep musculature and enhancement of proprioceptive feedback. Previous studies demonstrated limited effects after ≤5 minutes of stimulation, but the impact of extended protocols remains unclear. To compare the immediate effects of 5- and 10-minute shaking stimulation on postural sway under visual and non-visual conditions, and to explore possible neurophysiological mechanisms. Nineteen independent older adults (80.4 ± 4.2 years) underwent platform-based shaking stimulation (8 Hz, 1 cm amplitude) for 5 or 10 minutes. Postural sway was assessed using a pressure sensor across six conditions: baseline (eyes-open), post-5min (eyes-open/closed), post-10min (eyes-open/closed). Parameters included sway area, trajectory length, anteroposterior (AP), and mediolateral (ML) displacements. Data were analyzed using paired t-tests. Ten-minute stimulation significantly reduced sway area (−21.5%) and trajectory length (−25.7%) under eyes-open conditions (p<0.05), whereas the 5-minute protocol showed no significant improvement. Under eyes-closed conditions, benefits of the 10-minute protocol were attenuated, with only trajectory length showing modest improvement (−16.9%, p=0.047). AP displacement paradoxically increased in eyes-closed conditions (+13.7%, p=0.038). No significant ML effects were observed. Compared to 5-minute stimulation, a 10-minute protocol provides superior postural stabilization, particularly when visual feedback is available. These findings suggest that extended shaking enhances sensorimotor integration by strengthening somatosensory-visual synergy, whereas visual deprivation limits the efficacy. Shaking duration is a key determinant of therapeutic outcomes, supporting its application in fall-prevention strategies for older adults.