Postural stability as a predictor for reactive response to perturbations




Yasuda, Tai
Moudy, Sarah
Patterson, Rita
Hensel, Kendi


Journal Title

Journal ISSN

Volume Title



Purpose: The major cause of accidental death for people above 65 is fall-related injuries. Fall risk can be assessed through postural stability or gait analysis following a trip-like perturbation. Easy clinical assessment is a major advantage of using postural stability, but it is unclear if it represents the ability to recover from a trip. The purpose of this study is to investigate if postural stability can be used to predict reactive response to perturbations. Methods: Postural stability was examined by participants standing still for 30 seconds. Corresponding measures were extracted from center of pressure (COP) including: mean velocity of COP (mvN), distances from COP (net_area), base of support (net_bos), and ratio of change in net_area to net_bos support (net_ratio). Reactive recovery was assessed by COP-Center of Mass (COM) distance and step length after perturbations were elicited by accelerating the treadmill at 5 meters/sec2 while walking. To determine if postural stability is associated with reactive recovery, linear regressions and correlations were performed. Waveform analysis was applied for COP-COM distances. Results: Weak correlations (r= 0-01-0.31, p=0.002-0.05) were found between step length and postural stability measures. COP-COM distance found one significant relationship with mvN after perturbation (p= 0.022, r=0.29). No other significant relationships were found. Conclusions: Data points selected for quiet standing, or inherent differences between postural and dynamic components of gait, may explain these results. Additional research in understanding if postural stability can predict reactive response is recommended for future assessment of fall risk.