Correlation analysis of gait variability and center of pressure during stance in healthy older adults

Objectives: Gait variability has the potential to be an indicator of fall risk in healthy older adults, however, little is known about its association with the indicator of standing balance. Analyzing the correlation of gait variability and center of pressure during stance will help to explore the control mechanisms of dynamic and static balance, and clarify whether the standing balance ability that is easily measured can be extrapolated to walking dynamic balance ability. Methods: Forty-two healthy older adults (67.2±3.4 years) were recruited. Zebris FDM(Germany) electronic walkway gait analysis system collects 7 gait parameters of 5–7 consecutive steps: stride variability, step variability, step width variability, stride time variability, support phase variability, swing phase variability and double support phase variability, meanwhile, collects center of pressure (COP) ellipse area of natural standing with eyes open. The correlation and partial correlation analysis are conducted between gait variability and standing COP ellipse area. Results: Among the 7 gait variabilities, the stride and step variabilities are associated with the COP ellipse area, correlation coefficients were 0.45 (P<0.01) and 0.46 (P<0.01), respectively. The other 5 variability are uncorrelated with COP ellipse area. Conclusion: There is a moderate correlation between longitudinal step, stride variability and standing COP ellipse area. The lateral step width variability and all of temporal gait variability don't correlate to the COP ellipse area. It shows that the static standing stability could reflect the longitudinal stability of walking, to a certain extent, but couldn't be extrapolated to the walking dynamic stability that associated with step width variability and temporal gait variability. It is suggested that gait variability should be a necessary complement to the assessment of falls risk in healthy older adults.