Propensity to consciously control movements predicts foot placement and quiet standing performance in older adults

Abstract

The higher propensity to consciously control movements (i.e., reinvestment) has been suggested to be related to higher risk of falling in the elderly (Wong, Masters, Maxwell, & Abernethy, 2008). One of the most common causes of elderly falls is loss of balance. Foot placements have been shown to play an influential role in postural control during stance (Day, Steiger, Thompson, & Marsden, 1993). The aim of this study was to examine whether the propensity to reinvest is related to foot placement during assumption of comfortable stance in older adults. Furthermore, the relationship between reinvestment and balance performance was measured. Fifty-six older adults (Mean age=69.88, SD=4.07) were asked to fill in the Movement-Specific Reinvestment Scale (MSRS; Masters, Eves, & Maxwell, 2005). They were then required to step on a force platform and take their most comfortable stance. Stance width, foot angle, and number of adjustments were measured. Finally, participants’ quiet standing performance during one minute was assessed using four center of pressure measures of postural stability: path length, area of sway, sway variability in anterior-posterior and medio-lateral directions. Pearson’s correlation coefficient showed significant positive correlation between MSRS scores and the number of adjustments (r=.36, p=.006). Linear regression showed that movement-specific reinvestment predicted 13% of the variance in the number of adjustments (F(1,54)=8.026, p=.006). Furthermore, a significant positive correlation was found between MSRS scores and sway variability in anterior-posterior directions (r=.29, p=.031). Linear regression showed that movement-specific reinvestment predicted 8.5% of the variance in sway variability (F(1,54)=4.912, p=.031). These preliminary results suggest that the propensity to reinvest could be a contributing factor to foot placement during assumption of comfortable stance, and also to postural control during quiet standing. These findings contribute to our emerging understanding of the relationship between reinvestment and falling in older adults.