Differences between Young and Older Adults in the Control of Weight Shifting within the Surface of Support

Abstract

An important reason for falling in elderly is incorrect weight-shifting. In many daily life activities quick and accurate weight-shifting is needed to maintain balance and to prevent from falling. The present study aims to gain more insight in age-related differences in the control of weight-shifting. Nine healthy older adults (70.3±6.9 years) and twelve young adults (20.9±0.5 years) participated in the study. They performed a weight shifting task by moving the body's center of pressure, represented by a red dot on a screen, in different directions, towards targets of different sizes and at different distances projected on a screen. Movement time, fluency and accuracy of the movement were determined. Accuracy was quantified by the number of times the cursor hit the goal target before a target switch was realized (counts on goal) and by the time required to realize a target switch after the goal target was hit by the cursor for the first time (dwelling time). Fluency was expressed by the maximal deviation of the performed path with respect to the ideal path and the number of peaks, or inflections in the performed path. Significant main effects of target size, target distance and age on all outcome measures were found. With decreasing target size, increasing target distance and increasing age, movement time significantly increased and fluency and accuracy significantly decreased (i.e. increased number of peaks, maximal deviation, number of times on the goal target and longer dwelling time around the goal target). In addition, significant interaction effects of size*age and distance*age were found. Older adults needed more time to perform the weight-shifting task and their movements were less fluent and accurate compared to younger adults, especially with increasing task difficulty. This indicates that elderly might have difficulties with executing an adequate adaptation to a perturbation in daily life.

Quantifying Postural Control during Exergaming Using Multivariate Whole-Body Movement Data: A Self-Organizing Maps Approach

“…Our finding that older adults display more variability while performing complex tasks than young adults is consistent with results of previous studies showing that age-related deterioration of postural control is linked with increased movement variability under complex task conditions [ 16 , 37 , 38 ]. More specifically, the high TTvar score of older adults in the ‘maximum sway frequency’ condition is in line with results of Hernandez et al and de Vries et al [ 37 , 39 ] showing that rapid weight shifts are associated with an increased number of submovements as well as decreased fluency and accuracy in the elderly population.…”

Effects of Filtering the Center of Pressure Feedback Provided in Visually Guided Mediolateral Weight Shifting

“…Elderly subjects have been shown to complete weight shifting tasks more slowly and with greater difficulty than young adults [ 29 ]. Stroke patients, who are often advanced in years, are therefore likely to demonstrate differing results from younger subjects.…”

Implicit and Explicit Learning of a Sequential Postural Weight-Shifting Task in Young and Older Adults

“…Participants stood on two force platforms (Bertec FP4060-08). On a large screen, positioned 2.5 m in front of the participant, a cursor provided online feedback of the CoP displacements of the participant ( de Vries et al, 2014 ). The displacements of the CoP were displayed on the vertical screen as cursor movements from left to right for the medio-lateral component and from top to bottom for the anterior–posterior component.…”

“…For example, the sequence of asks needed to get a glass of water may include, leaning over to a cupboard, opening the cupboard, grasping a glass, moving to the tap, and turning on the faucet. Prediction of, adaptation to, and learning about, environmental regularities on the basis of preceding events may assist in how the body needs to be moved in order to achieve the task goal, and requires adequate postural control ( Sturnieks et al, 2008 ; de Vries et al, 2014 ).…”

“…In the target-directed weight-shifting task, participants control their CoP on a force platform by shifting their weight in order to move a cursor on a screen in front of them ( Jongman et al, 2012 ; de Vries et al, 2014 ). Participants are asked to move the cursor to a target that can appear in one of five locations.…”