Characteristics of step responses following varying magnitudes of unexpected lateral perturbations during standing among older people – a cross-sectional laboratory-based study

Abstract

Introduction The inability to recover from unexpected lateral loss of balance may be particularly relevant to the problem of falling. Aim We aimed to explore whether different kinematic patterns and strategies occur in the first recovery step in single-step trials in which a single step was required to recover from a fall, and in multiple-step trials in which more than one step was required to recover from a fall. In addition, in the multiple-step trials, we examined kinematic patterns of balance recovery where extra steps were needed to recover balance. Methods Eighty-four older adults (79.3 ± 5.2 years) were exposed to unannounced right/left perturbations in standing that were gradually increased to trigger a recovery stepping response. We performed a kinematic analysis of the first recovery step of all single-step and multiple-step trials for each participant and of total balance recovery in the multiple-step trial. Results Kinematic patterns and strategies of the first recovery step in the single-step trials were significantly dependent on the perturbation magnitude. It took a small, yet significantly longer time to initiate a recovery step and a significantly longer time to complete the recovery step as the magnitude increased. However, the first recovery step in the multiple-step trials showed no significant differences between different perturbation magnitudes; while, in total balance recovery of these trials, we observed a small, yet significant difference as the magnitude increased. Conclusions At relatively low perturbation magnitudes, i.e., single-step trials, older adults selected different first stepping strategies and kinematics as perturbation magnitudes increased, suggesting that this population activated pre-planned programs based on the perturbation magnitude. However, in the first recovery step of the multiple-step trials, i.e., high perturbation magnitudes, similar kinematic movement patterns were used at different magnitudes, suggesting a more rigid, automatic behavior, while the extra-steps were scaled to the perturbation magnitude. This suggest that older adults activate pre-planned programs based on the magnitude of the perturbation, even before the first step is completed..

Classification and Definitions of Compensatory Protective Step Strategies in Older Adults: A Scoping Review

“…In addition, it is important to know how to resolve motor problems in the presence of external perturbations. To answer this question, scientists have simulated perturbations in laboratory conditions to analyze the compensatory protective step strategies [21][22][23][24], terms suggested by Tisserand et al [13]. In this sense, different instruments have been used to train balance [25] or generate falls such as the waist-pull [22], mobile platforms [26,27], slippery floor surfaces [28], release system [29,30] or new robotic devices [31].…”

The Effect of Arm Restriction on Dynamic Stability and Upper Body Responses to Lateral Loss of Balance During Walking: An Observational Study

“…Reactive recovery responses are critical for maintaining dynamic stability following a sudden loss of balance. While extensive research has delved into understanding lower limb reactions to balance disruptions [1][2][3][4][5], the contribution of upper body responses in restoring balance are not fully understood. Increasing the understanding of upper body responses to balance perturbations is vital for identifying rehabilitation training targets for fall prevention.…”

Development of an Elliptical Perturbation System that provides unexpected perturbations during in-place walking (the EPES system)

“…and reactive balance [9,10], which may increase the risk of falls and require physical intervention. Falls may have severe consequences that can cause injuries such as broken bones or a head injury [11], [12].…”