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

• Published in: BMC geriatrics Vol. 22; no. 1; p. 400
• Main Authors: Batcir, Shani, Shani, Guy, Shapiro, Amir, Melzer, Itshak
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 06.05.2022; BioMed Central; BMC
• Subjects: Aged; Balance; Cross-Sectional Studies; Environmental aspects; Experiments; Falls; First step is completed; Fitness equipment; Geriatrics; Humans; Kinematics; Older adults; Older people; Physiological aspects; Postural Balance - physiology; Posture; Recovery (Medical); Standing Position; Step recovery response; Total balance recovery; Unexpected balance perturbation; Velocity; Walking - physiology; Israel; Falls; First step is completed; Older adults; Unexpected balance perturbation; Total balance recovery; Step recovery response
• ISSN: 1471-2318; 1471-2318
• DOI: 10.1186/s12877-022-03080-w

The inability to recover from unexpected lateral loss of balance may be particularly relevant to the problem of falling. 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. 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. 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. 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..