Xuan Liu1, Sasha Reschechtko2, Shuaijie Wang1, Yi-Chung Clive Pai3. 1. Department of Physical Therapy, University of Illinois at Chicago, Chicago, IL 60612, United States. 2. Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, United States. 3. Department of Physical Therapy, University of Illinois at Chicago, Chicago, IL 60612, United States. Electronic address: cpai@uic.edu.
Abstract
BACKGROUND: After a single slip, older adults rapidly make adaptive changes to avoid or eliminate further backward loss of balance or a fall. This rapid adaptation has been termed the "single trial effect". The purpose of this study was to explore the relationship between the motor errors subjects experienced upon a novel slip and the selection and execution of corrective response by which they modified their ongoing gait pattern and turned it into a protective step. METHODS: A forward slip was induced in the laboratory among 145 community-living older (≥65year old) adults who were protected by an overhead full body harness system. An eight-camera motion analysis system recorded subjects' kinematics, which was used to compute their instability (motor error), recovery step placement (response selection), and stability gain (motor correction). FINDINGS: A linear relationship was found between the stability errors at recovery foot liftoff and the distance between the recovery foot and slipping foot at the time of its touchdown, reflecting an appropriate selection of response that was proportionate to the motor error. A linear relationship was also found between this step modification and resulting stability gain, indicating that greater step modification resulted in greater stability gain. This learning behavior was surprisingly consistent regardless whether the outcome was a recovery or a fall. INTERPRETATIONS: These results suggest that fallers and non-fallers all have an intact motor learning foundation that has enabled them to rapidly improve their stability in subsequent exposures. Published by Elsevier Ltd.
BACKGROUND: After a single slip, older adults rapidly make adaptive changes to avoid or eliminate further backward loss of balance or a fall. This rapid adaptation has been termed the "single trial effect". The purpose of this study was to explore the relationship between the motor errors subjects experienced upon a novel slip and the selection and execution of corrective response by which they modified their ongoing gait pattern and turned it into a protective step. METHODS: A forward slip was induced in the laboratory among 145 community-living older (≥65year old) adults who were protected by an overhead full body harness system. An eight-camera motion analysis system recorded subjects' kinematics, which was used to compute their instability (motor error), recovery step placement (response selection), and stability gain (motor correction). FINDINGS: A linear relationship was found between the stability errors at recovery foot liftoff and the distance between the recovery foot and slipping foot at the time of its touchdown, reflecting an appropriate selection of response that was proportionate to the motor error. A linear relationship was also found between this step modification and resulting stability gain, indicating that greater step modification resulted in greater stability gain. This learning behavior was surprisingly consistent regardless whether the outcome was a recovery or a fall. INTERPRETATIONS: These results suggest that fallers and non-fallers all have an intact motor learning foundation that has enabled them to rapidly improve their stability in subsequent exposures. Published by Elsevier Ltd.
Entities:
Keywords:
Motor learning; Perturbation; Protective stepping; Stability
Authors: Paulo Cesar Barauce Bento; Gleber Pereira; Carlos Ugrinowitsch; André Luiz Felix Rodacki Journal: Clin Biomech (Bristol, Avon) Date: 2010-03-28 Impact factor: 2.063
Authors: Daina L Sturnieks; Jasmine Menant; Kim Delbaere; Jos Vanrenterghem; Mark W Rogers; Richard C Fitzpatrick; Stephen R Lord Journal: PLoS One Date: 2013-08-09 Impact factor: 3.240
Authors: Daniel Schoene; Stephen R Lord; Kim Delbaere; Connie Severino; Thomas A Davies; Stuart T Smith Journal: PLoS One Date: 2013-03-05 Impact factor: 3.240