title: Aging increases flexibility of postural reactive responses based on constraints imposed by a manual task.
abstract: This study compared the effect of stability constraints imposed by a manual task on the adaptation of postural responses between 16 healthy elderly (mean age = 71.56 years, SD = 7.38) and 16 healthy young (mean age = 22.94 years, SD = 4.82) individuals. Postural stability was perturbed through unexpected release of a load attached to the participant's trunk while performing two versions of a voluntary task: holding a tray with a cylinder placed with its flat side down (low constraint) or with its rolling round side down (high constraint). Low and high constraint tasks were performed in alternate blocks of trials. Results showed that young participants adapted muscular activation and kinematics of postural responses in association with previous experience with the first block of manual task constraint, whereas the elderly modulated postural responses based on the current manual constraint. This study provides evidence for flexibility of postural strategies in the elderly to deal with constraints imposed by a manual task.
authors.affiliation: Laboratory of Medical Investigation (LIM44), Institute of Radiology, Faculty of Medicine, University of São Paulo São Paulo, SP, Brazil.
authors.forename: Andrea Cristina
authors.initials: AC
authors.lastname: de Lima-Pardini
authors.affiliation: Human Motor Systems Laboratory, Department of Human Movement Biodynamics, School of Physical Education and Sport, University of São Paulo São Paulo, SP, Brazil.
authors.forename: Daniel Boari
authors.initials: DB
authors.lastname: Coelho
authors.affiliation: Human Motor Systems Laboratory, Department of Human Movement Biodynamics, School of Physical Education and Sport, University of São Paulo São Paulo, SP, Brazil.
authors.forename: Marina Brito
authors.initials: MB
authors.lastname: Silva
authors.affiliation: Human Motor Systems Laboratory, Department of Human Movement Biodynamics, School of Physical Education and Sport, University of São Paulo São Paulo, SP, Brazil.
authors.forename: Nametala Maia
authors.initials: NM
authors.lastname: Azzi
authors.affiliation: Human Motor Systems Laboratory, Department of Human Movement Biodynamics, School of Physical Education and Sport, University of São Paulo São Paulo, SP, Brazil.
authors.forename: Alessandra Rezende
authors.initials: AR
authors.lastname: Martinelli
authors.affiliation: Portland VA Medical Center and the Balance Disorders Laboratory, Department of Neurology, School of Medicine, Oregon Health and Science University Portland, OR, USA.
authors.forename: Fay Bahling
authors.initials: FB
authors.lastname: Horak
authors.affiliation: Human Motor Systems Laboratory, Department of Human Movement Biodynamics, School of Physical Education and Sport, University of São Paulo São Paulo, SP, Brazil.
authors.forename: Luis Augusto
authors.initials: LA
authors.lastname: Teixeira
keywords: balance control; dual task; elderly; manual constraint; postural adaptation; postural control