title: Precueing time but not direction of postural perturbation induces early muscular activation: comparison between young and elderly individuals.
abstract: In this study, we evaluated the effect of precueing characteristics of an impending perturbation to upright stance on reactive responses of distal leg muscles. Young and older individuals were compared in a task of recovering stable upright stance following rotation of the supporting platform to induce anterior or posterior body sway. Directions of the supporting platform rotation were randomized across trials. Immediately before postural perturbation participants were cued about direction and/or time of platform rotation, or performed the task under directional and temporal uncertainty of the impending perturbation. Results showed that precueing time of perturbation led to earlier muscular activation onset, while precueing perturbation direction did not modulate either latency or magnitude of muscular activation. Those effects were similar between age groups. Our findings suggest that awareness of the perturbation time favored shorter response latencies in both the young and older individuals.
authors.affiliation: Human Motor Systems Laboratory, School of Physical Education and Sport, University of São Paulo Av. Prof. Mello Moraes, 65, Cidade Universitária, São Paulo, SP, 05508-030, Brazil. Electronic address: marinabritos@hotmail.com.
authors.forename: Marina Brito
authors.initials: MB
authors.lastname: Silva
authors.affiliation: Human Motor Systems Laboratory, School of Physical Education and Sport, University of São Paulo Av. Prof. Mello Moraes, 65, Cidade Universitária, São Paulo, SP, 05508-030, Brazil. Electronic address: danielboari@gmail.com.
authors.forename: Daniel Boari
authors.initials: DB
authors.lastname: Coelho
authors.affiliation: Institute of Radiology, LIM44, Faculty of Medicine, University of São Paulo Av. Dr. Enéas de Carvalho Aguiar, s/n°, Rua 1 , Cerqueira César, São Paulo, SP, 5,403-900, Brazil. Electronic address: aclfisio@yahoo.com.br.
authors.forename: Andrea Cristina
authors.initials: AC
authors.lastname: de Lima-Pardini
authors.affiliation: Human Motor Systems Laboratory, School of Physical Education and Sport, University of São Paulo Av. Prof. Mello Moraes, 65, Cidade Universitária, São Paulo, SP, 05508-030, Brazil. Electronic address: lerezendemartinelli@yahoo.com.br.
authors.forename: Alessandra Rezende
authors.initials: AR
authors.lastname: Martinelli
authors.affiliation: Human Motor Systems Laboratory, School of Physical Education and Sport, University of São Paulo Av. Prof. Mello Moraes, 65, Cidade Universitária, São Paulo, SP, 05508-030, Brazil. Electronic address: thaissbaptista@gmail.com.
authors.forename: Thais da Silva
authors.initials: Tda S
authors.lastname: Baptista
authors.affiliation: Department of Psychiatry, Faculty of Medicine, University of São Paulo Rua Doutor Ovídio Pires de Campos,785 , Cerqueira César, São Paulo, SP, 5403,010, Brazil. Electronic address: rtramos@usp.br.
authors.forename: Renato Teodoro
authors.initials: RT
authors.lastname: Ramos
authors.affiliation: Human Motor Systems Laboratory, School of Physical Education and Sport, University of São Paulo Av. Prof. Mello Moraes, 65, Cidade Universitária, São Paulo, SP, 05508-030, Brazil. Electronic address: lateixei@usp.br.
authors.forename: Luis Augusto
authors.initials: LA
authors.lastname: Teixeira
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001288:Attention; D003463:Cues; D004576:Electromyography; D006801:Humans; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D004856:Postural Balance; D011187:Posture; D011897:Random Allocation; D011930:Reaction Time; D012399:Rotation; D013997:Time Factors
keywords: Aging; Balance perturbation; Muscular responses; Precueing; Uncertainty