Postural coordination in adults and elderly individuals during voluntary whole-body movements

Author(s)

Sandra Maria Sbeghen Ferreira de Freitas

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Escola de Educação Física e Esportes (EEFE/BT)
• Defense date: 2005-07-05

Examining board members

Marcos Duarte; José Angelo Barela; Ricardo Machado Leite de Barros; Edison de Jesus Manoel; Luis Augusto Teixeira

• Advisor: Marcos Duarte

Abstract

This study examined how postural coodination patterns during voluntary whole-body movements in standing are affected by aging using the speed-accuracy trade-off paradigm. Ten elderly subjects and ten young adults stood on a force plate and had their center of pressure (COP) instantaneous position shown as visual feedback on a computer monitor one meter ahead. The participants performed continuous fast and accurate movements in the anterior-posterior direction with the whole body shifting their COP position; between targets with different widths or in different movement frequencies, during 45 s. Movement time (MT), COP displacement, joint angle excursion and eletromyographic (EMG) activity of ankle, knee and hip muscles were analyzed. Principal component (PC) analyses of the joint angles were also carried out. Flexibility of the postural coordination was evaluated using uncontrolled manifold (UCM) approach to test the trunk and the center of mass (COM) stabilization hypothesis. Both groups increased the MT, EMG activity and kinematic variables with an increase in the accuracy and frequency. Elderly subjects increased joint angles and EMG amplitude compared to adults. PC analysis showed a high coupling among the joints and the UCM analysis confirmed the trunk and the COM stabilization hypothesis. The results indicated that postural coordination patterns are affected by accuracy of whole-body movements and some changes are correlated with to aging (AU)