Marcos Duarte

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A method of decomposing stabilograms into two components, termed rambling, was developed. The rambling component reveals the motion of a moving reference point with respect to which the body's equilibrium is instantly maintained. The trembling component reflects body oscillation around the reference point trajectory. The concepts of instant equilibrium(More)
Aging is known to have a degrading influence on many structures and functions of the human sensorimotor system. The present work assessed aging-related changes in postural sway using fractal and complexity measures of the center of pressure (COP) dynamics with the hypothesis that complexity and fractality decreases in the older individuals. Older subjects(More)
Maintenance of equilibrium was tested in conditions when humans assume different leaning postures during upright standing. Subjects (n=11) stood in 13 different body postures specified by visual center of pressure (COP) targets within their base of support (BOS). Different types of visual information were tested: continuous presentation of visual target, no(More)
Although water environment has been employed for different physical activities, there is little available information regarding the biomechanical characteristics of walking in shallow water. In the present study, we investigated the kinematics, ground reaction forces (GRF), and electromyographic (EMG) activation patterns of eight selected muscles of adults(More)
BACKGROUND The maintenance of balance and body orientation in humans is guaranteed by the adequate functioning of the postural control system. The investigation of this control has awakened the interest of professionals from several fields such as Physical Therapy, Physical Education, Engineering, Physics, Medicine, Psychology, and others. OBJECTIVES The(More)
We analyzed the temporal evolution of the displacement of the center of pressure (COP) during prolonged unconstrained standing (30 min) in non-impaired human subjects. The COP represents the collective outcome of the postural control system and the force of gravity and is the main parameter used in studies on postural control. Our analysis showed that the(More)
BACKGROUND Previous studies have shown that healthy young adults are able to decrease their standing postural sway when an additional postural visual task, such as reading, is performed. OBJECTIVE In this study, we investigated postural sway during dual tasks in young and elderly adults. METHODS Twelve healthy active elderly adults (aged 65-75 years)(More)
In this study, we examined Spatial-temporal gait stride parameters, lower extremity joint angles, ground reaction forces (GRF) components, and electromyographic activation patterns of 10 healthy elderly individuals (70+/-6 years) walking in water and on land and compared them to a reference group of 10 younger adults (29+/-6 years). They all walked at(More)