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Results 351 - 400 of 883
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Vaugoyeau M - - 2008
Maintaining erect human posture depends on graviceptive information. This can come from at least of three origins: vestibular, visual and somaesthetic. We hypothesize here that subject's use proprioception rather than visual or vestibular cues for their control of upright body posture and this even when subjects stand on a tilting ...
van der Kooij Herman - - 2007
Is human balance control dominated by time invariant continuous feedback mechanisms or do noncontinuous mechanisms play a significant role like intermittent control? The goal of this paper is to quantify how much of the postural responses evoked by pseudorandom external periodic perturbations can be explained by continuous time invariant feedback ...
Wong Wai Yin - - 2008
A method of using three tri-axial accelerometers for monitoring postural changes in sitting was introduced. Subjects were requested to perform forward trunk flexion and lateral bending. A motion analysis system and a three-dimensional rotation alignment device were used to verify the measurements of the accelerometers. The precision and reliability of ...
Plamondon A - - 2007
Ambulatory assessment of trunk posture is important in improving our understanding of the risk of low back injury. Recently, small inertial sensors combining accelerometers, gyroscopes and magnetometers were developed and appear to be promising for measuring human movement. However, the validity of such sensors for assessing three-dimensional (3D) trunk posture ...
Vaugoyeau M - - 2007
The aim of the present study was to investigate how the orientation and stabilization components of postural control may be affected as the result of the impaired proprioceptive integration possibly occurring in Parkinson's disease. To determine the proprioceptive contribution to postural control, parkinsonian patients and control subjects were asked to ...
Edmondston Stephen J - - 2007
OBJECTIVE: This study examines the influence of posture on the range of axial rotation of the thorax and the range and direction of the coupled lateral flexion. METHODS: The ranges of mid thoracic axial rotation and coupled lateral flexion were measured in 52 asymptomatic subjects (aged 18-43 years) using an ...
Johannsen Leif - - 2007
Light touch contact between the body and an environmental referent reduces fluctuations of center of pressure (CoP) in quiet standing although the contact forces are insufficient to provide significant forces to stabilize standing balance. Maintenance of upright standing posture (with light touch contact) may include both predictive and reactive components. ...
Mezzarane Rinaldo André RA Neuroscience Program and Biomedical Engineering Laboratory, Universidade de São Paulo, EPUSP, PTC, Av. Prof. Luciano Gualberto, Trav. 3, n. 158, Cx. Postal 61548, CEP 05424-970, São Paulo, SP, Brazil. - - 2007
The present work investigated the control of upright posture on inclined surfaces (14 degrees). Such conditions could, for example, change the contributions of muscle spindles resulting in alterations in postural sway. Subjects stood in quiet stance over a force platform positioned in one of three different fixed positions: horizontal (H), ...
Fujiwara Katsuo - - 2007
Investigated were postural movement pattern and action sequence of postural muscles while subjects rapidly flexed both arms during standing. The arm movement was started at the subject's own pace. Subjects were healthy individuals; 48 men and 53 women. Postural movement pattern was classified based on the movement angles of foot-leg ...
Wu Wen-Lan - - 2007
Although rugby is a popular contact sport and the isokinetic muscle torque assessment has recently found widespread application in the field of sports medicine, little research has examined the factors associated with the performance of game-specific skills directly by using the isokinetic-type rugby scrimmaging machine. This study is designed to ...
Paquette C - - 2007
Saccadic reaction times can be shortened by an additional sensory modality (e.g. auditory, tactile) presented in temporal proximity to the triggering cue. Whereas somatosensory cues given by sudden perturbations of the support surface can trigger appropriate postural adjustments to maintain upright stance, it is not known how gaze executions are ...
Ferry Myriam M GIPSA, UMR CNRS 5216, Equipe Systèmes BioMécaniques, ENSIEG, 961 Rue de la Houille Blanche, BP 46, 38402, Saint Martin d'Heres cedex, France. - - 2007
While research to date has been successful in quantifying postural behaviour, this paper examines the causes of transition between postural coordination mode using dynamical variables and, by inference, efficient control strategies underlying postural behaviour. To this end, six subjects in bipedal stance were instructed to maintain a constant distance between ...
Danna-Dos-Santos Alessander A Department of Kinesiology, Rec.Hall-267, The Pennsylvania State University, University Park, PA 16802, - - 2007
We studied the coordination of muscle activity during voluntary body sway performed by human subjects at different frequencies. Subjects stood on the force platform and performed cyclic shifts of the center of pressure (COP) while being paced by the metronome. A major question was: does the makeup of muscle synergies ...
Bhatkar Viprali V VV Electrical and Computer Engineering, Clarkson University, Potsdam, NY-13699, USA. - - 2007
This paper presents an innovative technique to study postural control. Our translating platform, the Sliding Linear Investigative Platform For Analyzing Lower Limb Stability and Simultaneous Tracking, EMG and Pressure mapping (SLIP-FALLS-STEPm), makes precise, vibration movements under controlled conditions. We look at the psychophysical thresholds to the perception of a sinusoidally ...
Tanahashi Shigehito - - 2007
BACKGROUND: Visual motion often provokes vection (the induced perception of self-motion) and postural movement. Postural movement is known to increase during vection, suggesting the same visual motion signal underlies vection and postural control. However, self-motion does not need to be consciously perceived to influence postural control. Therefore, visual motion itself ...
Fransson Per-Anders - - 2007
Control of orthograde posture and use of adaptive adjustments constitutes essential topics of human movement control, both in maintenance of static posture and in ensuring body stability during locomotion. The objective was to investigate, in twelve normal subjects, how head, shoulder, hip and knee movements and torques induced towards the ...
Muehlsteff J J Philips Research, PO Box 500145, 52085 Aachen, Germany. - - 2007
This paper presents a handheld miniaturized sensor embodiment that allows simultaneous measurement of the electrical and related mechanical cardio-vascular activity. Mechanical motion is detected with a continuous wave Doppler radar sensor and interpreted with a synchronously detected ECG. The patient's posture and activity is measured using accelerometers. Challenges of the ...
Blouin Jean - - 2007
The vestibular system of the inner ear provides information about head translation/rotation in space and about the orientation of the head with respect to the gravitoinertial vector. It also largely contributes to the control of posture through vestibulospinal pathways. Testing an individual severely deprived of somatosensory information below the nose, ...
Pilkar Rakesh B RB Electrical and Computer Engineering Department, Clarkson University, Potsdam, NY-13699 USA. - - 2007
This study modeled ankle angle changes during small forward perturbations of a standing platform. A two-dimensional biomechanical inverted pendulum model was developed that uses sway frequencies derived from quiet standing observations on a subject's Anterior Posterior Center of Pressure (APCoP) to track ankle angle changes during a 16 mm anterior ...
Dunne Lucy E LE School of Computer Science and Informatics, University College Dublin, Belfield, Dublin 4 Ireland. - - 2007
This work is part of a larger project developing wearable posture monitors for the work environment. We seek to evaluate the predictive power of individual spinal segment vector angles, towards the selection of the optimum angles for posture monitoring. A marker-based optoelectronic motion capture system was used to monitor seated ...
Sipp Amy R - - 2007
Force platforms and video tracking systems have been used to characterize subject movements and resultant forces to identify common characteristics of individuals who have experienced recurring falls. Short-term training using force platforms with feedback has been effective in reducing sway. Because of the expense and size requirements of these systems, ...
Rougier P R - - 2007
The resultant centre of pressure (CP(Res)) trajectories are aimed at controlling body movements in upright stance. When standing on two legs, these trajectories are generated by exerting reaction forces under each foot and by loading-unloading mechanisms intervening at the hip level. To assess the respective contribution of each of these ...
Kluzik JoAnn - - 2007
In previous studies, blindfolded, healthy subjects exhibited an after-effect of leaning while standing on a horizontal surface after a period of standing on an inclined surface. We investigated whether this kinesthetic after-effect would transfer from one task to another by asking blindfolded subjects to stand on a horizontal surface after ...
McKay J Lucas JL School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, - - 2007
During postural responses to perturbations, horizontal plane forces generated by the cat hindlimb are stereotypically directed either towards or away from the animal's center of mass, independent of perturbation direction. We used a static, three-dimensional musculoskeletal model of the hindlimb to investigate possible biomechanical determinants of this "force constraint strategy." ...
Guillou Emmanuel - - 2007
OBJECTIVE: Determine whether symmetrical or asymmetrical equilibrium training can enhance the proprioceptive input of the left versus right supporting leg (SL) motor control. METHODS: Proprioceptive input was tested using a seesaw platform through a cross-sectional study. The total spectral energy was recorded and divided into 0-2 and 2-20Hz frequency bands. ...
Jacobs Jesse V JV Neurological Sciences Institute, Oregon Health and Science University, 505 NW 185th Avenue, Beaverton, OR, 97006-3499, USA. - - 2007
Previous research on human balance recovery suggests that, prior to an externally triggered postural perturbation, healthy subjects can pre-select their postural response based on the environmental context, but it is unclear whether this pre-selection includes the selection of a stepping leg when performing compensatory steps. We sought to determine how ...
Kluzik Joann J Neurological Sciences Institute, Oregon Health & Science University, 505 NW 185th Avenue, Beaverton, OR 97006-3499, - - 2007
We previously showed that standing on an inclined surface resulted in an after-effect of leaning in many healthy, blindfolded subjects when they returned to standing on a horizontal surface (Kluzik et al. in Exp Brain Res 162:474-489, 2005). The direction of leaning depended on the direction of prior surface inclination, ...
Daley Monica A - - 2006
Legged animals routinely negotiate rough, unpredictable terrain with agility and stability that outmatches any human-built machine. Yet, we know surprisingly little about how animals accomplish this. Current knowledge is largely limited to studies of steady movement. These studies have revealed fundamental mechanisms used by terrestrial animals for steady locomotion. However, ...
Haibach Pamela S PS Department of Kinesiology, College of Health and Human Development, The Pennsylvania State University, 201 Henderson Building, University Park, PA 16802, - - 2007
This study investigated the hypothesis that virtual time-to-contact, which specifies the time to reach the functional stability boundary, is a variable controlled in the maintenance of upright posture. Three different levels of support surface compliance were used on a force platform (no foam, 5 cm of foam, and 15 cm ...
Nagano Akinori - - 2006
The purpose of this study was to test whether a light finger touch on one's own body (upper legs) reduces postural sway. Ten healthy males participated. In the first part of the study, the participants stood upright with their eyes closed on a force platform while ground reaction force data ...
Grant P M - - 2006
Accurate measurement of physical activity patterns can be used to identify sedentary behaviour and may facilitate interventions aimed at reducing inactivity. To evaluate the activPAL physical activity monitor as a measure of posture and motion in everyday activities using observational analysis as the criterion standard. Wearing three activPAL monitors, 10 ...
Loram Ian D - - 2006
While standing naturally and when manually or pedally balancing an equivalent inverted pendulum, the load sways slowly (characteristic unidirectional duration approximately 1 s) and the controller, calf muscles or hand, makes more frequent adjustments (characteristic unidirectional duration 400 ms). Here we test the hypothesis that these durations reflect load properties ...
Lakie Martin - - 2006
Ten subjects balanced their own body or a mechanically equivalent unstable inverted pendulum by hand, through a compliant spring linkage. Their balancing process was always characterized by repeated small reciprocating hand movements. These bias adjustments were an observable sign of intermittent alterations in neural output. On average, the adjustments occurred ...
Hillier Susan - - 2006
Sensory training post-stroke has been favourably reported in the literature for the hemiparetic upper limb. Little is known, however, of the usefulness of such techniques in the lower limb. This is despite the knowledge that accurate sensory feedback is vital for adaptability in motor control, particularly during balance and weight ...
Kawabe Takahiro T User Science Institute, Kyushu University, 6-19-1, Hakozaki, Higashi-ku, Fukuoka 8128581, Japan. - - 2006
Artists and cartoonists are able to dexterously depict a running person on paper with the aid of 'motion lines'. We scientifically examined whether the cognitive system can exploit motion lines in constructing memory representations of the location of a running person depicted in a still image. A target depicting a ...
Lê Thanh-Thuan - - 2006
Prior studies indicate that postural stability under binocular viewing is not better than under monocular viewing. This was tested at the distances of 145 cm [Fox, C.R. (1990). Some visual influences on human postural equilibrium: binocular versus monocular fixation. Perception and Psychophysics, 47 (5), 409-422] and 90 cm [Isotalo, E., ...
Madigan Michael L - - 2006
The purpose of this study was to investigate changes in postural sway and strategy elicited by lumbar extensor muscle fatigue. Specifically, changes in center of mass (COM), center of pressure (COP), and joint kinematics during quiet standing were determined, as well as selected cross correlations between these variables that are ...
Genthon N - - 2006
This study was aimed at assessing the possible relationship between upright and sitting postures in healthy adults. The center of pressure trajectories from the force platform on which the subjects stood or sat were analyzed through a frequency analysis and modeled through the fractional Brownian motion framework. The same type ...
Jeka John J Department of Kinesiology, University of Maryland, College Park, MD 20742-2611, USA. - - 2006
The properties of sensory reweighting for control of human upright stance have primarily been investigated through experimental techniques such as sinusoidal driving of postural sway. However, other forms of visual inputs that are commonly encountered, such as translation, may produce different adaptive responses. We directly compared sinusoidal and translatory inputs ...
Rosengren Karl S - - 2007
The goal of this investigation was to explore the use of spectral analysis to examine the data obtained during computerized dynamic posturography (CDP). In particular, we examined whether spectral analysis would provide more detailed information about underlying postural control strategies and potential learning across conditions and trials of the sensory ...
Carver Sean - - 2006
Reweighting sensory information adaptively is considered critical for flexible postural control, but little is known of the time scale of the reweighting process. We analyzed the transient dynamics of sensory reweighting in a previously published nonlinear adaptive model of sensory integration in the human postural control system. The model's dynamics ...
Adamcova Nada - - 2007
Sensory interaction in posture control in 20 healthy subjects was investigated by postural responses to differently timed proprioceptive and visual stimulation. As proprioceptive stimulation was used both soleus muscles vibration. Visual stimulation was rotating disc moving in forward and backward direction. Centre of foot pressure (CoP) and trunk tilts in ...
Crenna P P Institute of Human Physiology I, Faculty of Medicine, University of Milan, L.A.M.B. Pierfranco & Luisa Mariani, via Mangiagalli 32, 20133 Milan, Italy. - - 2006
The effects of subthalamic nucleus (STN) stimulation on the anticipatory postural actions associated with the initiation of gait were studied in ten patients with idiopathic Parkinson's disease undergoing therapeutic deep brain stimulation. Kinematic, dynamic and electromyographic analysis was performed before and while subjects were starting gait in response to an ...
Tokuno Craig D CD Department of Neuroscience, Karolinska Institutet, Stockholm, - - 2006
Previous research has shown that the postural configuration adopted by a subject, such as active leaning, influences the postural response to an unpredictable support surface translation. While those studies have examined large differences in postural conditions, it is of additional interest to examine the effects of naturally occurring changes in ...
Przybyszewski Andrzej W - - 2006
The increasing trend in use of marmoset monkeys in behavioral studies has necessitated a greater understanding of their natural behavior, especially within confined spatial environments. One way to approach this issue is to examine locomotor and exploratory strategies using the cylinder test, as done recently for the rat by Gharbawie ...
Deliagina Tatiana G - - 2006
The dorsal-side-up body posture in standing quadrupeds is maintained by coordinated activity of four limbs. We studied this coordination in the cat standing on the platform periodically tilted in the frontal plane. By suspending different body parts, we unloaded one, two, or three limbs. The activity of selected extensor muscles ...
Kapoula Zoï Z Laboratoire de Physiologie de la Perception et de l'Action (LPPA), IRIS Group, UMR 7152, CNRS-Collège de France, Paris, France. - - 2006
Visual stabilization of posture is known to improve when the distance to target fixation decreases; this is attributed to increased angular size of retinal slip induced by body sway. At near distance, however, the eyes converge and efferent or afferent oculomotor signals could also be involved in posture stabilization. The ...
Orlov I V - - 2006
Subjects were maintained in a vertical posture standing on a hard support with a limited degree of freedom in the frontal plane. The stability of the vertical posture was assessed on the basis of the standard deviations (sigma) from the mean amplitude of head oscillations (in the frontal and sagittal ...
Wilkenfeld Ari J - - 2006
We performed this study to determine the feasibility of controlling and stabilizing seated posture with functional electrical stimulation (FES) after paralysis from spinal cord injury (SCI) using computer simulations and a 3-dimensional model of the hip and trunk. We used the model to approximate the range of postures in the ...
Hong S Lee - - 2006
We investigated the relationship between macroscopic entropy and microscopic complexity of the dynamics of body rocking and sitting still across adults with stereotyped movement disorder and mental retardation (profound and severe) against controls matched for age, height, and weight. This analysis was performed through the examination of center of pressure ...
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