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Results 501 - 550 of 883
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Noé Frédéric - - 2003
This study examined the influence of the addition of handles on postural adjustments associated to a rocking on heels movement. Upper and lower limb muscle EMG activities were recorded and the forces applied to the handles and beneath the feet were measured. Without handles, the anticipatory activation of the Gastrocnemius ...
Silfies Sheri P - - 2003
Postural control of the lumbar spine in unstable sitting was quantified through the analysis of the center of pressure (CoP) movement recorded by a force plate situated underneath a seat that incorporated a hemisphere. Thirteen healthy subjects were tested under conditions of increasing seat instability and elimination of visual input. ...
Blackburn J Troy - - 2003
OBJECTIVE: To differentiate hip and trunk motion during double-leg stance. DESIGN: Trunk and hip angular position variances were measured on different support surfaces with and without vision. BACKGROUND: Postural control results from motion about the hips and trunk during bilateral stance. While the hip joint has been studied extensively, information ...
Dobie Thomas G - - 2003
BACKGROUND: It is apparent that visual information is used in maintaining stable posture and ambulating throughout the stationary world. Considerable previous research has indicated that significant perturbations of posture can be induced with a shift in the entire visual scene. In motion environments, it is assumed that posture and ambulatory ...
Pai Y-C - - 2003
Human upright posture is inherently unstable. To counter the mechanical effect of a large-scale perturbation such as a slip, the CNS can make adaptive adjustments in advance to improve the stability of the body center-of-mass (COM) state (i.e., its velocity and position). Such feedforward control relies on an accurate internal ...
Anand Vijay - - 2003
PURPOSE: To determine the influence of refractive blur on postural stability during somatosensory and vestibular system perturbation and dual tasking. METHODS: Fifteen healthy, elderly subjects (mean age, 71 +/- 5 years), who had no history of falls and had normal vision, were recruited. Postural stability during standing was assessed using ...
Reed Catherine L - - 2003
Researchers argue that faces are recognized via the configuration of their parts. An important behavioral finding supporting this claim is the face-inversion effect, in which inversion impairs recognition of faces more than nonface objects. Until recently, faces were the only class of objects producing the inversion effect for untrained individuals. ...
Bortolami S B SB Ashton Graybiel Spatial Orientation Laboratory, Brandeis University, Waltham, MA 2454-9110, USA. - - 2003
We studied the kinematics and kinetics of human postural responses to "recoverable falls." To induce brief falling we used a Hold and Release (H&R) paradigm. Standing subjects actively resisted a force applied to their sternum. When this force was quickly released they were suddenly off balance. For a brief period, ...
Grimstone Sarah K SK Department of Physiotherapy, University of Queensland, Brisbane, QLD 4072, - - 2003
This study evaluated the degree to which the disturbance to posture from respiration is compensated for in healthy normals and whether this is different in people with recurrent low back pain (LBP), and to compare the changes when respiratory demand is increased. Angular displacement of the lumbar spine and hips, ...
Dickstein R - - 2003
OBJECTIVES: To investigate the potential benefits from lightly touching an external supporting device on automatic postural responses to support surface translations, in subjects with profound sensory neuropathy in the feet due to diabetes mellitus (DM-PN). METHODS: Eight subjects with DM-PN and 10 age matched controls were tested under randomly ordered ...
Latash Mark L ML Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, USA. - - 2003
We introduce a method for quantification of movement sway--spontaneous migrations of the center of pressure (COP) during its voluntary shifts. Subjects stood on a force platform or on a board with a narrow support surface ("unstable board") and performed voluntary cyclic shifts of the COP at different frequencies. Movement sway ...
Isableu Brice B UFR Scientifique d'Orsay, UFR STAPS, Centre de Recherche en Sciences du Sport (CRESS-UPRES 1604), Université Paris-Sud XI, Bat 335, 91 405, Orsay CEDEX, France. - - 2003
The present paper attempts to clarify the between-subjects variability exhibited in both segmental stabilisation strategies and their subordinated or associated sensory contribution. Previous data have emphasised close relationships between the interindividual variability in both the visual control of posture and the spatial visual perception. In this study, we focused on ...
Yoshino Gengo - - 2003
To establish the relationship between the condition of the stomatognathic system and body posture, changes in the head position during clenching were observed and investigated when the occlusal supporting zone was lost unilaterally and bilaterally. The results were as follows: 1. Regardless of the occlusal conditions, the head position was ...
Ko Young-Gyu - - 2003
The present study investigated Bernstein's [The co-ordination and regulation of movements, 1967] proposal regarding the three stages of learning in the changing coordination and control of redundant joint-space degrees of freedom. Six participants practiced maintaining balance on a moving platform that was sinusoidally translated in the anterior-posterior direction for 30 ...
Mergner T - - 2003
We present a multisensory postural control model based on experiments where the balance in normal subjects and vestibular loss patients was perturbed by application of external torque produced by force-controlled pull stimuli. The stimuli were applied while subjects stood on a stationary or body-sway-referenced motion platform with eyes closed and ...
DeForge Donald H - - 2002
Ergonomics is the application of a body of knowledge addressing the interactions between man and the total working environment, such as atmosphere, heat, light and sound, as well as all tools and equipment of the workplace. Work related musculoskeletal injuries, caused by poor posture, have been discussed in human dentistry ...
Thurrell A E I AE Academic Department of Neuro-otology, Division of Neuroscience and Psychological Medicine, Imperial College Faculty of Medicine, Charing Cross Hospital, London W6 8RP, - - 2002
Movement of large visual scenes induces an illusion of self-motion (vection) and postural responses. We investigated if the conscious perception of self-motion influences the magnitude and directional accuracy of visually evoked postural responses. Five normal subjects fixated the centre of a large disk rotating in the roll (coronal) plane. The ...
Roll Régine - - 2002
We investigated whether the tactile information from the main supporting areas of the foot are used by the brain for perceptual purposes, namely body posture awareness and body representation in space. We applied various patterns of tactile stimulation to one or both soles of unmoving and blindfolded subjects by a ...
Kolb F P - - 2002
Unexpected external perturbations of body equilibrium elicit compensatory postural reflexes. The reflex patterns change only minimally, even after repetitive perturbations. This study addressed the question of whether classical conditioning can alter the reflex patterns. In the first session 27 healthy subjects were tested when standing on an unexpectedly tilting platform. ...
Maeda Setsuo - - 2002
The purpose of this paper is to investigate the effects of posture, push force and rate of temperature change on thermotactile thresholds and to clarify suitable measuring conditions for Japanese people. Thermotactile (warm and cold) thresholds on the right middle finger were measured with an HVLab thermal aesthesiometer. Subjects were ...
Smiley-Oyen Ann L - - 2002
Postural control requires accurate integration of visual, vestibular, cutaneous, and proprioceptive sensory information. Previous research suggests that patients with Parkinson's disease (PD) may have difficulty with this integration process, particularly involving incongruent visual information. The purpose of this study was to determine whether PD patients also show difficulty in adaptation ...
Krishnamoorthy Vijaya V Department of Kinesiology, Rec. Hall - 267L, The Pennsylvania State University, University Park, PA 16802, - - 2002
When a standing person applies a light finger touch to an external stable object, postural sway is reduced. We tested a hypothesis that two factors related to touch can induce this effect, the presence of a stable reference point and the modulation of contact forces leading to tissue deformation. Force ...
Brooke-Wavell K - - 2002
BACKGROUND: A poor postural stability in older people is associated with an increased risk of falling. It is recognized that visual environment factors (such as poor lighting and repeating patterns on escalators) may contribute to falls, but little is known about the effects of the visual environment on postural stability ...
Powell E S - - 2002
BACKGROUND: Evaluation of the effectiveness of therapy to improve sitting balance has been hampered by the limited number of sensitive objective clinical measures. We developed the Manchester Active Position Seat (MAPS) to provide a portable system to track change in the position of centre of force over time. OBJECTIVES: (1) ...
Peterka R J - - 2002
It is generally accepted that human bipedal upright stance is achieved by feedback mechanisms that generate an appropriate corrective torque based on body-sway motion detected primarily by visual, vestibular, and proprioceptive sensory systems. Because orientation information from the various senses is not always available (eyes closed) or accurate (compliant support ...
Bouisset Simon - - 2002
Aglobal biomechanical model of transient push efforts is proposed where transient efforts are taken into consideration, with the aim to examine in greater depth the postural adjustments associated with voluntary efforts. In this context, the push effort is considered as a perturbation of balance, and the other reaction forces as ...
Baraduc Pierre - - 2002
Previous studies have shown that human subjects can adapt to a new visuomotor relationship that depends on the trajectory of the arm. However, these studies have not distinguished between hand- and joint-based learning models. We have examined whether different endpoint kinematics are necessary to obtain a differential visuomotor shift. The ...
Speers R A - - 2002
We used multivariate kinematics and joint torque measurements during dynamic posturography to determine the relative contributions of changes in overall control gain, relative weighting of sensors, and noise-like effects on posture control in the elderly. Our results show that sway coordination and amplitude both change with age, but that changes ...
Creath Rob R Department of Kinesiology, 2359 HHP Building,University of Maryland, College Park, MD 20742-2611, - - 2002
When subjects stand on an unstable or compliant support surface, rather than a stable one, vestibular information becomes more important for the control of posture. We investigated how subjects with bilateral vestibular loss (BVL) controlled their upright posture, with and without light-touch contact at the fingertip, while standing on a ...
Oie Kelvin S - - 2002
We examined the generally held belief that the postural control system is able to re-weight its available sensory inputs in order to optimize stance control in altered sensory environments. Our view is that previous accounts of sensory re-weighting provide only indirect evidence, which is subject to alternative explanations. The present ...
Fiolkowski Paul - - 2002
During gait initiation (GI), decoupling of the center of mass and center of pressure allows the center of mass to fall forwards. Subjects initiated gait rapidly before and after tibial nerve block of the tibial nerve. Static single limb stability, stance limb ground reaction forces, electromyogram and temporal data were ...
Fransson P-A - - 2002
The short-term (i.e., days) and long-term (i.e., months) effects of adaptation to posturography examinations were investigated in 12 normal subjects who were repeatedly examined for five consecutive days and again after 90 days. The examinations were conducted both with eyes open and closed, and the perturbations were evoked by a ...
Kollmitzer Josef - - 2002
Any voluntary motion of the body causes an internal perturbation of balance. Load transfer during manual material handling may increase these perturbations. This study investigates effects of stance condition on postural control during lifting. Nineteen healthy subjects repeatedly lifted and lowered a load between a desk and a shelf. The ...
Schieppati Marco M Institute of Human Physiology, Univerisity of Pavia, Via Forlanini 6, 27100 Pavia, Italy. - - 2002
When humans stand upright on a platform that sinusoidally translates in the anterior-posterior direction, the movements of upper and lower body segments are appropriately coordinated, in order to keep the body within its limits of stability. A significant fluctuation in this behaviour is evident across subjects and perturbation conditions. The ...
Commissaris D A C M - - 2002
Human upright balance control can be quantified using movable platforms driven by servo-controlled torque motors (dynamic posturography). We introduce a new movable platform driven by the force of gravity acting upon the platform and the subject standing on it. The platform consists of a 1 m2 metal plate, supported at ...
Horak Fay B - - 2002
To better understand the role of the vestibular system in postural coordination, we compared the ability of subjects with complete, bilateral loss of vestibular function and age-matched control subjects to maintain equilibrium and postural orientation during sinusoidal displacements of the support surface at a variety of frequencies. We also examined ...
D'Amico Moreno - - 2002
Measurements of postural sway are used to determine a subject ability to maintain upright stance. In many clinical analyses, postural control measured during a quiet standing provides very useful insights about CNS and Motor control behaviour. The aim of this paper is to present a new posturographic methodology including both ...
Gillette Jason C - - 2002
Functional neuromuscular stimulation (FNS) systems have provided individuals with spinal cord injury (SCI) varying levels of standing capability. Our long-term goal is to enhance an FNS user's ability to perform activities of daily living by providing sufficient standing stability. However, control of standing posture with complete SCI is compromised by ...
Tossavainen Timo - - 2002
People relying much on vision in the control of posture are known to have an elevated risk of falling. Dependence on visual control is an important parameter in the diagnosis of balance disorders. We have previously shown that virtual reality methods can be used to produce visual stimuli that affect ...
Scinicariello Anthony P - - 2003
Galvanic vestibular stimulation (GVS) is a technique in which small currents are delivered transcutaneously to the afferent nerve endings of the vestibular system through electrodes placed over the mastoid bones. The applied current alters the firing rates of the peripheral vestibular afferents, causing a shift in a standing subject's vestibular ...
Olendorf M R - - 2001
To help in the design or redesign of workplaces it would be helpful to know in advance the postural stress consequences of a wide range of body postures. This experiment evaluated 168 postures chosen to represent those in the Ovako Working-posture Analysing System (OWAS) using Rated Perceived Exertion (RPE) and ...
Tanaka T - - 2001
The maintenance of postural balance depends on effective and efficient feedback from various sensory inputs. The importance of auditory inputs in this respect is not, as yet, fully understood. The purpose of this study was to analyse how the moving auditory stimuli could affect the standing balance in healthy adults ...
Ko Y G - - 2001
The present study investigated the compensatory postural coordination patterns that emerge in the face of dynamic changes in the surface of support. Adult subjects stood on a moving platform that was sinusoidally translated in the anterior-posterior direction. The frequency and amplitude of the support surface translation were manipulated over a ...
Dickstein R - - 2001
The purpose of this work was to determine whether fingertip touch on a stable surface could improve postural stability during stance in subjects with somatosensory loss in the feet from diabetic peripheral neuropathy. The contribution of fingertip touch to postural stability was determined by comparing postural sway in three touch ...
Fujiwara K - - 2001
We investigated postural movement associated with bilateral arm flexion in response to a light signal during standing in 179 healthy men and women to assess whether individual and sex differences arc evident in the postural movement pattern. The following results were obtained. (a) A correlation of -.87 was noted between ...
Tingey E M - - 2001
This prospective study was designed to establish how the positions of the molars and the condyles are related to incisor position in the mandibular rest position and how their positions are altered by changing head posture. Measurements of the mandibular rest position were taken on 24 men (age range, 23 ...
Johansson R - - 2001
In this study a method for the analysis of simultaneous multiple measurements of kinematics and stabilizing forces related to human postural dynamics is proposed. Each subject in a group of normal subjects (n=10) was tested with eyes-open and eyes-closed with simultaneous but uncorrelated vestibular and proprioceptive stimuli in order to ...
Borel L - - 2001
The aim of this study was to analyse how changes in vestibular and visual reference frames combine to modify body orientation in space, and to determine the relationship between postural, oculomotor and perceptive parameters. Changes in vestibular and visual references were investigated by comparing controls and vestibular defective patients (Ménière's ...
Rougier P - - 2001
Body leaning effects on postural control have been assessed by recording the centre of pressure (CP) displacements in healthy subjects under three experimental conditions (REF, BWD and FWD corresponding to upright, backward leaning and forward leaning of the body, respectively). The CP displacements were used to compute the motions of ...
Kay B A - - 2001
We investigate the temporal coordination of human gait and posture and infer the nature of their coupling. Participants viewed a sinusoidally oscillating visual display which induced medial-lateral postural sway during treadmill walking, while display frequency was varied (0.075-1.025 Hz). First, postural responses exhibited the usual low-pass characteristic but with an ...
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