KEY POINTS The passive stiffness of the calf muscles contributes to standing balance, although the properties of muscle tissue are highly labile. We investigated the effect of sway history upon intrinsic ankle stiffness and demonstrated reductions in stiffness of up to 43% during conditions of increased baseline sway. This sway dependence was most apparent when using low amplitude stiffness-mea...

Visual position and velocity cues improve human standing balance, reducing sway responses to external disturbances and sway variability. Previous work suggested that human balancing is based on sensory estimates of external disturbances and their compensation using feedback mechanisms (Disturbance Estimation and Compensation, DEC model). This study investigates the visual effects on sway respon...

Motion sickness (MS) usually occurs for a narrow band of frequencies of the imposed oscillation. It happens that this frequency band is close to that which are spontaneously produced by postural sway during natural stance. This study examined the relationship between reported susceptibility to motion sickness and postural control. The hypothesis is that the level of MS can be inferred from the ...

Human subjects standing in a sinusoidally moving visual environment display postural sway with characteristic dynamical properties. We analyzed the spatio-temporal properties of this sway in an experiment in which the frequency of the visual motion was varied. We found a constant gain near one, which implies that the sway motion matches the spatial parameters of the visual motion for a large ra...

A process employing a computer controlled crane system for controlling the motion of a movable trolley from which a load is suspended at a variable hoist length therefrom to meet a selected arbitrary horizontal velocity reference while preventing sway of the load involves the steps of first, determining a lateral acceleration to reduce by a factor of one-half the sway energy contributed by (1) ...

Abstract The main purpose of this paper is to study analytically the behavior slender reinforced concrete columns existing in sway and non-sway structures. studied variables were stiffness beam connected columns, bracing number bays stories structure model. stability was required limits for lateral determined using a finite element program perform buckling analysis, linear geometric nonlinear a...

Difficulty with literacy acquisition is only one of the symptoms of developmental dyslexia. Dyslexic children also show poor motor coordination and postural control. Those problems could be associated with automaticity, i.e., difficulty in performing a task without dispending a fair amount of conscious efforts. If this is the case, dyslexic children would show difficulties in using "unperceived...

Fall prevention technologies have the potential to improve the lives of older adults. Because of the multisensory nature of human balance control, sensory therapies, including some involving tactile and auditory noise, are being explored that might reduce increased balance variability due to typical age-related sensory declines. Auditory white noise has previously been shown to reduce postural ...

Research into the relationship between body sway, aim-point fluctuation, and performance in pistol shooting has been inconclusive. The present study reexamined this relationship on an interindividual basis, as done in previous studies, and via intraindividual analysis, not previously examined. Five elite pistol shooters performed 20 shots similar to competition conditions. For each shot, body-s...