Search results for "STABILITY"
showing 10 items of 3085 documents
Are postural responses to backward and forward perturbations processed by different neural circuits?
2013
Item does not contain fulltext Startle pathways may contribute to rapid accomplishment of postural stability. Here we investigate the possible influence of a startling auditory stimulus (SAS) on postural responses. We formulated four specific questions: (1) can a concurrent SAS shorten the onset of automatic postural responses?; and if so (2) is this effect different for forward versus backward perturbations?; (3) does this effect depend on prior knowledge of the perturbation direction?; and (4) is this effect different for low- and high-magnitude perturbations? Balance was perturbed in 11 healthy participants by a movable platform that suddenly translated forward or backward. Each particip…
A reanalysis of the center for epidemiological studies depression scale (CES-D) using non-parametric item response theory
2020
Abstract The “Center for Epidemiological Studies Depression Scale” (CES-D; Radloff, 1977 ) is a questionnaire used world-wide to measure depressive symptoms. Although the original four-factor-structure has been widely accepted and replicated, some studies point to other factor-structures like a one- and two-factor-structure. The goal of the current study was to evaluate the factor structure of the CES-D (one-, two- and four-factor-structure), which was found using classical test theory (CTT), with two non-parametric item-response-theory-models (Mokken-Scaling; Monotone-homogeneity-model; MHM and Double-monotonicity-model; DMM). To this end, a representative German sample was analyzed (N = 2…
Trunk muscle activity during different variations of the supine plank exercise.
2017
BACKGROUND: Exercises providing neuromuscular challenges of the spinal muscles are desired for core stability, which is important for workers with heavy manual labour as well as people recovering from back pain.PURPOSE: This study evaluated whether using a suspended modality increases trunk muscle activity during unilateral or bilateral isometric supine planks.DESIGN: Cross-sectional.METHODS: Twenty university students participated in this cross-sectional study. Each subject performed four different conditions: bilateral stable supine plank, unilateral stable supine plank, bilateral suspended supine plank and unilateral suspended supine plank. Surface electromyography (EMG) signals were rec…
Daily changes of individual gait patterns identified by means of support vector machines.
2016
Despite the common knowledge about the individual character of human gait patterns and about their non-repeatability, little is known about their stability, their interactions and their changes over time. Variations of gait patterns are typically described as random deviations around a stable mean curve derived from groups, which appear due to noise or experimental insufficiencies. The purpose of this study is to examine the nature of intrinsic inter-session variability in more detail by proving separable characteristics of gait patterns between individuals as well as within individuals in repeated measurement sessions. Eight healthy subjects performed 15 gait trials at a self-selected spee…
Tear film stability over a myopia control contact lens compared to a monofocal design
2021
Background: To compare the short-term effect of two contact lenses on pre-lens tear film stability and comfort: dual-focus contact lens (MiSight) and a monofocal contact lens (Proclear 1-day).Methods: This randomised, double-masked, crossover study was performed in twenty-eight healthy, myopic volunteers aged between 18 and 32 years (23.5 +/- 4.1 years). Only one randomly chosen eye was assessed. Distance vision and refraction were evaluated at baseline. Each contact lens type (monofocal and dual-focus) was randomly fitted, always in both eyes. A visual analogue scale between 0 and 10 was used to assess general comfort, physical comfort, and visual comfort. Tear Film Surface Quality (TFSQ) …
In Patients with Grade I and II Ankle Sprains, Dynamic Taping Seems to Be Helpful during Certain Tasks, Exercises and Tests in Selected Phases of the…
2022
We aimed to investigate changes in postural stability on a stable surface after the application of dynamic tape for patients with inversion ankle sprains. This study enrolled 30 patients (age 25.5 ± 8.0 years) with grade I and II ankle sprains, which occurred 7–21 days before enrolment. Postural stability (balance, coordination, feedback) was assessed before and after the application of dynamic tape using a stabilographic platform. Three 32-s exercises were performed on the stabilographic platform, one with eyes open, one with eyes closed and one with visual feedback. After the application of dynamic tape, an improvement was observed in terms of the mean radius of sway (4.2 &pl…
Effects of Aerobic and Anaerobic Fatigue Exercises on Postural Control and Recovery Time in Female Soccer Players
2020
Sixteen female soccer players (age = 20.19 ±
Assessment of haemophilic arthropathy through balance analysis: a promising tool
2019
[EN] The purpose of this study was to develop a tool able to distinguish between subjects who have haemophilic arthropathy in lower limbs and those who do not by analyzing the centre of pressure displacement. The second objective was to assess the possible different responses of haemophiliacs and healthy subjects by creating a classifier that could distinguish between both groups. Fiftyfour haemophilic patients (28 with and 26 without arthropathy) and 23 healthy subjects took part voluntarily in the study. A force plate was used to measure postural stability. A total of 276 centre of pressure displacement parameters were calculated under different conditions: unipedal/bipedal balance with e…
On reliability of systems with moving material subjected to fracture and instability
2015
Abstract The reliability of systems with moving cracked elastic and isotropic material is considered. The material is modeled as a moving plate which continually has a crack on the edge. The plate is subjected to homogeneous tension acting in the traveling direction and the tension varies temporally around a constant value, the set tension. The tension and the length of the crack are modeled by an Ornstein–Uhlenbeck process and an exponential Ornstein–Uhlenbeck process, respectively. Failure is regarded as the state at which the plate becomes unstable or fractures (or both) and a lower bound for the reliability of the system is derived. Considering reliability of the system leads to first p…
Stochastic analysis of the critical velocity of an axially moving cracked elastic plate
2014
In this study, a probabilistic analysis of the critical velocity for an axially moving cracked elastic and isotropic plate is presented. Axially moving materials are commonly used in modelling of manufacturing processes, like paper making and plastic forming. In such systems, the most serious threats to runnability are instability and material fracture, and finding the critical value of velocity is essential for efficiency. In this paper, a formula for the critical velocity is derived under constraints for the probabilities of instability and fracture. The significance of randomness in different model parameters is investigated for parameter ranges typical of paper material and paper machin…