Force Production and Coordination from Older Women in Water Fitness Exercises

The aim of this study was to compare bilateral propulsive forces and coordination while exercising at static and dynamic conditions in the water. A total of 27 older women (age: 65.1 ± 6.7 years old) performed the following exercises: (i) horizontal upper-limbs adduction (HA; static condition) and (ii) rocking horse (RH; dynamic condition) through an incremental protocol with music cadences from 105 up to 150 b·min−1. The duration of each trial was set at 30 second (sec). Propulsive peak force (in Newton, N) of dominant (PFD) and nondominant (PFND) upper limbs was retrieved using hand sensors coupled to a differential pressure system. Significant differences in force production were found between static and dynamic exercises at higher cadences (120, 135, and 150 b·min−1). The static condition elicited higher bilateral propulsive forces and a more symmetric pattern. The in-water static exercise with bilateral action from the upper limbs proved to be the most appropriate strategy for older women to work strength and to reduce asymmetries.

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Postural Control Disturbances Induced by Virtual Reality in Stroke Patients

Applied Sciences ◽

10.3390/app11041510 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1510

Author(s):

Charles Morizio ◽

Maxime Billot ◽

Jean-Christophe Daviet ◽

Stéphane Baudry ◽

Christophe Barbanchon ◽

...

Keyword(s):

Virtual Reality ◽

Postural Control ◽

Virtual Environments ◽

Center Of Pressure ◽

Dynamic Condition ◽

Static Condition ◽

Stroke Patients ◽

Post Stroke ◽

Subacute Stroke

People who survive a stroke are often left with long-term neurologic deficits that induce, among other impairments, balance disorders. While virtual reality (VR) is growing in popularity for postural control rehabilitation in post-stroke patients, studies on the effect of challenging virtual environments, simulating common daily situations on postural control in post-stroke patients, are scarce. This study is a first step to document the postural response of stroke patients to different challenging virtual environments. Five subacute stroke patients and fifteen age-matched healthy adults were included. All participants underwent posturographic tests in control conditions (open and closed eyes) and virtual environment without (one static condition) and with avatars (four dynamic conditions) using a head-mounted device for VR. In dynamic environments, we modulated the density of the virtual crowd (dense and light crowd) and the avoidance space with the avatars (near or far). Center of pressure velocity was collected by trial throughout randomized 30-s periods. Results showed that more challenging conditions (dynamic condition) induced greater postural disturbances in stroke patients than in healthy counterparts. Our study suggests that virtual reality environments should be adjusted in light of obtaining more or less challenging conditions.

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Short-term Training And Force Production In Older Women: A Comparison Of Land And Aquatic Models.

Medicine & Science in Sports & Exercise ◽

10.1249/01.mss.0000761708.94224.5a ◽

2021 ◽

Vol 53 (8S) ◽

pp. 231-231

Author(s):

Adam Korak ◽

Nicole A. Schwery ◽

Michael T. Kiely ◽

Christina P. Knudson ◽

Brett D. Bruininks

Keyword(s):

Older Women ◽

Force Production ◽

Short Term

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Kinetic Analysis of Water Fitness Exercises: Contributions for Strength Development

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16193784 ◽

2019 ◽

Vol 16 (19) ◽

pp. 3784 ◽

Cited By ~ 1

Author(s):

Santos ◽

Rama ◽

Marinho ◽

Barbosa ◽

Costa

Keyword(s):

Upper Limb ◽

Force Production ◽

Peak Force ◽

Strength Development ◽

Isokinetic Dynamometer ◽

Symmetric Motion ◽

Pressure System ◽

Dry Land ◽

Force Variation ◽

Selection Of

The evaluation of propulsive forces in water allows the selection of the most appropriate strategies to develop strength during water fitness sessions. The aim of this study was threefold: (i) to analyze the rate of force production; (ii) to analyze the rate of force variation; and (iii) to compare limbs’ symmetry in two water fitness exercises. Twenty-two young health subjects (age: 21.23 ± 1.51 years old, body mass: 67.04 ± 9.31 kg, and height: 166.36 ± 8.01 cm) performed incremental protocols of horizontal adduction (HA) and rocking horse (RHadd), from 105 until 150 b·min–1. Data acquisition required an isokinetic dynamometer and a differential pressure system that allowed the assessment of (a) isometric peak force of dominant upper limb (IsometricFD); (b) propulsive peak force of dominant upper limb (PropulsiveFD); and (c) propulsive peak force of nondominant upper limb (PropulsiveFND). Significant differences were found in the rate of force production (RateFD) between the majority cadences in both exercises. The RateFD reached ~68% of the force in dry-land conditions, and lower cadences promoted a higher rate of force variation (ΔForce). Most actions were asymmetric, except for the HA at 135 b·min–1. In conclusion, the musical cadence of 135 b·min–1 seems to elicit a desired rate of force production with a symmetric motion in both exercises.

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A Measurement-Data-Driven Control Approach towards Variance Reduction of Micromachined Resonant Accelerometer under Multi Unknown Disturbances

Micromachines ◽

10.3390/mi10050294 ◽

2019 ◽

Vol 10 (5) ◽

pp. 294 ◽

Cited By ~ 2

Author(s):

Qiang Shen ◽

Dengfeng Yang ◽

Jie Zhou ◽

Yixuan Wu ◽

Yinan Zhang ◽

...

Keyword(s):

Variance Reduction ◽

Dynamic Condition ◽

Measurement Data ◽

Static Condition ◽

Measurement Model ◽

Data Driven ◽

Least Mean Square ◽

Accelerometer Sensor ◽

Control Approach ◽

Resonant Accelerometer

This paper first presents an adaptive expectation-maximization (AEM) control algorithm based on a measurement-data-driven model to reduce the variance of microelectromechanical system (MEMS) accelerometer sensor under multi disturbances. Significantly different characteristics of the disturbances, consisting of drastic-magnitude, short-duration vibration in the external environment, and slowly-varying, long-duration fluctuation inside the sensor are first constructed together with the measurement model of the accelerometer. Next, through establishing a data-driven model based on a historical small measurement sample, the window length of filter of the presented algorithm is adaptively chosen to estimate the sensor state and identify these disturbances simultaneously. Simulation results of the proposed AEM algorithm based on experimental test are compared with the Kalman filter (KF), least mean square (LMS), and regular EM (REM) methods. Variances of the estimated equivalent input under static condition are 0.212 mV, 0.149 mV, 0.015 mV, and 0.004 mV by the KF, LMS, REM, and AEM, respectively. Under dynamic conditions, the corresponding variances are 35.5 mV, 2.07 mV, 2.0 mV, and 1.45 mV, respectively. The variances under static condition based on the proposed method are reduced to 1.9%, 2.8%, and 27.3%, compared with the KF, LMS, and REM methods, respectively. The corresponding variances under dynamic condition are reduced to 4.1%, 70.1%, and 72.5%, respectively. The effectiveness of the proposed method is verified to reduce the variance of the MEMS resonant accelerometer sensor.

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The Effect of Mental Fatigue on Neuromuscular Function is Similar in Young and Older Women

Brain Sciences ◽

10.3390/brainsci10040191 ◽

2020 ◽

Vol 10 (4) ◽

pp. 191 ◽

Cited By ~ 1

Author(s):

Amanda J. Morris ◽

Anita D. Christie

Keyword(s):

Older Women ◽

Age Groups ◽

Force Production ◽

Silent Period ◽

Neuromuscular Function ◽

Mental Fatigue ◽

Cortical Inhibition ◽

Force Output ◽

M Wave ◽

Period Duration

The purpose of this study was to examine the effect of a mentally fatiguing task on neuromuscular function in young and older women. Neuromuscular measures were obtained prior to and following 20 min of a mentally fatiguing task. Maximal force output significantly decreased after the mental fatigue task (p = 0.02) and this was not different between age groups (p = 0.32). Increases in cortical silent period duration approached significance in both young and older groups (p = 0.06), suggesting that mental fatigue may cause increased cortical inhibition. Measures of peripheral neuromuscular function (contractile properties of the muscle, M-wave) did not change (p ≥ 0.09), suggesting that changes in force production with mental fatigue are more likely due to supraspinal than peripheral mechanisms. These findings provide further evidence of an interaction between mental fatigue and physical function.

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Inter-Limb Symmetry at Simultaneous and Alternated Arms Flexion by the Elbow during Water Fitness Sessions

Symmetry ◽

10.3390/sym12111776 ◽

2020 ◽

Vol 12 (11) ◽

pp. 1776

Author(s):

Catarina C. Santos ◽

Tiago M. Barbosa ◽

Raúl F. Bartolomeu ◽

Nuno D. Garrido ◽

Mário J. Costa

Keyword(s):

Elderly Women ◽

Peak Force ◽

Medium Effect ◽

Upper Limbs ◽

Symmetry Index ◽

Full Attention ◽

Asymmetric Pattern ◽

Incremental Protocol ◽

Proper Strategy

The aim was to compare the inter-limb symmetry between alternated and simultaneous arms flexion during water fitness sessions. Twenty-three elderly women were recruited to perform flexion by the elbow with different mechanical strategies: (a) simultaneous and (b) alternated. An incremental protocol was used, with four music cadences, starting at 105 beats per minute up to 150. The peak force of dominant and non-dominant upper-limbs was retrieved. A symmetry index (SI, %) was also used to quantify coordination. There were significant variations in force produced by the dominant and non-dominant limbs in most of the cadences in the alternated or simultaneous actions. Differences with a medium effect between upper-limbs were shown when moving simultaneously indicating that an alternated movement can be a more proper strategy to work with. Despite that, both strategies seemed to be characterized by an asymmetric pattern (SI from 20 to 30%), requiring full attention from water fitness practitioners.

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Experimental Investigation of a New Derived Oleochemical Corrosion Inhibitor

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.796.112 ◽

2019 ◽

Vol 796 ◽

pp. 112-120

Author(s):

Mysara Eissa Mohyaldinn ◽

Wai Lin ◽

Ola Gawi ◽

Mokhtar Che Ismail ◽

Quosay A. Ahmed ◽

...

Keyword(s):

Mild Steel ◽

Corrosion Inhibitor ◽

Corrosion Inhibition ◽

Corrosion Inhibitors ◽

Inhibition Efficiency ◽

Dynamic Condition ◽

Methyl Esters ◽

Static Condition ◽

Chemical Corrosion ◽

Boron Fluoride

Most of the corrosion inhibitors that are used in industry contain chemicals that are harmful to health and environment. Corrosion inhibitors derived from green sources are, therefore, believed to be a good option for replacing the chemical corrosion inhibitors. In this work, a green oleochemical corrosion inhibitor derived from Jatropha Curcas is introduced. The paper discusses the methodology of deriving the corrosion inhibitor as well as the experimental test conducted for evaluating its corrosion inhibition efficiency. The new oleochemical corrosion inhibitor was derived via two reactions. Jatropha oil was firstly saponified with sodium hydroxide to yield gras acid and glycerol, which was then esterified with boron fluoride in presence of excess methanol to produce the oil methyl esters, which is used as oleo-chemical corrosion inhibitor. To evaluate the oleo-chemical corrosion inhibitor, the corrosion rate of mild steel in NaCl corrosive medium with CO2 is tested at static condition and two dynamic conditions, namely 500 and 1500 rpm. This is to simulate the transitional and turbulent flow in a pipeline. At each dynamic condition, the proposed corrosion inhibitor was tested at concentration dosages of 0, 50, 100, and 150 ppm. The experiments results revealed a good performance of the new oleochemical corrosion inhibitor. The inhibition efficiency was found to be highly affected by the concentration of corrosion inhibitor. Total corrosion inhibition of the mild steel was noticed by using 150 ppm at dynamic condition of 500 rpm.

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Research on Rubber Spring Model of High-speed EMU Based on Non-hyperelastic Forces

Mechanika ◽

10.5755/j02.mech.25630 ◽

2021 ◽

Vol 27 (1) ◽

pp. 12-21

Author(s):

Chuanbo XU ◽

Maoru CHI ◽

Liangcheng DAI ◽

Yiping JIANG ◽

Yongfa CHEN ◽

...

Keyword(s):

Energy Consumption ◽

Prediction Accuracy ◽

High Speed ◽

Dynamic Condition ◽

Static Condition ◽

Good Prediction ◽

Calculation Formula ◽

Good Prediction Accuracy ◽

Calculation Results ◽

Better Than

The research on the mechanical model of rubber spring is one of the hot spots in train dynamics. In order to accurately calculate the viscoelastic force of the rubber spring, especially the non-hyperelastic forces (NHEF) part, a NHEF model is proposed based on the elliptic approximation method. Furthermore, the calculation formula of periodic energy consumption is put forward. The NHEF model is verified by experiments, and the function λ isconstructed to verify the formula of periodic energy consumption. The calculation results showed that the NHEF model had high accuracy in predicting the dynamic and quasi-static NHEF of rubber spring, the prediction accuracy of shear condition was better than that of compression condition, and the accuracy of quasi-static condition was better than that of dynamic condition; the calculation formula of periodic energy consumption had a good prediction accuracy in all working conditions.

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Noninformative Vision of Body Movements can Enhance Tactile Discrimination

i-Perception ◽

10.1177/20416695211059203 ◽

2022 ◽

Vol 13 (1) ◽

pp. 204166952110592

Author(s):

Yosuke Suzuishi ◽

Souta Hidaka

Keyword(s):

Visual Information ◽

Dynamic Condition ◽

Discrimination Performance ◽

Static Condition ◽

The Body ◽

Enhancement Effect ◽

Body Parts ◽

Body Movements ◽

Tactile Discrimination ◽

Noninformative Vision

Vision of the body without task cues enhances tactile discrimination performance. This effect has been investigated only with static visual information, although our body usually moves, and dynamic visual and bodily information provides ownership (SoO) and agency (SoA) sensations to body parts. We investigated whether vision of body movements could enhance tactile discrimination performance. Participants observed white dots without any textural information showing lateral hand movements (dynamic condition) or static hands (static condition). For participants experiencing the dynamic condition first, it induced a lower tactile discrimination threshold, as well as a stronger SoO and SoA, compared to the static condition. For participants observing the static condition first, the magnitudes of the enhancement effect in the dynamic condition were positively correlated between the tactile discrimination and SoO/SoA. The enhancement of the dynamic visual information was not observed when the hand shape was not maintained in the scrambled white dot images. Our results suggest that dynamic visual information without task cues can enhance tactile discrimination performance by feeling SoO and SoA only when it maintains bodily information.

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Materials in action: The look and feel of soft

10.1101/2021.01.22.427730 ◽

2021 ◽

Author(s):

Müge Cavdan ◽

Knut Drewing ◽

Katja Doerschner

Keyword(s):

Dynamic Condition ◽

Prior Experience ◽

Static Condition ◽

Experimental Conditions ◽

Dynamic Conditions ◽

Similar Information ◽

The Senses ◽

The Look

AbstractThe softness of objects can be perceived through several senses. For instance, to judge the softness of our cat’s fur, we do not only look at it, we also run our fingers in idiosyncratic ways through its coat. Recently, we have shown that haptically perceived softness covaries with the compliance, viscosity, granularity, and furriness of materials (Dovencioglu et al.,2020). However, it is unknown whether vision can provide similar information about the various aspects of perceived softness. Here, we investigated this question in an experiment with three conditions: in the haptic condition, blindfolded participants explored materials with their hands, in the visual-static condition participants were presented with close-up photographs of the same materials, and in the visual-dynamic condition participants watched videos of the hand-material interactions that were recorded in the haptic condition. After haptically or visually exploring the materials participants rated them on various attributes. Our results show a high overall perceptual correspondence between the three experimental conditions. With a few exceptions, this correspondence tended to be strongest between haptic and visual-dynamic conditions. These results are discussed with respect to information potentially available through the senses, or through prior experience, when judging the softness of materials.

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