scholarly journals Redirection of center-of-mass velocity during the step-to-step transition of human walking

2009 ◽  
Vol 212 (16) ◽  
pp. 2668-2678 ◽  
Author(s):  
P. G. Adamczyk ◽  
A. D. Kuo
Keyword(s):  
Mass Velocity ◽  
Center Of Mass ◽  
Human Walking ◽  
Step Transition

scholarly journals Center of mass velocity-based predictions in balance recovery following pelvis perturbations during human walking

2016 ◽  
Vol 219 (10) ◽  
pp. 1514-1523 ◽  
Author(s):  
M. Vlutters ◽  
E. H. F. van Asseldonk ◽  
H. van der Kooij
Keyword(s):  
Mass Velocity ◽  
Center Of Mass ◽  
Human Walking ◽  
Balance Recovery

Momentum Removal to Obtain the Position-Dependent Diffusion Constant in Constrained Molecular Dynamics Simulation

2021 ◽  
Author(s):  
Kazushi Fujimoto ◽  
Tetsuro Nagai ◽  
Tsuyoshi Yamaguchi
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficient ◽  
Mass Velocity ◽  
Center Of Mass ◽  
Heterogeneous Systems ◽  
Diffusion Constant ◽  
Dynamics Simulation ◽  
Coulombic Interaction ◽  
Ewald Method ◽  
Theoretical Predictions

<div>The position-dependent diffusion coefficient along with free energy profile are important parameters needed to study mass transport in heterogeneous systems such as biological and polymer membranes, and molecular dynamics (MD) calculation is a popular tool to obtain them. Among many methodologies, the Marrink-Berendsen (MB) method is often employed to calculate the position-dependent diffusion coefficient, in which the autocorrelation function of the force on a fixed molecule is related to the friction on the molecule. However, the diffusion coefficient is shown to be affected by the period of the removal of the center-of-mass velocity, which is necessary when performing MD calculations using the Ewald method for Coulombic interaction. We have clarified theoretically in this study how this operation affects the diffusion coefficient calculated by the MB method, and the theoretical predictions are proven by MD calculations. Therefore, we succeeded in providing guidance on how to select an appropriate the period of the removal of the center-of-mass velocity in estimating the position-dependent diffusion coefficient by the MB method. This guideline is applicable also to the Woolf-Roux method.</div>

High Velocity Spectroscopic Binary Orbits from Photoelectric Radial Velocities: BD+20 5152, a Possible Triple System

2010 ◽  
Vol 19 (3-4) ◽  
Author(s):  
J. Sperauskas ◽  
A. Bartkevičius ◽  
R. P. Boyle ◽  
V. Deveikis
Keyword(s):  
Radial Velocity ◽  
Proper Motion ◽  
High Velocity ◽  
Triple System ◽  
Mass Velocity ◽  
Center Of Mass ◽  
Primary Component ◽  
Eccentric Orbit ◽  
Velocity Measurements ◽  
Spectroscopic Binary

AbstractThe spectroscopic orbit of a high proper motion star, BD+20 5152, is calculated from 34 CORAVEL-type radial velocity measurements. The star has a slightly eccentric orbit with a period of 5.70613 d, half-amplitude of 47.7 km/s and eccentricity of 0.049. The center-of-mass velocity of the system is -24.3 km/s. BD+20 5152 seems to be a triple system consisting of a G8 dwarf as a primary component and of two K6-M0 dwarfs as secondary and tertiary components. This model is based on the analysis of its UBVRI and JHK magnitudes. According to the SuperWASP photometry, spots on the surface of the primary are suspected. The excessive brightness in the Galex FUV and NUV magnitudes and a non-zero eccentricity suggest the age of this system to be less than 1 Gyr.

EXPERIENCE AND PRACTICE IN CARRYING A HEAVY, UNILATERAL LOAD: FOOTPRINT EVIDENCE

2017 ◽  
Vol 17 (01) ◽  
pp. 1750022 ◽  
Author(s):  
DAVID WEBB ◽  
SARA BRATSCH
Keyword(s):  
Anterior Part ◽  
Center Of Mass ◽  
Initial Study ◽  
Ease Of Use ◽  
Human Walking ◽  
Step Width ◽  
Heavy Load ◽  
Subtle Change ◽  
Foot Placement ◽  
Heavy Loads

Although a significant amount of research has examined the biomechanical effects of carrying a load on human walking, most has focussed on fore and aft loads, or evenly balanced loads. In addition, most research on human walking no longer considers footprint analysis, despite its ease of use and its effectiveness in studies of balance. However, one project, with a small number of subjects, suggested that people carrying a heavy load in one hand (e.g., a suitcase or toolbox) make two sorts of adjustments to the placement of their feet on the substrate. The first and most obvious change is a decrease in foot angle (in-toeing) on the unloaded side. This puts the anterior part of the foot further under the center of mass when carrying a load in the contralateral hand and has been amply documented in subsequent studies. The second and more subtle change is a decrease in step width, a practice which also moves the foot on the unloaded side closer to the center of mass. However, tests subsequent to the original study did not show a consistent or significant use of this technique. This discrepancy between original and subsequent results in step width can be explained by the level of expertise which various subjects have. Experience carrying heavy loads may be required for most subjects to develop ways of accommodating loads. For this project, subjects were tested under two conditions: carrying an empty canvas bag; carrying the same bag with 21% of their body weight in it. All subjects walked on paper runners, wearing paint-soaked socks to leave footprint trails. Subjects were asked to walk once with no weights followed by three more times with weights. They were then given 10–15[Formula: see text]min of practice with the weighted bag, then asked to repeat the protocol, for a total of eight trials (two unweighted and six weighted). Foot angle and step width were measured for all trials. Results show that practice does indeed make a difference in the use of a narrower step when carrying a heavy load. Specifically, the first three weighted trials show a decrease in step width that is nonsignificant, but the last three evince a significant reduction as compared to unweighted trials. In addition, lifetime experience carrying a heavy load led to more immediate changes in foot placement. We conclude that the initial study involved subjects who already had experience carrying a unilateral heavy load and that, as with other activities, mechanically more effective movements are acquired with greater experience and practice.

Ground reaction force and center of mass velocity during turning

2014 ◽  
Vol 39 ◽  
pp. S11-S12 ◽  
Author(s):  
Philippe C. Dixon ◽  
Julie Stebbins ◽  
Tim Theologis ◽  
Amy B. Zavatsky
Keyword(s):  
Ground Reaction Force ◽  
Mass Velocity ◽  
Center Of Mass ◽  
Reaction Force

A Spring-Mass Model of Locomotion With Full Asymptotic Stability

2011 ◽  
Author(s):  
Zhuohua Shen ◽  
Justin Seipel
Keyword(s):  
Mass Velocity ◽  
Inverted Pendulum ◽  
Center Of Mass ◽  
Legged Locomotion ◽  
Reduced Model ◽  
Asymptotically Stable ◽  
Slip Model ◽  
Mass Model ◽  
Improved Stability ◽  
Spring Loaded Inverted Pendulum

A reduced model of legged locomotion, called the Spring Loaded Inverted Pendulum (SLIP) has previously been developed to predict the dynamics of locomotion. However, due to energy conservation, the SLIP model can only be partially asymptotically stable in the center-of-mass velocity. The more recently developed Clock-Torqued Spring Loaded Inverted Pendulum (CT-SLIP) model is fully asymptotically stable, and has a significantly larger stability basin than SLIP, but requires more than twice as many parameters. To more completely explore the parameter space and understand the reason for improved stability, we develop and analyze a further reduced model called the Forced-Damped Spring Loaded Inverted Pendulum (FD-SLIP) model.

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