scholarly journals Changed Temporal Structure of Neuromuscular Control, Rather Than Changed Intersegment Coordination, Explains Altered Stabilographic Regularity after a Moderate Perturbation of the Postural Control System

Entropy ◽  
2019 ◽  
Vol 21 (6) ◽  
pp. 614 ◽  
Author(s):  
Felix Wachholz ◽  
Tove Kockum ◽  
Thomas Haid ◽  
Peter Federolf
Keyword(s):  
Control System ◽  
Postural Control ◽  
Center Of Pressure ◽  
Temporal Structure ◽  
Force Plate ◽  
Principal Component ◽  
Neuromuscular Control ◽  
Postural Control System ◽  
Temporal Regularity ◽  
Postural Movement

Sample entropy (SaEn) applied on center-of-pressure (COP) data provides a measure for the regularity of human postural control. Two mechanisms could contribute to altered COP regularity: first, an altered temporal structure (temporal regularity) of postural movements (H1); or second, altered coordination between segment movements (coordinative complexity; H2). The current study used rapid, voluntary head-shaking to perturb the postural control system, thus producing changes in COP regularity, to then assess the two hypotheses. Sixteen healthy participants (age 26.5 ± 3.5; seven females), whose postural movements were tracked via 39 reflective markers, performed trials in which they first stood quietly on a force plate for 30 s, then shook their head for 10 s, finally stood quietly for another 90 s. A principal component analysis (PCA) performed on the kinematic data extracted the main postural movement components. Temporal regularity was determined by calculating SaEn on the time series of these movement components. Coordinative complexity was determined by assessing the relative explained variance of the first five components. H1 was supported, but H2 was not. These results suggest that moderate perturbations of the postural control system produce altered temporal structures of the main postural movement components, but do not necessarily change the coordinative structure of intersegment movements.

scholarly journals Should the Minimal Intervention Principle Be Considered When Investigating Dual-Tasking Effects on Postural Control?

2019 ◽  
Vol 10 (1) ◽  
pp. 1 ◽  
Author(s):  
Felix Wachholz ◽  
Federico Tiribello ◽  
Arunee Promsri ◽  
Peter Federolf
Keyword(s):  
Postural Control ◽  
Center Of Pressure ◽  
Force Plate ◽  
Principal Component ◽  
Mean Velocity ◽  
Dual Tasking ◽  
Minimal Intervention ◽  
Eyes Closed ◽  
Eyes Open ◽  
Postural Movement

Dual-tasking charges the sensorimotor system with performing two tasks simultaneously. Center of pressure (COP) analysis reveals the postural control that is altered during dual-tasking, but may not reveal the underlying neural mechanisms. In the current study, we hypothesized that the minimal intervention principle (MIP) provides a concept by which dual-tasking effects on the organization and prioritization of postural control can be predicted. Postural movements of 23 adolescents (age 12.7 ± 1.3; 8 females) and 15 adults (26.9 ± 2.3) were measured in a bipedal stance with eyes open, eyes closed and eyes open while performing a dual-task using a force plate and 39 reflective markers. COP data was analyzed by calculating the mean velocity, standard deviation and amplitude of displacement. Kinematic data was examined by performing a principal component analysis (PCA) and extracting postural movement components. Two variables were determined to investigate changes in amplitude (aVark) and in control (Nk) of the principal movement components. Results in aVark and in Nk agreed well with the predicted dual-tasking effects. Thus, the current study corroborates the notion that the MIP should be considered when investigating postural control under dual-tasking conditions.

Center-of-Pressure Parameters Used in the Assessment of Postural Control

2002 ◽  
Vol 11 (1) ◽  
pp. 51-66 ◽  
Author(s):  
Riann M. Palmieri ◽  
Christopher D. Ingersoll ◽  
Marcus B. Stone ◽  
B. Andrew Krause
Keyword(s):  
Control System ◽  
Postural Control ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Data Sources ◽  
Postural Control System ◽  
Type Data

Objective:To define the numerous center-of-pressure derivatives used in the assessment of postural control and discuss what value each might provide in the assessment of balance.Data Sources:MEDLINE and SPORTDiscus were searched with the termsbalance, postural control, postural sway,andcenter of pressure. The remaining citations were collected from references of similar papers. A total of 67 references were studied.Conclusions:Understanding what is represented by each parameter used to assess postural control is crucial. At the present time the literature has failed to demonstrate how the variables reflect changes made by the postural-control system. Until it can be shown that the center of pressure and its derivatives actually reveal changes in the postural-control system, the value of using these measures to assess deficits in postural control is minimized.

scholarly journals Virtual-Reality-Induced Visual Perturbations Impact Postural Control System Behavior

2019 ◽  
Vol 9 (11) ◽  
pp. 113 ◽  
Author(s):  
Harish Chander ◽  
Sachini N. K. Kodithuwakku Arachchige ◽  
Christopher M. Hill ◽  
Alana J. Turner ◽  
Shuchisnigdha Deb ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Control System ◽  
Postural Control ◽  
Repeated Measures ◽  
Postural Stability ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Postural Control System ◽  
Postural Responses ◽  
The Impact

Background: Virtual reality (VR) is becoming a widespread tool in rehabilitation, especially for postural stability. However, the impact of using VR in a “moving wall paradigm” (visual perturbation), specifically without and with anticipation of the perturbation, is unknown. Methods: Nineteen healthy subjects performed three trials of static balance testing on a force plate under three different conditions: baseline (no perturbation), unexpected VR perturbation, and expected VR perturbation. The statistical analysis consisted of a 1 × 3 repeated-measures ANOVA to test for differences in the center of pressure (COP) displacement, 95% ellipsoid area, and COP sway velocity. Results: The expected perturbation rendered significantly lower (p < 0.05) COP displacements and 95% ellipsoid area compared to the unexpected condition. A significantly higher (p < 0.05) sway velocity was also observed in the expected condition compared to the unexpected condition. Conclusions: Postural stability was lowered during unexpected visual perturbations compared to both during baseline and during expected visual perturbations, suggesting that conflicting visual feedback induced postural instability due to compensatory postural responses. However, during expected visual perturbations, significantly lowered postural sway displacement and area were achieved by increasing the sway velocity, suggesting the occurrence of postural behavior due to anticipatory postural responses. Finally, the study also concluded that VR could be used to induce different postural responses by providing visual perturbations to the postural control system, which can subsequently be used as an effective and low-cost tool for postural stability training and rehabilitation.

Ski Boots Do Not Impair Standing Balance by Restricting Ankle-Joint Mobility

2018 ◽  
Vol 61 (2) ◽  
pp. 214-224
Author(s):  
Frédéric Noé ◽  
Xavier García-Massó ◽  
Damien Ledez ◽  
Thierry Paillard
Keyword(s):  
Control System ◽  
Postural Control ◽  
Center Of Pressure ◽  
Frontal Plane ◽  
Emg Activity ◽  
Hip Joints ◽  
Postural Control System ◽  
Postural Tasks ◽  
Ankle Movement ◽  
Insight Into

Objective: This study was undertaken in order to provide new insight into sensorimotor control of posture when wearing high-shaft (HS) boots as ski boots. Background: Previous studies into the effects of HS boots on postural control have produced controversial results. Some studies reported postural control impairments with ski boots in bipedal postural tasks due to ankle movement restrictions without quantifying the actual restrictive effect of these boots and specifying the adaptations of the postural control system. Method: Eighteen young healthy subjects took part in the experiment. Bilateral postural control was assessed on stable and unstable surfaces, while standing barefoot or wearing ski boots. Center of pressure (COP) parameters, ankle, knee, and hip joints movements were calculated and EMG activity from main postural muscles was recorded. Results: Ski boots did not restrict the amplitude of ankle angular movements and largely impacted COP parameters and EMG activity on stable ground. In conditions of mediolateral instability, COP data illustrated an enhanced postural control in the frontal plane when wearing ski boots. Conclusions: Ski boots do not affect bipedal postural balance by restricting the ankle angular motions but induce complex adaptations of the postural control system which combine factors of a mechanical, motor, and sensorial nature. They impede postural control mainly when standing on stable ground without producing similar deleterious effects on unstable surfaces. Application: Our results show that HS boots as ski boots can improve lateral balance on unstable surfaces, which can contribute to prevent fall risk and ankle sprain.

A New Interpretation of Spontaneous Sway Measures Based on a Simple Model of Human Postural Control

2005 ◽  
Vol 93 (1) ◽  
pp. 189-200 ◽  
Author(s):  
Christoph Maurer ◽  
Robert J. Peterka
Keyword(s):  
Control System ◽  
Postural Control ◽  
Noise Level ◽  
Center Of Pressure ◽  
Optimization Procedure ◽  
Elderly Subjects ◽  
Published Data ◽  
Model Parameters ◽  
Postural Control System ◽  
New Interpretation

This study shows that center-of-pressure (COP) traces that closely resemble physiologically measured COP functions can be produced by an appropriate selection of model parameters in a simple feedback model of the human postural control system. Variations in the values of stiffness, damping, time delay, and noise level determine the values of 15 sway measures commonly used to characterize spontaneous sway. Results from model simulations indicate that there is a high degree of correlation among these sway measures, and the measures cluster into three different groups. Only two principal components accounted for about 92% of the variation among the different sway measures analyzed. This model can be used to formulate hypotheses regarding the cause of postural control deficits reported in the literature. This is accomplished using a multidimensional optimization procedure to estimate model parameters from a diverse set of spontaneous sway measures. These model parameters describe physiologically meaningful features of the postural control system as opposed to conventional sway measures that provide only a parametric description of sway. To show the application of this method, we applied it to published data of spontaneous sway from elderly subjects and contrasted it to the data of young healthy subjects. We found that modest increases in stiffness and damping and a fairly large increase in noise level with aging could account for the variety of sway measures reported in the literature for elderly subjects.

scholarly journals Habitual Physical Activity as a Determinant of the Effect of Moderate Physical Exercise on Postural Control in Older Men

2012 ◽  
Vol 7 (1) ◽  
pp. 58-65 ◽  
Author(s):  
Rafał Stemplewski ◽  
Janusz Maciaszek ◽  
Maciej Tomczak ◽  
Robert Szeklicki ◽  
Dorota Sadowska ◽  
...  
Keyword(s):  
Physical Activity ◽  
Postural Control ◽  
Sagittal Plane ◽  
Center Of Pressure ◽  
Force Plate ◽  
Frontal Plane ◽  
Habitual Physical Activity ◽  
Similar Reaction ◽  
Mean Velocity ◽  
Ergometer Exercise

The aim of the study was to compare the effect of exercise on postural control (PC) among the elderly with lower or higher level of habitual physical activity (HPA). The study involved 17 elderly men (mean age 72.9 ± 4.79 years). Mean velocity of the center of pressure (COP) displacements was measured using a force plate both before and after cycle ergometer exercise. A significantly higher increase in mean velocity of COP displacements and its component in the sagittal plane were observed in the group with lower level of HPA in comparison with the group with higher HPA level. Simultaneously, a relatively similar reaction to the exercise in the frontal plane was observed in both groups, possibly connected to the specific type of used exercise, which mainly activated the sagittal muscles.

Whole-body adaptation to novel dynamics does not transfer between effectors

2021 ◽  
Author(s):  
Alison Pienciak-Siewert ◽  
Alaa A Ahmed
Keyword(s):  
Postural Control ◽  
Arm Movement ◽  
Movement Planning ◽  
Reaching Movements ◽  
Whole Body ◽  
Postural Control System ◽  
Movement Dynamics ◽  
Gradual Introduction ◽  
Postural Movement ◽  
The Brain

How does the brain coordinate concurrent adaptation of arm movements and standing posture? From previous studies, the postural control system can use information about previously adapted arm movement dynamics to plan appropriate postural control; however, it is unclear whether postural control can be adapted and controlled independently of arm control. The present study addresses that question. Subjects practiced planar reaching movements while standing and grasping the handle of a robotic arm, which generated a force field to create novel perturbations. Subjects were divided into two groups, for which perturbations were introduced in either an abrupt or gradual manner. All subjects adapted to the perturbations while reaching with their dominant (right) arm, then switched to reaching with their non-dominant (left) arm. Previous studies of seated reaching movements showed that abrupt perturbation introduction led to transfer of learning between arms, but gradual introduction did not. Interestingly, in this study neither group showed evidence of transferring adapted control of arm or posture between arms. These results suggest primarily that adapted postural control cannot be transferred independently of arm control in this task paradigm. In other words, whole-body postural movement planning related to a concurrent arm task is dependent on information about arm dynamics. Finally, we found that subjects were able to adapt to the gradual perturbation while experiencing very small errors, suggesting that both error size and consistency play a role in driving motor adaptation.

scholarly journals Lower Extremity Neuromuscular Control Immediately After Fatiguing Hip-Abduction Exercise

2011 ◽  
Vol 46 (6) ◽  
pp. 607-614 ◽  
Author(s):  
Kelly L. McMullen ◽  
Nicole L. Cosby ◽  
Jay Hertel ◽  
Christopher D. Ingersoll ◽  
Joseph M. Hart
Keyword(s):  
Lower Extremity ◽  
Postural Control ◽  
Center Of Pressure ◽  
Neuromuscular Control ◽  
Lower Extremity Injury ◽  
Median Frequency ◽  
Men And Women ◽  
Hip Abduction ◽  
Quality Of Movement

Context: Fatigue of the gluteus medius (GMed) muscle might be associated with decreases in postural control due to insufficient pelvic stabilization. Men and women might have different muscular recruitment patterns in response to GMed fatigue. Objective: To compare postural control and quality of movement between men and women after a fatiguing hip-abduction exercise. Design: Descriptive laboratory study. Setting: Controlled laboratory. Patients or Other Participants: Eighteen men (age = 22 ± 3.64 years, height = 183.37 ± 8.30 cm, mass = 87.02 ±12.53 kg) and 18 women (age = 22 ± 3.14, height = 167.65 ± 5.80 cm, mass = 66.64 ± 10.49 kg) with no history of low back or lower extremity injury participated in our study. Intervention(s): Participants followed a fatiguing protocol that involved a side-lying hip-abduction exercise performed until a 15% shift in electromyographic median frequency of the GMed was reached. Main Outcome Measure(s): Baseline and postfatigue measurements of single-leg static balance, dynamic balance, and quality of movement assessed with center-of-pressure measurements, the Star Excursion Balance Test, and lateral step-down test, respectively, were recorded for the dominant lower extremity (as identified by the participant). Results: We observed no differences in balance deficits between sexes (P &gt; .05); however, we found main effects for time with all of our postfatigue outcome measures (P ≤ .05). Conclusions: Our findings suggest that postural control and quality of movement were affected negatively after a GMed-fatiguing exercise. At similar levels of local muscle fatigue, men and women had similar measurements of postural control.

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