Unified theory regarding A/P and M/L balance in quiet stance

1996 ◽  
Vol 75 (6) ◽  
pp. 2334-2343 ◽  
Author(s):  
D. A. Winter ◽  
F. Prince ◽  
J. S. Frank ◽  
C. Powell ◽  
K. F. Zabjek
Keyword(s):  
Center Of Pressure ◽  
Balance Control ◽  
Standing Position ◽  
Force Platform ◽  
Control Line ◽  
Small Contribution ◽  
Quiet Stance ◽  
Single Force ◽  
P Balance ◽  
The Individual

1. Control of posture in quiet stance has been quantified by center of pressure (COP) changes in the anterior-posterior (A/P) and medial-lateral (M/L) directions from a single force platform. Recording from a single force platform, researchers are unable to recognize two separate mechanisms that become evident when two force platforms are used. Depending on the stance position taken, many combinations of an ankle mechanism and a hip (load/unload) mechanism are evident. In side-by-side stance, A/P balance is totally under ankle (plantar/dorsiflexor) control, whereas M/L balance is under hip (abductor/adductor) control. In tandem stance, the A/P balance is dominated by the hip mechanism, with mixed and small or sometimes negligible contributions by the ankle plantar/dorsiflexors: for M/L balance, the reverse is evident; ankle invertors/evertors dominate, with mixed and small contribution from the hip load/unload mechanism. In an intermediate 45 degrees stance position, both ankle and hip mechanisms contribute to the net balance control in totally different ways. In the M/L direction the two strategies reinforce, whereas in the A/P direction the ankle mechanism must overcome and cancel most of the inappropriate contribution by the hip load/unload mechanism. A spatial plot of the separate mechanisms reveals the fact that the random-looking COP scatter plot is nothing more than a spatial and temporal summation of two separate spatial plots. A straight line joining the individual COPs under each foot is the load/unload line controlled by the hip mechanism. At right angles to this load/unload line in the side-by-side and tandem positions is the independent control line by the ankle muscles. In an intermediate standing position, the separate control lines exist, but now the ankle control is not orthogonal to the load/unload line; rather, it acts at an angle of approximately 60 degrees. The direction of these ankle control and load/unload lines also allows us to pinpoint the muscle groups responsible at the ankle and hip in any of the stance positions.

scholarly journals Comparison of two methods of postural control analysis during upright and quiet stance

2009 ◽  
Vol 4 (1) ◽  
pp. 30-36
Author(s):  
Ana Maria Forti Barela ◽  
Diego Alveno ◽  
Claudia Garcia ◽  
Cássio A. Pereira
Keyword(s):  
Young Adults ◽  
Postural Control ◽  
Center Of Pressure ◽  
Force Platform ◽  
Control Analysis ◽  
Quiet Stance ◽  
Mean Velocity ◽  
Methods Of Analysis ◽  
Strong Relation ◽  
Base Of Support

The goal of this study was to compare two methods of analysis, the use of force platform and based on video system, to investigate the postural control of young adults during upright stance on three bases of support. Fifteen young adults (30±4.96 years old) were asked to maintain an upright and quiet stance on a force platform for 30 s on bipedal, semi-tandem stance, and reduced bipedal bases of support. One reflective marker was placed on their back to acquire the space coordinates. Mean sway amplitude and mean velocity in anterior-posterior (AP) and medial-lateral (ML) directions and the area of stabilogram were calculated and used to compare the two methods of analysis and the effects of bases of support. Coefficient of correlation values indicated strong relation between trajectories of center of pressure and reflective marker in both directions (AP and ML), and statistical analysis of both methods indicated similar results in terms of effects of base of support. According to these results it might be suggested that both methods of analysis to investigate the control of upright and quiet stance in young adults can be used.  

Letter to the editor regarding “The assessment of center of mass and center of pressure during quiet stance: Current applications and future directions”

2021 ◽  
Vol 128 ◽  
pp. 110729
Author(s):  
Peter Federolf ◽  
Rosa M Angulo-Barroso ◽  
Albert Busquets ◽  
Blai Ferrer-Uris ◽  
Øyvind Gløersen ◽  
...  
Keyword(s):  
Center Of Pressure ◽  
Center Of Mass ◽  
Quiet Stance ◽  
Future Directions ◽  
Letter To The Editor

Center of pressure estimation during running without a force platform

1992 ◽  
Vol 25 (6) ◽  
pp. 671
Author(s):  
B.P.E. David Andrews ◽  
James J. Dowling
Keyword(s):  
Center Of Pressure ◽  
Force Platform ◽  
Pressure Estimation

Neuroclusterization method of stabilometric data

2021 ◽  
Author(s):  
I.V. Stepanyan ◽  
S.S. Grokhovsky ◽  
O.V. Kubryak
Keyword(s):  
Center Of Pressure ◽  
Modern Method ◽  
Individual Characteristics ◽  
Automatic Mode ◽  
Support Reaction ◽  
Subsequent Determination ◽  
Euclidean Metrics ◽  
Postural Regulation ◽  
The Individual ◽  
Neural Maps

Stabilometry is a modern method for assessing the functional state of a person by the ability to maintain a stable balance of an upright posture. Technically, the implementation of the stabilometry method consists in measuring, with the help of specialized devices, the values that make up the support reaction, with the subsequent determination, according to these measurements, of the coordinates of the center of body pressure on the support. The nature of the migrations of the center of pressure during the stabilometric study is a source of information about the features of the processes of postural regulation. At the same time, up to the present time, there is a problem of the correct interpretation of the results of stabilometry. The adequacy of the conclusions is largely determined by the human factor, i.e. qualification of a specialist analyzing stabilometry data. Thus, in our opinion, the task of objectifying the assessment of stabilometry results is urgent. The aim of this work is to study the possibility of applying the neurocluster method using self-organizing neural networks to objectify the analysis of stabilometry data. The authors proposed a technique for analyzing the structure of individual and group stabilometric data by clustering them using selforganizing Kohonen neural maps with Euclidean metrics. Neuroclusterization of stabilometric data allows in automatic mode (without human intervention) to identify the type of group of subjects corresponding to the norm or pathology, various types of pathologies, as well as individual biometric characteristics of the subjects. The subsequent analysis of the individual characteristics of the data of the subjects, grouped in this way, makes it possible to detect deviations indicating the presence of abnormalities or the formation of various pathological conditions, which can be useful for the early diagnosis of diseases.

The Effect of Wave Motion Intensities on Performance in a Simulated Search and Rescue Task and the Concurrent Demands of Maintaining Balance

2020 ◽  
pp. 001872082095290
Author(s):  
Carolyn A. Duncan ◽  
Nicole Bishop ◽  
Vicki Komisar ◽  
Scott N. MacKinnon ◽  
Jeannette M. Byrne
Keyword(s):  
Wave Motion ◽  
Muscle Activation ◽  
Balance Control ◽  
Health And Safety ◽  
Search And Rescue ◽  
Worker Safety ◽  
Motion Platform ◽  
And Performance ◽  
The Individual ◽  
Maritime Search And Rescue

Objective The purpose of this study was to examine how intensity of wave motions affects the performance of a simulated maritime search and rescue (SAR) task. Background Maritime SAR is a critical maritime occupation; however, the effect of wave motion intensity on worker performance is unknown. Methods Twenty-four participants (12 male, 12 female) performed a simulated search and rescue task on a six-degree-of-freedom motion platform in two conditions that differed in motion intensity (low and high). Task performance, electromyography (EMG), and number of compensatory steps taken by the individual were examined. Results As magnitude of simulated motion increased, performance in the SAR task decreased, and was accompanied by increases in lower limb muscle activation and number of steps taken. Conclusions Performance of an SAR task and balance control may be impeded by high-magnitude vessel motions. Application This research has the potential to be used by maritime engineers, occupational health and safety professionals, and ergonomists to improve worker safety and performance for SAR operators.

scholarly journals Estimation and Closed-Loop Control of COG/ZMP in Biped Devices Blending CoP Measures and Kinematic Information

Robotics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 89 ◽  
Author(s):  
Giuseppe Menga ◽  
Marco Ghirardi
Keyword(s):  
Closed Loop ◽  
Inverted Pendulum ◽  
Joint Angle ◽  
Center Of Pressure ◽  
Balance Control ◽  
External Disturbance ◽  
Practical Implementation ◽  
Complex Nature ◽  
Simple Relationship ◽  
Loop Control

The zero moment point ( Z M P ) and the linearized inverted pendulum model linking the Z M P to the center of gravity ( C O G ) have an important role in the control of the postural equilibrium (balance) of biped robots and lower-limb exoskeletons. A solution for balance real time control, closing the loop from the joint actual values of the C O G and Z M P , has been proposed by Choi. However, this approach cannot be practically implemented: While the Z M P actual value is available from the center of pressure ( C o P ) measured under the feet soles, the C O G is not measurable, but it can only be indirectly assessed from the joint-angle measures, the knowledge of the kinematics, and the usually poorly known weight distribution of the links of the chain. Finally, the possible presence of unknown external disturbance forces and the nonlinear, complex nature of the kinematics perturb the simple relationship between the Z M P and C O G in the linearized model. The aim of this paper is to offer, starting from Choi’s model, a practical implementation of closed-loop balance control fusing C o P and joint-angle measures, eliminating possible inconsistencies. In order to achieve this result, we introduce a model of the linearized inverted pendulum for an extended estimation, not only of C O G and Z M P , but also of external disturbances. This model is then used, instead of Choi’s equations, for estimation and balance control, using H ∞ theory. As the C O G information is recovered from the joint-angle measures, the identification of a statistically equivalent serial chain ( S E S C ) linking the C O G to the joint angles is also discussed.

scholarly journals Applying the Minimal Detectable Change of a Static and Dynamic Balance Test Using a Portable Stabilometric Platform to Individually Assess Patients with Balance Disorders

Healthcare ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 402 ◽  
Author(s):  
Juan De la Torre ◽  
Javier Marin ◽  
Marco Polo ◽  
José J. Marín
Keyword(s):  
Center Of Pressure ◽  
Balance Control ◽  
Dynamic Balance ◽  
Static Balance ◽  
Minimal Detectable Change ◽  
Detectable Change ◽  
Balance Test ◽  
Balance Disorders ◽  
Eyes Closed ◽  
Specialist Physician

Balance disorders have a high prevalence among elderly people in developed countries, and falls resulting from balance disorders involve high healthcare costs. Therefore, tools and indicators are necessary to assess the response to treatments. Therefore, the aim of this study is to detect relevant changes through minimal detectable change (MDC) values in patients with balance disorders, specifically with vertigo. A test-retest of a static and dynamic balance test was conducted on 34 healthy young volunteer subjects using a portable stabilometric platform. Afterwards, in order to show the MDC applicability, eight patients diagnosed with balance disorders characterized by vertigo of vestibular origin performed the balance test before and after a treatment, contrasting the results with the assessment by a specialist physician. The balance test consisted of four tasks from the Romberg test for static balance control, assessing dynamic postural balance through the limits of stability (LOS). The results obtained in the test-retest show the reproducibility of the system as being similar to or better than those found in the literature. Regarding the static balance variables with the lowest MDC value, we highlight the average velocity of the center of pressure (COP) in all tasks and the root mean square (RMS), the area, and the mediolateral displacement in soft surface, with eyes closed. In LOS, all COP limits and the average speed of the COP and RMS were highlighted. Of the eight patients assessed, an agreement between the specialist physician and the balance test results exists in six of them, and for two of the patients, the specialist physician reported no progression, whereas the balance test showed worsening. Patients showed changes that exceeded the MDC values, and these changes were correlated with the results reported by the specialist physician. We conclude that (at least for these eight patients) certain variables were sufficiently sensitive to detect changes linked to balance progression. This is intended to improve decision making and individualized patient monitoring.

scholarly journals Comparison of postural balance between professional tae kwon do athletes and young adults

2014 ◽  
Vol 21 (2) ◽  
pp. 139-143 ◽  
Author(s):  
Lucas Maciel Rabello ◽  
Christiane de Souza Guerino Macedo ◽  
André Wilson Gil ◽  
Marcio Rogério de Oliveira ◽  
Vinícius Arantes Coelho ◽  
...  
Keyword(s):  
Postural Balance ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Force Platform ◽  
Adult Group ◽  
Tae Kwon Do ◽  
Rehabilitation Programs ◽  
Significant Difference ◽  
Single Leg Stance ◽  
Postural Assessment

This study aimed to compare the postural balance of professional tae kwon do athletes with a non-tae kwon do adult group. Nineteen participants (nine tae kwon do practitioners and ten non-tae kwon do practitioners) were tested. To measure the postural sway, a force platform was used and the equipment recorded the main parameters: area of center of pressure; mean frequency, and velocity of center of pressure for both anteroposterior and mediolateral directions were measured for all participants. Before starting the assessment, the subjects received instructions and performed familiarization with the equipment and protocol. Participants were instructed to carry out three balance tests on a single-leg stance position with eyes opened. Values obtained in the postural assessment of professional athletes with the force platform were lower for all parameters compared to non-practitioners, except the frequency of center of pressure in the mediolateral direction. However, a significant difference (p=0.021) between the groups was found only in the center of pressure velocity parameter in the anteroposterior direction. These results have any implications on sport rehabilitation programs for balance assessments in athletes.

scholarly journals Lower Limb Exoskeleton Gait Planning Based on Crutch and Human-Machine Foot Combined Center of Pressure

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7216
Author(s):  
Wei Yang ◽  
Jiyu Zhang ◽  
Sheng Zhang ◽  
Canjun Yang
Keyword(s):  
Lower Limb ◽  
Stride Length ◽  
Center Of Pressure ◽  
Balance Control ◽  
Effective Means ◽  
Stability Control ◽  
Planning Method ◽  
Gait Planning ◽  
Lower Limb Exoskeleton ◽  
Cord Injury

With the help of wearable robotics, the lower limb exoskeleton becomes a promising solution for spinal cord injury (SCI) patients to recover lower body locomotion ability. However, fewer exoskeleton gait planning methods can meet the needs of patient in real time, e.g., stride length or step width, etc., which may lead to human-machine incoordination, limit comfort, and increase the risk of falling. This work presents a human-exoskeleton-crutch system with the center of pressure (CoP)-based gait planning method to enable the balance control during the exoskeleton-assisted walking with crutches. The CoP generated by crutches and human-machine feet makes it possible to obtain the overall stability conditions of the system in the process of exoskeleton-assisted quasi-static walking, and therefore, to determine the next stride length and ensure the balance of the next step. Thus, the exoskeleton gait is planned with the guidance of stride length. It is worth emphasizing that the nominal reference gait is adopted as a reference to ensure that the trajectory of the swing ankle mimics the reference one well. This gait planning method enables the patient to adaptively interact with the exoskeleton gait. The online gait planning walking tests with five healthy volunteers proved the method’s feasibility. Experimental results indicate that the algorithm can deal with the sensed signals and plan the landing point of the swing leg to ensure balanced and smooth walking. The results suggest that the method is an effective means to improve human–machine interaction. Additionally, it is meaningful for the further training of independent walking stability control in exoskeletons for SCI patients with less assistance of crutches.

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