A Postural Model of Balance-Correcting Movement Strategies

1992 ◽  
Vol 2 (4) ◽  
pp. 323-347
Author(s):  
J.H.J. Allum ◽  
F. Honegger
Keyword(s):  
Normal Subjects ◽  
Opposite Polarity ◽  
The Body ◽  
Joint Torque ◽  
Support Surface ◽  
Joint Torques ◽  
Eyes Closed ◽  
Movement Strategies ◽  
Eyes Open ◽  
Balance Corrections

The patterns of joint torques and movement strategies underlying human balance corrections were examined using a postural model. Two types of support-surface perturbation, dorsiflexion rotation (ROT) and rearward translation (TRANS), were employed. These two perturbations were adjusted to produce similar profiles of ankle dorsiflexion in order to obtain information on the role of lower leg proprioceptive inputs on triggering balance corrections. In addition, the dependence of balance control on head angular and linear accelerations was investigated by comparing the responses of normal and vestibularly deficient subjects under eyes-closed and eyes-open conditions. Differences in ROT and TRANS movement strategies were examined in three ways First, the amplitude and polarity of active joint torques were analysed. These were obtained by altering joint torques applied to a postural model until movements of the model accurately duplicated those of measured responses. Second, the pattern of body-segment angular movements depicted by stick figures moving in response to the computed joint torques was investigated. Third, the peak amplitude and patterns of crosscorrelations between joint torques were measured. Active ankle, knee, and hip joint torques computed for normal subjects rotated the body forward for ROT. In the case of TRANS, computed active torques in normal were of opposite polarity to those of ROT and reversed the forward motion of the body. Subjects with vestibular deficits had lower amplitude torques for ROT and failed to counter the platform rotation. Hip torques for TRANS in vestibular deficient subjects were of opposite polarity to those of normal subjects and resulted in excessive forward trunk rotation. Normally, neck torques acted to stabilize the head in space when trunk angular velocity peaked. Vestibular deficient subjects displayed head movements in response to ROT similar to those generated when neck torques were absent. For TRANS, these same subjects exhibited overcompensatory neck torques. Stick figures of normal responses indicated a stiffening of the body into a leg and a trunk-head link for ROT and a flexible multilink motion for TRANS. Likewise, normal response strategies, defined by using crosscorrelations of joint torques, differed for ROT and TRANS. All joint torque crosscorrelations were significant for TRANS. Neck torques led those of all other joint torques by 40 ms or more, and hip joint led ankle torques by 30 ms. Joint torque correlations for ROT were organised around hip and ankle torques without a major correlation to neck torques. Fundamental changes in all torque crosscorrelations occurred for vestibularly deficient subjects under both eyes-open and eyes-closed conditions. These results support the hypothesis that the modulation of postural responses by vestibular signals occurs at all major joint links of the upright human body and that the strategy underlying balance corrections at the hip and neck is selected independent of local sensory input from the lower leg. Rearward translation and dorsiflexion rotation of a support-surface elicit different movement strategies when ankle angle, changes are matched for such disturbances to human upright balance.

scholarly journals The Ability of Gymnastics Motoric Perceptual Based on Local Culture for Early Childhood in Aceh Province

2020 ◽  
Vol 3 (2) ◽  
pp. 749-762
Author(s):  
Muhammad Riski Kurniawan ◽  
Syamsulrizal Syamsulrizal ◽  
Razali Razali ◽  
Israwati Israwati
Keyword(s):  
Early Childhood ◽  
The Body ◽  
Local Culture ◽  
Homogeneity Test ◽  
Tennis Ball ◽  
Eyes Closed ◽  
Aceh Province ◽  
Eyes Open ◽  
Perceptual Ability ◽  
The Impact

Local culture-based gymnastics is a combination of Seudati dance with Saman dances movements as well as cheerful healthy exercises that are already in kindergarten. The purpose of this study was to determine the impact of the implementation of local culture-based exercise on the motorized perceptual ability of early childhood in Banda Aceh Kindergarten. This study uses a quantitative approach to the type of experimental research. Population and a sample of 30 students were selected by purposive sampling. Data collection techniques of motoric perceptual ability using tests: (1) Standing on the beam while touching the limbs as instructed by the teacher with eyes open, (2 ) Standing on the beam while touching the body as instructed by the teacher with eyes closed, (3) Jumping and landing in a line with two feet pressed together as instructed by the teacher with eyes open, (4) Jumping and landing in a line with two feet pressed together as instructed by the teacher with eyes closed , (5) Walking in balance, (6) Throwing a tennis ball into a basket with a distance of 2 meters. Before the data is analyzed, the research data is tested for the analysis requirements, namely the normality and homogeneity test. Then the data is analyzed using the t-test. Based on the results of data analysis obtained t count (18.455)> t table (2.045), thus it can be concluded that there is a significant influence between local culture-based exercise on the motoric perceptual ability of early childhood in Aceh kindergarten.      

Stiffness Control of Balance in Quiet Standing

1998 ◽  
Vol 80 (3) ◽  
pp. 1211-1221 ◽  
Author(s):  
David A. Winter ◽  
Aftab E. Patla ◽  
Francois Prince ◽  
Milad Ishac ◽  
Krystyna Gielo-Perczak
Keyword(s):  
The Body ◽  
Quiet Standing ◽  
Error Signal ◽  
Reactive Control ◽  
Eyes Closed ◽  
Stiffness Model ◽  
Significant Difference ◽  
Eyes Open ◽  
Stiffness Control ◽  
Corrective Response

Winter, David A., Aftab E. Patla, Francois Prince, Milad Ishac, and Krystyna Gielo-Perczak. Stiffness control of balance in quiet standing. J. Neurophysiol. 80: 1211–1221, 1998. Our goal was to provide some insights into how the CNS controls and maintains an upright standing posture, which is an integral part of activities of daily living. Although researchers have used simple performance measures of maintenance of this posture quite effectively in clinical decision making, the mechanisms and control principles involved have not been clear. We propose a relatively simple control scheme for regulation of upright posture that provides almost instantaneous corrective response and reduces the operating demands on the CNS. The analytic model is derived and experimentally validated. A stiffness model was developed for quiet standing. The model assumes that muscles act as springs to cause the center-of-pressure (COP) to move in phase with the center-of-mass (COM) as the body sways about some desired position. In the sagittal plane this stiffness control exists at the ankle plantarflexors, in the frontal plane by the hip abductors/adductors. On the basis of observations that the COP-COM error signal continuously oscillates, it is evident that the inverted pendulum model is severely underdamped, approaching the undamped condition. The spectrum of this error signal is seen to match that of a tuned mass, spring, damper system, and a curve fit of this “tuned circuit” yields ωn the undamped natural frequency of the system. The effective stiffness of the system, K e , is then estimated from K e = Iω2 n, and the damping B is estimated from B = BW × I, where BW is the bandwidth of the tuned response (in rad/s), and I is the moment of inertia of the body about the ankle joint. Ten adult subjects were assessed while standing quietly at three stance widths: 50% hip-to-hip distance, 100 and 150%. Subjects stood for 2 min in each position with eyes open; the 100% stance width was repeated with eyes closed. In all trials and in both planes, the COP oscillated virtually in phase (within 6 ms) with COM, which was predicted by a simple 0th order spring model. Sway amplitude decreased as stance width increased, and K e increased with stance width. A stiffness model would predict sway to vary as K −0.5 e . The experimental results were close to this prediction: sway was proportional to K −0.55 e . Reactive control of balance was not evident for several reasons. The visual system does not appear to contribute because no significant difference between eyes open and eyes closed results was found at 100% stance width. Vestibular (otolith) and joint proprioceptive reactive control were discounted because the necessary head accelerations, joint displacements, and velocities were well below reported thresholds. Besides, any reactive control would predict that COP would considerably lag (150–250 ms) behind the COM. Because the average COP was only 4 ms delayed behind the COM, reactive control was not evident; this small delay was accounted for by the damping in the tuned mechanical system.

Réponses évoquées par le nystagmus spontané

Perception ◽  
1972 ◽  
Vol 1 (2) ◽  
pp. 177-185 ◽  
Author(s):  
Gabrielle C Lairy ◽  
Nicole Lesèvre ◽  
J F Baillon ◽  
A Rémond ◽  
D Godde-Jolly
Keyword(s):  
Complex Structure ◽  
Normal Subjects ◽  
Congenital Nystagmus ◽  
Wave Form ◽  
Average Response ◽  
Factors Associated ◽  
Eyes Closed ◽  
Form Recognition ◽  
Eyes Open ◽  
Lambda Response

A digital programme of wave form recognition was applied to a nystagmogram so as to pave the way for an average chronotopographic study of the occipital EEG activity triggered by the start of the rapid stage of the nystagmus. The programme was used in a clinical case of congenital nystagmus associated with a visual deficiency (coloboma of the optic nerve), with the following results: (i) in the patient examined, no average evoked response was observed either with eyes closed or with eyes open in the dark; (ii) an average response of small amplitude was observed with eyes open centred on a homogeneous illuminated field; this response was reinforced (greater amplitude and more complex structure) by a patterned field (checkerboard); (iii) the response to nystagmus showed characteristics similar to those of lambda response in the same subject. These results appear to confirm the conclusions of Bender and Shanzer (1964) according to which the calcarine activity in monkeys in response to experimental nystagmus is “light and vision dependent and correlates with the visual input and not with the oculomotor output”. Differences in amplitude, latency, and structure between the various responses recorded in the patient examined (response to nystagmus, to appearance of lighted checkerboard, and lambda response) and the same responses in normal subjects are considered and discussed in relation to factors associated with visual deficiency.

scholarly journals Optimization of Coupling Ratio and Kinematics of an Underactuated Robot Leg for Passive Terrain Adaptability

2012 ◽  
Author(s):  
Oren Y. Kanner ◽  
Aaron M. Dollar
Keyword(s):  
Performance Metrics ◽  
Reaction Force ◽  
The Body ◽  
Joint Torque ◽  
Design Parameters ◽  
Leg Length ◽  
Coupling Ratio ◽  
Joint Torques ◽  
Robot Leg ◽  
Underactuated Robot

This paper investigates how the passive adaptability of an underactuated robot leg to uneven terrain is affected by variations in design parameters. In particular, the ratio between the joint torques, the ratio between the link lengths, and the initial joint rest angles are varied to determine configurations that allow for maximum terrain roughness adaptability while minimizing the transmission of disturbance forces to the body. The results show that a proximal/distal joint torque coupling ratio of 1.58, proximal/distal leg length ratio of 0.5, and an initial proximal joint angle of −49 degrees maximize the terrain variability over which the robot can remain stable by exerting a near-constant vertical reaction force while minimizing lateral force and moment disturbances. In addition, the spring stiffness ratio allows for a tradeoff to be made between the different performance metrics.

scholarly journals Visual Modulation of Human Responses to Support Surface Translation

2021 ◽  
Vol 15 ◽  
Author(s):  
Mustafa Emre Akçay ◽  
Vittorio Lippi ◽  
Thomas Mergner
Keyword(s):  
Inverted Pendulum ◽  
Significant Degree ◽  
The Body ◽  
Resonance Phenomenon ◽  
Continuous Illumination ◽  
Support Surface ◽  
Position Information ◽  
Eyes Closed ◽  
Postural Responses ◽  
Visual Conditions

Vision is known to improve human postural responses to external perturbations. This study investigates the role of vision for the responses to continuous pseudorandom support surface translations in the body sagittal plane in three visual conditions: with the eyes closed (EC), in stroboscopic illumination (EO/SI; only visual position information) and with eyes open in continuous illumination (EO/CI; position and velocity information) with the room as static visual scene (or the interior of a moving cabin, in some of the trials). In the frequency spectrum of the translation stimulus we distinguished on the basis of the response patterns between a low-frequency, mid-frequency, and high-frequency range (LFR: 0.0165-0.14 Hz; MFR: 0.15–0.57 Hz; HFR: 0.58–2.46 Hz). With EC, subjects’ mean sway response gain was very low in the LFR. On average it increased with EO/SI (although not to a significant degree p = 0.078) and more so with EO/CI (p < 10−6). In contrast, the average gain in the MFR decreased from EC to EO/SI (although not to a significant degree, p = 0.548) and further to EO/CI (p = 0.0002). In the HFR, all three visual conditions produced, similarly, high gain levels. A single inverted pendulum (SIP) model controlling center of mass (COM) balancing about the ankle joints formally described the EC response as being strongly shaped by a resonance phenomenon arising primarily from the control’s proprioceptive feedback loop. The effect of adding visual information in these simulations lies in a reduction of the resonance, similar as in the experiments. Extending the model to a double inverted pendulum (DIP) suggested in addition a biomechanical damping effective from trunk sway in the hip joints on the resonance.

scholarly journals Haptic contact with a walking dog improves human balance during a quiet tandem task with various levels of difficulty

2021 ◽  
Vol 15 (3) ◽  
pp. 237-249
Author(s):  
Eliane Mauerberg-deCastro ◽  
Gabriella A. Figueiredo ◽  
Thayna P. Iasi ◽  
Debra F. Campbell ◽  
Renato Moraes
Keyword(s):  
Postural Control ◽  
Task Difficulty ◽  
Force Platform ◽  
Support Surface ◽  
Haptic Information ◽  
Dog Walking ◽  
Eyes Closed ◽  
Pulling Forces ◽  
Eyes Open ◽  
Human Balance

BACKGROUND: When a person walks a dog, information from variables of their own postural control is integrated with haptic information from the dog’s movements (e.g., direction, speed of movement, pulling forces). AIM: We examined how haptic information provided through contact with a moving endpoint (here, the leash of a dog walking on a treadmill) influenced an individual’s postural control during a quiet tandem standing task with and without restricted vision and under various elevations of the support surface (increased task difficulty levels). METHOD: Adults performed a 30-second quiet tandem stance task on a force platform while holding a leash attached to a dog who walked on a treadmill parallel to the force platform. Conditions included: haptic contact (dog and no-dog), vision constraint (eyes open, EO, and eyes closed, EC), and surfaces (4 heights). RESULTS: Interaction between haptic condition and vision showed that contact with the dog leash reduced root mean square (RMS) and mean sway speed (MSS). RMS showed that the highest surface had the greatest rate of sway reduction during haptic contact with EC, and an increase with EO. CONCLUSION: The dog’s movements were used as a haptic reference to aid balance when eyes were closed. In this condition, contact with the dog’s leash reduced the extent of sway variability on the higher surfaces.

scholarly journals Age-Related Changes in Human Posture Control: Sensory Organization Tests

1990 ◽  
Vol 1 (1) ◽  
pp. 73-85 ◽  
Author(s):  
R.J. Peterka ◽  
F.O. Black
Keyword(s):  
Visual Cues ◽  
Human Subjects ◽  
Body Sway ◽  
Support Surface ◽  
Eyes Closed ◽  
Sensory Organization ◽  
Age Related ◽  
Eyes Open ◽  
Orientation Cues ◽  
Anterior Posterior

Postural control was measured in 214 human subjects ranging in age from 7 to 81 y. Sensory organization tests measured the magnitude of anterior-posterior body sway during six 21 s trials in which visual and somatosensory orientation cues were normal, altered (by rotating the visual surround and support surface in proportion to the subject’s sway), or vision eliminated (eyes closed). No age-related increase in postoral sway was found for subjects standing on a fixed support surface with eyes open or closed. However, age-related increases in sway were found for conditions involving altered visual or somatosensory cues. Subjects older tban about 55 y showed the largest sway increases. Subjects younger than about 15 y were also sensitive to alteration of sensory cues. On average, the older subjects were more affected by altered visual cues, whereas younger subjects had more difficulty with altered somatosensory cues.

Effect of Head Orientation on Human Postural Stability Following Unilateral Vestibular Ablation

1991 ◽  
Vol 1 (2) ◽  
pp. 153-160
Author(s):  
Charles R. Fox ◽  
Gary D. Paige
Keyword(s):  
Postural Control ◽  
Postural Stability ◽  
Postural Sway ◽  
Normal Subjects ◽  
Head Orientation ◽  
Support Surface ◽  
Eyes Closed ◽  
Vestibular Information ◽  
Postural Equilibrium ◽  
Vestibular Pathology

Effective interpretation of vestibular inputs to postural control requires that orientation of head on body is known. Postural stability might deteriorate when vestibular information and neck information are not properly coupled, as might occur with vestibular pathology. Postural sway was assessed in unilateral vestibulopathic patients before and acutely, 1,4, and 18+ months after unilateral vestibular ablation (UVA) as well as in normal subjects. Postural equilibrium with eyes closed was quantified as scaled pk-pk sway during 20 s trials in which the support surface was modulated proportionally with sway. Subjects were tested with the head upright and facing forward, turned 45∘ right, and 45∘ left. Equilibrium was uninfluenced by head orientation in normal subjects. In contrast, patients after UV A showed both a general reduction in stability and a right/left head orientation-dependent asymmetry. These abnormalities adaptively recovered with time. It is concluded that vestibular inputs to postural control are interpreted within a sensory-motor context of head-on-body orientation.

Effects of lifetime ethanol consumption on postural control: A computerized dynamic posturography study

2002 ◽  
Vol 12 (1) ◽  
pp. 53-64
Author(s):  
Saad Ahmad ◽  
John W. Rohrbaugh ◽  
Andrey P. Anokhin ◽  
Erik J. Sirevaag ◽  
Joel A. Goebel
Keyword(s):  
Alcohol Consumption ◽  
Postural Control ◽  
Spectral Power ◽  
Support Surface ◽  
Dependent Manner ◽  
Dynamic Posturography ◽  
Eyes Closed ◽  
Sensory Organization ◽  
Computerized Dynamic Posturography ◽  
Eyes Open

The relationship between lifetime alcohol consumption and postural control was investigated in 35 subjects with no clinically-detectable neurologic abnormalities, using computerized dynamic posturography (CDP) procedures. The estimated total number of lifetime alcoholic drinks was positively correlated with anteroposterior sway spectral power within the 2–4 Hz and 4–6 Hz frequency bands, in three Sensory Organization Test (SOT) conditions: eyes closed with stable support surface (SOT 2), eyes open with sway-referenced support (SOT 4), and eyes closed with sway-referenced support (SOT 5). All correlations remained significant after controlling for subject age, and were increased after excluding nine drug-abusing subjects. In contrast to the strong findings for frequency-based measures, no correlation was observed using conventional amplitude-based sway measures. These results suggest that 1) alcohol consumption compromises postural control in an exposure-dependent manner, and 2) sway frequency analysis reveals pathological processes not manifested in conventional CDP measures of sway amplitude.

scholarly journals Prevalence of floating toe and its relationship with static postural stability in children: The Yamanashi adjunct study of the Japan Environment and Children’s Study (JECS-Y)

2021 ◽  
Author(s):  
Taro Fujimaki ◽  
Masanori Wako ◽  
Kensuke Koyama ◽  
Naoto Furuya ◽  
Ryoji Shinohara ◽  
...  
Keyword(s):  
Postural Stability ◽  
Center Of Pressure ◽  
The Body ◽  
Ground Contact ◽  
Foot Pressure ◽  
Eyes Closed ◽  
Stability Measurement ◽  
Eyes Open ◽  
The Relationship ◽  
Very High

AbstractFloating toe (FT) is a frequently seen condition in which a toe is inadequately in contact with the ground. Although toes play an important role in stabilizing standing posture and walking, many aspects of the effects of FT on the body remain unclear. To our knowledge, there have been no reports about the relationship between FT and postural stability, especially in children. This study aimed to clarify the prevalence of FT and its relationship with static postural stability in children. Of the 400 children aged 8 years who participated in our cohort study, 396, who were examined for static postural stability, were included in this study. Postural stability and FT were assessed using a foot pressure plate. The sway path length of the center of pressure and the area of the ellipse defined as the size of the area marked by the center of pressure were measured as an evaluation of static postural stability. We calculated the “floating toe score (FT score: small FT score indicates insufficient ground contact of the toes)” using the image of the plantar footprint obtained at the postural stability measurement. The FT rate was very high at more than 90%, and the FT score in the eyes-closed condition was significantly higher than that in the eyes-open condition in both sexes. The FT score significantly correlated with the center of pressure path and area. Our results suggest that ground contact of the toes is not directly related to static postural stability in children, but it may function to stabilize the body when the condition becomes unstable, such as when the eyes are closed.

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