Cervical and shoulder postural assessment of adolescents between 15 and 17 years old and association with upper quadrant pain

PubMed Central

Ruivo, Rodrigo M.; Pezarat-Correia, Pedro; Carita, Ana I.

2014-01-01

Background: There is sparse literature that provides evidence of cervical and shoulder postural alignment of 15 to 17-year-old adolescents and that analyzes sex differences. Objectives: To characterize the postural alignment of the head and shoulder in the sagittal plane of 15 to 17-year-old Portuguese adolescents in natural erect standing and explore the relationships between three postural angles and presence of neck and shoulder pain. Method: This cross-sectional study was conducted in two secondary schools in Portugal. 275 adolescent students (153 females and 122 males) aged 15 to 17 were evaluated. Sagittal head, cervical, and shoulder angles were measured with photogrammetry and PAS software. The American Shoulder and Elbow Surgeons Shoulder Assessment (ASES) was used to assess shoulder pain, whereas neck pain was self-reported with a single question. Results: Mean values of sagittal head, cervical, and shoulder angles were 17.2±5.7, 47.4±5.2, and 51.4±8.5º, respectively. 68% of the participants revealed protraction of the head, whereas 58% of them had protraction of the shoulder. The boys showed a significantly higher mean cervical angle, and adolescents with neck pain revealed lower mean cervical angle than adolescents without neck pain. 53% of the girls self-reported regular neck pain, contrasting with 19% of the boys. Conclusions: This data shows that forward head and protracted shoulder are common postural disorders in adolescents, especially in girls. Neck pain is prevalent in adolescents, especially girls, and it is associated with forward head posture. PMID:25054381

Cervical and shoulder postural assessment of adolescents between 15 and 17 years old and association with upper quadrant pain.

PubMed

Ruivo, Rodrigo M; Pezarat-Correia, Pedro; Carita, Ana I

2014-01-01

There is sparse literature that provides evidence of cervical and shoulder postural alignment of 15 to 17-year-old adolescents and that analyzes sex differences. To characterize the postural alignment of the head and shoulder in the sagittal plane of 15 to 17-year-old Portuguese adolescents in natural erect standing and explore the relationships between three postural angles and presence of neck and shoulder pain. This cross-sectional study was conducted in two secondary schools in Portugal. 275 adolescent students (153 females and 122 males) aged 15 to 17 were evaluated. Sagittal head, cervical, and shoulder angles were measured with photogrammetry and PAS software. The American Shoulder and Elbow Surgeons Shoulder Assessment (ASES) was used to assess shoulder pain, whereas neck pain was self-reported with a single question. Mean values of sagittal head, cervical, and shoulder angles were 17.2±5.7, 47.4±5.2, and 51.4±8.5º, respectively. 68% of the participants revealed protraction of the head, whereas 58% of them had protraction of the shoulder. The boys showed a significantly higher mean cervical angle, and adolescents with neck pain revealed lower mean cervical angle than adolescents without neck pain. 53% of the girls self-reported regular neck pain, contrasting with 19% of the boys. This data shows that forward head and protracted shoulder are common postural disorders in adolescents, especially in girls. Neck pain is prevalent in adolescents, especially girls, and it is associated with forward head posture.

Posture and performance: sitting vs. standing for security screening.

PubMed

Drury, C G; Hsiao, Y L; Joseph, C; Joshi, S; Lapp, J; Pennathur, P R

2008-03-01

A classification of the literature on the effects of workplace posture on performance of different mental tasks showed few consistent patterns. A parallel classification of the complementary effect of performance on postural variables gave similar results. Because of a lack of data for signal detection tasks, an experiment was performed using 12 experienced security operators performing an X-ray baggage-screening task with three different workplace arrangements. The current workplace, sitting on a high chair viewing a screen placed on top of the X-ray machine, was compared to a standing workplace and a conventional desk-sitting workplace. No performance effects of workplace posture were found, although the experiment was able to measure performance effects of learning and body part discomfort effects of workplace posture. There are implications for the classification of posture and performance and for the justification of ergonomics improvements based on performance increases.

Postural strategy and trunk muscle activation during prolonged standing in chronic low back pain patients.

PubMed

Ringheim, Inge; Austein, Helene; Indahl, Aage; Roeleveld, Karin

2015-10-01

Prolonged standing has been associated with development and aggravation of low back pain (LBP). However, the underlying mechanisms are not well known. The aim of the present study was to investigate postural control and muscle activation during and as a result of prolonged standing in chronic LBP (cLBP) patients compared to healthy controls (HCs). Body weight shifts and trunk and hip muscle activity was measured during 15 min standing. Prior and after the standing trial, strength, postural sway, reposition error (RE), flexion relaxation ratio (FRR), and pain were assessed and after the prolonged standing, ratings of perceived exertion. During prolonged standing, the cLBP patients performed significantly more body weight shifts (p<.01) with more activated back and abdominal muscles (p=.01) and similar temporal variability in muscle activation compared to HCs, while the cLBP patients reported more pain and perceived exertion at the end of prolonged standing. Moreover, both groups had a similar change in strength, postural sway, RE and FRR from before to after prolonged standing, where changes in HC were towards pre-standing values of cLBP patients. Thus, despite a more variable postural strategy, the cLBP patients did not have higher muscle activation variability, but a general increased muscle activation level. This may indicate a reduced ability to individually deactivate trunk muscles. Plausibly, due to the increased variable postural strategy, the cLBP patients could compensate for the relatively high muscle activation level, resulting in normal variation in muscle activation and normal reduction in strength, RE and FRR after prolonged standing. Copyright © 2015 Elsevier B.V. All rights reserved.

Assisting people with multiple disabilities actively correct abnormal standing posture with a Nintendo Wii balance board through controlling environmental stimulation.

PubMed

Shih, Ching-Hsiang; Shih, Ching-Tien; Chu, Chiung-Ling

2010-01-01

The latest researches adopted software technology turning the Nintendo Wii Balance Board into a high performance change of standing posture (CSP) detector, and assessed whether two persons with multiple disabilities would be able to control environmental stimulation using body swing (changing standing posture). This study extends Wii Balance Board functionality for standing posture correction (i.e., actively adjust abnormal standing posture) to assessed whether two persons with multiple disabilities would be able to actively correct their standing posture by controlling their favorite stimulation on/off using a Wii Balance Board with a newly developed standing posture correcting program (SPCP). The study was performed according to an ABAB design, in which A represented baseline and B represented intervention phases. Data showed that both participants significantly increased time duration of maintaining correct standing posture (TDMCSP) to activate the control system to produce environmental stimulation during the intervention phases. Practical and developmental implications of the findings were discussed.

Standing working posture compared in pregnant and non-pregnant conditions.

PubMed

Paul, J A; Frings-Dresen, M H

1994-09-01

During pregnancy, an increase in body weight occurs together with changes in body weight distribution and in fit between body dimensions and workplace layout. These changes may cause alterations in working posture which may, in turn, have adverse consequences for the biomechanical load on the musculoskeletal system and so increase the risk of musculoskeletal disorders. Using photographic posture registration, the standing working posture was studied in 27 women during the last stage of pregnancy and after delivery (the experimental group). The women performed an assembly task while standing at various workplace layouts. The postural differences between the pregnant condition and the non-pregnant condition were studied and the effect of the various workplace layouts assessed. Ten non-pregnant controls were also studied twice to establish the effect of the time interval between the measuring occasions. We found that the women of the experimental group stood further from the work surface in the pregnant condition compared to the non-pregnant condition, the hips were positioned more backwards, and, in order to reach the tesk, they increased the flexion of the trunk, increased the anteflexion of the upper arms, and extended the arms more. At the workplace layout in which the work surface height was self-selected, the postural differences due to pregnancy were smallest or even absent, compared to the postural differences in the other workplace layouts studied. Ergonomists and workers in occupational health services should be alert to the consequences for the biomechanical load on the musculoskeletal system and the risk of development of health complaints caused by postural changes due to pregnancy. An adjustable workplace layout may prevent some problems.

Differences in postural disturbances between female adolescents handball players and nontraining peers.

PubMed

Jandrić, Slavica Đ

2016-04-01

Physical activity and sport can influence the extent of the presence of the postural disturbances in children. The aim of this study was to investigate the occurrence of differences in the postural disturbances in female adolescents in relation to team handball training. This investigation involved 150 female adolescents with the average age of 13.4 ± 1.5 years divided into two groups (50 adolescents trained handball and 100 did non train it). The study determined a statistically significant difference in the total number of postural disturbances between the two groups of adolescents (p < 0.001). The presence of the flat foot was statistically significantly higher in untrained adolescents (p < 0.001), but the presence of the scoliosis, kyphosis, lordosis, and pes varus was not found (p > 0.05). Handball adolescents players have less postural disturbances than untrained adolescents. Flat foot is significantly less frequent in female adolescents handball players than in untrained ones. Findings obtained in this investigation can help us in planning continuous prevention, observation and care for untrained and trained team handball female adolescents with postural disturbances.

Association of biopsychosocial factors with degree of slump in sitting posture and self-report of back pain in adolescents: a cross-sectional study.

PubMed

O'Sullivan, Peter B; Smith, Anne J; Beales, Darren J; Straker, Leon M

2011-04-01

Conflicting evidence exists regarding relationships among sitting posture, factors that influence sitting posture, and back pain. This conflicting evidence may partially be due to the presence of multiple and overlapping factors associated with both sitting posture and back pain. The purpose of this study was to determine whether the degree of slump in sitting was associated with sex and other physical, lifestyle, or psychosocial factors. Additionally, the relationship between the report of back pain made worse by sitting and the degree of slump in sitting and other physical, lifestyle, or psychosocial factors was investigated. This was a cross-sectional study. Adolescents (n=1,596) completed questionnaires to determine lifestyle and psychosocial profiles and the experience of back pain. Sagittal sitting posture, body mass index (BMI), and back muscle endurance (BME) were recorded. Standing posture subgroup categorization was determined. Multivariate analysis revealed that the most significant factor associated with the degree of slump in sitting was male sex, followed by non-neutral standing postures, lower perceived self-efficacy, lower BME, greater television use, and higher BMI. Multivariable analysis indicated poorer Child Behaviour Checklist scores were the strongest correlate of report of back pain made worse by sitting, whereas degree of slump in sitting, female sex, and BME were more weakly related. Causality cannot be determined from this cross-sectional study, and 60% of sitting posture variation was not explained by the measured variables. Slump in sitting was associated with physical correlates, as well as sex, lifestyle, and psychosocial factors, highlighting the complex, multidimensional nature of usual sitting posture in adolescents. Additionally, this study demonstrated that a greater degree of slump in sitting was only weakly associated with adolescent back pain made worse by sitting after adjustment for other physical and psychosocial factors.

Rasterstereographic analysis of axial back surface rotation in standing versus forward bending posture in idiopathic scoliosis.

PubMed

Hackenberg, Lars; Hierholzer, Eberhard; Bullmann, Viola; Liljenqvist, Ulf; Götze, Christian

2006-07-01

The forward bending test according to Adams and rib hump quantification by scoliometer are common clinical examination techniques in idiopathic scoliosis, although precise data about the change of axial surface rotation in forward bending posture are not available. In a pilot study the influence of leg length inequalities on the back shape of five normal subjects was clarified. Then 91 patients with idiopathic scoliosis with Cobb-angles between 20 degrees and 82 degrees were examined by rasterstereography, a 3D back surface analysis system. The axial back surface rotation in standing posture was compared with that in forward bending posture and additionally with a scoliometer measurement in forward bending posture. The changes of back shape in forward bending posture were correlated with the Cobb-angle, the level of the apex of the scoliotic primary curve and the age of the patient. Averaged over all patients, the back surface rotation amplitude increased from 23.1 degrees in standing to 26.3 degrees in forward bending posture. The standard deviation of this difference was high (6.1 degrees ). The correlation of back surface rotation amplitude in standing with that in forward bending posture was poor (R (2)=0.41) as was the correlation of back surface rotation in standing posture with the scoliometer in forward bending posture measured rotation (R (2)=0.35). No significant correlation could be found between the change of back shape in forward bending and the degree of deformity (R (2)=0.07), likewise no correlation with the height of the apex of the scoliosis (R (2)=0.005) and the age of the patient (R (2)=0.001). Before forward bending test leg length inequalities have to be compensated accurately. Compared to the standing posture, forward bending changes back surface rotation. However, this change varies greatly between patients, and is independent of the type and degree of scoliosis. Furthermore remarkable differences were found between scoliometer measurement

Postural adjustments associated with voluntary contraction of leg muscles in standing man.

PubMed

Nardone, A; Schieppati, M

1988-01-01

The postural adjustments associated with a voluntary contraction of the postural muscles themselves have been studied in the legs of normal standing men. We focussed on the following questions. Do postural adjustments precede the focal movement as in the case of movements of the upper limb? Which muscle(s) are involved in the task of stabilizing posture? Can the same postural muscle be activated in postural stabilization and in voluntary movement at the same time, in spite of the opposite changes in activity possibly required by these conditions? Six subjects standing on a dynamometric platform were asked to rise onto the tips their toes by contracting their soleus muscles, or to rock on their heels by contracting their tibialis anterior muscles. The tasks were made in a reaction time (RT) situation or in a self-paced mode, standing either freely or holding onto a stable structure. Surface EMGs of leg and thigh muscles, and the foot-floor reaction forces were recorded. The following results were obtained in the RT mode, standing freely. 1. Rising onto toe tips: a striking silent period in soleus preceded its voluntary activation; during this silent period, a tibialis anterior burst could be observed in three subjects; these anticipatory activities induced a forward sway, as monitored by a change in the force exerted along the x axis of the platform. 2. Rocking on heels: an enhancement in tonic EMG of soleus was observed before tibialis anterior voluntary burst, at a mean latency from the go-signal similar to that of the silent period; this anticipatory activity induced a backward body sway. 3. Choice RT conditions showed that the above anticipatory patterns in muscle activity were pre-programmed, specific for the intended tasks, and closely associated with the focal movement. When both tasks were performed in a self-paced mode, all the above EMG and mechanical features were more pronounced and unfolded in time. If the subjects held onto the frame, the early

Contribution of Head Position, Standing Surface, and Vision to Postural Control in Community-Dwelling Older Adults.

PubMed

Pociask, Fredrick D; DiZazzo-Miller, Rosanne; Goldberg, Allon; Adamo, Diane E

2016-01-01

Postural control requires the integration of sensorimotor information to maintain balance and to properly position and orient the body in response to external stimuli. Age-related declines in peripheral and central sensory and motor function contribute to postural instability and falls. This study investigated the contribution of head position, standing surface, and vision on postural sway in 26 community-dwelling older adults. Participants were asked to maintain a stable posture under conditions that varied standing surface, head position, and the availability of visual information. Significant main and interaction effects were found for all three factors. Findings from this study suggest that postural sway responses require the integration of available sources of sensory information. These results have important implications for fall risks in older adults and suggest that when standing with the head extended and eyes closed, older adults may place themselves at risk for postural disequilibrium and loss of balance. Copyright © 2016 by the American Occupational Therapy Association, Inc.

Influence of prolonged wearing of unstable shoes on upright standing postural control.

PubMed

Sousa, Andreia S P; Macedo, Rui; Santos, Rubim; Sousa, Filipa; Silva, Andreia; Tavares, João Manuel R S

2016-02-01

To study the influence of prolonged wearing of unstable shoes on standing postural control in prolonged standing workers. The participants were divided into two groups: one wore unstable shoes while the other wore conventional shoes for 8weeks. Stabilometry parameters related to centre of pressure (CoP), rambling (RM) and trembling (TR) as well as the total agonist/antagonist muscle activity, antagonist co-activation and reciprocal activation were evaluated during upright standing, before and after the 8weeks period. In both moments, the subjects were evaluated wearing the unstable shoes and in barefoot. The unstable shoe condition presented increased CoP displacement related variables and decreased co-activation command compared to barefoot before and after the intervention. The prolonged wearing of unstable shoes led to: (1) reduction of medial-lateral CoP root mean square and area; (2) decreased anteroposterior RM displacement; (3) increased anteroposterior RM mean velocity and mediolateral RM displacement; (4) decreased anteroposterior TR RMS; and (5) increased thigh antagonist co-activation in the unstable shoe condition. The unstable shoe condition is associated to a higher destabilising effect that leads to a selection of more efficient and accurate postural commands compared to barefoot. Prolonged wearing of unstable shoes provides increased effectiveness and performance of the postural control system, while wearing of unstable shoes in upright standing, that are reflected by changes in CoP related variables and by a reorganisation of postural control commands. Copyright © 2015 Elsevier B.V. All rights reserved.

Trial-to-trial adaptation in control of arm reaching and standing posture

PubMed Central

Pienciak-Siewert, Alison; Horan, Dylan P.

2016-01-01

Classical theories of motor learning hypothesize that adaptation is driven by sensorimotor error; this is supported by studies of arm and eye movements that have shown that trial-to-trial adaptation increases with error. Studies of postural control have shown that anticipatory postural adjustments increase with the magnitude of a perturbation. However, differences in adaptation have been observed between the two modalities, possibly due to either the inherent instability or sensory uncertainty in standing posture. Therefore, we hypothesized that trial-to-trial adaptation in posture should be driven by error, similar to what is observed in arm reaching, but the nature of the relationship between error and adaptation may differ. Here we investigated trial-to-trial adaptation of arm reaching and postural control concurrently; subjects made reaching movements in a novel dynamic environment of varying strengths, while standing and holding the handle of a force-generating robotic arm. We found that error and adaptation increased with perturbation strength in both arm and posture. Furthermore, in both modalities, adaptation showed a significant correlation with error magnitude. Our results indicate that adaptation scales proportionally with error in the arm and near proportionally in posture. In posture only, adaptation was not sensitive to small error sizes, which were similar in size to errors experienced in unperturbed baseline movements due to inherent variability. This finding may be explained as an effect of uncertainty about the source of small errors. Our findings suggest that in rehabilitation, postural error size should be considered relative to the magnitude of inherent movement variability. PMID:27683888

Trial-to-trial adaptation in control of arm reaching and standing posture.

PubMed

Pienciak-Siewert, Alison; Horan, Dylan P; Ahmed, Alaa A

2016-12-01

Classical theories of motor learning hypothesize that adaptation is driven by sensorimotor error; this is supported by studies of arm and eye movements that have shown that trial-to-trial adaptation increases with error. Studies of postural control have shown that anticipatory postural adjustments increase with the magnitude of a perturbation. However, differences in adaptation have been observed between the two modalities, possibly due to either the inherent instability or sensory uncertainty in standing posture. Therefore, we hypothesized that trial-to-trial adaptation in posture should be driven by error, similar to what is observed in arm reaching, but the nature of the relationship between error and adaptation may differ. Here we investigated trial-to-trial adaptation of arm reaching and postural control concurrently; subjects made reaching movements in a novel dynamic environment of varying strengths, while standing and holding the handle of a force-generating robotic arm. We found that error and adaptation increased with perturbation strength in both arm and posture. Furthermore, in both modalities, adaptation showed a significant correlation with error magnitude. Our results indicate that adaptation scales proportionally with error in the arm and near proportionally in posture. In posture only, adaptation was not sensitive to small error sizes, which were similar in size to errors experienced in unperturbed baseline movements due to inherent variability. This finding may be explained as an effect of uncertainty about the source of small errors. Our findings suggest that in rehabilitation, postural error size should be considered relative to the magnitude of inherent movement variability. Copyright © 2016 the American Physiological Society.

Standing Postural Control in Individuals with Autism Spectrum Disorder: Systematic Review and Meta-Analysis

ERIC Educational Resources Information Center

Lim, Yi Huey; Partridge, Katie; Girdler, Sonya; Morris, Susan L.

2017-01-01

Impairments in postural control affect the development of motor and social skills in individuals with autism spectrum disorder (ASD). This review compared the effect of different sensory conditions on static standing postural control between ASD and neurotypical individuals. Results from 19 studies indicated a large difference in postural control…

Variation between seated and standing/walking postures among male and female call centre operators.

PubMed

Toomingas, Allan; Forsman, Mikael; Mathiassen, Svend Erik; Heiden, Marina; Nilsson, Tohr

2012-03-02

The dose and time-pattern of sitting has been suggested in public health research to be an important determinant of risk for developing a number of diseases, including cardiovascular disorders and diabetes. The aim of the present study was to assess the time-pattern of seated and standing/walking postures amongst male and female call centre operators, on the basis of whole-shift posture recordings, analysed and described by a number of novel variables describing posture variation. Seated vs. standing/walking was recorded using dichotomous inclinometers throughout an entire work shift for 43 male and 97 female call centre operators at 16 call centres. Data were analysed using an extensive set of variables describing occurrence of and switches between seated and standing/walking, posture similarity across the day, and compliance with standard recommendations for computer work. The majority of the operators, both male and female, spent more than 80% of the shift in a seated posture with an average of 10.4 switches/hour between seated and standing/walking or vice versa. Females spent, on average, 11% of the day in periods of sustained sitting longer than 1 hour; males 4.6% (p = 0.013). Only 38% and 11% of the operators complied with standard recommendations of getting an uninterrupted break from seated posture of at least 5 or 10 minutes, respectively, within each hour of work. Two thirds of all investigated variables showed coefficients of variation between subjects above 0.5. Since work tasks and contractual break schedules were observed to be essentially similar across operators and across days, this indicates that sedentary behaviours differed substantially between individuals. The extensive occurrence of uninterrupted seated work indicates that efforts should be made at call centres - and probably in other settings in the office sector - to introduce more physical variation in terms of standing/walking periods during the work day. We suggest the metrics used in

Effect of higher muscle coactivation on standing postural response to perturbation in older adults.

PubMed

Nagai, Koutatsu; Okita, Yusuke; Ogaya, Shinya; Tsuboyama, Tadao

2017-04-01

Although several studies have reported that muscle coactivation during postural control increases with age, the effect of higher muscle coactivation on standing postural response to perturbation is unknown. To investigate whether higher muscle coactivation affects standing postural response to perturbation in older adults. Thirty-four community-dwelling older participants were randomly assigned either to the coactivation group (CG), where muscle coactivation was increased intentionally, or to the non-coactivation group (NCG). The participants were instructed to stand on a force plate that moved forward or backward. Electromyography data were collected from the lower leg muscles. We requested the participants in the CG to increase the activity of their tibialis anterior, and to maintain this posture during the tasks. We moved the force plate with a constant amplitude and velocity, and measured kinematic data with a camera during the tasks. During forward transfer, the knee extension and hip flexion decreased in the CG after perturbation compared to NCG, and the trunk extension angle increased. The center of pressure (COP) displacement decreased around the peak of the movement in the CG compared to NCG. During backward transfer, ankle dorsal and knee flexion changed after perturbation in the CG compared to NCG. Our study found that higher muscle coactivation inhibits lower limb and COP movement as well as increases trunk tilt and the risk for falls during forward perturbations. Postural control with higher coactivation appears to be inefficient for maintaining balance during the backward sway of posture.

Diagnosing Postural Tachycardia Syndrome: Comparison of Tilt Test versus Standing Hemodynamics

PubMed Central

Plash, Walker B; Diedrich, André; Biaggioni, Italo; Garland, Emily M; Paranjape, Sachin Y; Black, Bonnie K; Dupont, William D; Raj, Satish R

2012-01-01

Postural tachycardia syndrome (POTS) is characterized by increased heart rate (ΔHR) of ≥30 bpm with symptoms related to upright posture. Active stand (STAND) and passive head-up tilt (TILT) produce different physiological responses. We hypothesized these different responses would affect the ability of individuals to achieve the POTS HR increase criterion. Patients with POTS (n=15) and healthy controls (n=15) underwent 30 min of TILT and STAND testing. ΔHR values were analyzed at 5 min intervals. Receiver Operating Characteristics analysis was performed to determine optimal cut point values of ΔHR for both TILT and STAND. TILT produced larger ΔHR than STAND for all 5 min intervals from 5 min (38±3 bpm vs. 33±3 bpm; P=0.03) to 30 min (51±3 bpm vs. 38±3 bpm; P<0.001). Sensitivity (Sn) of the 30 bpm criterion was similar for all tests (TILT-10=93%, STAND-10=87%, TILT30=100%, and STAND30=93%). Specificity (Sp) of the 30 bpm criterion was less at both 10 and 30 min for TILT (TILT10=40%, TILT30=20%) than STAND (STAND10=67%, STAND30=53%). The optimal ΔHR to discriminate POTS at 10 min were 38 bpm (TILT) and 29 bpm (STAND), and at 30 min were 47 bpm (TILT) and 34 bpm (STAND). Orthostatic tachycardia was greater for TILT (with lower specificity for POTS diagnosis) than STAND at 10 and 30 min. The 30 bpm ΔHR criterion is not suitable for 30 min TILT. Diagnosis of POTS should consider orthostatic intolerance criteria and not be based solely on orthostatic tachycardia regardless of test used. PMID:22931296

Components of Standing Postural Control Evaluated in Pediatric Balance Measures: A Scoping Review.

PubMed

Sibley, Kathryn M; Beauchamp, Marla K; Van Ooteghem, Karen; Paterson, Marie; Wittmeier, Kristy D

2017-10-01

To identify measures of standing balance validated in pediatric populations, and to determine the components of postural control captured in each tool. Electronic searches of MEDLINE, Embase, and CINAHL databases using key word combinations of postural balance/equilibrium, psychometrics/reproducibility of results/predictive value of tests, and child/pediatrics; gray literature; and hand searches. Inclusion criteria were measures with a stated objective to assess balance, with pediatric (≤18y) populations, with at least 1 psychometric evaluation, with at least 1 standing task, with a standardized protocol and evaluation criteria, and published in English. Two reviewers independently identified studies for inclusion. There were 21 measures included. Two reviewers extracted descriptive characteristics, and 2 investigators independently coded components of balance in each measure using a systems perspective for postural control, an established framework for balance in pediatric populations. Components of balance evaluated in measures were underlying motor systems (100% of measures), anticipatory postural control (72%), static stability (62%), sensory integration (52%), dynamic stability (48%), functional stability limits (24%), cognitive influences (24%), verticality (9%), and reactive postural control (0%). Assessing children's balance with valid and comprehensive measures is important for ensuring development of safe mobility and independence with functional tasks. Balance measures validated in pediatric populations to date do not comprehensively assess standing postural control and omit some key components for safe mobility and independence. Existing balance measures, that have been validated in adult populations and address some of the existing gaps in pediatric measures, warrant consideration for validation in children. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Effect of sitting pause times on postural stability after supine-to-standing transfer in dimly lit environments.

PubMed

Johnson, Eric G; Meltzer, Jonathan D

2012-01-01

Falls are common and often take place in the home. Risk of fall increases if the environment is dimly lit. Longer sitting pause times, before standing, might improve postural stability after standing from a supine position. The purpose of this investigation was to measure the effects of sitting pause times on postural sway velocity immediately following a supine-to-standing transfer in a dimly lit room in older and younger adult women. Five women aged 65 to 70 years and 5 aged 23 to 30 years participated in the study. On each of 2 consecutive days, study participants lay on a mat table with their eyes closed for 45 minutes before performing a supine-to-standing transfer in a dimly lit room. Sitting pause times of 2 seconds and 30 seconds preceded the transfers. Mean postural sway velocity for the whole sample and for younger and older groups was less after a 30-second pause time than that after a 2-second pause time (sample, P = .001; young, P = .019; old, P = .021). No significant difference in mean postural sway velocity was observed between the 2 groups (P > .05). Total mean postural sway velocity was less when study participants performed a sitting pause of 30 seconds before standing in a dimly lit room. These results suggest that longer sitting pause times may provide improved adaptability to dimly lit environments contributing to improved postural stability.

Support surface related changes in feedforward and feedback control of standing posture

PubMed Central

Mohapatra, Sambit; Kukkar, Komal K.; Aruin, Alexander S.

2013-01-01

The aim of the study was to investigate the effect of different support surfaces on feedforward and feedback components of postural control. Nine healthy subjects were exposed to external perturbations applied to their shoulders while standing on a rigid platform, foam, and wobble board with eyes open or closed. Electrical activity of nine trunk and leg muscles and displacements of the center of pressure were recorded and analyzed during the time frames typical of feedforward and feedback postural adjustments. Feedforward control of posture was characterized by earlier activation of anterior muscles when the subjects stood on foam compared to a wobble board or a firm surface. In addition, the magnitude of feedforward muscle activity was the largest when the foam was used. During the feedback control, anterior muscles were activated prior to posterior muscles irrespective of the nature of surface. Moreover, the largest muscle activity was seen when the supporting surface was foam. Maximum CoP displacement occurred when subjects were standing on a rigid surface. Altering support surface affects both feedforward and feedback components of postural control. This information should be taken into consideration in planning rehabilitation interventions geared towards improvement of balance. PMID:24268589

Prevalence of incorrect body posture in children and adolescents with overweight and obesity.

PubMed

Maciałczyk-Paprocka, Katarzyna; Stawińska-Witoszyńska, Barbara; Kotwicki, Tomasz; Sowińska, Anna; Krzyżaniak, Alicja; Walkowiak, Jarosław; Krzywińska-Wiewiorowska, Małgorzata

2017-05-01

The ever increasing epidemics of overweight and obesity in school children may be one of the reasons of the growing numbers of children with incorrect body posture. The purpose of the study was the assessment of the prevalence of incorrect body posture in children and adolescents with overweight and obesity in Poznań, Poland. The population subject to study consisted of 2732 boys and girls aged 3-18 with obesity, overweight, and standard body mass. The assessment of body mass was performed based on BMI, adopting Cole's cutoff values. The evaluation of body posture was performed according to the postural error chart based on criteria complied by professor Dega. The prevalence rates of postural errors were significantly higher among children and adolescents with overweight and obesity than among the group with standard body mass. In the overweight group, it amounted to 69.2% and in the obese group to 78.6%.  The most common postural deviations in obese children and adolescents were valgus knees and flat feet. Overweight and obesity in children and adolescents, predisposing to higher incidence of some types of postural errors, call for prevention programs addressing both health problems. What is Known: • The increase in the prevalence of overweight and obesity among children and adolescents has drawn attention to additional health complications which may occur in this population such as occurrence of incorrect body posture. What is New: • The modified chart of postural errors proved to be an effective tool in the assessment of incorrect body posture. • This chart may be used in the assessment of posture during screening tests and prevention actions at school.

Age-Related Differences in Postural Control and Attentional Cost During Tasks Performed in a One-Legged Standing Posture.

PubMed

Ihira, Hikaru; Makizako, Hyuma; Mizumoto, Atsushi; Makino, Keitarou; Matsuyama, Kiyoji; Furuna, Taketo

2016-01-01

In dual-task situations, postural control is closely associated with attentional cost. Previous studies have reported age-related differences between attentional cost and postural control, but little is known about the association in conditions with a one-legged standing posture. The purpose of this study was to determine age-related differences in postural control and attentional cost while performing tasks at various difficulty levels in a one-legged standing posture. In total, 29 healthy older adults aged 64 to 78 years [15 males, 14 females, mean (SD) = 71.0 (3.8) years] and 29 healthy young adults aged 20 to 26 years [14 males, 15 females, mean (SD) = 22.5 (1.5) years] participated in this study. We measured the reaction time, trunk accelerations, and lower limb muscle activity under 3 different one-legged standing conditions-on a firm surface, on a soft surface with a urethane mat, and on a softer more unstable surface with 2 piled urethane mats. Reaction time as an indication of attentional cost was measured by pressing a handheld button as quickly as possible in response to an auditory stimulus. A 2-way repeated-measures analysis of variance was performed to examine the differences between the 3 task conditions and the 2 age groups for each outcome. Trunk accelerations showed a statistically significant group-by-condition interaction in the anteroposterior (F = 9.1, P < .05), mediolateral (F = 9.9, P < .05), and vertical (F = 9.3, P < .05) directions. Muscle activity did not show a statistically significant group-by-condition interaction, but there was a significant main effect of condition in the tibialis anterior muscle (F = 33.1, P < .01) and medial gastrocnemius muscle (F = 14.7, P < .01) in young adults and the tibialis anterior muscle (F = 24.8, P < .01) and medial gastrocnemius muscle (F = 10.8, P < .01) in older adults. In addition, there was a statistically significant interaction in reaction time (F = 8.2, P < .05) for group-by-condition. The

Comparison of the effective dose rate to aircrew members using hybrid computational phantoms in standing and sitting postures.

PubMed

Alves, M C; Galeano, D C; Santos, W S; Lee, Choonsik; Bolch, Wesley E; Hunt, John G; da Silva, A X; Carvalho, A B

2016-12-01

Aircraft crew members are occupationally exposed to considerable levels of cosmic radiation at flight altitudes. Since aircrew (pilots and passengers) are in the sitting posture for most of the time during flight, and up to now there has been no data on the effective dose rate calculated for aircrew dosimetry in flight altitude using a sitting phantom, we therefore calculated the effective dose rate using a phantom in the sitting and standing postures in order to compare the influence of the posture on the radiation protection of aircrew members. We found that although the better description of the posture in which the aircrews are exposed, the results of the effective dose rate calculated with the phantom in the sitting posture were very similar to the results of the phantom in the standing posture. In fact we observed only a 1% difference. These findings indicate the adequacy of the use of dose conversion coefficients for the phantom in the standing posture in aircrew dosimetry. We also validated our results comparing the effective dose rate obtained using the standing phantom with values reported in the literature. It was observed that the results presented in this study are in good agreement with other authors (the differences are below 30%) who have measured and calculated effective dose rates using different phantoms.

Effect of obesity on posture and hip joint moments during a standing task, and trunk forward flexion motion.

PubMed

Gilleard, W; Smith, T

2007-02-01

Effects of obesity on trunk forward flexion motion in sitting and standing, and postural adaptations and hip joint moment for a standing work task. Cross-sectional comparison of obese and normal weight groups. Ten obese subjects (waist girth 121.2+/-16.8 cm, body mass index (BMI) 38.9+/-6.6 kg m(-2)) and 10 age- and height-matched normal weight subjects (waist girth 79.6+/-6.4 cm, BMI 21.7+/-1.5 kg m(-2)). Trunk motion during seated and standing forward flexion, and trunk posture, hip joint moment and hip-to-bench distance during a simulated standing work task were recorded. Forward flexion motion of the thoracic segment and thoracolumbar spine was decreased for the obese group with no change in pelvic segment and hip joint motion. Obese subjects showed a more flexed trunk posture and increased hip joint moment and hip-to-bench distance for a simulated standing work task. Decreased range of forward flexion motion, differing effects within the trunk, altered posture during a standing work task and concomitant increases in hip joint moment give insight into the aetiology of functional decrements and musculoskeletal pain seen in obesity.

Test-retest reliability of posture measurements in adolescents with idiopathic scoliosis.

PubMed

Heitz, Pierre-Henri; Aubin-Fournier, Jean-François; Parent, Éric; Fortin, Carole

2018-05-07

Posture changes are a major consequence of IS (IS). Posture changes can lead to psychosocial and physical impairments in adolescents with IS. Therefore, it is important to assess posture but the test-retest reliability of posture measurements still remains unknown in this population. The primary objective was to determine the test-retest reliability of 25 head and trunk posture indices using the Clinical Photographic Postural Assessment Tool (CPPAT) in adolescents with IS. The secondary objective was to determine the standard error of measurement and the minimal detectable change. This is a prospective test-retest reliability study carried out at two tertiary university hospital centers. Forty-one adolescents with IS, aged 10 to 16 years old with curves 10 to 45 o and treated non-operatively were recruited. Two posture assessments were done using the CPPAT five to 10 days apart following a standardized procedure. Photographs were analyzed with the CPPAT software by digitizing reference landmarks placed on the participant by a physiotherapist evaluator. Generalizability theory was used to obtain a coefficient of dependability, standard error of measurement and the minimal detectable change at the 90% confidence interval. This project was supported by the Canadian Pediatric Spine Society (CPSS: 10000$). There is no study-specific conflicts of interest-associated biases. Fourteen of 25 posture indices had a good reliability (ϕ ≥ 0.78), ten of 25 had moderate reliability (ϕ = 0.55 to 0.74) and one had poor reliability (ϕ = 0.45). The most reliable posture indices were waist angles asymmetry (ϕ = 0.93), right waist angle (ϕ = 0.91) and frontal trunk list (ϕ = 0.92). Right sagittal trunk list was the least reliable posture index (ϕ = 0.45). The MDC 90 values ranged from 2.6 to 10.3° for angular measurements and from 8.4 to 35.1 mm for linear measurements. This study demonstrates that most posture indices, especially the trunk posture indices, are reproducible

The Complexity of Standing Postural Sway Associates with Future Falls in Community-Dwelling Older Adults: The MOBILIZE Boston Study.

PubMed

Zhou, Junhong; Habtemariam, Daniel; Iloputaife, Ikechukwu; Lipsitz, Lewis A; Manor, Brad

2017-06-07

Standing postural control is complex, meaning that it is dependent upon numerous inputs interacting across multiple temporal-spatial scales. Diminished physiologic complexity of postural sway has been linked to reduced ability to adapt to stressors. We hypothesized that older adults with lower postural sway complexity would experience more falls in the future. 738 adults aged ≥70 years completed the Short Physical Performance Battery test (SPPB) test and assessments of single and dual-task standing postural control. Postural sway complexity was quantified using multiscale entropy. Falls were subsequently tracked for 48 months. Negative binomial regression demonstrated that older adults with lower postural sway complexity in both single and dual-task conditions had higher future fall rate (incident rate ratio (IRR) = 0.98, p = 0.02, 95% Confidence Limits (CL) = 0.96-0.99). Notably, participants in the lowest quintile of complexity during dual-task standing suffered 48% more falls during the four-year follow-up as compared to those in the highest quintile (IRR = 1.48, p = 0.01, 95% CL = 1.09-1.99). Conversely, traditional postural sway metrics or SPPB performance did not associate with future falls. As compared to traditional metrics, the degree of multi-scale complexity contained within standing postural sway-particularly during dual task conditions- appears to be a better predictor of future falls in older adults.

Posture Alignment of Adolescent Idiopathic Scoliosis: Photogrammetry in Scoliosis School Screening.

PubMed

Penha, Patrícia Jundi; Penha, Nárima Lívia Jundi; De Carvalho, Bárbarah Kelly Gonçalves; Andrade, Rodrigo Mantelatto; Schmitt, Ana Carolina Basso; João, Sílvia Maria Amado

The objective of this study was to describe the posture patterns of adolescents diagnosed with adolescent idiopathic scoliosis (AIS) in a scoliosis school screening (SSS). Two-dimensional photogrammetry was used to assess the posture of 37 adolescents diagnosed with scoliosis (scoliosis group, SG) (Cobb angle ≥10°) and 76 adolescents with a false positive diagnosis (false positive group, FPG) (Cobb angle <10°, angle of trunk rotation ≥7°). In total, 2562 10- to 14-year-old adolescents were enrolled in the SSS, which was performed in public schools in the cities of Amparo, Pedreira, and Mogi Mirim in the state of São Paulo, Brazil. Their posture was analyzed using Postural Analysis Software. Continuous variables were tested using Student t test, and categorical variables were tested using a χ2 test. The SG, FPG, simple curve group, and double curve group were all compared. Bivariate analysis was used to identify associations between postural deviations and scoliosis. The adopted significance level was α = .05. The SG (2.7 ± 1.9°) had greater shoulder obliquity than the FPG (1.9 ± 1.4°) (P = .010), and this deviation was associated with scoliosis (odds ratio [95% CI] P = 1.4 [1.1-1.8] 0.011). The SG had asymmetry between the right- and left-side lower limb frontal angle, shoulder sagittal alignment, and knee angle. The double curve group (3 ± 1.7°) presented a greater value of the vertical alignment of the torso than the simple curve group did (1.9 ± 1°; P = .032). Adolescents diagnosed with AIS in an SSS had greater shoulder obliquity and asymmetry between the right and left sides. Shoulder obliquity was the only postural deviation associated with AIS. Copyright © 2017. Published by Elsevier Inc.

Dementia alters standing postural adaptation during a visual search task in older adult men.

PubMed

Jor'dan, Azizah J; McCarten, J Riley; Rottunda, Susan; Stoffregen, Thomas A; Manor, Brad; Wade, Michael G

2015-04-23

This study investigated the effects of dementia on standing postural adaptation during performance of a visual search task. We recruited 16 older adults with dementia and 15 without dementia. Postural sway was assessed by recording medial-lateral (ML) and anterior-posterior (AP) center-of-pressure when standing with and without a visual search task; i.e., counting target letter frequency within a block of displayed randomized letters. ML sway variability was significantly higher in those with dementia during visual search as compared to those without dementia and compared to both groups during the control condition. AP sway variability was significantly greater in those with dementia as compared to those without dementia, irrespective of task condition. In the ML direction, the absolute and percent change in sway variability between the control condition and visual search (i.e., postural adaptation) was greater in those with dementia as compared to those without. In contrast, postural adaptation to visual search was similar between groups in the AP direction. As compared to those without dementia, those with dementia identified fewer letters on the visual task. In the non-dementia group only, greater increases in postural adaptation in both the ML and AP direction, correlated with lower performance on the visual task. The observed relationship between postural adaptation during the visual search task and visual search task performance--in the non-dementia group only--suggests a critical link between perception and action. Dementia reduces the capacity to perform a visual-based task while standing and thus, appears to disrupt this perception-action synergy. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Support surface related changes in feedforward and feedback control of standing posture.

PubMed

Mohapatra, Sambit; Kukkar, Komal K; Aruin, Alexander S

2014-02-01

The aim of the study was to investigate the effect of different support surfaces on feedforward and feedback components of postural control. Nine healthy subjects were exposed to external perturbations applied to their shoulders while standing on a rigid platform, foam, and wobble board with eyes open or closed. Electrical activity of nine trunk and leg muscles and displacements of the center of pressure were recorded and analyzed during the time frames typical of feedforward and feedback postural adjustments. Feedforward control of posture was characterized by earlier activation of anterior muscles when the subjects stood on foam compared to a wobble board or a firm surface. In addition, the magnitude of feedforward muscle activity was the largest when the foam was used. During the feedback control, anterior muscles were activated prior to posterior muscles irrespective of the nature of surface. Moreover, the largest muscle activity was seen when the supporting surface was foam. Maximum CoP displacement occurred when subjects were standing on a rigid surface. Altering support surface affects both feedforward and feedback components of postural control. This information should be taken into consideration in planning rehabilitation interventions geared towards improvement of balance. Copyright © 2013 Elsevier Ltd. All rights reserved.

Impaired Postural Control Reduces Sit-to-Stand-to-Sit Performance in Individuals with Chronic Obstructive Pulmonary Disease

PubMed Central

Janssens, Lotte; Brumagne, Simon; McConnell, Alison K.; Claeys, Kurt; Pijnenburg, Madelon; Goossens, Nina; Burtin, Chris; Janssens, Wim; Decramer, Marc; Troosters, Thierry

2014-01-01

Background Functional activities, such as the sit-to-stand-to-sit (STSTS) task, are often impaired in individuals with chronic obstructive pulmonary disease (COPD). The STSTS task places a high demand on the postural control system, which has been shown to be impaired in individuals with COPD. It remains unknown whether postural control deficits contribute to the decreased STSTS performance in individuals with COPD. Methods Center of pressure displacement was determined in 18 individuals with COPD and 18 age/gender-matched controls during five consecutive STSTS movements with vision occluded. The total duration, as well as the duration of each sit, sit-to-stand, stand and stand-to-sit phase was recorded. Results Individuals with COPD needed significantly more time to perform five consecutive STSTS movements compared to healthy controls (19±6 vs. 13±4 seconds, respectively; p = 0.001). The COPD group exhibited a significantly longer stand phase (p = 0.028) and stand-to-sit phase (p = 0.001) compared to the control group. In contrast, the duration of the sit phase (p = 0.766) and sit-to-stand phase (p = 0.999) was not different between groups. Conclusions Compared to healthy individuals, individuals with COPD needed significantly more time to complete those phases of the STSTS task that require the greatest postural control. These findings support the proposition that suboptimal postural control is an important contributor to the decreased STSTS performance in individuals with COPD. PMID:24533072

Diagnosing postural tachycardia syndrome: comparison of tilt testing compared with standing haemodynamics.

PubMed

Plash, Walker B; Diedrich, André; Biaggioni, Italo; Garland, Emily M; Paranjape, Sachin Y; Black, Bonnie K; Dupont, William D; Raj, Satish R

2013-01-01

POTS (postural tachycardia syndrome) is characterized by an increased heart rate (ΔHR) of ≥30 bpm (beats/min) with symptoms related to upright posture. Active stand (STAND) and passive head-up tilt (TILT) produce different physiological responses. We hypothesized these different responses would affect the ability of individuals to achieve the POTS HR increase criterion. Patients with POTS (n=15) and healthy controls (n=15) underwent 30 min of tilt and stand testing. ΔHR values were analysed at 5 min intervals. ROC (receiver operating characteristic) analysis was performed to determine optimal cut point values of ΔHR for both tilt and stand. Tilt produced larger ΔHR than stand for all 5 min intervals from 5 min (38±3 bpm compared with 33±3 bpm; P=0.03) to 30 min (51±3 bpm compared with 38±3 bpm; P<0.001). Sn (sensitivity) of the 30 bpm criterion was similar for all tests (TILT10=93%, STAND10=87%, TILT30=100%, and STAND30=93%). Sp (specificity) of the 30 bpm criterion was less at both 10 and 30 min for tilt (TILT10=40%, TILT30=20%) than stand (STAND10=67%, STAND30=53%). The optimal ΔHR to discriminate POTS at 10 min were 38 bpm (TILT) and 29 bpm (STAND), and at 30 min were 47 bpm (TILT) and 34 bpm (STAND). Orthostatic tachycardia was greater for tilt (with lower Sp for POTS diagnosis) than stand at 10 and 30 min. The 30 bpm ΔHR criterion is not suitable for 30 min tilt. Diagnosis of POTS should consider orthostatic intolerance criteria and not be based solely on orthostatic tachycardia regardless of test used.

Influence of visual inputs on quasi-static standing postural steadiness in individuals with spinal cord injury.

PubMed

Lemay, Jean-François; Gagnon, Dany; Duclos, Cyril; Grangeon, Murielle; Gauthier, Cindy; Nadeau, Sylvie

2013-06-01

Postural steadiness while standing is impaired in individuals with spinal cord injury (SCI) and could be potentially associated with increased reliance on visual inputs. The purpose of this study was to compare individuals with SCI and able-bodied participants on their use of visual inputs to maintain standing postural steadiness. Another aim was to quantify the association between visual contribution to achieve postural steadiness and a clinical balance scale. Individuals with SCI (n = 15) and able-bodied controls (n = 14) performed quasi-static stance, with eyes open or closed, on force plates for two 45 s trials. Measurements of the centre of pressure (COP) included the mean value of the root mean square (RMS), mean COP velocity (MV) and COP sway area (SA). Individuals with SCI were also evaluated with the Mini-Balance Evaluation Systems Test (Mini BESTest), a clinical outcome measure of postural steadiness. Individuals with SCI were significantly less stable than able-bodied controls in both conditions. The Romberg ratios (eyes open/eyes closed) for COP MV and SA were significantly higher for individuals with SCI, indicating a higher contribution of visual inputs for postural steadiness in that population. Romberg ratios for RMS and SA were significantly associated with the Mini-BESTest. This study highlights the contribution of visual inputs in individuals with SCI when maintaining quasi-static standing posture. Copyright © 2012 Elsevier B.V. All rights reserved.

Survey of faulty postures and associated factors among Chinese adolescents.

PubMed

Cho, Chiung-Yu

2008-03-01

This study investigates the prevalence of common faulty postures among adolescents and identify if significant relationships existed among the number of faulty postures, psychologic distress, and musculoskeletal symptoms. The Musculoskeletal Questionnaire and Chinese Health Questionnaire were randomly distributed to 300 high school students in the Tainan area. On-campus postural screening, which included digital photography, manual muscle tests, and flexibility tests, was also performed. Two hundred eighty-seven participants completed all of the evaluations. The most common faulty posture was uneven shoulder level (36%), followed by forward head posture (25%). There was a sex difference between groups. The incidence of forward head posture for the male students was higher than that of the female students (P < .0001). In addition, the high psychologic distress group tended to have a higher prevalence of uneven shoulder height than that of the low psychologic distress group (P < .0001). As for the correlation analysis, the researchers did not find a high correlation among the scores of the faulty posture, psychologic distress, and musculoskeletal symptoms. The results of this study show that the incidence of faulty posture was high for the adolescent group, especially for the uneven shoulder level. Subjects' awareness about being assessed might decrease the incidence for some faulty posture. However, the relationships among the number of faulty postures, psychologic distress, and musculoskeletal symptoms were low. We suggest that there are multiple factors that might contribute to musculoskeletal symptoms; faulty posture could be one important factor that causes symptoms.

Postural response latencies are related to balance control during standing and walking in patients with multiple sclerosis

PubMed Central

Huisinga, Jessie M.; St. George, Rebecca J.; Spain, Rebecca; Overs, Shannon; Horak, Fay B.

2015-01-01

Objective To understand examined the relationship between postural response latencies obtained during postural perturbations and representative measures of balance during standing (sway variables) and during walking (trunk motion). Design Cross-sectional Setting University medical center balance disorders laboratory Participants Forty persons with MS were compared with 20 similar aged control subjects. Twenty subjects with MS had normal walking velocity group and 20 had slow walking velocity based on the 25-foot walk time greater than 5 seconds. Interventions None Main Outcome Measures Postural response latency, sway variables, trunk motion variables Results: We found that subjects with MS with either slow or normal walking velocities had significantly longer postural response latencies than the healthy control group. Postural response latency was not correlated with the 25-ft walk time. Postural response latency was significantly correlated with center of pressure sway variables during quiet standing: root mean square (ρ = 0.334, p=0.040), range (ρ=0.385, p=0.017), mean velocity (ρ=0.337, p=0.038), and total sway area (ρ=0.393, p=0.015). Postural response latency was also significantly correlated with motion of the trunk during walking: sagittal plane range of motion (ρ=0.316, p=0.050) and standard deviation of transverse plane range of motion (ρ=-0.430, p=0.006). Conclusions These findings clearly indicate that slow postural responses to external perturbations in patients with MS contribute to disturbances in balance control, both during standing and walking. PMID:24445088

Postural Rehabilitation for Adolescent Idiopathic Scoliosis during Growth

PubMed Central

Weiss, Hans-Rudolf; Moramarco, Marc Michael; Borysov, Maksym; Lee, Sang Gil; Nan, Xiaofeng; Moramarco, Kathryn Ann

2016-01-01

Long-term follow-up of untreated patients with adolescent idiopathic scoliosis (AIS) indicates that, with the exception of some extremely severe cases, AIS does not have a significant impact on quality of life and does not result in dire consequences. In view of the relatively benign nature of AIS and the long-term complications of surgery, the indications for treatment should be reviewed. Furthermore, recent studies have shown that scoliosis-specific exercises focusing on postural rehabilitation can positively influence the spinal curvatures in growing adolescents. Experiential postural re-education is a conservative, non-invasive approach, and its role in the management of AIS warrants further study. This article reviews current evidence for the inclusion of various forms of postural reeducation in the management of AIS. Recent comprehensive reviews have been researched including a manual and PubMed search for evidence regarding the effectiveness of physical/postural re-education/physiotherapy programs in growing AIS patients. This search revealed that there were few studies on the application of postural re-education in the management of AIS. These studies revealed that postural re-education in the form of exercise rehabilitation programs may have a positive influence on scoliosis; however, the various programs were difficult to compare. More research is necessary. There is at present Level 1 evidence for the effectiveness of Schroth scoliosis exercises in the management of AIS. Whether this evidence can be extrapolated to include other forms of scoliosis- pattern-specific exercises requires further investigation. Because corrective postures theoretically reduce the asymmetric loading of the spinal deformities and reverse the vicious cycle of spinal curvature progression, their integration into AIS programs may be beneficial and should be further examined. PMID:27340540

Decreasing Internal Focus of Attention Improves Postural Control during Quiet Standing in Young Healthy Adults

ERIC Educational Resources Information Center

Nafati, Gilel; Vuillerme, Nicolas

2011-01-01

This experiment was designed to investigate whether and how decreasing the amount of attentional focus invested in postural control could affect bipedal postural control. Twelve participants were asked to stand upright as immobile as possible on a force platform in one control condition and one cognitive condition. In the latter condition, they…

Assisting People with Multiple Disabilities Actively Correct Abnormal Standing Posture with a Nintendo Wii Balance Board through Controlling Environmental Stimulation

ERIC Educational Resources Information Center

Shih, Ching-Hsiang; Shih, Ching-Tien; Chu, Chiung-Ling

2010-01-01

The latest researches adopted software technology turning the Nintendo Wii Balance Board into a high performance change of standing posture (CSP) detector, and assessed whether two persons with multiple disabilities would be able to control environmental stimulation using body swing (changing standing posture). This study extends Wii Balance Board…

Decreasing internal focus of attention improves postural control during quiet standing in young healthy adults.

PubMed

Nafati, Gilel; Vuillerme, Nicolas

2011-12-01

This experiment was designed to investigate whether and how decreasing the amount of attentional focus invested in postural control could affect bipedal postural control. Twelve participants were asked to stand upright as immobile as possible on a force platform in one control condition and one cognitive condition. In the latter condition, they performed a short-term digit-span memory task. Decreased center-of-gravity displacements and decreased center-of-foot-pressure displacements minus center-of-gravity displacements were observed in the cognitive condition relative to the control condition. These results suggest that shifting the attentional focus away from postural control by executing a concurrent attention-demanding task could increase postural performance and postural efficiency.

Electromyographic analysis of standing posture and demi-plié in ballet and modern dancers.

PubMed

Trepman, E; Gellman, R E; Solomon, R; Murthy, K R; Micheli, L J; De Luca, C J

1994-06-01

Surface electromyography was used to analyze lower extremity muscle activity during standing posture and demi-plié in first position with lower extremities turned out, in five ballet and seven modern female professional dancers. In standing posture, increased electromyographic (EMG) activity above baseline was detected most frequently at the medial gastrocnemius (54% standing repetitions) and tibialis anterior (29%) electrodes (all dancers); in ballet dancers, increased EMG activity during standing was significantly less frequent at the medial gastrocnemius, but more frequent at the tibialis anterior, than in modern dancers. In demi-plié, the tibialis anterior had a discrete peak of EMG activity at midcycle in all dancers (97% demi-pliés). All dancers also had midcycle EMG activity in both vastus lateralis and medialis (100% demi-pliés). At the end of rising phase of demi-plié, ballet dancers had greater EMG activity than at midcycle in vastus lateralis (100% demi-pliés) and medialis (92%); in modern dancers, end-rising phase voltage was lower than at midcycle for vastus lateralis (71% demi-pliés) and medialis (83%). Genu recurvatum > or = 10 degrees was observed at the beginning and end of demi-plié in all ballet dancers, but not in modern dancers. There was marked variation of EMG activity during demi-plié in the lateral gastrocnemius, medial gastrocnemius, gluteus maximus, hamstrings, and adductors. The results support the hypothesis that ballet and modern dancers have different patterns of muscle use in standing posture and demi-plié, which in part may be a result of differences in genu recurvatum and turnout between the two groups.

Long-Term Effects from Bacterial Meningitis in Childhood and Adolescence on Postural Control

PubMed Central

Petersen, Hannes; Patel, Mitesh; Ingason, Einar F.; Einarsson, Einar J.; Haraldsson, Ásgeir; Fransson, Per-Anders

2014-01-01

Bacterial meningitis in childhood is associated with cognitive deficiencies, sensorimotor impairments and motor dysfunction later in life. However, the long-term effects on postural control is largely unknown, e.g., whether meningitis subjects as adults fully can utilize visual information and adaptation to enhance stability. Thirty-six subjects (20 women, mean age 19.3 years) treated in childhood or adolescence for bacterial meningitis, and 25 controls (13 women, mean age 25.1 years) performed posturography with eyes open and closed under unperturbed and perturbed standing. The meningitis subjects were screened for subjective vertigo symptoms using a questionnaire, clinically tested with headshake and head thrust test, as well as their hearing was evaluated. Meningitis subjects were significantly more unstable than controls during unperturbed (p≤0.014) and perturbed standing, though while perturbed only with eyes open in anteroposterior direction (p = 0.034) whereas in lateral direction both with eyes open and closed (p<0.001). Meningitis subjects had poorer adaption ability to balance perturbations especially with eyes open, and they frequently reported symptoms of unsteadiness (88% of the subjects) and dizziness (81%), which was found significantly correlated to objectively decreased stability. Out of the 36 subjects only 3 had unilateral hearing impairment. Hence, survivors of childhood bacterial meningitis may suffer long-term disorders affecting postural control, and would greatly benefit if these common late effects became generally known so treatments can be developed and applied. PMID:25405756

Static Standing Balance in Adolescents with Down Syndrome

ERIC Educational Resources Information Center

Villarroya, M. Adoracion; Gonzalez-Aguero, Alejandro; Moros-Garcia, Teresa; de la Flor Marin, Mario; Moreno, Luis A.; Casajus, Jose A.

2012-01-01

Aim: To analyse static-standing-balance of adolescents with Down syndrome (DS). Methods: Thirty-two adolescents with DS aged 10-19 years (DSG); 33 adolescents, age/sex-matched, without DS (CG). Static-standing-balance under four conditions (C1: open-eyes/fixed-foot-support; C2: closed-eyes/fixed-foot-support; C3: open-eyes/compliant-foot-support;…

A method for paraplegic upper-body posture estimation during standing: a pilot study for rehabilitation purposes.

PubMed

Pages, Gaël; Ramdani, Nacim; Fraisse, Philippe; Guiraud, David

2009-06-01

This paper presents a contribution for restoring standing in paraplegia while using functional electrical stimulation (FES). Movement generation induced by FES remains mostly open looped and stimulus intensities are tuned empirically. To design an efficient closed-loop control, a preliminary study has been carried out to investigate the relationship between body posture and voluntary upper body movements. A methodology is proposed to estimate body posture in the sagittal plane using force measurements exerted on supporting handles during standing. This is done by setting up constraints related to the geometric equations of a two-dimensional closed chain model and the hand-handle interactions. All measured quantities are subject to an uncertainty assumed unknown but bounded. The set membership estimation problem is solved via interval analysis. Guaranteed uncertainty bounds are computed for the estimated postures. In order to test the feasibility of our methodology, experiments were carried out with complete spinal cord injured patients.

Sitting and standing postures are corrected by adjustable furniture with lowered muscle tension in high-school students.

PubMed

Koskelo, R; Vuorikari, K; Hänninen, O

2007-10-01

This study compared the effect of 24 months of adjustable school desks and chairs usage (the intervention) and traditional non-adjustable usage (the control condition) on sitting and standing postures, muscle strength, classroom muscle tension, pain and learning in 15 (8 female and 7 male) high-school students and 15 anthropometrically and gender matched control students from neighbouring schools. It was assessed whether any responses took place after growth cessation. In comparison with controls, the intervention group of students' sitting postures standing kyphosis, scoliosis and lordosis became significantly better, both before and after growth cessation. Trunk muscle strength increased in the intervention students whose muscle tension during classes fell significantly in the trapezius and lumbar muscles, whereas in control students' lumbar tension increased. Headache and low-back pain correlated with neck-shoulder pain and trapezius muscle tension. Intervention students reported that they experienced benefits from the adjustable tables and chairs. They also received significantly better overall marks than the controls at the end of high school. It is concluded that the adjustable school desks and chairs promoted better sitting and standing postures, increased muscle strength, alleviated pain and appeared to be associated with better overall academic marks.

Association between home posture habits and neck pain in High School adolescents.

PubMed

Meziat-Filho, Ney; Azevedo E Silva, Gulnar; Coutinho, Evandro Silva; Mendonça, Roberta; Santos, Vivian

2017-01-01

Neck pain (NP) in adolescence is as frequent as in adulthood. However, the relationship between home posture habits and neck pain is still unknown. To investigate the prevalence of NP and the association with home posture habits (HPH) in adolescents. Cross-sectional study with High School adolescents. Students answered questions regarding sociodemographic variables, lifestyle, HPH (illustration in the questionnaire), time (TV, computer, video-game) and the presence of NP. Multivariate logistic regression was used to investigate the association between HPH and NP. The prevalence of NP was 48.9%. The ones who watched TV lying supine in bed for 2 hours or more a day yielded an odds ratio (OR) of 6.21 (1.45-26.52) for acute neck pain (ANP). Who watched TV and used the desktop in the slump posture yielded, respectively, an OR of 4.0 (1.63-9.85), and 2.03 (1.23-3.34) for chronic neck pain (CNP). The ones who frequently changed their positions while using the desktop and used it for 2 hours or more a day yielded an OR of 0.34 (0.14-0.85) for ANP. Our findings support the high prevalence of NP in adolescence and raise the association between some HPH and neck pain.

Should Ballet Dancers Vary Postures and Underfoot Surfaces When Practicing Postural Balance?

PubMed

Steinberg, Nili; Waddington, Gordon; Adams, Roger; Karin, Janet; Tirosh, Oren

2018-01-01

Postural balance (PB) is an important component skill for professional dancers. However, the effects of different types of postures and different underfoot surfaces on PB have not adequately been addressed. The main aim of this study was to investigate the effect of different conditions of footwear, surfaces, and standing positions on static and dynamic PB ability of young ballet dancers. A total of 36 male and female young professional ballet dancers (aged 14-19 years) completed static and dynamic balance testing, measured by head and lumbar accelerometers, while standing on one leg in the turnout position, under six different conditions: (1) "relaxed" posture; (2) "ballet" posture; (3) barefoot; (4) ballet shoes with textured insoles; (5) barefoot on a textured mat; and (6) barefoot on a spiky mat. A condition effect was found for static and dynamic PB. Static PB was reduced when dancers stood in the ballet posture compared with standing in the relaxed posture and when standing on a textured mat and on a spiky mat (p < .05), and static PB in the relaxed posture was significantly better than PB in all the other five conditions tested. Dynamic PB was significantly better while standing in ballet shoes with textured insoles and when standing on a spiky mat compared with all other conditions (p < .05). The practical implications derived from this study are that both male and female dancers should try to be relaxed in their postural muscles when practicing a ballet aligned position, including dance practice on different types of floors and on different types of textured/spiky materials may result in skill transfer to practice on normal floor surfaces, and both static and dynamic PB exercises should be assessed and generalized into practical dance routines.

Reaching while standing in microgravity: a new postural solution to oversimplify movement control.

PubMed

Casellato, Claudia; Tagliabue, Michele; Pedrocchi, Alessandra; Papaxanthis, Charalambos; Ferrigno, Giancarlo; Pozzo, Thierry

2012-01-01

Many studies showed that both arm movements and postural control are characterized by strong invariants. Besides, when a movement requires simultaneous control of the hand trajectory and balance maintenance, these two movement components are highly coordinated. It is well known that the focal and postural invariants are individually tightly linked to gravity, much less is known about the role of gravity in their coordination. It is not clear whether the effect of gravity on different movement components is such as to keep a strong movement-posture coordination even in different gravitational conditions or whether gravitational information is necessary for maintaining motor synergism. We thus set out to analyze the movements of eleven standing subjects reaching for a target in front of them beyond arm's length in normal conditions and in microgravity. The results showed that subjects quickly adapted to microgravity and were able to successfully accomplish the task. In contrast to the hand trajectory, the postural strategy was strongly affected by microgravity, so to become incompatible with normo-gravity balance constraints. The distinct effects of gravity on the focal and postural components determined a significant decrease in their reciprocal coordination. This finding suggests that movement-posture coupling is affected by gravity, and thus, it does not represent a unique hardwired and invariant mode of control. Additional kinematic and dynamic analyses suggest that the new motor strategy corresponds to a global oversimplification of movement control, fulfilling the mechanical and sensory constraints of the microgravity environment.

Sex Differences in Landing Biomechanics and Postural Stability During Adolescence: A Systematic Review with Meta-Analyses.

PubMed

Holden, Sinéad; Boreham, Colin; Delahunt, Eamonn

2016-02-01

The adolescent 'growth spurt' results in rapid growth of the skeletal system. It has been theorised that absence of a concomitant increase in muscular adaptations in female athletes may predispose them to an increased risk of anterior cruciate ligament injuries. To determine if sex differences exist in landing biomechanics and postural stability of adolescent athletes; with a further objective of determining if such differences are propagated during adolescence. The following databases were searched: MEDLINE, EMBASE, CINAHL, PEDro, PubMed, SPORTDiscus and Web of Science. Research papers were identified by including search terms for neuromuscular control, lower limb and pubertal development. Studies were required to be written in English; report on biomechanical analyses; include landing or postural control tasks; be cross-sectional or longitudinal; and include healthy adolescent/pubertal subjects. A modified version of the Strengthening the Reporting of Observational studies in Epidemiology checklist was used to rate methodological quality. Meta-analyses were performed when more than one study reported on an outcome measure. Sixteen articles were included. The overall methodological quality of evaluated studies was low (mean score = 5.75/10 points). Adolescent females exhibited increased knee valgus with increasing maturity. There was no consensus on sex differences in postural stability. With increasing maturation, females are characterized by increased knee valgus during landing tasks. To date, no research has longitudinally investigated postural stability development during adolescence in females, despite the importance of postural control training in injury prevention programmes. Therefore, further research on this topic is warranted.

Adaptation of postural responses during different standing perturbation conditions in individuals with incomplete spinal cord injury.

PubMed

Thigpen, Mary T; Cauraugh, James; Creel, Gwen; Day, Kristin; Flynn, Sheryl; Fritz, Stacy; Frost, Shirley; Respess, Robert; Gardner-Smith, Portia; Brack, Mia; Behrman, Andrea

2009-01-01

Incomplete spinal cord injury (ISCI) frequently disrupts afferent and efferent neural pathways underlying co-requisite voluntary and involuntary muscle activation required for functional standing and walking. To understand involuntary postural control mechanisms necessary for standing, we compared eight individuals with ISCI to eight controls with no impairment. The aim of this study was to investigate anticipatory and reactive balance responses in individuals with ISCI. The ability to adapt to changes in balance conditions was assessed by monitoring automatic postural responses (APRs) during a series of expected and unexpected changes in perturbation direction (backward translation versus toes-up rotation). Both groups were able to modulate appropriately within one or two trials following an unexpected change in condition. Onset times of anterior tibialis and medial gastrocnemius (MG) were significantly slower in the ISCI group during expected and unexpected conditions. These findings demonstrate that persons with mild to moderate lower extremity sensorimotor deficits are able to generate and adapt APRs to a rapid and unexpected contextual change during a simple standing balance task.

Active ankle dorsiflexion and the Mingazzini manoeuvre: two clinical bedside tests related to prognosis of postural transferring, standing and walking ability in patients with stroke.

PubMed

Smania, N; Gambarin, M; Paolucci, S; Girardi, P; Bortolami, M; Fiaschi, A; Santilli, V; Picelli, A

2011-09-01

Lower limb paresis is one of the main determinants of postural transferring, standing and walking disability in patients with stroke. Early prognosis of recovery of lower limb function and of related functional disability is an important issue in neurorehabilitation clinical practice. Aim of this study was to assess the relationship between active ankle dorsiflexion and the Mingazzini manoeuvre with the prognosis of lower limb function and of postural transferring, standing and walking ability in patients with stroke. This was a longitudinal study with prospectively collected data. University hospital. The study included 53 patients with first unilateral brain ischemic stroke. Patients were evaluated initially (mean 4.02 days) and approximately at six months (mean 178.6 days) after stroke. Initial assessment included active ankle dorsiflexion and the Mingazzini manoeuvre. The assessment after six months included three outcome measures evaluating the rate of improvement of lower limb function and of postural transferring, standing and walking ability (Postural Assessment Scale for Stroke patients, Functional Ambulation Category, Motricity Index leg subtest). The active ankle dorsiflexion showed to be related with the prognosis of lower limb function and of walking ability, while the Mingazzini manoeuvre was related with the improvement of postural transferring and standing ability. Active ankle dorsiflexion and the Mingazzini manoeuvre are related with the prognosis of lower limb function and of postural transferring, standing and walking ability in patients with stroke. These simple bedside tests give a picture of improvement potential of motor activities connected to lower limb function in patients with acute stroke.

Complexity-Based Measures Inform Effects of Tai Chi Training on Standing Postural Control: Cross-Sectional and Randomized Trial Studies

PubMed Central

Wayne, Peter M.; Gow, Brian J.; Costa, Madalena D.; Peng, C.-K.; Lipsitz, Lewis A.; Hausdorff, Jeffrey M.; Davis, Roger B.; Walsh, Jacquelyn N.; Lough, Matthew; Novak, Vera; Yeh, Gloria Y.; Ahn, Andrew C.; Macklin, Eric A.; Manor, Brad

2014-01-01

Background Diminished control of standing balance, traditionally indicated by greater postural sway magnitude and speed, is associated with falls in older adults. Tai Chi (TC) is a multisystem intervention that reduces fall risk, yet its impact on sway measures vary considerably. We hypothesized that TC improves the integrated function of multiple control systems influencing balance, quantifiable by the multi-scale “complexity” of postural sway fluctuations. Objectives To evaluate both traditional and complexity-based measures of sway to characterize the short- and potential long-term effects of TC training on postural control and the relationships between sway measures and physical function in healthy older adults. Methods A cross-sectional comparison of standing postural sway in healthy TC-naïve and TC-expert (24.5±12 yrs experience) adults. TC-naïve participants then completed a 6-month, two-arm, wait-list randomized clinical trial of TC training. Postural sway was assessed before and after the training during standing on a force-plate with eyes-open (EO) and eyes-closed (EC). Anterior-posterior (AP) and medio-lateral (ML) sway speed, magnitude, and complexity (quantified by multiscale entropy) were calculated. Single-legged standing time and Timed-Up–and-Go tests characterized physical function. Results At baseline, compared to TC-naïve adults (n = 60, age 64.5±7.5 yrs), TC-experts (n = 27, age 62.8±7.5 yrs) exhibited greater complexity of sway in the AP EC (P = 0.023), ML EO (P<0.001), and ML EC (P<0.001) conditions. Traditional measures of sway speed and magnitude were not significantly lower among TC-experts. Intention-to-treat analyses indicated no significant effects of short-term TC training; however, increases in AP EC and ML EC complexity amongst those randomized to TC were positively correlated with practice hours (P = 0.044, P = 0.018). Long- and short-term TC training were positively associated with physical function

Complexity-Based Measures Inform Effects of Tai Chi Training on Standing Postural Control: Cross-Sectional and Randomized Trial Studies.

PubMed

Wayne, Peter M; Gow, Brian J; Costa, Madalena D; Peng, C-K; Lipsitz, Lewis A; Hausdorff, Jeffrey M; Davis, Roger B; Walsh, Jacquelyn N; Lough, Matthew; Novak, Vera; Yeh, Gloria Y; Ahn, Andrew C; Macklin, Eric A; Manor, Brad

2014-01-01

Diminished control of standing balance, traditionally indicated by greater postural sway magnitude and speed, is associated with falls in older adults. Tai Chi (TC) is a multisystem intervention that reduces fall risk, yet its impact on sway measures vary considerably. We hypothesized that TC improves the integrated function of multiple control systems influencing balance, quantifiable by the multi-scale "complexity" of postural sway fluctuations. To evaluate both traditional and complexity-based measures of sway to characterize the short- and potential long-term effects of TC training on postural control and the relationships between sway measures and physical function in healthy older adults. A cross-sectional comparison of standing postural sway in healthy TC-naïve and TC-expert (24.5±12 yrs experience) adults. TC-naïve participants then completed a 6-month, two-arm, wait-list randomized clinical trial of TC training. Postural sway was assessed before and after the training during standing on a force-plate with eyes-open (EO) and eyes-closed (EC). Anterior-posterior (AP) and medio-lateral (ML) sway speed, magnitude, and complexity (quantified by multiscale entropy) were calculated. Single-legged standing time and Timed-Up-and-Go tests characterized physical function. At baseline, compared to TC-naïve adults (n = 60, age 64.5±7.5 yrs), TC-experts (n = 27, age 62.8±7.5 yrs) exhibited greater complexity of sway in the AP EC (P = 0.023), ML EO (P<0.001), and ML EC (P<0.001) conditions. Traditional measures of sway speed and magnitude were not significantly lower among TC-experts. Intention-to-treat analyses indicated no significant effects of short-term TC training; however, increases in AP EC and ML EC complexity amongst those randomized to TC were positively correlated with practice hours (P = 0.044, P = 0.018). Long- and short-term TC training were positively associated with physical function. Multiscale entropy offers a complementary

The posture of adolescent male handball players: A two-year study.

PubMed

Grabara, Małgorzata

2018-02-06

Young athletes at the stage of growth acceleration tend to exhibit increased susceptibility to postural abnormalities, especially in the trunk region. The aim of this study was to assess and compare the posture in male adolescent handball players over two years of regular training sessions. The study group comprised 21 handball players. At the start of the study 15 participants were aged 14 and 6 participants were aged 15 (mean 14.25 ± 0.58). The measurements were repeated three times. Posture was assessed with a photogrammetric method based on the moiré phenomenon. The analysis of posture relative to symmetry in the frontal and transverse planes did not reveal any significant differences between posture indicators obtained during the successive measurements. Sagittal plane posture indicators revealed significant changes in torso forward inclination angle and the shape of anteroposterior spinal curvatures. The latter consisted of significant deepening of the upper thoracic curve (angle α) and flattening of the lumbosacral curve (angle γ). A two-year period of handball training did not result in posture asymmetries in young male handball players. The observed changes in the shape of anteroposterior spinal curvatures might be related both to sports training and somatic parameters.

The degree of postural automaticity influences the prime movement and the anticipatory postural adjustments during standing in healthy young individuals.

PubMed

Sakamoto, Sadanori; Iguchi, Masaki

2018-06-08

Less attention to a balance task reduces the center of foot pressure (COP) variability by automating the task. However, it is not fully understood how the degree of postural automaticity influences the voluntary movement and anticipatory postural adjustments. Eleven healthy young adults performed a bipedal, eyes closed standing task under the three conditions: Control (C, standing task), Single (S, standing + reaction tasks), and Dual (D, standing  +  reaction + mental tasks). The reaction task was flexing the right shoulder to an auditory stimulus, which causes counter-clockwise rotational torque, and the mental task was arithmetic task. The COP variance before the reaction task was reduced in the D condition compared to that in the C and S conditions. On average the onsets of the arm movement and the vertical torque (Tz, anticipatory clockwise rotational torque) were both delayed, and the maximal Tz slope (the rate at which the torque develops) became less steep in the D condition compared to those in the S condition. When these data in the D condition were expressed as a percentage of those in the S condition, the arm movement onset and the Tz slope were positively and negatively, respectively, correlated with the COP variance. By using the mental-task induced COP variance reduction as the indicator of postural automaticity, our data suggest that the balance task for those with more COP variance reduction is less cognitively demanding, leading to the shorter reaction time probably due to the attention shift from the automated balance task to the reaction task. Copyright © 2018 Elsevier B.V. All rights reserved.

Organization of Functional Postural Responses Following Perturbations in Multiple Directions in Elderly Fallers Standing Quietly

ERIC Educational Resources Information Center

Matjacic, Zlatko; Sok, David; Jakovljevic, Miroljub; Cikajlo, Imre

2013-01-01

The objective of the study was to assess functional postural responses by analyzing the center-of-pressure trajectories resulting from perturbations delivered in multiple directions to elderly fallers. Ten elderly individuals were standing quietly on two force platforms while an apparatus delivered controlled perturbations at the level of pelvis…

Kinematic error magnitude in the single-mass inverted pendulum model of human standing posture.

PubMed

Fok, Kai Lon; Lee, Jae; Vette, Albert H; Masani, Kei

2018-06-01

Many postural control studies employ a single-mass inverted pendulum model (IPM) to represent the body during standing. However, it is not known to what degree and for what conditions the model's kinematic assumptions are valid. Our first objective was to quantify the IPM error, corresponding to a distance change between the ankle joint and center of mass (COM) during unrestricted, natural, unperturbed standing. A second objective was to quantify the error of having the ankle joint angle represent the COM angle. Eleven young participants completed five standing conditions: quiet standing with eyes open (EO) and closed (EC), voluntarily swaying forward (VSf) and backward (VSb), and freely moving (FR). The modified Helen-Hayes marker model was used to capture the body kinematics. The COM distance changed <0.1% during EO and EC, <0.25% during VSf and VSb, and <1.5% during FR. The ankle angle moderately and positively correlated with the COM angle for EO, EC, and VSf, indicating that temporal features of the ankle angle moderately represent those of the COM angle. However, a considerable offset between the two existed, which needs to be considered when estimating the COM angle using the ankle angle. For VSb and FR, the correlation coefficients were low and/or negative, suggesting that a large error would result from using the ankle angle as an estimate of the COM angle. Insights from this study will be critical for deciding when to use the IPM in postural control research and for interpreting associated results. Copyright © 2018 Elsevier B.V. All rights reserved.

Control of vertical posture while standing on a sliding board and pushing an object.

PubMed

Lee, Yun-Ju; Chen, Bing; Liang, Jing-Nong; Aruin, Alexander S

2018-03-01

Voluntary pushing or translation perturbation of the support surface each induces a body perturbation that affects postural control. The objective of the study was to investigate anticipatory (APA) and compensatory (CPA) postural adjustments when pushing an object (that induces self-initiated perturbation) and standing on a sliding board (that induces translational perturbation). Thirteen healthy young participants were instructed to push a handle with both hands while standing on a sliding board that was either free to move in the anterior-posterior direction or stationary. Electromyographic activity (EMG) of trunk and lower extremity muscles, center of pressure (COP) displacements, and the forces exerted by the hand were recorded and analyzed during the APA and CPA phases. When the sliding board was free to move during pushing (translation perturbation), onsets of activity of ventral leg muscles and COP displacement were delayed as compared to pushing when standing on a stationary board. Moreover, magnitudes of shank muscle activity and the COP displacement were decreased. When pushing heavier weight, magnitudes of muscle activity, COP displacement, and pushing force increased. The magnitude of activity of the shank muscles during the APA and CPA phases in conditions with translational perturbation varied with the magnitude of the pushing weight. The outcome of the study suggests that the central nervous system prioritizes the pushing task while attenuates the source of additional perturbation induced by translation perturbation. These results could be used in the development of balance re-training paradigms involving pushing weight while standing on a sliding surface.

Comparison of standing postural control and gait parameters in people with and without chronic low back pain: a cross-sectional case-control study.

PubMed

MacRae, Catharine Siân; Critchley, Duncan; Lewis, Jeremy S; Shortland, Adam

2018-01-01

Differences in postural control and gait have been identified between people with and without chronic low back pain (CLBP); however, many previous studies present data from small samples, or have used methodologies with questionable reliability. This study, employing robust methodology, hypothesised that there would be a difference in postural control, and spatiotemporal parameters of gait in people with CLBP compared with asymptomatic individuals. This cross-sectional case-control study age-matched and gender-matched 16 CLBP and 16 asymptomatic participants. Participants were assessed barefoot (1) standing, over three 40 s trials, under four posture challenging conditions (2) during gait. Primary outcome was postural stability (assessed by root mean squared error of centre of pressure (CoP) displacement (CoP RMSEAP ) and mean CoP velocity (CoP VELAP ), both in the anteroposterior direction); gait outcomes were hip range of movement and peak moments, walking speed, cadence and stride length, assessed using force plates and a motion analysis system. There were no differences between groups in CoP RMSEAP (P=0.26), or CoP VELAP (P=0.60) for any standing condition. During gait, no differences were observed between groups for spatiotemporal parameters, maximum, minimum and total ranges of hip movement, or peak hip flexor or extensor moments in the sagittal plane. In contrast to previous research, this study suggests that people with mild to moderate CLBP present with similar standing postural control, and parameters of gait to asymptomatic individuals. Treatments directed at influencing postural stability (eg, standing on a wobble board) or specific parameters of gait may be an unnecessary addition to a treatment programme.

Effect of sacroiliac manipulation on postural sway in quiet standing: a randomized controlled trial.

PubMed

Farazdaghi, Mohammad Reza; Motealleh, Alireza; Abtahi, Forough; Panjan, Andrej; Šarabon, Nejc; Ghaffarinejad, Farahnaz

Sacroiliac joint manipulation can alter joint and muscle control mechanisms through local and remote effects. Postural balance is controlled by supraspinal (rambling) and spinal-peripheral (trembling) mechanisms. A manipulation may interfere with postural control in quiet standing. To evaluate the immediate effects of sacroiliac joint manipulation on postural control in patients with (1) sacroiliac dysfunction and (2) to determine whether rambling and trembling are affected by sacroiliac joint manipulation. 32 patients aged between 20 and 50 years old were selected by convenience after confirmation of sacroiliac joint dysfunction by clinical examination. These patients were randomly allocated either to manipulation or sham manipulation group. Displacement, velocity and frequency of the center of pressure, rambling and trembling in the anterior-posterior and medial-lateral directions were our primary outcomes and analyzed immediately before and after the intervention in quiet standing. The physical therapists who performed the physical, biomechanical and statistical examinations, were all blinded to the patients' grouping. No differences were found between the two groups but trembling velocity (0.14 and -0.11 for intervention and sham group, respectively) and frequency (0.17 and 0.11 for intervention and sham group respectively) increased after intervention in the treatment group in the anterior-posterior direction. Generally, sacroiliac joint manipulation had no superiority than sham treatment regarding postural control as measured by rambling-trembling analysis of center of pressure. Manipulation may increase muscle activation in the treatment group due to increased trembling parameters. Trial number: IRCT2014072715932N8 - http://www.irct.ir/searchresult.php?keyword=%D8%B3%D9%88%DB%8C%D9%87&id=15932&field=&number=8&prt=13&total=10&m=1. Copyright © 2017 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier Editora Ltda. All

Postural control strategies related to anticipatory perturbation and quick perturbation in adolescent idiopathic scoliosis.

PubMed

Kuo, Fang-Chuan; Hong, Chang-Zern; Lai, Chung-Liang; Tan, Shih-Hsin

2011-05-01

Cross-sectional study. To investigate the automatic balance correction related to anticipatory perturbation (AP) and quick backward perturbation in adolescent idiopathic scoliosis (AIS). Most previous studies on AIS patients focused on posture sway and lacked analysis of muscle activated patterns in dynamic standing control. Thirty-two AIS patients and 23 age-matched normal subjects received perturbation balance tests on an unstable platform. The tilting angle of the platform and the muscle activity of the bilateral lumbar multifidi, gluteus medii, and gastrocnemii muscles were recorded. Electromyographic (EMG) amplitude, onset latencies, and duration were calculated with software accompanied with machine. The AIS group had less posture tilting but higher muscle activities than normal subjects under both perturbation conditions (P < 0.05). Under the AP test, AIS showed earlier onset and prolonged activation of left multifidus and right gastrocnemius compared with normal subjects (P < 0.05). The latency of the multifidus on the lumbar convex side occurred earlier than on the concave side. However, the asymmetric onset timing of the gastrocnemius was the opposite of the multifidi in the AIS group (P < 0.05). In contrast to the AP condition, bilateral leg and trunk muscles activated at similar latencies and durations in the AIS group (P < 0.05). Under the quick backward perturbation test, the control group had longer active duration of right multifidus and bilateral gastrocnemii than AIS to cope with larger platform tilting. In addition, asymmetric onset of gluteus medii and duration of multifidi was observed in the control group (P < 0.05). There were significant differences in posture control patterns between AIS and normal subjects. AIS subjects have asymmetric habitual muscle activities for AP, whereas when coping with sudden balance threats, they react with synchronized recruitment of bilateral postural muscles.

Is the size of the useful field of view affected by postural demands associated with standing and stepping?

PubMed

Reed-Jones, James G; Reed-Jones, Rebecca J; Hollands, Mark A

2014-04-30

The useful field of view (UFOV) is the visual area from which information is obtained at a brief glance. While studies have examined the effects of increased cognitive load on the visual field, no one has specifically looked at the effects of postural control or locomotor activity on the UFOV. The current study aimed to examine the effects of postural demand and locomotor activity on UFOV performance in healthy young adults. Eleven participants were tested on three modified UFOV tasks (central processing, peripheral processing, and divided-attention) while seated, standing, and stepping in place. Across all postural conditions, participants showed no difference in their central or peripheral processing. However, in the divided-attention task (reporting the letter in central vision and target location in peripheral vision amongst distracter items) a main effect of posture condition on peripheral target accuracy was found for targets at 57° of eccentricity (p=.037). The mean accuracy reduced from 80.5% (standing) to 74% (seated) to 56.3% (stepping). These findings show that postural demands do affect UFOV divided-attention performance. In particular, the size of the useful field of view significantly decreases when stepping. This finding has important implications for how the results of a UFOV test are used to evaluate the general size of the UFOV during varying activities, as the traditional seated test procedure may overestimate the size of the UFOV during locomotor activities. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Modelling resonances of the standing body exposed to vertical whole-body vibration: Effects of posture

NASA Astrophysics Data System (ADS)

Subashi, G. H. M. J.; Matsumoto, Y.; Griffin, M. J.

2008-10-01

Lumped parameter mathematical models representing anatomical parts of the human body have been developed to represent body motions associated with resonances of the vertical apparent mass and the fore-and-aft cross-axis apparent mass of the human body standing in five different postures: 'upright', 'lordotic', 'anterior lean', 'knees bent', and 'knees more bent'. The inertial and geometric parameters of the models were determined from published anthropometric data. Stiffness and damping parameters were obtained by comparing model responses with experimental data obtained previously. The principal resonance of the vertical apparent mass, and the first peak in the fore-and-aft cross-axis apparent mass, of the standing body in an upright posture (at 5-6 Hz) corresponded to vertical motion of the viscera in phase with the vertical motion of the entire body due to deformation of the tissues at the soles of the feet, with pitch motion of the pelvis out of phase with pitch motion of the upper body above the pelvis. Upward motion of the body was in phase with the forward pitch motion of the pelvis. Changing the posture of the upper body had minor effects on the mode associated with the principal resonances of the apparent mass and cross-axis apparent mass, but the mode changed significantly with bending of the legs. In legs-bent postures, the principal resonance (at about 3 Hz) was attributed to bending of the legs coupled with pitch motion of the pelvis in phase with pitch motion of the upper body. In this mode, extension of the legs was in phase with the forward pitch motion of the upper body and the upward vertical motion of the viscera.

Mechanisms of postural control in alcoholic men and women: biomechanical analysis of musculoskeletal coordination during quiet standing.

PubMed

Sullivan, Edith V; Rose, Jessica; Pfefferbaum, Adolf

2010-03-01

Excessive sway during quiet standing is a common sequela of chronic alcoholism even with prolonged sobriety. Whether alcoholic men and women who have remained abstinent from alcohol for weeks to months differ from each other in the degree of residual postural instability and biomechanical control mechanisms has not been directly tested. We used a force platform to characterize center-of-pressure biomechanical features of postural sway, with and without stabilizing conditions from touch, vision, and stance, in 34 alcoholic men, 15 alcoholic women, 22 control men, and 29 control women. Groups were matched in age (49.4 years), general intelligence, socioeconomic status, and handedness. Each alcoholic group was sober for an average of 75 days. Analysis of postural sway when using all 3 stabilizing conditions versus none revealed diagnosis and sex differences in ability to balance. Alcoholics had significantly longer sway paths, especially in the anterior-posterior direction, than controls when maintaining erect posture without balance aids. With stabilizing conditions the sway paths of all groups shortened significantly, especially those of alcoholic men, who demonstrated a 3.1-fold improvement in sway path difference between the easiest and most challenging conditions; the remaining 3 groups, each showed a approximately 2.4-fold improvement. Application of a mechanical model to partition sway paths into open-loop and closed-loop postural control systems revealed that the sway paths of the alcoholic men but not alcoholic women were characterized by greater short-term (open-loop) diffusion coefficients without aids, often associated with muscle stiffening response. With stabilizing factors, all 4 groups showed similar long-term (closed loop) postural control. Correlations between cognitive abilities and closed-loop sway indices were more robust in alcoholic men than alcoholic women. Reduction in sway and closed-loop activity during quiet standing with stabilizing

Standing economy: does the heterogeneity in the energy cost of posture maintenance reside in differential patterns of spontaneous weight-shifting?

PubMed

Miles-Chan, Jennifer L; Fares, Elie-Jacques; Berkachy, Redina; Jacquet, Philippe; Isacco, Laurie; Schutz, Yves; Montani, Jean-Pierre; Dulloo, Abdul G

2017-04-01

Due to sedentarity-associated disease risks, there is much interest in methods to increase low-intensity physical activity. In this context, it is widely assumed that altering posture allocation can modify energy expenditure (EE) to impact body-weight regulation and health. However, we have recently shown the existence of two distinct phenotypes pertaining to the energy cost of standing-with most individuals having no sustained increase in EE during steady-state standing relative to sitting comfortably. Here, we investigated whether these distinct phenotypes are related to the presence/absence of spontaneous "weight-shifting", i.e. the redistribution of body-weight from one foot to the other. Using indirect calorimetry to measure EE in young adults during sitting and 10 min of steady-state standing, we examined: (i) heterogeneity in EE during standing (n = 36); (ii) EE and spontaneous weight-shifting patterns (n = 18); (iii) EE during spontaneous weight-shifting versus experimentally induced weight-shifting (n = 7), and; (iv) EE during spontaneous weight-shifting versus intermittent leg/body displacement (n = 6). Despite heterogeneity in EE response to steady-state standing, no differences were found in the amount or pattern of spontaneous weight-shifting between the two phenotypes. Whilst experimentally induced weight-shifting resulted in a mean EE increase of only 11% (range: 0-25%), intermittent leg/body displacement increased EE to >1.5 METs in all participants. Although the variability in spontaneous weight-shifting signatures between individuals does not appear to underlie heterogeneity in the energy cost of standing posture maintenance, these studies underscore the fact that leg/body displacement, rather than standing posture alone, is needed to increase EE above the currently defined sedentary threshold.

Study of the human postural control system during quiet standing using detrended fluctuation analysis

NASA Astrophysics Data System (ADS)

Teresa Blázquez, M.; Anguiano, Marta; de Saavedra, Fernando Arias; Lallena, Antonio M.; Carpena, Pedro

2009-05-01

The detrended fluctuation analysis is used to study the behavior of different time series obtained from the trajectory of the center of pressure, the output of the activity of the human postural control system. The results suggest that these trajectories present two different regimes in their scaling properties: persistent (for high frequencies, short-range time scale) to antipersistent (for low frequencies, long-range time scale) behaviors. The similitude between the results obtained for the measurements, done with both eyes open and eyes closed, indicate either that the visual system may be disregarded by the postural control system while maintaining the quiet standing, or that the control mechanisms associated with each type of information (visual, vestibular and somatosensory) cannot be disentangled with the type of analysis performed here.

Take a stand on your decisions, or take a sit: posture does not affect risk preferences in an economic task.

PubMed

O'Brien, Megan K; Ahmed, Alaa A

2014-01-01

Physiological and emotional states can affect our decision-making processes, even when these states are seemingly insignificant to the decision at hand. We examined whether posture and postural threat affect decisions in a non-related economic domain. Healthy young adults made a series of choices between economic lotteries in various conditions, including changes in body posture (sitting vs. standing) and changes in elevation (ground level vs. atop a 0.8-meter-high platform). We compared three metrics between conditions to assess changes in risk-sensitivity: frequency of risky choices, and parameter fits of both utility and probability weighting parameters using cumulative prospect theory. We also measured skin conductance level to evaluate physiological response to the postural threat. Our results demonstrate that body posture does not significantly affect decision making. Secondly, despite increased skin conductance level, economic risk-sensitivity was unaffected by increased threat. Our findings indicate that economic choices are fairly robust to the physiological and emotional changes that result from posture or postural threat.

Take a stand on your decisions, or take a sit: posture does not affect risk preferences in an economic task

PubMed Central

O’Brien, Megan K.

2014-01-01

Physiological and emotional states can affect our decision-making processes, even when these states are seemingly insignificant to the decision at hand. We examined whether posture and postural threat affect decisions in a non-related economic domain. Healthy young adults made a series of choices between economic lotteries in various conditions, including changes in body posture (sitting vs. standing) and changes in elevation (ground level vs. atop a 0.8-meter-high platform). We compared three metrics between conditions to assess changes in risk-sensitivity: frequency of risky choices, and parameter fits of both utility and probability weighting parameters using cumulative prospect theory. We also measured skin conductance level to evaluate physiological response to the postural threat. Our results demonstrate that body posture does not significantly affect decision making. Secondly, despite increased skin conductance level, economic risk-sensitivity was unaffected by increased threat. Our findings indicate that economic choices are fairly robust to the physiological and emotional changes that result from posture or postural threat. PMID:25083345

Coordination between posture and movement: interaction between postural and accuracy constraints.

PubMed

Berrigan, Félix; Simoneau, Martin; Martin, Olivier; Teasdale, Normand

2006-04-01

We examined the interaction between the control of posture and an aiming movement. Balance control was varied by having subjects aim at a target from a seated or a standing position. The aiming difficulty was varied using a Fitts'-like paradigm (movement amplitude=30 cm; target widths=0.5, 1.0, 2.5 and 5 cm). For both postural conditions, all targets were within the reaching space in front of the subjects and kept at a fixed relative position with respect to the subjects' body. Hence, for a given target size, the aiming was differentiated only by the postural context (seated vs. upright standing). For both postural conditions, movement time (MT) followed the well-known Fitts' law, that is, it increased with a decreasing target size. For the smallest target width, however, the increased MT was greater when subjects were standing than when they were seated suggesting that the difficulty of the aiming task could not be determined solely by the target size. When standing, a coordination between the trunk and the arm was observed. Also, as the target size decreased, the center of pressure (CP) displacement increased without any increase in CP speed suggesting that the subjects were regulating their CP to provide a controlled referential to assist the hand movement. When seated, the CP kinematics was scaled with the hand movement kinematics. Increasing the index of difficulty led to a strong correlation between the hand speed and CP displacement and speed. The complex organization between posture and movement was revealed only by examining the specific interactions between speed-accuracy and postural constraints.

Measurement of three-dimensional posture and trajectory of lower body during standing long jumping utilizing body-mounted sensors.

PubMed

Ibata, Yuki; Kitamura, Seiji; Motoi, Kosuke; Sagawa, Koichi

2013-01-01

The measurement method of three-dimensional posture and flying trajectory of lower body during jumping motion using body-mounted wireless inertial measurement units (WIMU) is introduced. The WIMU is composed of three-dimensional (3D) accelerometer and gyroscope of two kinds with different dynamic range and one 3D geomagnetic sensor to adapt to quick movement. Three WIMUs are mounted under the chest, right thigh and right shank. Thin film pressure sensors are connected to the shank WIMU and are installed under right heel and tiptoe to distinguish the state of the body motion between grounding and jumping. Initial and final postures of trunk, thigh and shank at standing-still are obtained using gravitational acceleration and geomagnetism. The posture of body is determined using the 3D direction of each segment updated by the numerical integration of angular velocity. Flying motion is detected from pressure sensors and 3D flying trajectory is derived by the double integration of trunk acceleration applying the 3D velocity of trunk at takeoff. Standing long jump experiments are performed and experimental results show that the joint angle and flying trajectory agree with the actual motion measured by the optical motion capture system.

Variations in rest vertical dimension: effects of standing posture in edentulous patients.

PubMed

Makzoume, Joseph E

2007-01-01

The orientation of a patient's head changes, depending on whether he or she is sitting or standing in a relaxed upright position. An edentulous patient's vertical dimension at rest may show variations that can result in an inaccurate determination of his or her occlusal vertical dimension. This study recorded the rest vertical dimension (RVD) established among 60 totally edentulous subjects who were standing in the position of greatest comfort (self-balance position) and compared it with the patients' RVD when they were seated in a relaxed upright position, with the Frankfort Plane parallel to the horizontal. The RVD was measured (in mm) between two dots located on the midline of the face. Two measurements were made: one when the patient was seated upright and relaxed (with the Frankfort Plane parallel to the horizontal) with no head support, and the other when the patient was standing relaxed on both feet in a self-balance position. Five alternated measurements were made for each subject in each position. A mean RVD was calculated for each subject in each body posture and the mean values from both positions were compared. Statistical analysis was performed using Student's t-test (alpha = 0.05). No significant differences were noted between the RVD of the seated and standing positions (P = 0.67).

Automated reconstruction of standing posture panoramas from multi-sector long limb x-ray images

NASA Astrophysics Data System (ADS)

Miller, Linzey; Trier, Caroline; Ben-Zikri, Yehuda K.; Linte, Cristian A.

2016-03-01

Due to the digital X-ray imaging system's limited field of view, several individual sector images are required to capture the posture of an individual in standing position. These images are then "stitched together" to reconstruct the standing posture. We have created an image processing application that automates the stitching, therefore minimizing user input, optimizing workflow, and reducing human error. The application begins with pre-processing the input images by removing artifacts, filtering out isolated noisy regions, and amplifying a seamless bone edge. The resulting binary images are then registered together using a rigid-body intensity based registration algorithm. The identified registration transformations are then used to map the original sector images into the panorama image. Our method focuses primarily on the use of the anatomical content of the images to generate the panoramas as opposed to using external markers employed to aid with the alignment process. Currently, results show robust edge detection prior to registration and we have tested our approach by comparing the resulting automatically-stitched panoramas to the manually stitched panoramas in terms of registration parameters, target registration error of homologous markers, and the homogeneity of the digitally subtracted automatically- and manually-stitched images using 26 patient datasets.

Effects of disease severity and medication state on postural control asymmetry during challenging postural tasks in individuals with Parkinson's disease.

PubMed

Barbieri, Fabio A; Polastri, Paula F; Baptista, André M; Lirani-Silva, Ellen; Simieli, Lucas; Orcioli-Silva, Diego; Beretta, Victor S; Gobbi, Lilian T B

2016-04-01

The aim of this study was to investigate the effects of disease severity and medication state on postural control asymmetry during challenging tasks in individuals with Parkinson's disease (PD). Nineteen people with PD and 11 neurologically healthy individuals performed three standing task conditions: bipedal standing, tandem and unipedal adapted standing; the individuals with PD performed the tasks in ON and OFF medication state. The participants with PD were distributed into 2 groups according to disease severity: unilateral group (n=8) and bilateral group (n=11). The two PD groups performed the evaluations both under and without the medication. Two force plates were used to analyze the posture. The symmetric index was calculated for various of center of pressure. ANOVA one-way (groups) and two-way (PD groups×medication), with repeated measures for medication, were calculated. For main effects of group, the bilateral group was more asymmetric than CG. For main effects of medication, only unipedal adapted standing presented effects of PD medication. There was PD groups×medication interaction. Under the effects of medication, the unilateral group presented lower asymmetry of RMS in anterior-posterior direction and area than the bilateral group in unipedal adapted standing. In addition, the unilateral group presented lower asymmetry of mean velocity, RMS in anterior-posterior direction and area in unipedal standing and area in tandem adapted standing after a medication dose. Postural control asymmetry during challenging postural tasks was dependent on disease severity and medication state in people with PD. The bilateral group presented higher postural control asymmetry than the control and unilateral groups in challenging postural tasks. Finally, the medication dose was able to reduce postural control asymmetry in the unilateral group during challenging postural tasks. Copyright © 2015 Elsevier B.V. All rights reserved.

Comparison of posture among adolescent male volleyball players and non-athletes

PubMed Central

2014-01-01

Due to high training loads and frequently repeated unilateral exercises, several types of sports training can have an impact on the process of posture development in young athletes. The objective of the study was to assess and compare the postures of adolescent male volleyball players and their non-training peers. The study group comprised 104 volleyball players while the control group consisted of 114 non-training individuals aged 14-16 years. Body posture was assessed by the Moiré method. The volleyball players were significantly taller, and had greater body weight and fat-free mass. The analysis of posture relative to symmetry in the frontal and transverse planes did not show any significant differences between the volleyball players and non-athletes. Postural asymmetries were observed in both the volleyball players and the control participants. Lumbar lordosis was significantly less defined in the volleyball players compared to non-training individuals while no difference was observed in thoracic kyphosis. All athletes demonstrated a loss of lumbar lordosis and an increase in thoracic kyphosis. Significant differences in anteroposterior curvature of the spine between the volleyball players and the non-athletes might be associated with both training and body height. Considering the asymmetric spine overloads which frequently occur in sports training, meticulous posture assessment in young athletes seems well justified. PMID:25729154

Standing on a declining surface reduces transient prolonged standing induced low back pain development.

PubMed

Gallagher, Kaitlin M; Callaghan, Jack P

2016-09-01

While alternating standing position on a sloped surface has proven successful at reducing low back pain during standing, the purpose of this study was to evaluate standing solely on a declining surface to isolate the influence of the postural change. Seventeen participants performed two 75-min prolonged standing occupational simulations- level ground and declining surface. Fifty-three percent of participants (9/17) were categorized as pain developers during the level ground standing condition. For these same pain developers, their average maximum pain scores were 58% lower during sloped standing. All participants showed greater hip flexion, trunk-to-thigh angle flexion, and posterior translation of the trunk center of gravity when standing on the sloped surface. These postural changes could cause the muscles crossing the hip posteriorly to increase passive stiffness and assist with stabilizing the pelvis. This study stresses the importance of hip kinematics, not just lumbar spine posture, in reducing prolonged standing induced low back pain. Copyright © 2016 Elsevier Ltd. All rights reserved.

Universal and individual characteristics of postural sway during quiet standing in healthy young adults

PubMed Central

Yamamoto, Tomohisa; Smith, Charles E; Suzuki, Yasuyuki; Kiyono, Ken; Tanahashi, Takao; Sakoda, Saburo; Morasso, Pietro; Nomura, Taishin

2015-01-01

The time course of the center of pressure (CoP) during human quiet standing, corresponding to body sway, is a stochastic process, influenced by a variety of features of the underlying neuro-musculo-skeletal system, such as postural stability and flexibility. Due to complexity of the process, sway patterns have been characterized in an empirical way by a number of indices, such as sway size and mean sway velocity. Here, we describe a statistical approach with the aim of estimating “universal” indices, namely parameters that are independent of individual body characteristics and thus are not “hidden” by the presence of individual, daily, and circadian variations of sway; in this manner it is possible to characterize the common aspects of sway dynamics across healthy young adults, in the assumption that they might reflect underlying neural control during quiet standing. Such universal indices are identified by analyzing intra and inter-subject variability of various indices, after sorting out individual-specific indices that contribute to individual discriminations. It is shown that the universal indices characterize mainly slow components of sway, such as scaling exponents of power-law behavior at a low-frequency regime. On the other hand, most of the individual-specific indices contributing to the individual discriminations exhibit significant correlation with body parameters, and they can be associated with fast oscillatory components of sway. These results are consistent with a mechanistic hypothesis claiming that the slow and the fast components of sway are associated, respectively, with neural control and biomechanics, supporting our assumption that the universal characteristics of postural sway might represent neural control strategies during quiet standing. PMID:25780094

Total body composition estimated by standing-posture 8-electrode bioelectrical impedance analysis in male wrestlers.

PubMed

Cheng, M-F; Chen, Y-Y; Jang, T-R; Lin, W-L; Chen, J; Hsieh, K-C

2016-12-01

Standing-posture 8-electrode bioelectrical impedance analysis is a fast and practical method for evaluating body composition in clinical settings, which can be used to estimate percentage body fat (BF%) and skeletal muscle mass in a subject's total body and body segments. In this study, dual-energy X-ray absorptiometry (DXA) was used as a reference method for validating the standing 8-electrode bioelectrical impedance analysis device BC-418 (BIA 8 , Tanita Corp., Tokyo, Japan). Forty-eight Taiwanese male wrestlers aged from 17.9 to 22.3 years volunteered to participate in this study. The lean soft tissue (LST) and BF% in the total body and body segments were measured in each subject by the BIA 8 and DXA. The correlation coefficients between total body, arm, leg segments impedance index (BI, ht 2 /Z) and lean soft tissue mass measured from DXA were r = 0.902, 0.453, 0.885, respectively (p < 0.01). In addition, the total body and segmental LST estimated by the BIA 8 were highly correlated with the DXA data (r = 0.936, 0.466, 0.886, p < 0.01). The estimation of total body and segmental BF% measured by BIA 8 and DXA also showed a significant correlation (r > 0.820, p < 0.01). The estimated LST and BF% from BIA 8 in the total body and body segments were highly correlated with the DXA results, which indicated that the standing-posture 8-electrode bioelectrical impedance analysis may be used to derive reference measures of LST and BF% in Taiwanese male wrestlers.

Total body composition estimated by standing-posture 8-electrode bioelectrical impedance analysis in male wrestlers

PubMed Central

Cheng, M-F; Chen, Y-Y; Jang, T-R; Lin, W-L; Chen, J

2015-01-01

Standing-posture 8-electrode bioelectrical impedance analysis is a fast and practical method for evaluating body composition in clinical settings, which can be used to estimate percentage body fat (BF%) and skeletal muscle mass in a subject’s total body and body segments. In this study, dual-energy X-ray absorptiometry (DXA) was used as a reference method for validating the standing 8-electrode bioelectrical impedance analysis device BC-418 (BIA8, Tanita Corp., Tokyo, Japan). Forty-eight Taiwanese male wrestlers aged from 17.9 to 22.3 years volunteered to participate in this study. The lean soft tissue (LST) and BF% in the total body and body segments were measured in each subject by the BIA8 and DXA. The correlation coefficients between total body, arm, leg segments impedance index (BI, ht2/Z) and lean soft tissue mass measured from DXA were r = 0.902, 0.453, 0.885, respectively (p < 0.01). In addition, the total body and segmental LST estimated by the BIA8 were highly correlated with the DXA data (r = 0.936, 0.466, 0.886, p < 0.01). The estimation of total body and segmental BF% measured by BIA8 and DXA also showed a significant correlation (r > 0.820, p < 0.01). The estimated LST and BF% from BIA8 in the total body and body segments were highly correlated with the DXA results, which indicated that the standing-posture 8-electrode bioelectrical impedance analysis may be used to derive reference measures of LST and BF% in Taiwanese male wrestlers. PMID:28090145

A systematic review of posture and psychosocial factors as contributors to upper quadrant musculoskeletal pain in children and adolescents.

PubMed

Prins, Yolandi; Crous, Lynette; Louw, Q A

2008-01-01

Musculoskeletal pain has become a major symptomatic complaint among children and adolescents and is increasingly occurring at a younger age. This systematic review was done to evaluate the evidence for the contribution of posture and psychosocial factors to the development of upper quadrant musculoskeletal pain in children and adolescents. The review describes the measurement tools used to assess musculoskeletal pain, sitting posture, and psychosocial factors. Two independent reviewers searched seven databases for observational studies that included prospective and cross-sectional study designs. Ten studies were extracted and assessed by two reviewers using the Critical Appraisal Form-Quantitative Studies (Law et al, 1998). The studies measured upper quadrant musculoskeletal pain as an outcome measure. Five studies evaluated sitting posture and found an association between the duration of static sitting and upper quadrant musculoskeletal pain. Six studies measured psychosocial factors of which depression, stress, and psychosomatic symptoms were the factors most commonly found to influence the development of upper quadrant musculoskeletal pain. The eligible studies used different pain measurement tools and different measurement tools to assess sitting posture and psychosocial factors. This review concludes that the duration of sitting posture and psychosocial factors may influence the experience of musculoskeletal pain among children and adolescents.

A standing posture is associated with increased susceptibility to the sound-induced flash illusion in fall-prone older adults.

PubMed

Stapleton, John; Setti, Annalisa; Doheny, Emer P; Kenny, Rose Anne; Newell, Fiona N

2014-02-01

Recent research has provided evidence suggesting a link between inefficient processing of multisensory information and incidence of falling in older adults. Specifically, Setti et al. (Exp Brain Res 209:375-384, 2011) reported that older adults with a history of falling were more susceptible than their healthy, age-matched counterparts to the sound-induced flash illusion. Here, we investigated whether balance control in fall-prone older adults was directly associated with multisensory integration by testing susceptibility to the illusion under two postural conditions: sitting and standing. Whilst standing, fall-prone older adults had a greater body sway than the age-matched healthy older adults and their body sway increased when presented with the audio-visual illusory but not the audio-visual congruent conditions. We also found an increase in susceptibility to the sound-induced flash illusion during standing relative to sitting for fall-prone older adults only. Importantly, no performance differences were found across groups in either the unisensory or non-illusory multisensory conditions across the two postures. These results suggest an important link between multisensory integration and balance control in older adults and have important implications for understanding why some older adults are prone to falling.

Spinal postural training: Comparison of the postural and mobility effects of electrotherapy, exercise, biofeedback trainer in addition to postural education in university students.

PubMed

Çelenay, Şeyda Toprak; Kaya, Derya Özer; Özüdoğru, Anıl

2015-01-01

Spinal posture and mobility are significant for protecting spine. The aim was to compare effects of different postural training interventions on spinal posture and mobility. Ninety-six university students (ages: 18–25 years) were allocated into Electrical Stimulation (ES) (n = 24), Exercise (n = 24), Biofeedback Posture Trainer (Backtone) (n = 24), and Postural Education (n = 24, Controls) groups. All the groups got postural education. The interventions were carried out 3 days a week for 8 weeks. Spinal Mouse device (Idiag, Fehraltorf, Switzerland) was used to detect thoracic and lumbar curvatures and mobility (degrees) in standing and sitting positions. Paired Student’s t-test, one-way ANOVA, and pairwise post-hoc tests were used. ES decreased thoracic curvature, the exercise decreased thoracic and lumbar curvature and increased thoracic mobility in standing position between pre-post training (p < 0.05). Exercise and Backtone improved thoracic curvature in sitting (p <0.05). In Exercise Group, thoracic curvature decreased compared to Backtone and Education Groups, and thoracic mobility increased compared to all groups (p < 0.05). The exercise was effective and superior in improving thoracic and lumbar curves, and mobility among university students. ES decreased thoracic curve. Biofeedback posture trainer improved sitting posture. A prospective randomized controlled trial, Level 1.

Do older adults perceive postural constraints for reach estimation?

PubMed

Cordova, Alberto; Gabbard, Carl

2014-01-01

BACKGROUND/STUDY CONTEXT: Recent evidence indicates that older persons have difficulty mentally representing intended movements. Furthermore, in an estimation of reach paradigm using motor imagery, a form of mental representation, older persons significantly overestimated their ability compared with young adults. The authors tested the notion that older adults may also have difficulty perceiving the postural constraints associated with reach estimation. The authors compared young (Mage = 22 years) and older (Mage = 67) adults on reach estimation while seated and in a more postural demanding standing and leaning forward position. The expectation was a significant postural effect with the standing condition, as evidenced by reduced overestimation. Whereas there was no difference between groups in the seated condition (both overestimated), older adults underestimated whereas the younger group once again overestimated in the standing condition. From one perspective, these results show that older adults do perceive postural constraints in light of their own physical capabilities. That is, that group perceived greater postural demands with the standing posture and elected to program a more conservative strategy, resulting in underestimation.

Neural mechanisms and functional correlates of altered postural responses to perturbed standing balance with chronic low back pain

PubMed Central

Jacobs, Jesse V.; Roy, Carrie L.; Hitt, Juvena R.; Popov, Roman E.; Henry, Sharon M.

2016-01-01

This study sought to determine the effects of chronic low back pain (LBP) on the cortical evoked potentials, muscle activation, and kinematics of postural responses to perturbations of standing balance. Thirteen subjects with chronic, recurrent, non-specific LBP and 13 subjects without LBP participated. The subjects responded to unpredictably timed postural perturbations while standing on a platform that randomly rotated either “toes up” or “toes down”. Electroencephalography (EEG) was used to calculate the negative peak (N1) and subsequent positive peak (P2) amplitudes of the perturbation evoked cortical potentials. Passive-marker motion capture was used to calculate joint and center-of-mass (CoM) displacements. Surface electromyography was used to record muscle onset latencies. Questionnaires assessed pain, interference with activity, fear of activity, and pain catastrophizing. Results demonstrated that subjects with LBP exhibited significantly larger P2 potentials, delayed erector spinae, rectus abdominae, and external oblique onset latencies, as well as smaller trunk extension yet larger trunk flexion, knee flexion, and ankle dorsiflexion displacements compared to subjects without LBP. For the subjects with LBP, CoM displacements significantly and positively correlated with knee displacements as well as activity interference and fear scores. The P2 potentials significantly and negatively correlated with CoM displacements as well as activity interference, catastrophizing, and fear scores. These results demonstrate that people with LBP exhibit altered late-phase cortical processing of postural perturbations concomitant with altered kinematic and muscle responses, and these cortical and postural response characteristics correlate with each other as well as with clinical reports of pain-related fears and activity interference. PMID:27771534

Hemispheric specificity for proprioception: Postural control of standing following right or left hemisphere damage during ankle tendon vibration.

PubMed

Duclos, Noémie C; Maynard, Luc; Abbas, Djawad; Mesure, Serge

2015-11-02

Right brain damage (RBD) following stroke often causes significant postural instability. In standing (without vision), patients with RBD are more unstable than those with left brain damage (LBD). We hypothesised that this postural instability would relate to the cortical integration of proprioceptive afferents. The aim of this study was to use tendon vibration to investigate whether these changes were specific to the paretic or non-paretic limbs. 14 LBD, 12 RBD patients and 20 healthy subjects were included. Displacement of the Centre of Pressure (CoP) was recorded during quiet standing, then during 3 vibration conditions (80 Hz - 20s): paretic limb, non-paretic limb (left and right limbs for control subjects) and bilateral. Vibration was applied separately to the peroneal and Achilles tendons. Mean antero-posterior position of the CoP, variability and velocity were calculated before (4s), during and after (24s) vibration. For all parameters, the strongest perturbation was during Achilles vibrations. The Achilles non-paretic condition induced a larger backward displacement than the Achilles paretic condition. This condition caused specific behaviour on the velocity: the LBD group was perturbed at the onset of the vibrations, but gradually recovered their stability; the RBD group was significantly perturbed thereafter. After bilateral Achilles vibration, RBD patients required the most time to restore initial posture. The reduction in use of information from the paretic limb may be a central strategy to deal with risk-of-fall situations such as during Achilles vibration. The postural behaviour is profoundly altered by lesions of the right hemisphere when proprioception is perturbed. Copyright © 2015 Elsevier B.V. All rights reserved.

The variability of the force produced by the plantar flexor muscles does not associate with postural sway in older adults during upright standing.

PubMed

Barbosa, Roberto N; Silva, Nilson R S; Santos, Daniel P R; Moraes, Renato; Gomes, Matheus M

2018-05-31

The force variability of the plantar flexor muscles (PFM) appears to be directly related to the control of upright standing. Nevertheless, this association is still uncertain in older adults. This study aimed to evaluate the relationship between PFM force variability and postural sway in the upright standing in older women. Forty older women performed submaximal plantar flexion movements measured by force transducers coupled to an experimental chair. They performed this task during three sets of 20 s at 5% and 10% of their maximum voluntary isometric contraction with and without the aid of visual feedback of the force produced. The volunteers then stood barefoot, with eyes closed and feet parallel on a force platform, which allowed the measurement of the center of pressure displacement in the anteroposterior direction. The results did not indicate a significant association between force variability of the PFMs and postural sway in older women. It can be inferred that the force variability of the PFM does not play an important role in controlling the posture in this population, suggesting that other factors may influence the functioning of the postural control system in older adults. Copyright © 2018. Published by Elsevier B.V.

Postural effects on the noninvasive baselines of ventricular performance

NASA Technical Reports Server (NTRS)

Lance, V. Q.; Spodick, D. H.

1977-01-01

The effects of posture on time-based noninvasive measurements were determined utilizing the sequence supine-sitting-standing in a formal protocol in which observer biases were eliminated by blinding the measurement and calculation phases. Compared to the supine posture, the sitting and standing postures produced significant increases in heart rate, isovolumic contraction time, pre-ejection period and pre-ejection period/left-ventricular ejection time and significant decreases in ejection time and ejection time index. The response patterns are consistent with the hemodynamic correlates cited in the literature which show increased adrenergic activity and decreased venous return in the sitting and standing postures, the effect on venous return being dominant.

Influence of obesity on accurate and rapid arm movement performed from a standing posture.

PubMed

Berrigan, F; Simoneau, M; Tremblay, A; Hue, O; Teasdale, N

2006-12-01

Obesity yields a decreased postural stability. The potentially negative impact of obesity on the control of upper limb movements, however, has not been documented. This study sought to examine if obesity imposes an additional balance control constraint limiting the speed and accuracy with which an upper limb goal-directed movement performed from an upright standing position can be executed. Eight healthy lean subjects (body mass index (BMI) between 20.9 and 25.0 kg/m(2)) and nine healthy obese subjects (BMI between 30.5 and 48.6 kg/m(2)) pointed to a target located in front of them from an upright standing posture. The task was to aim at the target as fast and as precisely as possible after an auditory signal. The difficulty of the task was varied by using different target sizes (0.5, 1.0, 2.5 and 5.0 cm width). Hand movement time (MT) and velocity profiles were measured to quantify the aiming. Centre of pressure and segmental kinematics were analysed to document postural stability. When aiming, the forward centre of pressure (CP) displacement was greater for the obese group than for the normal BMI group (4.6 and 1.9 cm, respectively). For the obese group, a decrease in the target size was associated with an increase in backward CP displacement and CP peak speed whereas for the normal BMI group backward CP displacements and CP peak speed were about the same across all target sizes. Obese participants aimed at the target moving their whole body forward whereas the normal BMI subjects predominantly made an elbow extension and shoulder flexion. For both groups, MT increased with a decreasing target size. Compare to the normal BMI group, this effect was exacerbated for the obese group. For the two smallest targets, movements were on average 115 and 145 ms slower for the obese than for the normal BMI group suggesting that obesity added a balance constraint and limited the speed with which an accurate movement could be done. Obesity, because of its effects on the control

Point-of-care-testing of standing posture with Wii balance board and Microsoft Kinect during transcranial direct current stimulation: a feasibility study.

PubMed

Dutta, Arindam; Chugh, Sanjay; Banerjee, Alakananda; Dutta, Anirban

2014-01-01

Non-invasive brain stimulation (NIBS) is a promising tool for facilitating motor function. NIBS therapy in conjunction with training using postural feedback may facilitate physical rehabilitation following posture disorders (e.g., Pusher Syndrome). The objectives of this study were, 1) to develop a low-cost point-of-care-testing (POCT) system for standing posture, 2) to investigate the effects of anodal tDCS on functional reach tasks using the POCT system. Ten community-dwelling elderly (age >50 years) subjects evaluated the POCT system for standing posture during functional reach tasks where their balance score on Berg Balance Scale was compared with that from Center-of-Mass (CoM) - Center-of-Pressure (CoP) posturography. Then, in a single-blind, sham-controlled study, five healthy right-leg dominant subjects (age: 26.4 ± 5.3 yrs) were evaluated using the POCT system under two conditions - with anodal tDCS of primary motor representations of right tibialis anterior muscle and with sham tDCS. The maximum CoP-CoM lean-angle was found to be well correlated with the BBS score in the elderly subjects The anodal tDCS strongly (p = 0.0000) affected the maximum CoP excursions but not the return reaction time in healthy. It was concluded that the CoM-CoP lean-line could be used for posture feedback and monitoring during tDCS therapy in conjunction with balance training exercises.

[The significance of visual analyzer in controlling the standing posture in individuals with the spastic form of child cerebral paralysis while wearing "Adel" suit].

PubMed

Sologubov, E G; Iavorskii, A B; Kobrin, V I

1996-01-01

The paper discussed the results of stabilographic examination of the children suffered from the spastic form of child cerebral paralysis (CCP) treated by means of graded wearing of "Adel" suit which is a modification of the "Penguin" spacesuit. There has been studied the state of 30 children before treatment with the use of "Adel" suit and after the treatment as well as following the several courses of wearing the suit. Besides the patients, eleven healthy volunteer subjects (control group) were examined. There have been obtained the results pointing to the fact that in the healthy persons when they try to achieve the standing posture the leading role pertains to visual analyzer, at the same time, in the patients with spastic form of CCP the realization of standing posture depends upon the severity of the motor function disorders. When in the process of control stabilographic examination the patients suffered from spastic form of CCP demonstrate the significant role of the visual analyzer in achieving the standing posture, the use of the "Adel" suit is most desirable. The use of the "Adel" suit in the CCP patients with a decreased role of visual analyzer in achieving the standing pose as it was found under control examination enhances its significance in controlling the position of the center of gravity of the body.

Transfer of Dynamic Learning Across Postures

PubMed Central

Wolpert, Daniel M.

2009-01-01

When learning a difficult motor task, we often decompose the task so that the control of individual body segments is practiced in isolation. But on re-composition, the combined movements can result in novel and possibly complex internal forces between the body segments that were not experienced (or did not need to be compensated for) during isolated practice. Here we investigate whether dynamics learned in isolation by one part of the body can be used by other parts of the body to immediately predict and compensate for novel forces between body segments. Subjects reached to targets while holding the handle of a robotic, force-generating manipulandum. One group of subjects was initially exposed to the novel robot dynamics while seated and was then tested in a standing position. A second group was tested in the reverse order: standing then sitting. Both groups adapted their arm dynamics to the novel environment, and this movement learning transferred between seated and standing postures and vice versa. Both groups also generated anticipatory postural adjustments when standing and exposed to the force field for several trials. In the group that had learned the dynamics while seated, the appropriate postural adjustments were observed on the very first reach on standing. These results suggest that the CNS can immediately anticipate the effect of learned movement dynamics on a novel whole-body posture. The results support the existence of separate mappings for posture and movement, which encode similar dynamics but can be adapted independently. PMID:19710374

"Stand up straight": notes toward a history of posture.

PubMed

Gilman, Sander L

2014-03-01

The essay presents a set of interlinked claims about posture in modern culture. Over the past two centuries it has come to define a wide range of assumptions in the West from what makes human beings human (from Lamarck to Darwin and beyond) to the efficacy of the body in warfare (from Dutch drill manuals in the 17th century to German military medical studies of soldiers in the 19th century). Dance and sport both are forms of posture training in terms of their own claims. Posture separates 'primitive' from 'advanced' peoples and the 'ill' from the 'healthy.' Indeed an entire medical sub-specialty developed in which gymnastics defined and recuperated the body. But all of these claims were also part of a Western attempt to use posture (and the means of altering it) as the litmus test for the healthy modern body of the perfect citizen. Focusing on the centrality of posture in two oddly linked moments of modern thought--modern Zionist thought and Nationalism in early 20th century China--in terms of bodily reform, we show how "posture" brings all of the earlier debates together to reform the body.

Sequencing sit-to-stand and upright posture for mobility limitation assessment: determination of the timing of the task phases from force platform data.

PubMed

Mazzà, Claudia; Zok, Mounir; Della Croce, Ugo

2005-06-01

The identification of quantitative tools to assess an individual's mobility limitation is a complex and challenging task. Several motor tasks have been designated as potential indicators of mobility limitation. In this study, a multiple motor task obtained by sequencing sit-to-stand and upright posture was used. Algorithms based on data obtained exclusively from a single force platform were developed to detect the timing of the motor task phases (sit-to-stand, preparation to the upright posture and upright posture). To test these algorithms, an experimental protocol inducing predictable changes in the acquired signals was designed. Twenty-two young, able-bodied subjects performed the task in four different conditions: self-selected natural and high speed with feet kept together, and self-selected natural and high speed with feet pelvis-width apart. The proposed algorithms effectively detected the timing of the task phases, the duration of which was sensitive to the four different experimental conditions. As expected, the duration of the sit-to-stand was sensitive to the speed of the task and not to the foot position, while the duration of the preparation to the upright posture was sensitive to foot position but not to speed. In addition to providing a simple and effective description of the execution of the motor task, the correct timing of the studied multiple task could facilitate the accurate determination of variables descriptive of the single isolated phases, allowing for a more thorough description of the motor task and therefore could contribute to the development of effective quantitative functional evaluation tests.

Postural orientation and equilibrium processes associated with increased postural sway in autism spectrum disorder (ASD).

PubMed

Wang, Zheng; Hallac, Rami R; Conroy, Kaitlin C; White, Stormi P; Kane, Alex A; Collinsworth, Amy L; Sweeney, John A; Mosconi, Matthew W

2016-01-01

Increased postural sway has been repeatedly documented in children with autism spectrum disorder (ASD). Characterizing the control processes underlying this deficit, including postural orientation and equilibrium, may provide key insights into neurophysiological mechanisms associated with ASD. Postural orientation refers to children's ability to actively align their trunk and head with respect to their base of support, while postural equilibrium is an active process whereby children coordinate ankle dorsi-/plantar-flexion and hip abduction/adduction movements to stabilize their upper body. Dynamic engagement of each of these control processes is important for maintaining postural stability, though neither postural orientation nor equilibrium has been studied in ASD. Twenty-two children with ASD and 21 age and performance IQ-matched typically developing (TD) controls completed three standing tests. During static stance, participants were instructed to stand as still as possible. During dynamic stances, participants swayed at a comfortable speed and magnitude in either anterior-posterior (AP) or mediolateral (ML) directions. The center of pressure (COP) standard deviation and trajectory length were examined to determine if children with ASD showed increased postural sway. Postural orientation was assessed using a novel virtual time-to-contact (VTC) approach that characterized spatiotemporal dimensions of children's postural sway (i.e., body alignment) relative to their postural limitation boundary, defined as the maximum extent to which each child could sway in each direction. Postural equilibrium was quantified by evaluating the amount of shared or mutual information of COP time series measured along the AP and ML directions. Consistent with prior studies, children with ASD showed increased postural sway during both static and dynamic stances relative to TD children. In regard to postural orientation processes, children with ASD demonstrated reduced spatial

Comparison of Biodynamic Responses in Standing and Seated Human Bodies

NASA Astrophysics Data System (ADS)

MATSUMOTO, Y.; GRIFFIN, M. J.

2000-12-01

The dynamic responses of the human body in a standing position and in a sitting position have been compared. The apparent mass and transmissibilities to the head, six locations along the spine, and the pelvis were measured with eight male subjects exposed to vertical whole-body vibration. In both postures, the principal resonance in the apparent mass occurred in the range 5-6 Hz, with slightly higher frequencies and lower apparent mass in the standing posture. There was greater transmission of vertical vibration to the pelvis and the lower spine and greater relative motion within the lower spine in the standing posture than in the sitting posture at the principal resonance and at higher frequencies. Transmissibilities from the supporting surface (floor or seat) to the thoracic region had similar magnitudes for both standing and sitting subjects. The lumbar spine has less lordosis and may be more compressed and less flexible in the sitting posture than in the standing posture. This may have reduced the relative motions between lumbar vertebrae and both the supporting vibrating surface and the other vertebrae in the sitting posture. The characteristics of the vibration transmitted to the pelvis may have differed in the two postures due to different transmission paths. Increased forward rotation of the pelvis in the standing posture may have caused the differences in responses of the pelvis and the lower spine that were observed between the two postures.

The influence of age, anxiety and concern about falling on postural sway when standing at an elevated level.

PubMed

Sturnieks, Daina L; Delbaere, Kim; Brodie, Matthew A; Lord, Stephen R

2016-10-01

Psychological processes may influence balance and contribute to the risk of falls in older people. While a self-reported fear of falling is associated with increased postural sway, inducing fear using an elevated platform can lead to reduced sway, suggesting different underlying mechanisms whereby fear may influence balance control. This study examined changes in postural sway, muscle activity and physiological measures of arousal while standing on a 65cm elevated platform, compared to floor level, in young and older adults. The older adults were classified as fall concerned or not fall concerned based on the Falls Efficacy Scale-International and anxious or not anxious based on the Goldberg Anxiety Scale. Fall concern did not affect the physiological and sway response to the elevated platform. In response to the postural threat, the anxious participants increased their sway frequency (p=0.001) but did not reduce sway range (p=0.674). Conversely, non-anxious participants showed an adaptive tightening of balance control, effectively reducing sway range in the elevated condition (p<0.001). Generalised anxiety in older adults appears to differentially affect postural control strategies under threatening conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Cerebellar transcranial direct current stimulation improves adaptive postural control.

PubMed

Poortvliet, Peter; Hsieh, Billie; Cresswell, Andrew; Au, Jacky; Meinzer, Marcus

2018-01-01

Rehabilitation interventions contribute to recovery of impaired postural control, but it remains a priority to optimize their effectiveness. A promising strategy may involve transcranial direct current stimulation (tDCS) of brain areas involved in fine-tuning of motor adaptation. This study explored the effects of cerebellar tDCS (ctDCS) on postural recovery from disturbance by Achilles tendon vibration. Twenty-eight healthy volunteers participated in this sham-ctDCS controlled study. Standing blindfolded on a force platform, four trials were completed: 60 s quiet standing followed by 20 min active (anodal-tDCS, 1 mA, 20 min, N = 14) or sham-ctDCS (40 s, N = 14) tDCS; three quiet standing trials with 15 s of Achilles tendon vibration and 25 s of postural recovery. Postural steadiness was quantified as displacement, standard deviation and path derived from the center of pressure (COP). Baseline demographics and quiet standing postural steadiness, and backwards displacement during vibration were comparable between groups. However, active-tDCS significantly improved postural steadiness during vibration and reduced forward displacement and variability in COP derivatives during recovery. We demonstrate that ctDCS results in short-term improvement of postural adaptation in healthy individuals. Future studies need to investigate if multisession ctDCS combined with training or rehabilitation interventions can induce prolonged improvement of postural balance. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Standing postural reaction to visual and proprioceptive stimulation in chronic acquired demyelinating polyneuropathy.

PubMed

Provost, Clement P; Tasseel-Ponche, Sophie; Lozeron, Pierre; Piccinini, Giulia; Quintaine, Victorine; Arnulf, Bertrand; Kubis, Nathalie; Yelnik, Alain P

2018-02-28

To investigate the weight of visual and proprioceptive inputs, measured indirectly in standing position control, in patients with chronic acquired demyelinating polyneuropathy (CADP). Prospective case study. Twenty-five patients with CADP and 25 healthy controls. Posture was recorded on a double force platform. Stimulations were optokinetic (60°/s) for visual input and vibration (50 Hz) for proprioceptive input. Visual stimulation involved 4 tests (upward, downward, rightward and leftward) and proprioceptive stimulation 2 tests (triceps surae and tibialis anterior). A composite score, previously published and slightly modified, was used for the recorded postural signals from the different stimulations. Despite their sensitivity deficits, patients with CADP were more sensitive to proprioceptive stimuli than were healthy controls (mean composite score 13.9 ((standard deviation; SD) 4.8) vs 18.4 (SD 4.8), p = 0.002). As expected, they were also more sensitive to visual stimuli (mean composite score 10.5 (SD 8.7) vs 22.9 (SD 7.5), p <0.0001). These results encourage balance rehabilitation of patients with CADP, aimed at promoting the use of proprioceptive information, thereby reducing too-early development of visual compensation while proprioception is still available.

Standing Tall: The Benefits of Standing Devices

ERIC Educational Resources Information Center

Warner, Mark P.

2007-01-01

In the author's opinion as a pediatric physical therapist, with the exception of a wheelchair, there is no other piece of assistive technology that is more beneficial to children and adults with special needs than a standing device. Postural symmetry during standing and walking activities is extremely important for everyone. Very few children…

Assessment of postural balance function.

PubMed

Kostiukow, Anna; Rostkowska, Elzbieta; Samborski, Włodzimierz

2009-01-01

Postural balance is defined as the ability to stand unassisted without falling. Examination of the patient's postural balance function is a difficult diagnostic task. Most of the balance tests used in medicine provide incomplete information on this coordination ability of the human body. The aim of this study was to review methods of assessment of the patient's postural balance function, including various tests used in medical diagnostics centers.

Comparison of the postural and physiological effects of two dynamic workstations to conventional sitting and standing workstations.

PubMed

Botter, Juliane; Ellegast, Rolf P; Burford, Eva-Maria; Weber, Britta; Könemann, Reinier; Commissaris, Dianne A C M

2016-03-01

Increasing evidence is being found for the association of health risk factors with work-related physical inactivity. An increasing number of people are being exposed to this form of inactivity, and as a result, various interventions aimed at increasing physical activity during working hours are being developed. This study aims to investigate the differences in postural, muscular and physical activities resulting from two dynamic workstations, namely an elliptical trainer and a treadmill workstation, compared with a conventional sitting and standing workstation. Twelve participants completed five standardised office tasks in a laboratory setting at all workstations. No significant effect was found regarding changes in posture and the muscular activity was only significantly higher for the trapezius muscle (50th percentile: 8.1 %MVC) at the dynamic workstations. For the dynamic workstations, physical activity ranged from 4.0 to 14.9 × 10(-2) g, heart rate from 14.3 to 27.5 %HRR and energy expenditure from 1.8 to 3.1 METs. Practitioner Summary: Work-related physical inactivity is associated with health risk factors. In this study, physiological and postural effects of dynamic workstations were assessed in comparison to conventional workstations. No significant effects were found regarding changes in posture and muscular activity. Physical activity, heart rate and energy expenditure increased for the dynamic workstations.

Increased alertness, better than posture prioritization, explains dual-task performance in prosthesis users and controls under increasing postural and cognitive challenge.

PubMed

Howard, Charla L; Perry, Bonnie; Chow, John W; Wallace, Chris; Stokic, Dobrivoje S

2017-11-01

Sensorimotor impairments after limb amputation impose a threat to stability. Commonly described strategies for maintaining stability are the posture first strategy (prioritization of balance) and posture second strategy (prioritization of concurrent tasks). The existence of these strategies was examined in 13 below-knee prosthesis users and 15 controls during dual-task standing under increasing postural and cognitive challenge by evaluating path length, 95% sway area, and anterior-posterior and medial-lateral amplitudes of the center of pressure. The subjects stood on two force platforms under usual (hard surface/eyes open) and difficult (soft surface/eyes closed) conditions, first alone and while performing a cognitive task without and then with instruction on cognitive prioritization. During standing alone, sway was not significantly different between groups. After adding the cognitive task without prioritization instruction, prosthesis users increased sway more under the dual-task than single-task standing (p ≤ 0.028) during both usual and difficult conditions, favoring the posture second strategy. Controls, however, reduced dual-task sway under a greater postural challenge (p ≤ 0.017), suggesting the posture first strategy. With prioritization of the cognitive task, sway was unchanged or reduced in prosthesis users, suggesting departure from the posture second strategy, whereas controls maintained the posture first strategy. Individual analysis of dual tasking revealed that greater postural demand in controls and greater cognitive challenge in prosthesis users led to both reduced sway and improved cognitive performance, suggesting cognitive-motor facilitation. Thus, activation of additional resources through increased alertness, rather than posture prioritization, may explain dual-task performance in both prosthesis users and controls under increasing postural and cognitive challenge.

Distal Lower-Extremity Pain and Work Postures in the Quebec Population

PubMed Central

Messing, Karen; Tissot, France; Stock, Susan

2008-01-01

Objectives. Standing at work has been associated with discomfort and cardiovascular symptoms. Because standing postures vary in duration, mobility, and constraint, we explored associations between specific postures and pain in the lower extremities. Methods. We used multiple logistic regression to analyze associations between work factors and pain in the lower extremities during the previous 12 months that interfered with usual activities. We used data from among 7757 workers who were interviewed in the 1998 Quebec Health and Social Survey. Results. Among all respondents, 9.4% reported significant ankle or foot pain, and 6.4% had lower-leg or calf pain. Significantly more women than men had pain at both sites. Both leg or calf and ankle or foot pain were strongly associated with standing postures, whole-body vibration, psychological distress, female gender, and being aged 50 years or older. Constrained standing postures were associated with increased ankle or foot pain for both men and women and with leg or calf pain for women, compared with standing with freedom to sit at will. Conclusions. Freedom to sit at work may prevent lower-extremity pain. The effects of specific sitting and standing postures on cartilage, muscle, and the cardiovascular system may help explain discomfort in the lower extremities. PMID:17761561

Postural asymmetries in young adults with cerebral palsy

PubMed Central

Rodby-Bousquet, Elisabet; Czuba, Tomasz; Hägglund, Gunnar; Westbom, Lena

2013-01-01

Aim The purpose was to describe posture, ability to change position, and association between posture and contractures, hip dislocation, scoliosis, and pain in young adults with cerebral palsy (CP). Methods Cross-sectional data of 102 people (63 males, 39 females; age range 19–23y, median 21y) out of a total population with CP was analysed in relation to Gross Motor Function Classification System (GMFCS) levels I (n=38), II (n=21), III (n=13), IV (n=10), and V (n=20). The CP subtypes were unilateral spastic (n=26), bilateral spastic (n=45), ataxic (n=12), and dyskinetic CP (n=19). The Postural Ability Scale was used to assess posture. The relationship between posture and joint range of motion, hip dislocation, scoliosis, and pain was analysed using logistic regression and Spearman’s correlation. Results At GMFCS levels I to II, head and trunk asymmetries were most common; at GMFCS levels III to V postural asymmetries varied with position. The odds ratios (OR) for severe postural asymmetries were significantly higher for those with scoliosis (OR=33 sitting), limited hip extension (OR=39 supine), or limited knee extension (OR=37 standing). Postural asymmetries correlated to hip dislocations: supine (rs=0.48), sitting (rs=0.40), standing (rs=0.41), and inability to change position: supine (rs=0.60), sitting (rs=0.73), and standing (rs=0.64). Conclusions Postural asymmetries were associated with scoliosis, hip dislocations, hip and knee contractures, and inability to change position. This article is commented on by Novak on page 974 of this issue. PMID:23834239

Experimental muscle pain challenges the postural stability during quiet stance and unexpected posture perturbation.

PubMed

Hirata, Rogério Pessoto; Ervilha, Ulysses Fernandes; Arendt-Nielsen, Lars; Graven-Nielsen, Thomas

2011-08-01

Musculoskeletal pain impairs postural control and stability. Nine subjects stood as quietly as possible on a moveable force platform before, during, and after experimental pain in the right leg muscles. A moveable force platform was used to measure the center of pressure and provided unexpected perturbations. Lower limb muscle activity, joint angles, and foot pressure distributions were measured. Hypertonic saline was used to induce pain in the vastus lateralis, vastus medialis, or biceps femoris muscle of the right leg. Compared to baseline and control sessions, pain in the knee extensor muscles during quiet standing evoked: 1) larger sway area, greater medial-lateral center of pressure displacement and higher speed (P < .05); 2) increased sway displacement in the anterior-posterior direction (P < .05); and 3) increased electromyography (EMG) activity for left tibialis anterior and left erector spinae muscles (P < .05). Pain provoked longer time to return to an equilibrium posture after forward EMG activity for, and pain in vastus medialis muscle decreased the time for the maximum hip flexion during this perturbation (P < .05). These results show that muscle pain impairs postural stability during quiet standing and after unexpected perturbation, which suggest that people suffering from leg muscle pain are more vulnerable to falls. This article presents the acute responses to leg muscle pain on the postural control. This measure could potentially help clinicians who seek to assess how pain responses may contribute to patient's postural control and stability during quiet standing and after recovering from unexpected perturbations. Copyright © 2011 American Pain Society. Published by Elsevier Inc. All rights reserved.

Quantifying and Reducing Posture-Dependent Distortion in Ballistocardiogram Measurements

PubMed Central

Javaid, Abdul Q.; Wiens, Andrew D.; Fesmire, N. Forrest; Weitnauer, Mary A.; Inan, Omer T.

2015-01-01

Ballistocardiography is a non-invasive measurement of the mechanical movement of the body caused by cardiac ejection of blood. Recent studies have demonstrated that ballistocardiogram (BCG) signals can be measured using a modified home weighing scale, and used to track changes in myocardial contractility and cardiac output. With this approach, the BCG can potentially be used both for preventive screening and for chronic disease management applications. However, for achieving high signal quality, subjects are required to stand still on the scale in an upright position for the measurement; the effects of intentional (for user comfort) or unintentional (due to user error) modifications in the position or posture of the subject during the measurement have not been investigated in the existing literature. In this study, we quantified the effects of different standing and seated postures on the measured BCG signals, and on the most salient BCG-derived features compared to reference standard measurements (e.g., impedance cardiography). We determined that the standing upright posture led to the least distorted signals as hypothesized, and that the correlation between BCG-derived timing interval features (R-J interval) and the pre-ejection period, PEP (measured using ICG), decreased significantly with impaired posture or sitting position. We further implemented two novel approaches to improve the PEP estimates from other standing and sitting postures, using system identification and improved J-wave detection methods. These approaches can improve the usability of standing BCG measurements in unsupervised settings (i.e. the home), by improving the robustness to non-ideal posture, as well as enabling high quality seated BCG measurements. PMID:26058064

Spherical Lenses and Prisms Lead to Postural Instability in Both Dyslexic and Non Dyslexic Adolescents

PubMed Central

Kapoula, Zoi; Gaertner, Chrystal; Matheron, Eric

2012-01-01

There is controversy as to whether dyslexic children present systematic postural deficiency. Clinicians use a combination of ophthalmic prisms and proprioceptive soles to improve postural performances. This study examines the effects of convergent prisms and spherical lenses on posture. Fourteen dyslexics (13–17 years-old) and 11 non dyslexics (13–16 years-old) participated in the study. Quiet stance posturography was performed with the TechnoConcept device while subjects fixated a target at eye-level from a distance of 1_m. Four conditions were run: normal viewing; viewing the target with spherical lenses of −1 diopter (ACCOM1) over each eye; viewing with −3 diopters over each eye (ACCOM3); viewing with a convergent prism of 8 diopters per eye. Relative to normal viewing, the −1 lenses increased the surface of body sway significantly whereas the −3 diopter lenses only resulted in a significant increase of antero-posterior body sway. Thus, adolescents would appear to cope more effectively with stronger conflicts rather than subtle ones. The prism condition resulted in a significant increase in both the surface and the antero-posterior body sway. Importantly, all of these effects were similar for the two groups. Wavelet analysis (time frequency domain) revealed high spectral power of antero-posterior sway for the prism condition in both groups. In the ACCOM3 condition, the spectral power of antero-posterior sway decreased for non dyslexics but increased for dyslexics suggesting that dyslexics encounter more difficulty with accommodation. The cancelling time for medium range frequency (believed to be controlled by the cerebellum), was shorter in dyslexics, suggesting fewer instances of optimal control. We conclude that dyslexics achieve similar postural performances albeit less efficiently. Prisms and lenses destabilize posture for all teenagers. Thus, contrary to adults, adolescents do not seem to use efferent, proprioceptive ocular motor signals to

Postural asymmetries in young adults with cerebral palsy.

PubMed

Rodby-Bousquet, Elisabet; Czuba, Tomasz; Hägglund, Gunnar; Westbom, Lena

2013-11-01

The purpose was to describe posture, ability to change position, and association between posture and contractures, hip dislocation, scoliosis, and pain in young adults with cerebral palsy (CP). Cross-sectional data of 102 people (63 males, 39 females; age range 19-23 y, median 21 y) out of a total population with CP was analysed in relation to Gross Motor Function Classification System (GMFCS) levels I (n=38), II (n=21), III (n=13), IV (n=10), and V (n=20). The CP subtypes were unilateral spastic (n=26), bilateral spastic (n=45), ataxic (n=12), and dyskinetic CP (n=19). The Postural Ability Scale was used to assess posture. The relationship between posture and joint range of motion, hip dislocation, scoliosis, and pain was analysed using logistic regression and Spearman's correlation. At GMFCS levels I to II, head and trunk asymmetries were most common; at GMFCS levels III to V postural asymmetries varied with position. The odds ratios (OR) for severe postural asymmetries were significantly higher for those with scoliosis (OR=33 sitting), limited hip extension (OR=39 supine), or limited knee extension (OR=37 standing). Postural asymmetries correlated to hip dislocations: supine (r(s) =0.48), sitting (r(s) =0.40), standing (r(s) =0.41), and inability to change position: supine (r(s) =0.60), sitting (r(s) =0.73), and standing (r(s) =0.64). Postural asymmetries were associated with scoliosis, hip dislocations, hip and knee contractures, and inability to change position. © 2013 The Authors. Developmental Medicine & Child Neurology published by John Wiley & Sons Ltd on behalf of Mac Keith Press.

Development of prolonged standing strain index to quantify risk levels of standing jobs.

PubMed

Halim, Isa; Omar, Abdul Rahman

2012-01-01

Many occupations in industry such as metal stamping workers, electronics parts assembly operators, automotive industry welders, and lathe operators require working in a standing posture for a long time. Prolonged standing can contribute to discomfort and muscle fatigue particularly in the back and legs. This study developed the prolonged standing strain index (PSSI) to quantify the risk levels caused by standing jobs, and proposed recommendations to minimize the risk levels. Risk factors associated with standing jobs, such as working posture, muscles activity, standing duration, holding time, whole-body vibration, and indoor air quality, were the basis for developing the PSSI. All risk factors were assigned multipliers, and the PSSI was the product of those multipliers. Recommendations for improvement are based on the PSSI; however, extensive studies are required to validate their effectiveness. multipliers, and the PSSI was the product of those multipliers. Recommendations for improvement are based on the PSSI; however, extensive studies are required to validate their effectiveness.

The influence of changes in trunk and pelvic posture during single leg standing on hip and thigh muscle activation in a pain free population.

PubMed

Prior, Simon; Mitchell, Tim; Whiteley, Rod; O'Sullivan, Peter; Williams, Benjamin K; Racinais, Sebastien; Farooq, Abdulaziz

2014-03-27

Thigh muscle injuries commonly occur during single leg loading tasks and patterns of muscle activation are thought to contribute to these injuries. The influence trunk and pelvis posture has on hip and thigh muscle activation during single leg stance is unknown and was investigated in a pain free population to determine if changes in body posture result in consistent patterns of changes in muscle activation. Hip and thigh muscle activation patterns were compared in 22 asymptomatic, male subjects (20-45 years old) in paired functionally relevant single leg standing test postures: Anterior vs. Posterior Trunk Sway; Anterior vs. Posterior Pelvic Rotation; Left vs. Right Trunk Shift; and Pelvic Drop vs. Raise. Surface EMG was collected from eight hip and thigh muscles calculating Root Mean Square. EMG was normalized to an "upright standing" reference posture. Repeated measures ANOVA was performed along with associated F tests to determine if there were significant differences in muscle activation between paired test postures. In right leg stance, Anterior Trunk Sway (compared to Posterior Sway) increased activity in posterior sagittal plane muscles, with a concurrent deactivation of anterior sagittal plane muscles (p: 0.016 - <0.001). Lateral hip abductor muscles increased activation during Left Trunk Shift (compared to Right) (p :≤ 0.001). Lateral Pelvic Drop (compared to Raise) decreased activity in hip abductors and increased hamstring, adductor longus and vastus lateralis activity (p: 0.037 - <0.001). Changes in both trunk and pelvic posture during single leg stance generally resulted in large, predictable changes in hip and thigh muscle activation in asymptomatic young males. Changes in trunk position in the sagittal plane and pelvis position in the frontal plane had the greatest effect on muscle activation. Investigation of these activation patterns in clinical populations such as hip and thigh muscle injuries may provide important insights into injury

Altered postural control strategies in quiet standing more than 20 years after rupture of the anterior cruciate ligament.

PubMed

Stensdotter, Ann-Katrin; Tengman, Eva; Häger, Charlotte

2016-05-01

To explore long-term consequences of anterior cruciate ligament (ACL) rupture on postural sway and control strategies during bilateral quiet standing, in subjects treated with or without reconstructive surgery compared to uninjured controls. 70 individuals who had unilateral ACL rupture 23±2.4 years ago (33 received ACL reconstructive surgery, ACLR, and 37 had physiotherapy only, ACLPT) and 33 uninjured matched controls (CTRL) (mean age 46±5.3) stood quietly with eyes closed for 3min on a firm and on a compliant surface, respectively. Center of pressure (CoP) was registered with a force plate and postural sway was calculated from center of mass (CoM) derived from 3D kinematics. Sway density (SD) analyses of CoP assessed distance and duration of stable phases. The torque controlling postural sway was estimated from CoP-CoM. Comparisons across conditions to CTRL revealed larger CoP-CoM-area in ACLR (p=0.017, CI: 10.95, 143.10), but not in ACLPT. Mean distance between SD-peaks was greater for ACLR (p<0.001, CI: 1.73, 5.31) than for ACLPT (p=0.006, CI: 0.56, 4.12) relative to CTRL. Duration of SD-peaks was smaller for both ACLR and ACLPT (p<0.001, CI: -4.04, -1.23 and -3.82, -1.03, respectively) compared to CTRL. CoM-area in the ACL-groups did not differ from CTRL. ACL-injured subjects demonstrated greater postural control efforts than CTRL but without significant differences in postural sway. Control efforts were thus not directly associated with sway and further research should be focused on variance in postural control strategies. Copyright © 2016. Published by Elsevier B.V.

Reaching to multiple targets when standing: the spatial organization of feedforward postural adjustments.

PubMed

Leonard, Julia A; Brown, Ryan H; Stapley, Paul J

2009-04-01

We examined the spatial organization of feedforward postural adjustments produced prior to and during voluntary arm reaching movements executed while standing. We sought to investigate whether the activity of postural muscles before and during reaching was directionally tuned and whether a strategy of horizontal force constraint could be observed. To this end, eight human subjects executed self-paced reach-to-point movements on the random illumination of one of 13 light targets placed within a 180 degrees array centered along the midline of the body. Analysis was divided into two periods: a first corresponding to the 250 ms preceding the onset of the reaching movements (termed pPA period) and a second 250-ms period immediately preceding target attainment (the aPA period). For both periods, electromyographic activity of the lower limb muscles revealed a clear directional tuning, with groups of muscles being activated for similar directions of reach. Analysis of horizontal ground reaction forces supported the existence of a force constraint strategy only for the pPA period, however, with those in the aPA period being more widely dispersed. We suggest that the strategy adopted for feedforward pPAs is one where the tuned muscle synergies constrain the forces diagonally away from the center of mass (CoM) to move it within the support base. However, the need to control for final finger and body position for each target during the aPA phase resulted in a distribution of vectors across reaching directions. Overall, our results would support the idea that endpoint limb force during postural tasks depends on the use of functional muscle synergies, which are used to displace the CoM or decelerate the body at the end of the reach.

Posture changes and subfoveal choroidal blood flow.

PubMed

Longo, Antonio; Geiser, Martial H; Riva, Charles E

2004-02-01

To evaluate the effect of posture change on subfoveal choroidal blood flow (ChBF) in normal volunteers. The pulsatile, nonpulsatile, and mean ChBF were measured with laser Doppler flowmetry in 11 healthy volunteers with a mean age of 32 +/- 13 (SD) years. The posture of the subjects was changed from standing (90 degrees ), to supine (-8 degrees ), and back to standing, with a mechanically driven table. During the whole experimental procedure, ChBF and heart rate (HR) were continuously recorded. After 30 seconds in standing position, the subjects were tilted to supine during approximately 30 seconds. They remained in this position for approximately 2 minutes, after which they were tilted back to the standing position (recovery), where they remained for another approximately 2 minutes. Systemic brachial artery blood pressure (BP) was measured in the baseline, supine, and recovery positions. This procedure was repeated to measure the intraocular pressure (IOP) at the different postures. Mean BP did not change significantly throughout the experimental procedure. As the body was tilted from standing to supine, HR decreased by 16% (P < 0.0004), IOP increased by 29% (P < 0.001), and mean ChBF increased by 11% (P < 0.01). The increase in ChBF was primarily due to an increase in the nonpulsatile component of the blood velocity. Based on previously reported experimental data that indicate that the ocular perfusion pressure increases less than predicted by purely hydrostatic considerations when the body is tilted from the standing to the supine position, the observed increase in ChBF suggests a passive response of the choroidal circulation to the posture change.

Risk factors associated with structural postural changes in the spinal column of children and adolescents

PubMed Central

Sedrez, Juliana Adami; da Rosa, Maria Izabel Zaniratti; Noll, Matias; Medeiros, Fernanda da Silva; Candotti, Claudia Tarragô

2015-01-01

OBJECTIVE: To investigate the association between behavioral risk factors, specifically postural habits, with the presence of structural changes in the spinal column of children and adolescents. METHODS: 59 students were evaluated through the self-reporting Back Pain and Body Posture Evaluation Instrument and spinal panoramic radiographic examination. Spine curvatures were classified based on Cobb angles, as normal or altered in the saggital plane and as normal or scoliotic in the frontal plane. Data were analyzed using SPSS 18.0, based on descriptive statistics and chi-square association test (a=0,05). RESULTS: The prevalence of postural changes was 79.7% (n=47), of which 47.5% (n=28) showed frontal plane changes and 61% (n=36) sagital plane changes. Significant association was found between the presence of thoracic kyphosis and female gender, practice of physical exercises only once or twice a week, sleep time greater than 10 hours, inadequate postures when sitting on a seat and sitting down to write, and how school supplies are carried. Lumbar lordosis was associated with the inadequate way of carrying the school backpack (asymmetric); and scoliosis was associated wuth the practice of competitive sports and sleep time greater than 10 hours. CONCLUSIONS: Lifestyle may be associated with postural changes. It is important to develop health policies in order to reduce the prevalence of postural changes, by decreasing the associated risk factors. PMID:25623725

Comparison of conversion coefficients for equivalent dose in terms of air kerma for photons using a male adult voxel simulator in sitting and standing posture with geometry of irradiation antero-posterior

NASA Astrophysics Data System (ADS)

Galeano, D. C.; Cavalcante, F. R.; Carvalho, A. B.; Hunt, J.

2014-02-01

The dose conversion coefficient (DCC) is important to quantify and assess effective doses associated with medical, professional and public exposures. The calculation of DCCs using anthropomorphic simulators and radiation transport codes is justified since in-vivo measurement of effective dose is extremely difficult and not practical for occupational dosimetry. DCCs have been published by the ICRP using simulators in a standing posture, which is not always applicable to all exposure scenarios, providing an inaccurate dose estimation. The aim of this work was to calculate DCCs for equivalent dose in terms of air kerma (H/Kair) using the Visual Monte Carlo (VMC) code and the VOXTISS8 adult male voxel simulator in sitting and standing postures. In both postures, the simulator was irradiated by a plane source of monoenergetic photons in antero-posterior (AP) geometry. The photon energy ranged from 15 keV to 2 MeV. The DCCs for both postures were compared and the DCCs for the standing simulator were higher. For certain organs, the difference of DCCs were more significant, as in gonads (48% higher), bladder (16% higher) and colon (11% higher). As these organs are positioned in the abdominal region, the posture of the anthropomorphic simulator modifies the form in which the radiation is transported and how the energy is deposited. It was also noted that the average percentage difference of conversion coefficients was 33% for the bone marrow, 11% for the skin, 13% for the bone surface and 31% for the muscle. For other organs, the percentage difference of the DCCs for both postures was not relevant (less than 5%) due to no anatomical changes in the organs of the head, chest and upper abdomen. We can conclude that is important to obtain DCCs using different postures from those present in the scientific literature.

Automatic recognition of postural allocations.

PubMed

Sazonov, Edward; Krishnamurthy, Vidya; Makeyev, Oleksandr; Browning, Ray; Schutz, Yves; Hill, James

2007-01-01

A significant part of daily energy expenditure may be attributed to non-exercise activity thermogenesis and exercise activity thermogenesis. Automatic recognition of postural allocations such as standing or sitting can be used in behavioral modification programs aimed at minimizing static postures. In this paper we propose a shoe-based device and related pattern recognition methodology for recognition of postural allocations. Inexpensive technology allows implementation of this methodology as a part of footwear. The experimental results suggest high efficiency and reliability of the proposed approach.

Are automatic postural responses in patients with Parkinson's disease abnormal due to their stooped posture?

PubMed

Bloem, B R; Beckley, D J; van Dijk, J G

1999-02-01

Abnormal automatic postural responses are thought to contribute to balance impairment in Parkinson's disease. However, because postural responses are modifiable by stance, we have speculated that some postural abnormalities in patients with Parkinson's disease are secondary to their stooped stance. We have studied this assumption by assessing automatic postural responses in 30 healthy subjects who were instructed either to stand upright or to assume a typical parkinsonian posture. During both conditions, subjects received 20 serial 4 degrees 'toe-up' rotational perturbations from a supporting forceplate. We recorded short-latency (SL) and medium-latency (ML) responses from stretched gastrocnemius muscles and long-latency (LL) responses from shortened tibialis anterior muscles. We also assessed changes in the center of foot pressure (CFP) and the center of gravity (COG). The results were qualitatively compared to a previously described group of patients with Parkinson's disease who, under these circumstances, typically have large ML responses, small LL responses and insufficient voluntary postural corrections, accompanied by a slow rate of backward CFP displacement and an increased posterior COG displacement. The stooped posture resulted in unloading of medial gastrocnemius muscles and loading of tibialis anterior muscles. Onset latencies of stretch responses in gastrocnemius muscles were delayed in stooped subjects, but the onset of LL responses was markedly reduced. Amplitudes of both ML and LL responses were reduced in stooped subjects. Prestimulus COG and, to a lesser extent, CFP were shifted forwards in stooped subjects. Posterior COG displacement and the rate of backward CFP displacement were diminished in stooped subjects. Voluntary postural corrections were unchanged while standing stooped. These results indicate that some postural abnormalities of patients with Parkinson's disease (most notably the reduced LL responses) can be reproduced in healthy subjects

[Posture and aging. Current fundamental studies and management concepts].

PubMed

Mourey, F; Camus, A; Pfitzenmeyer, P

2000-02-19

FUNDAMENTAL IMPORTANCE OF POSTURE: In the elderly subject, preservation of posture is fundamental to maintaining functional independence. In recent years, there has been much progress in our understanding of the mechanisms underlying strategies used to control equilibrium in the upright position. Physiological aging, associated with diverse disease states, dangerously alters the postural function, particularly anticipated adjustments which allow an adaptation of posture to movement. CLINICAL ASSESSMENT OF POSTURE: Several tests have been developed to assess posture in the elderly subject, particularly the time it takes to start walking. We selected certain tests which can be used in everyday practice to predict falls: the stance test, the improved Romberg test, the "timed get up and go test", measurement of walking cadence, assessment of balance reactions, sitting-standing and standing-sitting movements and capacity to get up off the floor. PATIENT CARE: Elderly patients with equilibrium disorders can benefit from specific personalized rehabilitation protocols. Different techniques have been developed for multiple afferential stimulation, reprogramming postural strategies, and correcting for deficient motor automatisms.

Effects of posture on shear rates in human brachial and superficial femoral arteries

PubMed Central

Newcomer, S. C.; Sauder, C. L.; Kuipers, N. T.; Laughlin, M. H.; Ray, C. A.

2012-01-01

Shear rate is significantly lower in the superficial femoral compared with the brachial artery in the supine posture. The relative shear rates in these arteries of subjects in the upright posture (seated and/or standing) are unknown. The purpose of this investigation was to test the hypothesis that upright posture (seated and/or standing) would produce greater shear rates in the superficial femoral compared with the brachial artery. To test this hypothesis, Doppler ultrasound was used to measure mean blood velocity (MBV) and diameter in the brachial and superficial femoral arteries of 21 healthy subjects after being in the supine, seated, and standing postures for 10 min. MBV was significantly higher in the brachial compared with the superficial femoral artery during upright postures. Superficial femoral artery diameter was significantly larger than brachial artery diameter. However, posture had no significant effect on either brachial or superficial femoral artery diameter. The calculated shear rate was significantly greater in the brachial (73 ± 5, 91 ± 11, and 97 ± 13 s−1) compared with the superficial femoral (53 ± 4, 39 ± 77, and 44 ± 5 s−1) artery in the supine, seated, and standing postures, respectively. Contrary to our hypothesis, our current findings indicate that mean shear rate is lower in the superficial femoral compared with the brachial artery in the supine, seated, and standing postures. These findings of lower shear rates in the superficial femoral artery may be one mechanism for the higher propensity for atherosclerosis in the arteries of the leg than of the arm. PMID:18245564

The effect of anatomic variations of circle of Willis on cerebral blood distribution during posture change from supination to standing: a model study.

PubMed

Zhang, Chi; Li, Shuyu; Pu, Fang; Fan, Yubo; Li, Deyu

2014-01-01

The anatomic variation of Circle of Willis (CoW) has great impact on its compensatory capacity during stroke and cerebral ischemia. In the present study, a series of lumped parameter models were developed and used to simulate the effect of postural changes on the cerebral blood flow in ICA stenosis patients with different anatomic variants of the CoW. The results showed that the asymmetric distribution of cerebral blood flow caused by stenosis was attenuated in standing position in complete and half-complete CoW. However, in incomplete CoW, the decrease in blood flow in the ipsilateral cerebral arteries caused by unilateral ICA stenosis was dramatic in both supine and standing positions, a likely result of inadequate collateral circulation within the CoW. In conclusion, the anatomic variation of CoW plays a significant role in maintaining the balance of cerebral blood supply in patients with ICA stenosis, especially during postural change.

Voluntarily controlled but not merely observed visual feedback affects postural sway

PubMed Central

Asai, Tomohisa; Hiromitsu, Kentaro; Imamizu, Hiroshi

2018-01-01

Online stabilization of human standing posture utilizes multisensory afferences (e.g., vision). Whereas visual feedback of spontaneous postural sway can stabilize postural control especially when observers concentrate on their body and intend to minimize postural sway, the effect of intentional control of visual feedback on postural sway itself remains unclear. This study assessed quiet standing posture in healthy adults voluntarily controlling or merely observing visual feedback. The visual feedback (moving square) had either low or high gain and was either horizontally flipped or not. Participants in the voluntary-control group were instructed to minimize their postural sway while voluntarily controlling visual feedback, whereas those in the observation group were instructed to minimize their postural sway while merely observing visual feedback. As a result, magnified and flipped visual feedback increased postural sway only in the voluntary-control group. Furthermore, regardless of the instructions and feedback manipulations, the experienced sense of control over visual feedback positively correlated with the magnitude of postural sway. We suggest that voluntarily controlled, but not merely observed, visual feedback is incorporated into the feedback control system for posture and begins to affect postural sway. PMID:29682421

Challenging Postural Tasks Increase Asymmetry in Patients with Parkinson’s Disease

PubMed Central

Beretta, Victor Spiandor; Gobbi, Lilian Teresa Bucken; Lirani-Silva, Ellen; Simieli, Lucas; Orcioli-Silva, Diego; Barbieri, Fabio Augusto

2015-01-01

The unilateral predominance of Parkinson’s disease (PD) symptoms suggests that balance control could be asymmetrical during static tasks. Although studies have shown that balance control asymmetries exist in patients with PD, these analyses were performed using only simple bipedal standing tasks. Challenging postural tasks, such as unipedal or tandem standing, could exacerbate balance control asymmetries. To address this, we studied the impact of challenging standing tasks on postural control asymmetry in patients with PD. Twenty patients with PD and twenty neurologically healthy individuals (control group) participated in this study. Participants performed three 30s trials for each postural task: bipedal, tandem adapted and unipedal standing. The center of pressure parameter was calculated for both limbs in each of these conditions, and the asymmetry between limbs was assessed using the symmetric index. A significant effect of condition was observed, with unipedal standing and tandem standing showing greater asymmetry than bipedal standing for the mediolateral root mean square (RMS) and area of sway parameters, respectively. In addition, a group*condition interaction indicated that, only for patients with PD, the unipedal condition showed greater asymmetry in the mediolateral RMS and area of sway than the bipedal condition and the tandem condition showed greater asymmetry in the area of sway than the bipedal condition. Patients with PD exhibited greater asymmetry while performing tasks requiring postural control when compared to neurologically healthy individuals, especially for challenging tasks such as tandem and unipedal standing. PMID:26367032

Children's catching performance when the demands on the postural system is altered.

PubMed

Angelakopoulos, Georgios T; Tsorbatzoudis, Haralambos; Grouios, George

2014-07-01

In many dynamic interceptive actions performers need to integrate activity of manual and postural subsystems for successful performance. Groups of different skill level (poor and good catchers), (mean age = 9.1 and 9.4 respectively) were required to perform one-handed catches under different postural constraints: standing; standing in contact with a postural support aid by their side (PSAS) or to the left of their trunk (PSAF); Tandem; and sitting (control). Results revealed that, for poor catchers, the number of successful catches increased and grasp errors decreased significantly when sitting and with both postural aids in comparison with standing alone and Tandem conditions. Kinematic analyses showed that the postural aid devices reduced head sway in the anterior-posterior direction, while the PSAF reduced lateral head sway. The poor catchers' performance benefited from an enlarged support surface, and reduction of lateral sway. Good catchers performed successfully under all task constraints, signifying the existence of a functional relationship between postural and grasping subsystems during performance. The results are discussed in the frame of Bernstein's (1967) and Newell's (1986) theory.

Neck pain and postural balance among workers with high postural demands - a cross-sectional study

PubMed Central

2011-01-01

Background Neck pain is related to impaired postural balance among patients and is highly prevalent among workers with high postural demands, for example, cleaners. We therefore hypothesised, that cleaners with neck pain suffer from postural dysfunction. This cross-sectional study tested if cleaners with neck pain have an impaired postural balance compared with cleaners without neck pain. Methods Postural balance of 194 cleaners with (n = 85) and without (N = 109) neck pain was studied using three different tests. Success or failure to maintain the standing position for 30 s in unilateral stance was recorded. Participants were asked to stand on a force platform for 30 s in the Romberg position with eyes open and closed. The centre of pressure of the sway was calculated, and separated into a slow (rambling) and fast (trembling) component. Subsequently, the 95% confidence ellipse area (CEA) was calculated. Furthermore a perturbation test was performed. Results More cleaners with neck pain (81%) failed the unilateral stance compared with cleaners without neck pain (61%) (p < 0.01). However, the risk of failure in unilateral stance was statistically elevated in cleaners with concurrent neck/low back pain compared to cleaners without neck/low back pain (p < 0.01), whereas pain at only neck or only low back did not increase the risk. Impaired postural balance, measured as CEA (p < 0.01), rambling (p < 0.05) and trembling (p < 0.05) was observed among cleaners with neck pain in comparison with cleaners without neck pain in the Romberg position with eyes closed, but not with eyes open. Conclusions Postural balance is impaired among cleaners with neck pain and the current study suggests a particular role of the slow component of postural sway. Furthermore, the unilateral stance test is a simple test to illustrate functional impairment among cleaners with concurrent neck and low back pain. Trial registration ISRCTN96241850 PMID:21806796

Postural control system influences intrinsic alerting state.

PubMed

Barra, Julien; Auclair, Laurent; Charvillat, Agnès; Vidal, Manuel; Pérennou, Dominic

2015-03-01

Numerous studies using dual-task paradigms (postural and cognitive) have shown that postural control requires cognitive resources. However, the influence of postural control on attention components has never been directly addressed. Using the attention network test (ANT), which assesses specifically each of the 3 components of attention-alertness, orientation, and executive control-within a single paradigm, we investigated the effect of postural balance demand on these 3 components. Forty-two participants completed the ANT in 3 postural conditions: (a) supine, a very stable position; (b) sitting on a chair, an intermediate position; and (c) standing with feet lined up heel to toe, a very instable position known as the Romberg position. Our results revealed that the difficulty of postural control does modulate alerting in such a way that it improves with the level of instability of the position. Regarding the orienting and executive control components of attention, performance was not different when participants were standing upright or seated, whereas in the supine position, performance dropped. The strong and specific interaction between postural control and the alerting system suggests that these mechanisms may share parts of the underlying neural circuits. We discuss the possible implication of the locus coeruleus, known to be involved in both postural balance and alerting. Also, our findings concerning orienting and executive control systems suggest that supine posture could have a specific effect on cognitive activities. These effects are discussed in terms of particularities resulting from the supine position. PsycINFO Database Record (c) 2015 APA, all rights reserved.

Relationship between static foot posture and foot mobility

PubMed Central

2011-01-01

Background It is not uncommon for a person's foot posture and/or mobility to be assessed during a clinical examination. The exact relationship, however, between static posture and mobility is not known. Objective The purpose of this study was to determine the degree of association between static foot posture and mobility. Method The static foot posture and foot mobility of 203 healthy individuals was assessed and then analyzed to determine if low arched or "pronated" feet are more mobile than high arched or "supinated" feet. Results The study demonstrated that those individuals with a lower standing dorsal arch height and/or a wider standing midfoot width had greater mobility in their foot. In addition, those individuals with higher Foot Posture Index (FPI) values demonstrated greater mobility and those with lower FPI values demonstrated less mobility. Finally, the amount of foot mobility that an individual has can be predicted reasonably well using either a 3 or 4 variable linear regression model. Conclusions Because of the relationship between static foot posture and mobility, it is recommended that both be assessed as part of a comprehensive evaluation of a individual with foot problems. PMID:21244705

Improvement in Functioning and Psychological Distress in Adolescents With Postural Orthostatic Tachycardia Syndrome Following Interdisciplinary Treatment.

PubMed

Bruce, Barbara K; Harrison, Tracy E; Bee, Susan M; Luedtke, Connie A; Porter, Co-Burn J; Fischer, Philip R; Hayes, Sarah E; Allman, Daniel A; Ale, Chelsea M; Weiss, Karen E

2016-12-01

Significant functional impairment and psychological distress have been observed in adolescent patients with postural orthostatic tachycardia syndrome (POTS). Interdisciplinary rehabilitation programs have been shown to be beneficial in the treatment of chronic pain in adults and adolescents. Only preliminary data have examined interdisciplinary rehabilitation efforts in patients with POTS. This study evaluated the impact of an interdisciplinary rehabilitation program on the functional impairment and psychological distress in 33 adolescents diagnosed with POTS. Patients included in the study were adolescents ages 11 to 18 diagnosed with POTS. Measures completed at admission and discharge from the program included the Functional Disability Index, Center for Epidemiological Studies-Depression-Child scale, and the Pain Catastrophizing Scale for Children. After participation in the 3-week program, adolescents with POTS demonstrated a significant increase in overall functional ability and significant reductions in depression and catastrophizing.

Effects of Recipient Posture on Persuasion.

ERIC Educational Resources Information Center

Heesacker, Martin; Petty, Richard E.

Sixty-five female undergraduate students who were either standing or reclining listened to a tape-recorded counterattitudinal speech containing either strong or weak arguments. Their evaluations revealed a significant interaction between posture (standing or reclining) and quality of arguments (strong or weak) on a measure of attitude change.…

Lumbar Spine Alignment in Six Common Postures: An ROM Analysis With Implications for Deformity Correction.

PubMed

Hey, Hwee Weng Dennis; Lau, Eugene Tze-Chun; Tan, Kimberly-Anne; Lim, Joel L; Choong, Denise; Lau, Leok-Lim; Liu, Ka-Po G; Wong, Hee-Kit

2017-10-01

A cross-sectional study of prospectively collected data. To compare lumbar spine alignment in six common postures, and estimate loss in range of motion (ROM) relative to standing. Ideal position for fusion of lumbar spine remains unknown. Although surgical fusion is necessary for deformity correction and symptom relief, the final position in which the vertebrae are immobilized should provide maximum residual function. Data were collected prospectively from 70 patients with low back pain recruited over a year. All subjects had x-rays performed in slump sitting, forward bending, supine, half squatting, standing, and backward bending postures. ROM quantified in terms of sagittal global and segmental Cobb angles was measured from L1 to S1. Loss of ROM relative to standing was calculated for each posture. Analysis of variance and unpaired t tests were used to identify differences in alignment between postures. Slump sitting gives the greatest lumbar flexion followed by forward bending, and supine postures (P < 0.001). Backward bending produces greater lumbar extension than standing (P = 0.035). Half-squatting and standing postures were not significantly different (P = 0.938). For all postures, L4-5 and L5-S1 segments remained in lordosis, with L4-5 having greater ROM than L5-S1. L1-2 turns kyphotic in lying supine, L2-3 at forward bending, and L3-4 at slump sitting in the form of a "kyphosing cascade." Should the entire lumbar spine be fused in standing position from L1-S1, there would likely be a mean loss of 47.6° of lumbar flexion and 5.9° of lumbar extension. The present study demonstrates the extent of flexibility required of the lumbar spine in assuming various postures. It also enables comparison of the differences in degree of motion occurring in the lumbar spine, both across postures and across segments. Significant loss in ROM, particularly flexion, is anticipated with fusion modeled after the lordotic standing lumbar spine. 2.

Improved ambulation and speech production in an adolescent post-traumatic brain injury through a therapeutic intervention to increase postural control.

PubMed

Reinthal, Ann Karas; Mansour, Linda Moeller; Greenwald, Glenna

2004-01-01

This case study examined the effectiveness of a programme designed to improve anticipatory postural control in an adolescent over years 2 and 3 post-traumatic brain injury (TBI). It was hypothesized that her difficulty in walking and talking simultaneously was caused by excessive co-activation of extremity, trunk, and oral musculature during upright activities. The participant was treated weekly by physical and speech therapy. Treatment focussed on improving anticipatory postural control during gross motor activities in conjunction with oral-motor function. Initially, the participant walked using a walker at a speed of 23 cm s(-1). Two years later, she could walk without a device at 53 cm s(-1). Initial laryngoscopic examination showed minimal movement of the velum or pharyngeal walls; full movement was present after treatment. The measure of intelligibility improved from no single word intelligible utterances to 85% intelligible utterances after 2 years. The results suggest that less compensatory rigidification of oral musculature was needed to maintain an upright position against gravity as postural control improved. An adolescent 1-year post-TBI was followed as she underwent additional rehabilitation focussed on improving anticipatory postural control. The functional goal of simultaneously talking while walking was achieved through this intervention.

Standing orthostatic blood pressure measurements cannot be replaced by sitting measurements.

PubMed

Breeuwsma, Anna C; Hartog, Laura C; Kamper, Adriaan M; Groenier, Klaas H; Bilo, Henk Jg; Kleefstra, Nanne; Van Hateren, Kornelis Jj

2017-08-01

As many elderly patients are not able to stand for several minutes, sitting orthostatic blood pressure (BP) measurements are sometimes used as an alternative. We aimed to investigate the difference in BP response and orthostatic hypotension (OH) prevalence between the standard postural change to the sitting and the standing position in a cross-sectional observational study. BP was measured with a continuous BP measurement device during two postural changes, from supine to the sitting and from supine to the standing position. Linear mixed models were used to investigate the differences in changes (Δ) of systolic BP (SBP) and diastolic BP (DBP) between the two postural changes. The prevalence and the positive and negative proportions of agreement of OH were calculated of the two postural changes. One hundred and four patients with a mean age of 69 years were included. ΔSBP was significantly larger in the standing position compared with the sitting between 0 and 44 s. ΔDBP was significantly larger in the sitting position compared with the standing 75-224 s after postural change. The prevalence of OH was 66.3% (95% confidence interval (CI) 57.2, 75.4) in the standing position and 67.3% (95% CI 58.3, 76.3) in the sitting position. The positive proportion of agreement was 74.8% and the negative proportion of agreement was 49.3%. A clear difference was seen in BP response between the two postural changes. Although no significant difference in prevalence of OH was observed, the positive and negative proportion of agreement of the prevalence of OH were poor to moderate, which indicates a different outcome between both postural changes.

Effect of different head-neck-jaw postures on cervicocephalic kinesthetic sense.

PubMed

Zafar, H; Alghadir, A H; Iqbal, Z A

2017-12-01

To investigate the effect of different induced head-neck-jaw postures on head-neck relocation error among healthy subjects. 30 healthy adult male subjects participated in this study. Cervicocephalic kinesthetic sense was measured while standing, habitual sitting, habitual sitting with clenched jaw and habitual sitting with forward head posture during right rotation, left rotation, flexion and extension using kinesthetic sensibility test. Head-neck relocation error was least while standing, followed by habitual sitting, habitual sitting with forward head posture and habitual sitting with jaw clenched. However, there was no significant difference in error between different tested postures during all the movements. To the best of our knowledge, this is the first study to see the effect of different induced head-neck-jaw postures on head-neck position sense among healthy subjects. Assuming a posture for a short duration of time doesn't affect head-neck relocation error in normal healthy subjects.

Physiological complexity and system adaptability: evidence from postural control dynamics of older adults.

PubMed

Manor, Brad; Costa, Madalena D; Hu, Kun; Newton, Elizabeth; Starobinets, Olga; Kang, Hyun Gu; Peng, C K; Novak, Vera; Lipsitz, Lewis A

2010-12-01

The degree of multiscale complexity in human behavioral regulation, such as that required for postural control, appears to decrease with advanced aging or disease. To help delineate causes and functional consequences of complexity loss, we examined the effects of visual and somatosensory impairment on the complexity of postural sway during quiet standing and its relationship to postural adaptation to cognitive dual tasking. Participants of the MOBILIZE Boston Study were classified into mutually exclusive groups: controls [intact vision and foot somatosensation, n = 299, 76 ± 5 (SD) yr old], visual impairment only (<20/40 vision, n = 81, 77 ± 4 yr old), somatosensory impairment only (inability to perceive 5.07 monofilament on plantar halluxes, n = 48, 80 ± 5 yr old), and combined impairments (n = 25, 80 ± 4 yr old). Postural sway (i.e., center-of-pressure) dynamics were assessed during quiet standing and cognitive dual tasking, and a complexity index was quantified using multiscale entropy analysis. Postural sway speed and area, which did not correlate with complexity, were also computed. During quiet standing, the complexity index (mean ± SD) was highest in controls (9.5 ± 1.2) and successively lower in the visual (9.1 ± 1.1), somatosensory (8.6 ± 1.6), and combined (7.8 ± 1.3) impairment groups (P = 0.001). Dual tasking resulted in increased sway speed and area but reduced complexity (P < 0.01). Lower complexity during quiet standing correlated with greater absolute (R = -0.34, P = 0.002) and percent (R = -0.45, P < 0.001) increases in postural sway speed from quiet standing to dual-tasking conditions. Sensory impairments contributed to decreased postural sway complexity, which reflected reduced adaptive capacity of the postural control system. Relatively low baseline complexity may, therefore, indicate control systems that are more vulnerable to cognitive and other stressors.

Physiological complexity and system adaptability: evidence from postural control dynamics of older adults

PubMed Central

Costa, Madalena D.; Hu, Kun; Newton, Elizabeth; Starobinets, Olga; Kang, Hyun Gu; Peng, C. K.; Novak, Vera; Lipsitz, Lewis A.

2010-01-01

The degree of multiscale complexity in human behavioral regulation, such as that required for postural control, appears to decrease with advanced aging or disease. To help delineate causes and functional consequences of complexity loss, we examined the effects of visual and somatosensory impairment on the complexity of postural sway during quiet standing and its relationship to postural adaptation to cognitive dual tasking. Participants of the MOBILIZE Boston Study were classified into mutually exclusive groups: controls [intact vision and foot somatosensation, n = 299, 76 ± 5 (SD) yr old], visual impairment only (<20/40 vision, n = 81, 77 ± 4 yr old), somatosensory impairment only (inability to perceive 5.07 monofilament on plantar halluxes, n = 48, 80 ± 5 yr old), and combined impairments (n = 25, 80 ± 4 yr old). Postural sway (i.e., center-of-pressure) dynamics were assessed during quiet standing and cognitive dual tasking, and a complexity index was quantified using multiscale entropy analysis. Postural sway speed and area, which did not correlate with complexity, were also computed. During quiet standing, the complexity index (mean ± SD) was highest in controls (9.5 ± 1.2) and successively lower in the visual (9.1 ± 1.1), somatosensory (8.6 ± 1.6), and combined (7.8 ± 1.3) impairment groups (P = 0.001). Dual tasking resulted in increased sway speed and area but reduced complexity (P < 0.01). Lower complexity during quiet standing correlated with greater absolute (R = −0.34, P = 0.002) and percent (R = −0.45, P < 0.001) increases in postural sway speed from quiet standing to dual-tasking conditions. Sensory impairments contributed to decreased postural sway complexity, which reflected reduced adaptive capacity of the postural control system. Relatively low baseline complexity may, therefore, indicate control systems that are more vulnerable to cognitive and other stressors. PMID:20947715

Cardio-postural interactions and short-arm centrifugation.

NASA Astrophysics Data System (ADS)

Blaber, Andrew; Goswami, Nandu; Xu, Da; Laurin, Alexendre

INTRODUCTION: We are interested in mechanisms associated with orthostatic tolerance. In previous studies we have shown that postural muscles in the calf contribute to both posture and blood pressure regulation during orthostatic stress. In this study we investigated the relationship between cardiovascular and postural muscle control before, during and after short arm human centrifuge (SAHC) up to 2.2 G. METHODS: Eleven healthy young subjects (6 m, 5 f), with no history of cardiovascular disease, falls or orthostatic hypotension, participated. All were familiarized with the SAHC with 10 minutes at 1-G at the feet. Each subject was instrumented in the supine position on the SAHC for beat-to-beat ECG and blood pressure (Portapres derived SBP). Bilateral lower leg EMG was collected from four leg postural muscles: tibialis anterior, medial gastrocnemius, lateral gastrocnemius, and medial soleus. Transdermal differential recording of signals was performed using an 8-channel EMG system, (Myosystem 1200, Noraxon Inc., Arizona, USA). Postural sway data of the body COP was computed from the force and moment data collected with a force platform (Accusway, AMTI, MA, USA). Before and after SAHC, the subject stood on a force platform with their gaze fixed on a point at eye level, closed their eyes and stood quietly for 5 min. A final stand was conducted 30 min after centrifugation with supine rest in between. During clockwise centrifugation (10-min 1g and 10-min 2.2g at the foot) the subjects’ head was hooded and in the dark. The subject’s body was restrained into the rotation arm with a parachute harness and given additional body support with a foot-plate. ECG, EMG and BP data were collected throughout and centre of pressure trajectory (COP) collected during the stand test. Subjects were requested to relax and not to voluntarily contract the leg muscles; however, they were not to suppress contractions as they occurred involuntarily or by reflex. A Continuous Wavelet

Can smartwatches replace smartphones for posture tracking?

PubMed

Mortazavi, Bobak; Nemati, Ebrahim; VanderWall, Kristina; Flores-Rodriguez, Hector G; Cai, Jun Yu Jacinta; Lucier, Jessica; Naeim, Arash; Sarrafzadeh, Majid

2015-10-22

This paper introduces a human posture tracking platform to identify the human postures of sitting, standing or lying down, based on a smartwatch. This work develops such a system as a proof-of-concept study to investigate a smartwatch's ability to be used in future remote health monitoring systems and applications. This work validates the smartwatches' ability to track the posture of users accurately in a laboratory setting while reducing the sampling rate to potentially improve battery life, the first steps in verifying that such a system would work in future clinical settings. The algorithm developed classifies the transitions between three posture states of sitting, standing and lying down, by identifying these transition movements, as well as other movements that might be mistaken for these transitions. The system is trained and developed on a Samsung Galaxy Gear smartwatch, and the algorithm was validated through a leave-one-subject-out cross-validation of 20 subjects. The system can identify the appropriate transitions at only 10 Hz with an F-score of 0.930, indicating its ability to effectively replace smart phones, if needed.

Postural education and behavior among students in a city in southern Brazil: student postural education and behavior

PubMed Central

Fonseca, Cíntia Detsch; Cardoso dos Santos, Antônio; Candotti, Cláudia Tarragô; Noll, Matias; Luz, Anna Maria Hecker; Corso, Carlos Otávio

2015-01-01

[Purpose] The aim of the present study was to assess the knowledge of the spine and posture among adolescent female students and to determine if they had access to postural education in or outside school. [Subjects and Methods] This was an epidemiological survey of a representative sample of 495 female students aged 14 to 18 years attending a regular secondary school in São Leopoldo, RS, Brazil. Data were collected through a questionnaire. [Results] The results showed that 16.8% of teens did not know what a spine was, 8.3% had no knowledge of posture, and 61% reported receiving no posture education. Posture awareness was associated only with posture while using a computer, while having postural education class was not associated with any postural behavior. [Conclusion] The results showed that, although most students are familiar with the spine and posture, a sizable group is not, and over half had no postural education. These findings suggest that inclusion of postural education programs in schools should be encouraged in order to promote health and prevent diseases related to the spine. PMID:26504322

Postural education and behavior among students in a city in southern Brazil: student postural education and behavior.

PubMed

Fonseca, Cíntia Detsch; Cardoso Dos Santos, Antônio; Candotti, Cláudia Tarragô; Noll, Matias; Luz, Anna Maria Hecker; Corso, Carlos Otávio

2015-09-01

[Purpose] The aim of the present study was to assess the knowledge of the spine and posture among adolescent female students and to determine if they had access to postural education in or outside school. [Subjects and Methods] This was an epidemiological survey of a representative sample of 495 female students aged 14 to 18 years attending a regular secondary school in São Leopoldo, RS, Brazil. Data were collected through a questionnaire. [Results] The results showed that 16.8% of teens did not know what a spine was, 8.3% had no knowledge of posture, and 61% reported receiving no posture education. Posture awareness was associated only with posture while using a computer, while having postural education class was not associated with any postural behavior. [Conclusion] The results showed that, although most students are familiar with the spine and posture, a sizable group is not, and over half had no postural education. These findings suggest that inclusion of postural education programs in schools should be encouraged in order to promote health and prevent diseases related to the spine.

Comparison of postural sway depending on balance pad type

PubMed Central

Lee, DongGeon; Kim, HaNa; An, HyunJi; Jang, JiEun; Hong, SoungKyun; Jung, SunHye; Lee, Kyeongbong; Choi, Myong-Ryol; Lee, Kyung-Hee; Lee, GyuChang

2018-01-01

[Purpose] The purpose of the present study was to compare the postural sway of healthy adults standing on different types of balance pads. [Subjects and Methods] Nine healthy adults participated in this study. Postural body sway was measured while participants were standing on four different types of balance pads: Balance-pad Elite (BE), Aero-Step XL (AS), Dynair Ballkissen Senso (DBS), and Dynair Ballkissen XXL Meditation and Yoga (DBMY). A Wii Balance Board interfaced with Balancia software was used to measure postural body sway. [Results] In the sway velocity, sway path length, and sway area, no significant differences were found between baseline conditions (participants were standing on the floor with no balance pad) and the use of the BE or AS. However, significant increases in all parameters were found comparing baseline conditions to the use of either Dynair balance pad. Furthermore, the use of either Dynair balance pad significantly increased postural sway compared to both the BE and the AS. [Conclusion] These findings suggest that the DBS and DBMY balance pads may serve as superior tools for providing unstable condition for balance training than the BE and the AS balance pads. PMID:29545688

Comparison of postural sway depending on balance pad type.

PubMed

Lee, DongGeon; Kim, HaNa; An, HyunJi; Jang, JiEun; Hong, SoungKyun; Jung, SunHye; Lee, Kyeongbong; Choi, Myong-Ryol; Lee, Kyung-Hee; Lee, GyuChang

2018-02-01

[Purpose] The purpose of the present study was to compare the postural sway of healthy adults standing on different types of balance pads. [Subjects and Methods] Nine healthy adults participated in this study. Postural body sway was measured while participants were standing on four different types of balance pads: Balance-pad Elite (BE), Aero-Step XL (AS), Dynair Ballkissen Senso (DBS), and Dynair Ballkissen XXL Meditation and Yoga (DBMY). A Wii Balance Board interfaced with Balancia software was used to measure postural body sway. [Results] In the sway velocity, sway path length, and sway area, no significant differences were found between baseline conditions (participants were standing on the floor with no balance pad) and the use of the BE or AS. However, significant increases in all parameters were found comparing baseline conditions to the use of either Dynair balance pad. Furthermore, the use of either Dynair balance pad significantly increased postural sway compared to both the BE and the AS. [Conclusion] These findings suggest that the DBS and DBMY balance pads may serve as superior tools for providing unstable condition for balance training than the BE and the AS balance pads.

Cybersickness without the wobble: Experimental results speak against postural instability theory.

PubMed

Dennison, Mark Stephen; D'Zmura, Michael

2017-01-01

It has been suggested that postural instability is necessary for cybersickness to occur. Seated and standing subjects used a head-mounted display to view a virtual tunnel that rotated about their line of sight. We found that the offset direction of perceived vertical settings matched the direction of the tunnel's rotation, so replicating earlier findings. Increasing rotation speed caused cybersickness to increase, but had no significant impact on perceived vertical settings. Postural sway during rotation was similar to postural sway during rest. While a minority of subjects exhibited postural sway in response to the onset of tunnel rotation, the majority did not. Furthermore, cybersickness increased with rotation speed similarly for the seated and standing conditions. Finally, subjects with greater levels of cybersickness exhibited less variation in postural sway. These results lead us to conclude that the link between postural instability and cybersickness is a weak one in the present experiment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of different head-neck-jaw postures on cervicocephalic kinesthetic sense

PubMed Central

Zafar, Hamayun; Alghadir, Ahmad H.; Iqbal, Zaheen A.

2017-01-01

Objectives: To investigate the effect of different induced head-neck-jaw postures on head-neck relocation error among healthy subjects. Methods: 30 healthy adult male subjects participated in this study. Cervicocephalic kinesthetic sense was measured while standing, habitual sitting, habitual sitting with clenched jaw and habitual sitting with forward head posture during right rotation, left rotation, flexion and extension using kinesthetic sensibility test. Results: Head-neck relocation error was least while standing, followed by habitual sitting, habitual sitting with forward head posture and habitual sitting with jaw clenched. However, there was no significant difference in error between different tested postures during all the movements. Conclusions: To the best of our knowledge, this is the first study to see the effect of different induced head-neck-jaw postures on head-neck position sense among healthy subjects. Assuming a posture for a short duration of time doesn’t affect head-neck relocation error in normal healthy subjects. PMID:29199196

Postural control is altered in patients with ankylosing spondylitis.

PubMed

Vergara, Martin E; O'Shea, Finbar D; Inman, Robert D; Gage, William H

2012-05-01

Ankylosing spondylitis is a chronic inflammatory disorder that can lead to increased axial and peripheral joint stiffness, impairing joint mobility. Impaired axial mobility due to vertebral ankylosis may result in changes in standing postural control. Little research has addressed changes in standing postural control in the ankylosing spondylitis population, nor how these issues might affect clinical understanding and treatment. Sixteen ankylosing spondylitis patients, and 17 healthy controls participated. Each individual completed two 120-second quiet standing trials with eyes open and eyes closed, while standing upon two force platforms. Net center of pressure displacement and mean power frequency in the frontal and sagittal planes were calculated. A Spearman's rank correlation analysis was performed between net center of pressure measures and several clinical measures of disease activity. Frontal plane net center of pressure displacement and frequency content, and sagittal plane net center of pressure displacement were significantly greater within the ankylosing spondylitis patient group. Ankylosing spondylitis patients demonstrated a significant increase in frontal plane net center of pressure displacement in the eyes-closed condition. Net center of pressure displacement and frequency were significantly correlated to the Bath Ankylosing Spondylitis Functional Index, and individual components of the Bath Ankylosing Spondylitis Metrology Index. Quiet standing postural control was altered particularly so in the frontal plane in patients with ankylosing spondylitis, which may be associated with increased fall risk. Posturographic measures of postural control may serve as valuable clinical tools for the monitoring of disease progression and disease status in ankylosing spondylitis. Copyright © 2011 Elsevier Ltd. All rights reserved.

Comparison of postural stability between injured and uninjured ballet dancers.

PubMed

Lin, Cheng-Feng; Lee, I-Jung; Liao, Jung-Hsien; Wu, Hong-Wen; Su, Fong-Chin

2011-06-01

Ballet movements require a limited base of support; thus, ballet dancers require a high level of postural control. However, postural stability in ballet dancers is still unclear and needs to be understood. To evaluate ballet dancers' postural stability in performing single-leg standing, the en pointe task, and the first and fifth positions and to determine differences in task performance among healthy nondancers, healthy dancers, and dancers with ankle sprains. Controlled laboratory study. Injured dancers, uninjured dancers, and nondancers were recruited for this study (N = 33 age-matched participants; n= 11 per group). The tasks tested were single-leg standing with eyes open and closed, first position, fifth position, and en pointe. Center of pressure parameters were calculated from the ground-reaction force collected with 1 force plate. Analysis of variance was used to assess the differences of center of pressure parameters among 3 groups in single-leg standing; independent t test was used to examine the differences of center of pressure parameters between injured and uninjured dancers. During single-leg standing, injured dancers had significantly greater maximum displacement in the medial-lateral direction and total trajectory of center of pressure, compared with the uninjured dancers and nondancers. During the first and fifth positions, the injured dancers demonstrated significantly greater standard deviation of center of pressure position in the medial-lateral and anterior-posterior directions, compared with the uninjured dancers. During en pointe, the injured dancers had significantly greater maximum displacement in the medial-lateral direction and the anterior-posterior direction, compared with the uninjured dancers. The injured and uninjured dancers demonstrated differences in postural stability in the medial-lateral direction during single-leg standing and the ballet postures. Although the injured dancers received ballet training, their postural stability

Active self-correction of spinal posture in pain-free women in response to the command "straighten your back".

PubMed

Barczyk-Pawelec, Katarzyna; Sipko, Tomasz

2017-10-01

Evidence is limited regarding the regional changes in spinal posture after self-correction. The aim of the present study was to evaluate whether active self-correction improved standing and sitting spinal posture. Photogrammetry was used to assess regional spinal curvatures and vertical global spine orientation (GSO) in 42 asymptotic women aged 20-24 years. Upper thoracic spine angle and GSO increased in response to self-correction, while the thoracolumbar and lumbosacral angles decreased. Self-correction in the standing position resulted in decreased inclination of the upper thoracic and thoracolumbar spinal angles. Correction of sitting posture reduced the angle of the upper thoracic spine and GSO. The effects of active self-correction on spinal curvature and GSO were different for the standing versus sitting position; the greatest effects of active correction were noted in the thoracic spine. Balanced and lordotic postures were most prevalent in the habitual and actively self-corrected standing positions, whereas the kyphotic posture was most prevalent in the habitual sitting position, indicative that self-correction back posture in the standing position could be an important health-related daily activity, especially during prolonged sitting.

Immediate Beneficial Effects of Mental Rotation Using Foot Stimuli on Upright Postural Stability in Healthy Participants

PubMed Central

Kawasaki, Tsubasa

2013-01-01

The present study was designed to investigate whether an intervention during which participants were involved in mental rotation (MR) of a foot stimulus would have immediate beneficial effects on postural stability (Experiment 1) and to confirm whether it was the involvement of MR of the foot, rather than simply viewing foot stimuli, that could improve postural stability (Experiment 2). Two different groups of participants (n = 16 in each group) performed MR intervention of foot stimuli in each of the two experiments. Pre- and postmeasurements of postural stability during unipedal and bipedal standing were made using a force plate for the intervention. Consistently, postural sway values for unipedal standing, but not for bipedal standing, were decreased immediately after the MR intervention using the foot stimuli. Such beneficial effects were not observed after the MR intervention using car stimuli (Experiment 1) or when participants observed the same foot stimuli during a simple reaction task (Experiment 2). These findings suggest that the MR intervention using the foot stimuli could contribute to improving postural stability, at least when it was measured immediately after the intervention, under a challenging standing condition (i.e., unipedal standing). PMID:24459588

Regional differences in lumbar spinal posture and the influence of low back pain

PubMed Central

Mitchell, Tim; O'Sullivan, Peter B; Burnett, Angus F; Straker, Leon; Smith, Anne

2008-01-01

Background Spinal posture is commonly a focus in the assessment and clinical management of low back pain (LBP) patients. However, the link between spinal posture and LBP is not fully understood. Recent evidence suggests that considering regional, rather than total lumbar spine posture is important. The purpose of this study was to determine; if there are regional differences in habitual lumbar spine posture and movement, and if these findings are influenced by LBP. Methods One hundred and seventy female undergraduate nursing students, with and without LBP, participated in this cross-sectional study. Lower lumbar (LLx), Upper lumbar (ULx) and total lumbar (TLx) spine angles were measured using an electromagnetic tracking system in static postures and across a range of functional tasks. Results Regional differences in lumbar posture and movement were found. Mean LLx posture did not correlate with ULx posture in sitting (r = 0.036, p = 0.638), but showed a moderate inverse correlation with ULx posture in usual standing (r = -0.505, p < 0.001). Regional differences in range of motion from reference postures in sitting and standing were evident. BMI accounted for regional differences found in all sitting and some standing measures. LBP was not associated with differences in regional lumbar spine angles or range of motion, with the exception of maximal backward bending range of motion (F = 5.18, p = 0.007). Conclusion This study supports the concept of regional differences within the lumbar spine during common postures and movements. Global lumbar spine kinematics do not reflect regional lumbar spine kinematics, which has implications for interpretation of measures of spinal posture, motion and loading. BMI influenced regional lumbar posture and movement, possibly representing adaptation due to load. PMID:19014712

Adolescents with Intellectual Disability Have Reduced Postural Balance and Muscle Performance in Trunk and Lower Limbs Compared to Peers without Intellectual Disability

ERIC Educational Resources Information Center

Blomqvist, Sven; Olsson, Josefine; Wallin, Louise; Wester, Anita; Rehn, Borje

2013-01-01

For adolescent people with ID, falls are more common compared to peers without ID. However, postural balance among this group is not thoroughly investigated. The aim of this study was to compare balance and muscle performance among adolescents aged between 16 and 20 years with a mild to moderate intellectual disability (ID) to age-matched…

Tai Chi training reduced coupling between respiration and postural control.

PubMed

Holmes, Matthew L; Manor, Brad; Hsieh, Wan-hsin; Hu, Kun; Lipsitz, Lewis A; Li, Li

2016-01-01

In order to maintain stable upright stance, the postural control system must account for the continuous perturbations to the body's center-of-mass including those caused by spontaneous respiration. Both aging and disease increase "posturo-respiratory synchronization;" which reflects the degree to which respiration affects postural sway fluctuations over time. Tai Chi training emphasizes the coordination of respiration and bodily movements and may therefore optimize the functional interaction between these two systems. The purpose of the project was to examine the effect of Tai Chi training on the interaction between respiration and postural control in older adults. We hypothesized that Tai Chi training would improve the ability of the postural control system to compensate for respiratory perturbations and thus, reduce posturo-respiratory synchronization. Participants were recruited from supportive housing facilities and randomized to a 12-week Tai Chi intervention (n=28; 86 ± 5 yrs) or educational-control program (n=34, 85 ± 6 yrs). Standing postural sway and respiration were simultaneously recorded with a force plate and respiratory belt under eyes-open and eyes-closed conditions. Posturo-respiratory synchronization was determined by quantifying the variation of the phase relationship between the dominant oscillatory mode of respiration and corresponding oscillations within postural sway. Groups were similar in age, gender distribution, height, body mass, and intervention compliance. Neither intervention altered average sway speed, sway magnitude or respiratory rate. As compared to the education-control group, however, Tai Chi training reduced posturo-respiratory synchronization when standing with eyes open or closed (p<0.001). Tai Chi training did not affect traditional parameters of standing postural control or respiration, yet reduced the coupling between respiration and postural control. The beneficial effects of Tai Chi training may therefore stem in part

Tai Chi training reduced coupling between respiration and postural control

PubMed Central

Holmes, Matthew L; Manor, Brad; Hsieh, Wan-hsin; Hu, Kun; Lipsitz, Lewis A; Li, Li

2015-01-01

In order to maintain stable upright stance, the postural control system must account for the continuous perturbations to the body’s center-of-mass including those caused by spontaneous respiration. Both aging and disease increase “posturo-respiratory synchronization;” which reflects the degree to which respiration affects postural sway fluctuations over time. Tai Chi training emphasizes the coordination of respiration and bodily movements and may therefore optimize the functional interaction between these two systems. The purpose of the project was to examine the effect of Tai Chi training on the interaction between respiration and postural control in older adults. We hypothesized that Tai Chi training would improve the ability of the postural control system to compensate for respiratory perturbations and thus, reduce posturo-respiratory synchronization. Participants were recruited from supportive housing facilities and randomized to a 12-week Tai Chi intervention (n=28; 86±5yrs) or educational-control program (n=34, 85±6yrs). Standing postural sway and respiration were simultaneously recorded with a force plate and respiratory belt under eyes-open and eyes-closed conditions. Posturo-respiratory synchronization was determined by quantifying the variation of the phase relationship between the dominant oscillatory mode of respiration and corresponding oscillations within postural sway. Groups were similar in age, gender distribution, height, body mass, and intervention compliance. Neither intervention altered average sway speed, sway magnitude or respiratory rate. As compared to the education-control group, however, Tai Chi training reduced posturo-respiratory synchronization when standing with eyes open or closed (p<0.001). Tai Chi training did not affect traditional parameters of standing postural control or respiration, yet reduced the coupling between respiration and postural control. The beneficial effects of Tai Chi training may therefore stem in part

Evaluating biomechanics of user-selected sitting and standing computer workstation.

PubMed

Lin, Michael Y; Barbir, Ana; Dennerlein, Jack T

2017-11-01

A standing computer workstation has now become a popular modern work place intervention to reduce sedentary behavior at work. However, user's interaction related to a standing computer workstation and its differences with a sitting workstation need to be understood to assist in developing recommendations for use and set up. The study compared the differences in upper extremity posture and muscle activity between user-selected sitting and standing workstation setups. Twenty participants (10 females, 10 males) volunteered for the study. 3-D posture, surface electromyography, and user-reported discomfort were measured while completing simulated tasks with each participant's self-selected workstation setups. Sitting computer workstation associated with more non-neutral shoulder postures and greater shoulder muscle activity, while standing computer workstation induced greater wrist adduction angle and greater extensor carpi radialis muscle activity. Sitting computer workstation also associated with greater shoulder abduction postural variation (90th-10th percentile) while standing computer workstation associated with greater variation for should rotation and wrist extension. Users reported similar overall discomfort levels within the first 10 min of work but had more than twice as much discomfort while standing than sitting after 45 min; with most discomfort reported in the low back for standing and shoulder for sitting. These different measures provide understanding in users' different interactions with sitting and standing and by alternating between the two configurations in short bouts may be a way of changing the loading pattern on the upper extremity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessment of postural instability in patients with Parkinson's disease.

PubMed

Błaszczyk, J W; Orawiec, R; Duda-Kłodowska, D; Opala, G

2007-10-01

Postural instability is one of the most disabling features of idiopathic Parkinson's disease (PD). In this study, we focused on postural instability as the main factor predisposing parkinsonians to falls. For this purpose, changes in sway characteristics during quiet stance due to visual feedback exclusion were studied. We searched for postural sway measures that could be potential discriminators for an increased fall risk. A group of 110 subjects: 55 parkinsonians (Hoehn and Yahr: 1-3), and 55 age-matched healthy volunteers participated in the experiment. Their spontaneous sway characteristics while standing quiet with eyes open and eyes closed were analyzed. We found that an increased mediolateral sway and sway area while standing with eyes closed are characteristic of parkinsonian postural instability and may serve to quantify well a tendency to fall. These sway indices significantly correlated with disease severity rated both by the Hoehn and Yahr scale as well as by the Motor Section of the UPDRS. A forward shift of a mean COP position in parkinsonians which reflects their flexed posture was also significantly greater to compare with the elderly subjects and exhibited a high sensitivity to visual conditions. Both groups of postural sway abnormalities identified here may be used as accessible and reliable measures which allow for quantitative assessment of postural instability in Parkinson's disease.

Do children perceive postural constraints when estimating reach or action planning?

PubMed

Gabbard, Carl; Cordova, Alberto; Lee, Sunghan

2009-03-01

Estimation of whether an object is reachable from a specific body position constitutes an important aspect in effective motor planning. Researchers who estimate reachability by way of motor imagery with adults consistently report the tendency to overestimate, with some evidence of a postural effect (postural stability hypothesis). This idea suggests that perceived reaching limits depend on an individual's perceived postural constraints. Based on previous work with adults, the authors expected a significant postural effect with the Reach 2 condition, as evidenced by reduced overestimation. Furthermore, the authors hypothesized that the postural effect would be greater in younger children. They then tested these propositions among children aged 7, 9, and 11 years by asking them to estimate reach while seated (Reach 1) and in the more demanding posture of standing on 1 foot and leaning forward (Reach 2). Results indicated no age or condition difference, therefore providing no support for a postural effect. When the authors compared these data to a published report of adults, a developmental difference emerged. That is, adults recognize the perceived postural constraint of the standing position resulting in under- rather than overestimation, as displayed in the seated condition. Although preliminary, these observations suggest that estimates of reach (action planning) continue to be refined between late childhood and young adulthood.

Static Postural Stability Is Normal in Dyslexic Children.

ERIC Educational Resources Information Center

Brown, Brian; And Others

1985-01-01

An experiment on 15 dyslexic and 23 carefully matched control subjects (10- to 12-year-old males), examining their ability to maintain standing posture with eyes open and closed and with standard and tandem foot placement, revealed no differences under any condition tested and no differences in use of visual information to maintain their posture.…

THE ELEMENTARY SCHOOL CHILD AND HIS POSTURE PATTERNS.

ERIC Educational Resources Information Center

DAVIES, EVELYN A.

A CHILD'S POSTURE PATTERNS MAY LEAD TO AN ADULT'S PHYSICAL HANDICAP. THE MAIN THEME OF THIS BOOK IS TO SERVE AS A GUIDE FOR THE ELEMENTARY TEACHER OR PARENT IN THE DETECTION AND UNDERSTANDING OF DEVIATIONS FROM THE NORMAL POSTURE PATTERNS WHILE THE CHILD IS SITTING, STANDING, OR MOVING ABOUT SO AS TO PREVENT FUTURE HANDICAPPING CONDITIONS.…

Childhood obesity affects postural control and aiming performance during an upper limb movement.

PubMed

Boucher, François; Handrigan, Grant A; Mackrous, Isabelle; Hue, Olivier

2015-07-01

Obesity reduces the efficiency of postural and movement control mechanisms. However, the effects of obesity on a functional motor task and postural control in standing and seated position have not been closely quantified among children. The aim of this study is to examine the effects of obesity on the execution of aiming tasks performed in standing and seated conditions in children. Twelve healthy weight children and eleven obese children aged between 8 and 11 years pointed to a target in standing and seated position. The difficulty of the aiming task was varied by using 2 target sizes (1.0 cm and 5.0 cm width; pointing to the smaller target size needs a more precise movement and constitutes a more difficult task). Hand movement time (MT) and its phases were measured to quantify the aiming task. Mean speed of the center of pressure displacement (COP speed) was calculated to assess postural stability during the movement. Obese children had significantly higher MTs compared to healthy-weight children in seated and standing conditions explained by greater durations of deceleration phase when aiming. Concerning the COP speed during the movement, obese children showed significantly higher values when standing compared to healthy-weight children. This was also observed in the seated position. In conclusion, obesity adds a postural constraint during an aiming task in both seated and standing conditions and requires obese children to take more time to correct their movements due to a greater postural instability of the body when pointing to a target with the upper-limb. Copyright © 2015 Elsevier B.V. All rights reserved.

Postural Stability is Altered by Blood Shift

NASA Astrophysics Data System (ADS)

Marais, M.; Denise, P.; Guincetre, J. Y.; Normand, H.

2008-06-01

Non-vestibular influences as shift in blood volume changed perception of body posture. Then, factors affecting blood shift may alter postural control. The purpose of our study was to investigate the effects of leg venous contention on postural stability. Twelve subjects were studied on a balance plate for 5 minutes with the eyes closed, in 3 conditions: with no leg venous contention or grade 1 and 3 support stockings. Standard deviation of x and y position was calculated before and after the closure of the eyes. Strong venous contention altered postural stability, after the eyes were closed, during the first 10 s of standing. As support stockings prevent blood shift induced by upright posture, this result is in line with the hypothesis that blood shifts influence the perception of body orientation and postural control among others factors as vision, vestibular inputs... This strong venous contention could induce an increase of fall.

Effect of alternating postures on cognitive performance for healthy people performing sedentary work.

PubMed

Schwartz, Bernhard; Kapellusch, Jay M; Schrempf, Andreas; Probst, Kathrin; Haller, Michael; Baca, Arnold

2018-06-01

Prolonged sitting is a risk factor for several diseases and the prevalence of worksite-based interventions such as sit-to-stand workstations is increasing. Although their impact on sedentary behaviour has been regularly investigated, the effect of working in alternating body postures on cognitive performance is unclear. To address this uncertainty, 45 students participated in a two-arm, randomised controlled cross-over trial under laboratory conditions. Subjects executed validated cognitive tests (working speed, reaction time, concentration performance) either in sitting or alternating working postures on two separate days (ClinicalTrials.gov Identifier: NCT02863731). MANOVA results showed no significant difference in cognitive performance between trials executed in alternating, standing or sitting postures. Perceived workload did not differ between sitting and alternating days. Repeated measures ANOVA revealed significant learning effects regarding concentration performance and working speed for both days. These results suggest that working posture did not affect cognitive performance in the short term. Practitioner Summary: Prior reports indicated health-related benefits based on alternated (sit/stand) body postures. Nevertheless, their effect on cognitive performance is unknown. This randomised controlled trial showed that working in alternating body postures did not influence reaction time, concentration performance, working speed or workload perception in the short term.

Fatigue does not conjointly alter postural and cognitive performance when standing in a shooting position under dual-task conditions.

PubMed

Bermejo, José Luis; García-Massó, Xavier; Paillard, Thierry; Noé, Frédéric

2018-02-01

This study investigated the effects of fatigue on balance control and cognitive performance in a standing shooting position. Nineteen soldiers were asked to stand while holding a rifle (single task - ST). They also had to perform this postural task while simultaneously completing a cognitive task (dual task - DT). Both the ST and DT were performed in pre- and post-fatigue conditions. In pre-fatigue, participants achieved better balance control in the DT than in the ST, thus suggesting that the increased cognitive activity associated with the DT improves balance control by shifting the attentional focus away from a highly automatised activity. In post-fatigue, balance control was degraded in both the ST and DT, while reaction time was enhanced in the first minutes following the fatiguing exercise without affecting the accuracy of response in the cognitive task, which highlights the relative independent effects of fatigue on balance control and cognitive performance.

Effects of sitting versus standing and scanner type on cashiers.

PubMed

Lehman, K R; Psihogios, J P; Meulenbroek, R G

2001-06-10

In the retail supermarket industry where cashiers perform repetitive, light manual material-handling tasks when scanning and handling products, reports of musculoskeletal disorders and discomfort are high. Ergonomics tradeoffs exist between sitting and standing postures, which are further confounded by the checkstand design and point-of-sale technology, such as the scanner. A laboratory experiment study was conducted to understand the effects of working position (sitting versus standing) and scanner type (bi-optic versus single window) on muscle activity, upper limb and spinal posture, and subjective preference of cashiers. Ten cashiers from a Dutch retailer participated in the study. Cashiers exhibited lower muscle activity in the neck and shoulders when standing and using a bi-optic scanner. Shoulder abduction was also less for standing conditions. In addition, all cashiers preferred using the bi-optic scanner with mixed preferences for sitting (n = 6) and standing (n = 4). Static loading of the muscles was relatively high compared with benchmarks, suggesting that during the task of scanning, cashiers may not have adequate recovery time to prevent fatigue. It is recommended that retailers integrate bi-optic scanners into standing checkstands to minimize postural stress, fatigue and discomfort in cashiers.

Posture-specific phantoms representing female and male adults in Monte Carlo-based simulations for radiological protection

NASA Astrophysics Data System (ADS)

Cassola, V. F.; Kramer, R.; Brayner, C.; Khoury, H. J.

2010-08-01

Does the posture of a patient have an effect on the organ and tissue absorbed doses caused by x-ray examinations? This study aims to find the answer to this question, based on Monte Carlo (MC) simulations of commonly performed x-ray examinations using adult phantoms modelled to represent humans in standing as well as in the supine posture. The recently published FASH (female adult mesh) and MASH (male adult mesh) phantoms have the standing posture. In a first step, both phantoms were updated with respect to their anatomy: glandular tissue was separated from adipose tissue in the breasts, visceral fat was separated from subcutaneous fat, cartilage was segmented in ears, nose and around the thyroid, and the mass of the right lung is now 15% greater than the left lung. The updated versions are called FASH2_sta and MASH2_sta (sta = standing). Taking into account the gravitational effects on organ position and fat distribution, supine versions of the FASH2 and the MASH2 phantoms have been developed in this study and called FASH2_sup and MASH2_sup. MC simulations of external whole-body exposure to monoenergetic photons and partial-body exposure to x-rays have been made with the standing and supine FASH2 and MASH2 phantoms. For external whole-body exposure for AP and PA projection with photon energies above 30 keV, the effective dose did not change by more than 5% when the posture changed from standing to supine or vice versa. Apart from that, the supine posture is quite rare in occupational radiation protection from whole-body exposure. However, in the x-ray diagnosis supine posture is frequently used for patients submitted to examinations. Changes of organ absorbed doses up to 60% were found for simulations of chest and abdomen radiographs if the posture changed from standing to supine or vice versa. A further increase of differences between posture-specific organ and tissue absorbed doses with increasing whole-body mass is to be expected.

Effect of intermittent feedback control on robustness of human-like postural control system

NASA Astrophysics Data System (ADS)

Tanabe, Hiroko; Fujii, Keisuke; Suzuki, Yasuyuki; Kouzaki, Motoki

2016-03-01

Humans have to acquire postural robustness to maintain stability against internal and external perturbations. Human standing has been recently modelled using an intermittent feedback control. However, the causality inside of the closed-loop postural control system associated with the neural control strategy is still unknown. Here, we examined the effect of intermittent feedback control on postural robustness and of changes in active/passive components on joint coordinative structure. We implemented computer simulation of a quadruple inverted pendulum that is mechanically close to human tiptoe standing. We simulated three pairs of joint viscoelasticity and three choices of neural control strategies for each joint: intermittent, continuous, or passive control. We examined postural robustness for each parameter set by analysing the region of active feedback gain. We found intermittent control at the hip joint was necessary for model stabilisation and model parameters affected the robustness of the pendulum. Joint sways of the pendulum model were partially smaller than or similar to those of experimental data. In conclusion, intermittent feedback control was necessary for the stabilisation of the quadruple inverted pendulum. Also, postural robustness of human-like multi-link standing would be achieved by both passive joint viscoelasticity and neural joint control strategies.

Effect of intermittent feedback control on robustness of human-like postural control system.

PubMed

Tanabe, Hiroko; Fujii, Keisuke; Suzuki, Yasuyuki; Kouzaki, Motoki

2016-03-02

Humans have to acquire postural robustness to maintain stability against internal and external perturbations. Human standing has been recently modelled using an intermittent feedback control. However, the causality inside of the closed-loop postural control system associated with the neural control strategy is still unknown. Here, we examined the effect of intermittent feedback control on postural robustness and of changes in active/passive components on joint coordinative structure. We implemented computer simulation of a quadruple inverted pendulum that is mechanically close to human tiptoe standing. We simulated three pairs of joint viscoelasticity and three choices of neural control strategies for each joint: intermittent, continuous, or passive control. We examined postural robustness for each parameter set by analysing the region of active feedback gain. We found intermittent control at the hip joint was necessary for model stabilisation and model parameters affected the robustness of the pendulum. Joint sways of the pendulum model were partially smaller than or similar to those of experimental data. In conclusion, intermittent feedback control was necessary for the stabilisation of the quadruple inverted pendulum. Also, postural robustness of human-like multi-link standing would be achieved by both passive joint viscoelasticity and neural joint control strategies.

Comparative shoulder kinematics during free standing, standing depression lifts and daily functional activities in persons with paraplegia: considerations for shoulder health.

PubMed

Riek, L M; Ludewig, P M; Nawoczenski, D A

2008-05-01

Case series; nonparametric repeated-measures analysis of variance. To compare and contrast three-dimensional shoulder kinematics during frequently utilized upper extremity weight-bearing activities (standing depression lifts used in brace walking, weight-relief raises, transfers) and postures (sitting rest, standing in a frame) in spinal cord injury (SCI). Movement Analysis Laboratory, Department of Physical Therapy, Ithaca College, Rochester, NY, USA. Three female and two male subjects (39.2+/-6.1 years old) at least 12 months post-SCI (14.6+/-6.7 years old), SCI distal to T2 and with an ASIA score of A. The Flock of Birds magnetic tracking device was used to measure three-dimensional positions of the scapula, humerus and thorax during various activities. Standing in a frame resulted in significantly less scapular anterior tilt (AT) and greater glenohumeral external rotation (GHER) than standing depression lifts and weight-relief raises. Standing frame posture offers the most favorable shoulder joint positions (less scapular AT and greater GHER) when compared to sitting rest posture, weight-relief raises, transfers and standing depression lifts. Knowledge of kinematic patterns associated with each activity is an essential first step to understanding the potential impact on shoulder health. Choosing specific activities or modifying techniques within functional activities that promote favorable shoulder positions may preserve long-term shoulder health.

A new method for sudden mechanical perturbation with axial load, to assess postural control in sitting and standing.

PubMed

Claus, Andrew P; Verrel, Julius; Pounds, Paul E I; Shaw, Renee C; Brady, Niamh; Chew, Min T; Dekkers, Thomas A; Hodges, Paul W

2016-05-03

Sudden application of load along a sagittal or coronal axis has been used to study trunk stiffness, but not axial (vertical) load. This study introduces a new method for sudden-release axial load perturbation. Prima facie validity was supported by comparison with standard mechanical systems. We report the response of the human body to axial perturbation in sitting and standing and within-day repeatability of measures. Load of 20% of body weight was released from light contact onto the shoulders of 22 healthy participants (10 males). Force input was measured via force transducers at shoulders, output via a force plate below the participant, and kinematics via 3-D motion capture. System identification was used to fit data from the time of load release to time of peak load-displacement, fitting with a 2nd-order mass-spring-damper system with a delay term. At peak load-displacement, the mean (SD) effective stiffness measured with this device for participants in sitting was 12.0(3.4)N/mm, and in standing was 13.3(4.2)N/mm. Peak force output exceeded input by 44.8 (10.0)% in sitting and by 30.4(7.9)% in standing. Intra-class correlation coefficients for within-day repeatability of axial stiffness were 0.58 (CI: -0.03 to 0.83) in sitting and 0.82(0.57-0.93) in standing. Despite greater degrees of freedom in standing than sitting, standing involved lesser time, downward displacement, peak output force and was more repeatable in defending upright postural control against the same axial loads. This method provides a foundation for future studies of neuromuscular control with axial perturbation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Inadequate interaction between open- and closed-loop postural control in phobic postural vertigo.

PubMed

Wuehr, M; Pradhan, C; Novozhilov, S; Krafczyk, S; Brandt, T; Jahn, K; Schniepp, R

2013-05-01

Phobic postural vertigo (PPV) is characterized by a subjective dizziness and postural imbalance. Changes in postural control strategy may cause the disturbed postural performance in PPV. A better understanding of the mechanisms behind this change in strategy is required to improve the diagnostic tools and therapeutic options for this prevalent disorder. Here we apply stabilogram diffusion analysis (SDA) to examine the characteristics and modes of interaction of open- and closed-loop processes that make up the postural control scheme in PPV. Twenty patients with PPV and 20 age-matched healthy controls were recorded on a stabilometer platform with eyes open and with eyes closed. Spatio-temporal changes of the center of pressure (CoP) displacement were analyzed by means of SDA and complementary CoP amplitude measures. (1) Open-loop control mechanisms in PPV were disturbed because of a higher diffusion activity (p < 0.001). (2) The interaction of open- and closed-loop processes was altered in that the sensory feedback threshold of the system was lowered (p = 0.010). These two changes were comparable to those observed in healthy subjects during more demanding balance conditions such as standing with eyes closed. These data indicate that subjective imbalance in PPV is associated with characteristic changes in the coordination of open- and closed-loop mechanisms of postural control. Patients with PPV use sensory feedback inadequately during undisturbed stance, and this impairs postural performance. These changes are compatible with higher levels of anti-gravity muscle activity and co-contraction during the conscious concentration on control of postural stability.

Evaluation of the lambda model for human postural control during ankle strategy.

PubMed

Micheau, Philippe; Kron, Aymeric; Bourassa, Paul

2003-09-01

An accurate modeling of human stance might be helpful in assessing postural deficit. The objective of this article is to validate a mathematical postural control model for quiet standing posture. The postural dynamics is modeled in the sagittal plane as an inverted pendulum with torque applied at the ankle joint. The torque control system is represented by the physiological lambda model. Two neurophysiological command variables of the central nervous system, designated lambda and micro, establish the dynamic threshold muscle at which motoneuron recruitment begins. Kinematic data and electromyographic signals were collected on four young males in order to measure small voluntary sway and quiet standing posture. Validation of the mathematical model was achieved through comparison of the experimental and simulated results. The mathematical model allows computation of the unmeasurable neurophysiological commands lambda and micro that control the equilibrium position and stability. Furthermore, with the model it is possible to conclude that low-amplitude body sway during quiet stance is commanded by the central nervous system.

The influence of the aquatic environment on the control of postural sway.

PubMed

Marinho-Buzelli, Andresa R; Rouhani, Hossein; Masani, Kei; Verrier, Mary C; Popovic, Milos R

2017-01-01

Balance training in the aquatic environment is often used in rehabilitation practice to improve static and dynamic balance. Although aquatic therapy is widely used in clinical practice, we still lack evidence on how immersion in water actually impacts postural control. We examined how postural sway measured using centre of pressure and trunk acceleration parameters are influenced by the aquatic environment along with the effects of visual information. Our results suggest that the aquatic environment increases postural instability, measured by the centre of pressure parameters in the time-domain. The mean velocity and area were more significantly affected when individuals stood with eyes closed in the aquatic environment. In addition, a more forward posture was assumed in water with eyes closed in comparison to standing on land. In water, the low frequencies of sway were more dominant compared to standing on dry land. Trunk acceleration differed in water and dry land only for the larger upper trunk acceleration in mediolateral direction during standing in water. This finding shows that the study participants potentially resorted to using their upper trunk to compensate for postural instability in mediolateral direction. Only the lower trunk seemed to change acceleration pattern in anteroposterior and mediolateral directions when the eyes were closed, and it did so depending on the environment conditions. The increased postural instability and the change in postural control strategies that the aquatic environment offers may be a beneficial stimulus for improving balance control. Copyright © 2016 Elsevier B.V. All rights reserved.

Nonlinear Variability of Body Sway in Patients with Phobic Postural Vertigo

PubMed Central

Schniepp, Roman; Wuehr, Max; Pradhan, Cauchy; Novozhilov, Sergej; Krafczyk, Siegbert; Brandt, Thomas; Jahn, Klaus

2013-01-01

Background: Subjective postural imbalance is a key symptom in the somatoform phobic postural vertigo (PPV). It has been assumed that more attentional control of body posture and / or co-contraction of leg muscles during standing is used to minimize the physiological body sway in PPV. Here we analyze nonlinear variability of body sway in patients with PPV in order to disclose changes in postural control strategy associated with PPV. Methods: Twenty patients with PPV and 20 age-matched healthy subjects (HS) were recorded on a stabilometer platform with eyes open (EO), eyes closed (EC), and while standing on a foam rubber with eyes closed (ECF). Spatio-temporal changes of the center of pressure (CoP) displacement were analyzed to assess the structure of postural variability by computing the scaling exponent α and the sample entropy (SEn) of the time series. Results: With EO on firm ground α and SEn of CoP displacement were significantly lower in patients (p < 0.001). For more difficult conditions (EC, ECF) postural variability in PPV assimilated to that of HS. Conclusion: Postural control in PPV patients differs from HS under normal stance condition. It is characterized by a reduced scaling behavior and higher regularity. These changes in the structure of postural variability might suggest an inappropriate attentional involvement with stabilizing strategies, which are used by HS only for more demanding balance tasks. PMID:23966974

Use of Postural Reconstruction® physiotherapy to treat an adolescent with asymmetric bilateral genu varum and idiopathic scoliosis.

PubMed

Destieux, C; Gaudreault, N; Isner-Horobeti, M E; Vautravers, P

2013-05-01

To document the effect of Postural Reconstruction® physiotherapy on two postural disorders commonly observed in adolescents: genu varum and idiopathic scoliosis. A case report on a 16-year-old boy suffering from knee pain and presenting with bilateral genu varum and mild scoliosis. At the initial evaluation (T0), the intercondylar space was 7 cm and the Cobb angles for the right lumbar curve and left thoracic curve were 18° and 13°, respectively. The boy was treated with Postural Reconstruction(®), a neuromuscular physiotherapy intervention using facilitation/inhibition techniques. The outcomes used to quantify the effect of 6 months (T1), 12 months (T2) and 26 months (T3) of treatment were pain levels, the intercondylar space, the lumbar gibbosity and the lumbar and thoracic Cobb angles. The knee pain disappeared rapidly. At T3, the intercondylar space had decreased by 4 cm, the lumbar gibbosity angle had decreased by 2° and the lumbar and thoracic Cobb angles had decreased by 8° and 7°, respectively. This non-invasive physiotherapy intervention appears to have considerable promise for the long-term correction of postural disorders. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

(De)stabilization of Required and Spontaneous Postural Dynamics with Learning

ERIC Educational Resources Information Center

Faugloire, Elise; Bardy, Benoit G.; Stoffregen, Thomas A.

2009-01-01

The present research examined how learning a new ankle-hip coordination influenced the preexisting postural repertoire. Standing participants learned a new ankle-hip coordination mode (relative phase of 90[degrees]). Before and after practice, postural patterns were evaluated in two different tasks. In the required task, specific ankle-hip…

Blood Pressure Associates with Standing Balance in Elderly Outpatients

PubMed Central

Pasma, Jantsje H.; Bijlsma, Astrid Y.; Klip, Janneke M.; Stijntjes, Marjon; Blauw, Gerard Jan; Muller, Majon; Meskers, Carel G. M.; Maier, Andrea B.

2014-01-01

Objectives Assessment of the association of blood pressure measurements in supine and standing position after a postural change, as a proxy for blood pressure regulation, with standing balance in a clinically relevant cohort of elderly, is of special interest as blood pressure may be important to identify patients at risk of having impaired standing balance in routine geriatric assessment. Materials and Methods In a cross-sectional cohort study, 197 community-dwelling elderly referred to a geriatric outpatient clinic of a middle-sized teaching hospital were included. Blood pressure was measured intermittently (n = 197) and continuously (subsample, n = 58) before and after a controlled postural change from supine to standing position. The ability to maintain standing balance was assessed during ten seconds of side-by-side, semi-tandem and tandem stance, with both eyes open and eyes closed. Self-reported impaired standing balance and history of falls were recorded by questionnaires. Logistic regression analyses were used to examine the association between blood pressure and 1) the ability to maintain standing balance; 2) self-reported impaired standing balance; and 3) history of falls, adjusted for age and sex. Results Blood pressure decrease after postural change, measured continuously, was associated with reduced ability to maintain standing balance in semi-tandem stance with eyes closed and with increased self-reported impaired standing balance and falls. Presence of orthostatic hypotension was associated with reduced ability to maintain standing balance in semi-tandem stance with eyes closed for both intermittent and continuous measurements and with increased self-reported impaired standing balance for continuous measurements. Conclusion Continuous blood pressure measurements are of additional value to identify patients at risk of having impaired standing balance and may therefore be useful in routine geriatric care. PMID:25222275

Back posture education in elementary schoolchildren: a 2-year follow-up study.

PubMed

Geldhof, Elisabeth; Cardon, Greet; De Bourdeaudhuij, Ilse; De Clercq, Dirk

2007-06-01

Within the scope of primary prevention regarding back functioning in children, research on the stability of intervention effects is indispensable. Along this line, the transition from childhood to adolescence is an important phase to evaluate the potential stability of intervention effects because of the typically mechanical and psychological demands related to adolescence. The main aim of the current study was to investigate the effects of a back education program at 2-year follow-up, in youngsters aged 13-14 years, on back posture knowledge, fear-avoidance beliefs and self-reported pain. An additional purpose was to evaluate which aspects of postural behavior were integrated in youngsters' lifestyles. At 2-year follow-up, the study sample included 94 secondary schoolchildren in the intervention group (mean age 13.3 +/- 0.8 years) and 101 controls (mean age 13.2 +/- 0.7 years). The back posture program that had been implemented for two school years consisted of back education and the stimulation of postural dynamism in the class through support and environmental changes. A questionnaire was completed comparable to the pretest, posttest and follow-up evaluations. The current study demonstrated at 2-year follow-up stability of the improved general (F = 1.590, ns) and specific (F = 0.049, ns) back posture knowledge in children who had received early back posture education. Back posture education did not result in increased fear-avoidance beliefs (F = 1.163, ns) or mounting back and/or neck pain reports (F = 0.001, ns). Based on self-reports for postural behavior, youngsters who had received the back posture program in the elementary school curriculum integrated crucial sitting and lifting principles conform to biomechanical favorable postural behavior. The steady intervention effects 2-year post-intervention demonstrated that intensive back posture education through the elementary school curriculum is effective till adolescence. Future research on the impact of early

Anatomy and histochemistry of hindlimb flight posture in birds. I. The extended hindlimb posture of shorebirds.

PubMed

McFarland, Joshua C; Meyers, Ron A

2008-08-01

Birds utilize one of two hindlimb postures during flight: an extended posture (with the hip and knee joints flexed, while the ankle joint is extended caudally) or a flexed posture (with the hip, knee, and ankle joints flexed beneath the body). American Avocets (Recurvirostra americana) and Black-necked Stilts (Himantopus mexicanus) extend their legs caudally during flight and support them for extended periods. Slow tonic and slow twitch muscle fibers are typically found in muscles functioning in postural support due to the fatigue resistance of these fibers. We hypothesized that a set of small muscles composed of high percentages of slow fibers and thus dedicated to postural support would function in securing the legs in the extended posture during flight. This study examined the anatomy and histochemical profile of eleven hindlimb muscles to gain insight into their functional roles during flight. Contrary to our hypothesis, all muscles possessed both fast twitch and slow twitch or slow tonic fibers. We believe this finding is due to the versatility of dynamic and postural functions the leg muscles must facilitate, including standing, walking, running, swimming, and hindlimb support during flight. Whether birds use an extended or flexed hindlimb flight posture may be related to the aerodynamic effect of leg position or may reflect evolutionary history. (c) 2008 Wiley-Liss, Inc.

Dynamic genetic linkage of intermediate blood pressure phenotypes during postural adaptations in a founder population

PubMed Central

Arenas, I. A.; Tremblay, J.; Deslauriers, B.; Sandoval, J.; Šeda, O.; Gaudet, D.; Merlo, E.; Kotchen, T.; Cowley, A. W.

2013-01-01

Blood pressure (BP) is a dynamic phenotype that varies rapidly to adjust to changing environmental conditions. Standing upright is a recent evolutionary trait, and genetic factors that influence postural adaptations may contribute to BP variability. We studied the effect of posture on the genetics of BP and intermediate BP phenotypes. We included 384 sib-pairs in 64 sib-ships from families ascertained by early-onset hypertension and dyslipidemia. Blood pressure, three hemodynamic and seven neuroendocrine intermediate BP phenotypes were measured with subjects lying supine and standing upright. The effect of posture on estimates of heritability and genetic covariance was investigated in full pedigrees. Linkage was conducted on 196 candidate genes by sib-pair analyses, and empirical estimates of significance were obtained. A permutation algorithm was implemented to study the postural effect on linkage. ADRA1A, APO, CAST, CORIN, CRHR1, EDNRB, FGF2, GC, GJA1, KCNB2, MMP3, NPY, NR3C2, PLN, TGFBR2, TNFRSF6, and TRHR showed evidence of linkage with any phenotype in the supine position and not upon standing, whereas AKR1B1, CD36, EDNRA, F5, MMP9, PKD2, PON1, PPARG, PPARGC1A, PRKCA, and RET were specifically linked to standing phenotypes. Genetic profiling was undertaken to show genetic interactions among intermediate BP phenotypes and genes specific to each posture. When investigators perform genetic studies exclusively on a single posture, important genetic components of BP are missed. Supine and standing BPs have distinct genetic signatures. Standardized maneuvers influence the results of genetic investigations into BP, thus reflecting its dynamic regulation. PMID:23269701

[Brief on the standardization of the practitioner's posture in acupuncture operation].

PubMed

Lu, Yonghui

2015-07-01

To discuss the standardization of the practitioner's posture in acupuncture operation. Based on the relevant discussion on 'way to holding needle' recorded in Lingshu (Miraculous Pivot) and in association with the clinical acupuncture practice, it was required to standardize the practitioner's posture in acupuncture operation in reference to Lingshu (Miraculous Pivot). The standard standing posture of the practitioner is the precondition of acupuncture operation; the standard holding needle with the puncture hand is the key to the exercise of acupuncture technique and the regular standing orientation is the need of acupuncture operation. The three aspects are complemented each other, which is the coordinative procedure in acupuncture operation and enable the practitioner's high concentration with the body, qi and mind involved.

Posture Allocation Revisited: Breaking the Sedentary Threshold of Energy Expenditure for Obesity Management

PubMed Central

Miles-Chan, Jennifer L.; Dulloo, Abdul G.

2017-01-01

There is increasing recognition that low-intensity physical activities of daily life play an important role in achieving energy balance and that their societal erosion through substitution with sedentary (mostly sitting) behaviors, whether occupational or for leisure, impact importantly on the obesity epidemic. This has generated considerable interest for better monitoring, characterizing, and promoting countermeasures to sedentariness through a plethora of low-level physical activities (e.g., active workstations, standing desks, sitting breaks), amid the contention that altering posture allocation (lying, sitting, standing) can modify energy expenditure to impact upon body weight regulation and health. In addressing this contention, this paper first revisits the past and more recent literature on postural energetics, with particular emphasis on potential determinants of the large inter-individual variability in the energy cost of standing and the impact of posture on fat oxidation. It subsequently analyses the available data pertaining to various strategies by which posture allocations, coupled with light physical activity, may increase energy expenditure beyond the sedentary threshold, and their relevance as potential targets for obesity management. PMID:28690547

Temporal parameter change of human postural control ability during upright swing using recursive least square method

NASA Astrophysics Data System (ADS)

Goto, Akifumi; Ishida, Mizuri; Sagawa, Koichi

2010-01-01

The purpose of this study is to derive quantitative assessment indicators of the human postural control ability. An inverted pendulum is applied to standing human body and is controlled by ankle joint torque according to PD control method in sagittal plane. Torque control parameters (KP: proportional gain, KD: derivative gain) and pole placements of postural control system are estimated with time from inclination angle variation using fixed trace method as recursive least square method. Eight young healthy volunteers are participated in the experiment, in which volunteers are asked to incline forward as far as and as fast as possible 10 times over 10 [s] stationary intervals with their neck joint, hip joint and knee joint fixed, and then return to initial upright posture. The inclination angle is measured by an optical motion capture system. Three conditions are introduced to simulate unstable standing posture; 1) eyes-opened posture for healthy condition, 2) eyes-closed posture for visual impaired and 3) one-legged posture for lower-extremity muscle weakness. The estimated parameters Kp, KD and pole placements are applied to multiple comparison test among all stability conditions. The test results indicate that Kp, KD and real pole reflect effect of lower-extremity muscle weakness and KD also represents effect of visual impairment. It is suggested that the proposed method is valid for quantitative assessment of standing postural control ability.

Multi-joint postural behavior in patients with knee osteoarthritis.

PubMed

Turcot, Katia; Sagawa, Yoshimasa; Hoffmeyer, Pierre; Suvà, Domizio; Armand, Stéphane

2015-12-01

Previous studies have demonstrated balance impairment in patients with knee osteoarthritis (OA). Although it is currently accepted that postural control depends on multi-joint coordination, no study has previously considered this postural strategy in patients suffering from knee OA. The objectives of this study were to investigate the multi-joint postural behavior in patients with knee OA and to evaluate the association with clinical outcomes. Eighty-seven patients with knee OA and twenty-five healthy elderly were recruited to the study. A motion analysis system and two force plates were used to investigate the joint kinematics (trunk and lower body segments), the lower body joint moments, the vertical ground reaction force ratio and the center of pressure (COP) during a quiet standing task. Pain, functional capacity and quality of life status were also recorded. Patients with symptomatic and severe knee OA adopt a more flexed posture at all joint levels in comparison with the control group. A significant difference in the mean ratio was found between groups, showing an asymmetric weight distribution in patients with knee OA. A significant decrease in the COP range in the anterior-posterior direction was also observed in the group of patients. Only small associations were observed between postural impairments and clinical outcomes. This study brings new insights regarding the postural behavior of patients with severe knee OA during a quiet standing task. The results confirm the multi-joint asymmetric posture adopted by this population. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of intermittent feedback control on robustness of human-like postural control system

PubMed Central

Tanabe, Hiroko; Fujii, Keisuke; Suzuki, Yasuyuki; Kouzaki, Motoki

2016-01-01

Humans have to acquire postural robustness to maintain stability against internal and external perturbations. Human standing has been recently modelled using an intermittent feedback control. However, the causality inside of the closed-loop postural control system associated with the neural control strategy is still unknown. Here, we examined the effect of intermittent feedback control on postural robustness and of changes in active/passive components on joint coordinative structure. We implemented computer simulation of a quadruple inverted pendulum that is mechanically close to human tiptoe standing. We simulated three pairs of joint viscoelasticity and three choices of neural control strategies for each joint: intermittent, continuous, or passive control. We examined postural robustness for each parameter set by analysing the region of active feedback gain. We found intermittent control at the hip joint was necessary for model stabilisation and model parameters affected the robustness of the pendulum. Joint sways of the pendulum model were partially smaller than or similar to those of experimental data. In conclusion, intermittent feedback control was necessary for the stabilisation of the quadruple inverted pendulum. Also, postural robustness of human-like multi-link standing would be achieved by both passive joint viscoelasticity and neural joint control strategies. PMID:26931281

Barnacle geese achieve significant energetic savings by changing posture.

PubMed

Tickle, Peter G; Nudds, Robert L; Codd, Jonathan R

2012-01-01

Here we report the resting metabolic rate in barnacle geese (Branta leucopsis) and provide evidence for the significant energetic effect of posture. Under laboratory conditions flow-through respirometry together with synchronous recording of behaviour enabled a calculation of how metabolic rate varies with posture. Our principal finding is that standing bipedally incurs a 25% increase in metabolic rate compared to birds sitting on the ground. In addition to the expected decrease in energy consumption of hindlimb postural muscles when sitting, we hypothesise that a change in breathing mechanics represents one potential mechanism for at least part of the observed difference in energetic cost. Due to the significant effect of posture, future studies of resting metabolic rates need to take into account and/or report differences in posture.

Dynamic postural control and associated attentional demands in contemporary dancers versus non-dancers

PubMed Central

Sirois-Leclerc, Geneviève; Remaud, Anthony

2017-01-01

Postural control is not a fully automatic process, but requires a certain level of attention, particularly as the difficulty of the postural task increases. This study aimed at testing whether experienced contemporary dancers, because of their specialized training involving the control of posture/balance, would present with a dual-task performance suggesting lesser attentional demands associated with dynamic postural control compared with non-dancers. Twenty dancers and 16 non-dancers performed a dynamic postural tracking task in both antero-posterior and side-to-side directions, while standing on a force platform. The postural task was performed, in turn, 1) as a stand-alone task, and concurrently with both 2) a simple reaction time task and 3) a choice reaction time task. Postural control performance was estimated through variables calculated from centre of pressure movements. Although no overall group difference was found in reaction time values, we found a better ability to control the side to side movements of the centre of pressure during the tracking task in dancers compared with non-dancers, which was dependent on the secondary task. This suggests that such increased ability is influenced by available attentional resources. PMID:28323843

Dynamic postural control and associated attentional demands in contemporary dancers versus non-dancers.

PubMed

Sirois-Leclerc, Geneviève; Remaud, Anthony; Bilodeau, Martin

2017-01-01

Postural control is not a fully automatic process, but requires a certain level of attention, particularly as the difficulty of the postural task increases. This study aimed at testing whether experienced contemporary dancers, because of their specialized training involving the control of posture/balance, would present with a dual-task performance suggesting lesser attentional demands associated with dynamic postural control compared with non-dancers. Twenty dancers and 16 non-dancers performed a dynamic postural tracking task in both antero-posterior and side-to-side directions, while standing on a force platform. The postural task was performed, in turn, 1) as a stand-alone task, and concurrently with both 2) a simple reaction time task and 3) a choice reaction time task. Postural control performance was estimated through variables calculated from centre of pressure movements. Although no overall group difference was found in reaction time values, we found a better ability to control the side to side movements of the centre of pressure during the tracking task in dancers compared with non-dancers, which was dependent on the secondary task. This suggests that such increased ability is influenced by available attentional resources.

Advantages and disadvantages of stiffness instructions when studying postural control.

PubMed

Bonnet, Cédrick T

2016-05-01

To understand the maintenance of upright stance, researchers try to discover the fundamental mechanisms and attentional resources devoted to postural control and eventually to the performance of other tasks (e.g., counting in the head). During their studies, some researchers require participants to stand as steady as possible and other simply ask participants to stand naturally. Surprisingly, a clear and direct explanation of the usefulness of the steadiness requirement seems to be lacking, both in experimental and methodological discussions. Hence, the objective of the present note was to provide advantages and disadvantages of this steadiness requirement in studies of postural control. The advantages may be to study fundamental postural control, to eliminate useless postural variability, to control spurious body motions and to control the participants' thoughts. As disadvantages, this steadiness requirement only leads to study postural control in unnatural upright stance, it changes the focus of attention (internal vs. external) and the nature of postural control (unconscious vs. conscious), it increases the difficulty of a supposedly easy control task and it eliminates or reduces the opportunity to record exploratory behaviors. When looking carefully at the four advantages of the steadiness requirement, one can believe that they are, in fact, more disadvantageous than advantageous. Overall therefore, this requirement seems illegitimate and it is proposed that researchers should not use it in the study of postural control. They may use this requirement only if they search to know the limit until which participants can consciously reduce their postural sway. Copyright © 2015 Elsevier B.V. All rights reserved.

Resisted side-stepping: the effect of posture on hip abductor muscle activation

PubMed Central

Berry, Justin W.; Lee, Theresa S.; Foley, Hanna D.; Lewis, Cara L.

2016-01-01

Study Design Controlled laboratory study, repeated-measures design. Objectives To compare hip abductor muscle activity and hip and knee joint kinematics in the moving limb to the stance limb during resisted side-stepping and also to determine if muscle activity was affected by the posture (upright standing versus squat) used to perform the exercise. Background Hip abductor weakness has been associated with a variety of lower extremity injuries. Resisted side-stepping is often used as an exercise to increase strength and endurance of the hip abductors. Exercise prescription would benefit from knowing the relative muscle activity level generated in each limb and for different postures during the side-stepping exercise. Methods Twenty-four healthy adults participated in this study. Kinematics and surface electromyographic (EMG) data from the gluteus maximus, gluteus medius, and tensor fascia lata (TFL) were collected as participants performed side-stepping with a resistive band around the ankle while maintaining each of 2 postures: 1) upright standing and 2) squat. Results Mean normalized EMG signal amplitude of the gluteus maximus, gluteus medius, and TFL was higher in the stance limb than the moving limb (P≤.001). Gluteal muscle activity was higher, while TFL muscle activity was lower, in the squat posture compared to the upright standing posture (P<.001). Hip abduction excursion was greater in the stance limb than in the moving limb (P<.001). Conclusions The 3 hip abductor muscles respond differently to the posture variations of side-stepping exercise in healthy individuals. When prescribing resisted side-stepping exercises, therapists should consider the differences in hip abductor activation across limbs and variations in trunk posture. PMID:26161629

Impact of soft and hard insole density on postural stability in older adults.

PubMed

Losa Iglesias, Marta Elena; Becerro de Bengoa Vallejo, Ricardo; Palacios Peña, Domingo

2012-01-01

A significant predictor of falls in the elderly population is attributed to postural instability. Thus, it is important to identify and implement practical clinical interventions to enhance postural stability in older adults. Shoe insoles have been identified as a mechanism to enhance postural control, and our study aimed to evaluate the impact of 2 shoe insoles on static standing balance in healthy, older adults compared with standing posture while barefoot. We hypothesized that both hard and soft shoe insoles would decrease postural sway compared with the barefoot condition. Indeed, excursion distances and sway areas were reduced, and sway velocity was decreased when wearing insoles. The hard insole was also effective when visual feedback was removed, suggesting that the more rigid an insole, the greater potential reduction in fall risk. Thus, shoe insoles may be a cost-effective, clinical intervention that is easy to implement to reduce the risk of falling in the elderly population. Copyright © 2012 Mosby, Inc. All rights reserved.

Rater reliability and construct validity of a mobile application for posture analysis

PubMed Central

Szucs, Kimberly A.; Brown, Elena V. Donoso

2018-01-01

[Purpose] Measurement of posture is important for those with a clinical diagnosis as well as researchers aiming to understand the impact of faulty postures on the development of musculoskeletal disorders. A reliable, cost-effective and low tech posture measure may be beneficial for research and clinical applications. The purpose of this study was to determine rater reliability and construct validity of a posture screening mobile application in healthy young adults. [Subjects and Methods] Pictures of subjects were taken in three standing positions. Two raters independently digitized the static standing posture image twice. The app calculated posture variables, including sagittal and coronal plane translations and angulations. Intra- and inter-rater reliability were calculated using the appropriate ICC models for complete agreement. Construct validity was determined through comparison of known groups using repeated measures ANOVA. [Results] Intra-rater reliability ranged from 0.71 to 0.99. Inter-rater reliability was good to excellent for all translations. ICCs were stronger for translations versus angulations. The construct validity analysis found that the app was able to detect the change in the four variables selected. [Conclusion] The posture mobile application has demonstrated strong rater reliability and preliminary evidence of construct validity. This application may have utility in clinical and research settings. PMID:29410561

Rater reliability and construct validity of a mobile application for posture analysis.

PubMed

Szucs, Kimberly A; Brown, Elena V Donoso

2018-01-01

[Purpose] Measurement of posture is important for those with a clinical diagnosis as well as researchers aiming to understand the impact of faulty postures on the development of musculoskeletal disorders. A reliable, cost-effective and low tech posture measure may be beneficial for research and clinical applications. The purpose of this study was to determine rater reliability and construct validity of a posture screening mobile application in healthy young adults. [Subjects and Methods] Pictures of subjects were taken in three standing positions. Two raters independently digitized the static standing posture image twice. The app calculated posture variables, including sagittal and coronal plane translations and angulations. Intra- and inter-rater reliability were calculated using the appropriate ICC models for complete agreement. Construct validity was determined through comparison of known groups using repeated measures ANOVA. [Results] Intra-rater reliability ranged from 0.71 to 0.99. Inter-rater reliability was good to excellent for all translations. ICCs were stronger for translations versus angulations. The construct validity analysis found that the app was able to detect the change in the four variables selected. [Conclusion] The posture mobile application has demonstrated strong rater reliability and preliminary evidence of construct validity. This application may have utility in clinical and research settings.

Screening initial entry training trainees for postural faults and low back or hip pain.

PubMed

Lane, John R

2014-01-01

The frequency of postural faults and postural awareness in military trainees has not been assessed. Five hundred Soldiers entering Advanced Individual Training were screened for standing posture and completed an anonymous questionnaire during inprocessing. Postural faults were identified in 202 subjects. Chi square analysis demonstrated a relationship between posture observed and posture reported: 87% of subjects with postural faults were unaware of postural faults; 12% with proper posture reported having poor posture. Subjects reported comparable frequencies of back pain and hip pain with postural faults (33.2%, 21.2%) and without faults (28.5%, 14.7%). Anonymous reporting was higher than formal reporting and requests for care during the same period (37% vs 3.4%).

Postural steadiness and ankle force variability in peripheral neuropathy

PubMed Central

Paxton, Roger J.; Feldman-Kothe, Caitlin; Trabert, Megan K.; Hitchcock, Leah N.; Reiser, Raoul F.; Tracy, Brian L.

2015-01-01

Introduction The purpose was to determine the effect of peripheral neuropathy (PN) on motor output variability for ankle muscles of older adults, and the relation between ankle motor variability and postural stability in PN patients. Methods Older adults with (O-PN) and without PN (O), and young adults (Y) underwent assessment of standing postural stability and ankle muscle force steadiness. Results O-PN displayed impaired ankle muscle force control and postural stability compared with O and Y groups. For O-PN, the amplitude of plantarflexor force fluctuations was moderately correlated with postural stability under no-vision conditions (r = 0.54, P = 0.01). Discussion The correlation of variations in ankle force with postural stability in PN suggests a contribution of ankle muscle dyscontrol to the postural instability that impacts physical function for older adults with PN. PMID:26284897

Case report: delayed presentation of postural headache in an adolescent girl after microscopic lumbar discectomy.

PubMed

Kundu, Anjana; Sano, Yuko; Pagel, Paul S

2008-10-01

To discuss the diagnostic and therapeutic challenges presented by an adolescent girl with delayed postural headaches and photophobia that occurred three months after an apparently uncomplicated microscopic lumbar discectomy. A previously healthy girl was admitted to our hospital with a one-week history of an unremitting, frontal-retroorbital postural headache and photophobia. Three months before admission, the patient had undergone a L5-S1 left hemilaminotomy and foraminotomy with microdiscectomy for excision of a herniated intervertebral disc. Conservative treatment failed to provide symptomatic relief. Cranial magnetic resonance imaging showed enhancement of the pachymeninges, consistent with intracranial hypotension. A chronic cerebrospinal leak was identified by high-resolution computed tomography (CT) myelography. Epidural blood patches were performed, with and without CT guidance, that provided temporary relief of the patient's symptoms; however, direct suture plication of the dural tear was eventually required for definitive treatment. This case emphasizes that delayed presentation of dural injury may occur after lumbar surgery and describes the potential therapeutic implications for this unusual complication.

Postural Stability Margins as a Function of Support Surface Slopes.

PubMed

Dutt-Mazumder, Aviroop; Slobounov, Seymon M; Challis, John Henry; Newell, Karl Maxim

2016-01-01

This investigation examined the effects of slope of the surface of support (35°, 30°, 20°, 10° Facing(Toe) Down, 0° Flat and 10°, 20°, 25° Facing (Toe) Up) and postural orientation on the margins of postural stability in quiet standing of young adults. The findings showed that the center of pressure-CoP (displacement, area and length) had least motion at the baseline (0° Flat) platform condition that progressively increased as a function of platform angle in both facing up and down directions. The virtual time to collision (VTC) dynamics revealed that the spatio-temporal margins to the functional stability boundary were progressively smaller and the VTC time series also more regular (SampEn-Sample Entropy) as slope angle increased. Surface slope induces a restricted stability region with lower dimension VTC dynamics that is more constrained when postural orientation is facing down the slope. These findings provide further evidence that VTC acts as a control variable in standing posture that is influenced by the emergent dynamics of the individual-environment-task interaction.

Experimental neck muscle pain impairs standing balance in humans.

PubMed

Vuillerme, Nicolas; Pinsault, Nicolas

2009-02-01

Impaired postural control has been reported in patients with chronic neck pain of both traumatic and non-traumatic etiologies, but whether painful stimulation of neck muscle per se can affect balance control during quiet standing in humans remains unclear. The purpose of the present experiment was thus to investigate the effect of experimental neck muscle pain on standing balance in young healthy adults. To achieve this goal, 16 male university students were asked to stand upright as still as possible on a force platform with their eyes closed in two conditions of No pain and Pain of the neck muscles elicited by experimental painful electrical stimulation. Postural control and postural performance were assessed by the displacements of the center of foot pressure (CoP) and of the center of mass (CoM), respectively. The results showed increased CoP and CoM displacements variance, range, mean velocity, and mean and median frequencies in the Pain relative to the No pain condition. The present findings emphasize the destabilizing effect of experimental neck muscle pain per se, and more largely stress the importance of intact neck neuromuscular function on standing balance.

Free-Standing Canes.

ERIC Educational Resources Information Center

Ehresman, Paul

1995-01-01

A precane device, called the "free-standing cane," was developed to help children with blindness along with other disabilities. The cane detects obstacles; guides the user's hands into a relaxed, static position in front of the hips; facilitates postural security and control; and offers tactile and kinesthetic feedback. (JDD)

A model-based approach to stabilizing crutch supported paraplegic standing by artificial hip joint stiffness.

PubMed

van der Spek, Jaap H; Veltink, Peter H; Hermens, Hermie J; Koopman, Bart F J M; Boom, Herman B K

2003-12-01

The prerequisites for stable crutch supported standing were analyzed in this paper. For this purpose, a biomechanical model of crutch supported paraplegic stance was developed assuming the patient was standing with extended knees. When using crutches during stance, the crutches will put a position constraint on the shoulder, thus reducing the number of degrees of freedom. Additional hip-joint stiffness was applied to stabilize the hip joint and, therefore, to stabilize stance. The required hip-joint stiffness for changing crutch placement and hip-joint offset angle was studied under static and dynamic conditions. Modeling results indicate that, by using additional hip-joint stiffness, stable crutch supported paraplegic standing can be achieved, both under static as well as dynamic situations. The static equilibrium postures and the stability under perturbations were calculated to be dependent on crutch placement and stiffness applied. However, postures in which the hip joint was in extension (C postures) appeared to the most stable postures. Applying at least 60 N x m/rad hip-joint stiffness gave stable equilibrium postures in all cases. Choosing appropriate hip-joint offset angles, the static equilibrium postures changed to more erect postures, without causing instability or excessive arm forces to occur.

Effect of Sitting Pause Times on Balance After Supine to Standing Transfer in Dim Light.

PubMed

Johnson, Eric G; Albalwi, Abdulaziz A; Al-Dabbak, Fuad M; Daher, Noha S

2017-06-01

The risk of falling for older adults increases in dimly lit environments. Longer sitting pause times, before getting out of bed and standing during the night, may improve postural stability. The purpose of this study was to measure the effect of sitting pause times on postural sway velocity immediately after a supine to standing transfer in a dimly lit room in older adult women. Eighteen healthy women aged 65 to 75 years who were able to independently perform supine to standing transfers participated in the study. On each of 2 consecutive days, participants assumed the supine position on a mat table and closed their eyes for 45 minutes. Then, participants were instructed to open their eyes and transfer from supine to sitting, with either 2- or 30-second pause in the sitting position followed by standing. The sitting pause time order was randomized. A significant difference was observed in postural sway velocity between the 2- and 30-second sitting pause times. The results revealed that there was less postural sway velocity after 30-second than 2-second sitting pause time (0.61 ± 0.19 vs 1.22 ± 0.68, P < .001). Falls related to bathroom usage at night are the most common reported falls among older adults. In the present study, the investigators studied the effect of sitting pause times on postural sway velocity after changing position from supine to standing in a dimly lit environment. The findings showed that the mean postural sway velocity was significantly less after 30-second sitting pause time compared with 2-second sitting pause time. Postural sway velocity decreased when participants performed a sitting pause of 30 seconds before standing in a dimly lit environment. These results suggest that longer sitting pause times may improve adaptability to dimly lit environments, contributing to improved postural stability and reduced risk of fall in older adult women when getting out of bed at night.

Longitudinal Associations of Electronic Aggression and Victimization with Social Standing during Adolescence

ERIC Educational Resources Information Center

Badaly, Daryaneh; Kelly, Brynn M.; Schwartz, David; Dabney-Lieras, Karen

2013-01-01

Prior empirical work has documented that the dynamics of social standing can play a critical role in the perpetration and receipt of aggression during adolescence. Recently, investigators have emphasized the emergence of new, electronic modalities for aggressive acts. Our longitudinal project therefore considered electronic forms of aggression and…

School Furniture Dimensions: Standing and Reaching.

ERIC Educational Resources Information Center

Department of Education and Science, London (England).

Performance of school children in regard to their standing and reach postures are described with dimensions given on the limits of their performance only. The facts of task performances are presented for the following tasks--(1) seeing into a shelf, (2) reaching into a shelf, (3) drawing on a vertical surface, (4) sitting or standing while…

A mobile system for assessment of physiological response to posture transitions.

PubMed

Jovanov, Emil; Milosevic, Mladen; Milenković, Aleksandar

2013-01-01

Posture changes initiate a dynamic physiological response that can be used as an indicator of the overall health status. We introduce an inconspicuous mobile wellness monitoring system (imWell) that continuously assesses the dynamic physiological response to posture transitions during activities of daily living. imWell utilizes a Zephyr BioHarness 3 physiological monitor that continually reports heart activity and physical activity via Bluetooth to a personal device (e.g. smartphone). The personal device processes the reported activity data in real-time to recognize posture transitions from the accelerometer data and to characterize dynamic heart response to posture changes. It annotates, logs, and uploads the heart activity data to our mHealth server. In this paper we present algorithms for detection of posture transitions and heart activity characterization during a sit-to-stand transition. The proposed system was tested on seven healthy subjects performing a predefined protocol. The total average and standard deviation for sit-to-stand transition time is 2.7 ± 0.69 s, resulting in the change of heart rate of 27.36 ± 9.30 bpm (from 63.3 ± 9.02 bpm to 90.66 ± 10.09 bpm).

Barnacle Geese Achieve Significant Energetic Savings by Changing Posture

PubMed Central

Tickle, Peter G.; Nudds, Robert L.; Codd, Jonathan R.

2012-01-01

Here we report the resting metabolic rate in barnacle geese (Branta leucopsis) and provide evidence for the significant energetic effect of posture. Under laboratory conditions flow-through respirometry together with synchronous recording of behaviour enabled a calculation of how metabolic rate varies with posture. Our principal finding is that standing bipedally incurs a 25% increase in metabolic rate compared to birds sitting on the ground. In addition to the expected decrease in energy consumption of hindlimb postural muscles when sitting, we hypothesise that a change in breathing mechanics represents one potential mechanism for at least part of the observed difference in energetic cost. Due to the significant effect of posture, future studies of resting metabolic rates need to take into account and/or report differences in posture. PMID:23071672

Back posture education in elementary schoolchildren: a 2-year follow-up study

PubMed Central

Geldhof, Elisabeth; De Bourdeaudhuij, Ilse; De Clercq, Dirk

2006-01-01

Within the scope of primary prevention regarding back functioning in children, research on the stability of intervention effects is indispensable. Along this line, the transition from childhood to adolescence is an important phase to evaluate the potential stability of intervention effects because of the typically mechanical and psychological demands related to adolescence. The main aim of the current study was to investigate the effects of a back education program at 2-year follow-up, in youngsters aged 13–14 years, on back posture knowledge, fear-avoidance beliefs and self-reported pain. An additional purpose was to evaluate which aspects of postural behavior were integrated in youngsters’ lifestyles. At 2-year follow-up, the study sample included 94 secondary schoolchildren in the intervention group (mean age 13.3 ± 0.8 years) and 101 controls (mean age 13.2 ± 0.7 years). The back posture program that had been implemented for two school years consisted of back education and the stimulation of postural dynamism in the class through support and environmental changes. A questionnaire was completed comparable to the pretest, posttest and follow-up evaluations. The current study demonstrated at 2-year follow-up stability of the improved general (F = 1.590, ns) and specific (F = 0.049, ns) back posture knowledge in children who had received early back posture education. Back posture education did not result in increased fear-avoidance beliefs (F = 1.163, ns) or mounting back and/or neck pain reports (F = 0.001, ns). Based on self-reports for postural behavior, youngsters who had received the back posture program in the elementary school curriculum integrated crucial sitting and lifting principles conform to biomechanical favorable postural behavior. The steady intervention effects 2-year post-intervention demonstrated that intensive back posture education through the elementary school curriculum is effective till adolescence. Future research on

Mobile Phone Use Behaviors and Postures on Public Transportation Systems.

PubMed

Liang, Huey-Wen; Hwang, Yaw-Huei

2016-01-01

Mobile phones are common in our daily life, but the users' preferences for postures or screen operating styles have not been studied. This was a cross-sectional and observational study. We randomly sampled passengers who used mobile phones on the Mass Rapid Transit (MRT) system in metropolitan Taipei. A checklist was used to observe their body postures and screen operating styles while sitting or standing. As a result, 1,230 subjects from 400 trips were observed. Overall, of all the passengers who were sitting, 41% of them were using mobile phones. The majority of the tasks involved browsing (84%) with their phones in a portrait orientation (93%). Different-hand holding/operating was the most commonly used operating style while sitting (46%) and same-hand holding/operating was the most common while standing (46%). The distribution of screen operating styles was significantly different for those sitting than for those standing and for different genders and age groups. The most frequently observed postures while sitting were having one's trunk against a backrest, feet on the floor and with or without an arm supported (58%). As for the users who were standing, the both- and different-hands groups had a high proportion of arms unsupported, feet on the floor and either their trunk supported or not. In contrast, the same-hand group tended to have their trunk unsupported, were holding a pole or handstrap and had both feet on floor. Further studies are warranted to characterize the ergonomic exposure of these commonly used postures and operating styles, and our results will help guide the selection of experimental conditions for laboratory settings.

Mobile Phone Use Behaviors and Postures on Public Transportation Systems

PubMed Central

Liang, Huey-Wen; Hwang, Yaw-Huei

2016-01-01

Mobile phones are common in our daily life, but the users’ preferences for postures or screen operating styles have not been studied. This was a cross-sectional and observational study. We randomly sampled passengers who used mobile phones on the Mass Rapid Transit (MRT) system in metropolitan Taipei. A checklist was used to observe their body postures and screen operating styles while sitting or standing. As a result, 1,230 subjects from 400 trips were observed. Overall, of all the passengers who were sitting, 41% of them were using mobile phones. The majority of the tasks involved browsing (84%) with their phones in a portrait orientation (93%). Different-hand holding/operating was the most commonly used operating style while sitting (46%) and same-hand holding/operating was the most common while standing (46%). The distribution of screen operating styles was significantly different for those sitting than for those standing and for different genders and age groups. The most frequently observed postures while sitting were having one’s trunk against a backrest, feet on the floor and with or without an arm supported (58%). As for the users who were standing, the both- and different-hands groups had a high proportion of arms unsupported, feet on the floor and either their trunk supported or not. In contrast, the same-hand group tended to have their trunk unsupported, were holding a pole or handstrap and had both feet on floor. Further studies are warranted to characterize the ergonomic exposure of these commonly used postures and operating styles, and our results will help guide the selection of experimental conditions for laboratory settings. PMID:26828797

The effects of anxiety and external attentional focus on postural control in patients with Parkinson's disease

PubMed Central

Jazaeri, Seyede Zohreh; Azad, Akram; Mehdizadeh, Hajar; Habibi, Seyed Amirhassan; Mandehgary Najafabadi, Mahbubeh; Saberi, Zakieh Sadat; Rahimzadegan, Hawre; Moradi, Saeed; Behzadipour, Saeed; Parnianpour, Mohamad; Khalaf, Kinda

2018-01-01

Background Although anxiety is a common non-motor outcome of Parkinson's disease (PD) affecting 40% of patients, little attention has been paid so far to its effects on balance impairment and postural control. Improvement of postural control through focusing on the environment (i.e. external focus) has been reported, but the role of anxiety, as a confounding variable, remains unclear. Objectives This study aimed to investigate the influence of anxiety and attentional focus instruction on the standing postural control of PD patients. Methods Thirty-four patients with PD (17 with high anxiety (HA-PD) and 17 with low anxiety (LA-PD)), as well as 17 gender- and age-matched healthy control subjects (HC) participated in the study. Postural control was evaluated using a combination of two levels of postural difficulty (standing on a rigid force plate surface with open eyes (RO) and standing on a foam surface with open eyes (FO)), as well as three attentional focus instructions (internal, external and no focus). Results Only the HA-PD group demonstrated significant postural control impairment as compared to the control, as indicated by significantly greater postural sway measures. Moreover, external focus significantly reduced postural sway in all participants especially during the FO condition. Conclusion The results of the current study provide evidence that anxiety influences balance control and postural stability in patients with PD, particularly those with high levels of anxiety. The results also confirmed that external focus is a potential strategy that significantly improves the postural control of these patients. Further investigation of clinical applicability is warranted towards developing effective therapeutic and rehabilitative treatment plans. PMID:29390029

Examining the effects of postural constraints on estimating reach.

PubMed

Gabbard, Carl; Cordova, Alberto; Lee, Sunghan

2007-07-01

The tendency to overestimate has consistently been reported in studies of reachability estimation. According to one of the more prominent explanations, the postural stability hypothesis, the perceived reaching limit depends on the individual's perceived postural constraints. To test that proposition, the authors compared estimates of reachability of 38 adults (a) in the seated posture (P1) and (b) in the more demanding posture of standing on one foot and leaning forward (P2). Although there was no difference between conditions for total error, results for the distribution and direction of error indicated that participants overestimated in the P1 condition and underestimated in the P2 condition. It therefore appears that perceived postural constraints could be a factor in judgments of reachability. When participants in the present study perceived greater postural demands, they may have elected to program a more conservative strategy that resulted in underestimation.

Orthostatic symptoms, blood pressure and working postures of factory and service workers over an observed workday.

PubMed

Ngomo, Suzy; Messing, Karen; Perrault, Hélène; Comtois, Alain

2008-11-01

North American workers usually stand while working, and prolonged standing is associated with discomfort and cardiovascular problems. Moving may alleviate the problems, but optimum mobility is unknown. The effects of variations in mobility were explored among (1) 34 health care workers whose symptoms of orthostatic intolerance (OI) were recorded after work; (2) 45 factory and laundry workers. Postures were observed over a workday and blood pressure (BP) and heart rate (HR) of both groups were recorded before and after work. Among health care workers, 65% manifested OI symptoms. In a multiple logistic regression, presence of >or= 1 symptom of OI was associated with static postures and being female (p=0.001). More static standing was associated with a larger drop in BP (p=0.04) in both populations. The results suggest that more static standing postures are associated with OI and musculoskeletal symptoms and with a subclinical drop in BP.

Validity of the Microsoft Kinect for assessment of postural control.

PubMed

Clark, Ross A; Pua, Yong-Hao; Fortin, Karine; Ritchie, Callan; Webster, Kate E; Denehy, Linda; Bryant, Adam L

2012-07-01

Clinically feasible methods of assessing postural control such as timed standing balance and functional reach tests provide important information, however, they cannot accurately quantify specific postural control mechanisms. The Microsoft Kinect™ system provides real-time anatomical landmark position data in three dimensions (3D), and given that it is inexpensive, portable and simple to setup it may bridge this gap. This study assessed the concurrent validity of the Microsoft Kinect™ against a benchmark reference, a multiple-camera 3D motion analysis system, in 20 healthy subjects during three postural control tests: (i) forward reach, (ii) lateral reach, and (iii) single-leg eyes-closed standing balance. For the reach tests, the outcome measures consisted of distance reached and trunk flexion angle in the sagittal (forward reach) and coronal (lateral reach) planes. For the standing balance test the range and deviation of movement in the anatomical landmark positions for the sternum, pelvis, knee and ankle and the lateral and anterior trunk flexion angle were assessed. The Microsoft Kinect™ and 3D motion analysis systems had comparable inter-trial reliability (ICC difference=0.06±0.05; range, 0.00-0.16) and excellent concurrent validity, with Pearson's r-values >0.90 for the majority of measurements (r=0.96±0.04; range, 0.84-0.99). However, ordinary least products analyses demonstrated proportional biases for some outcome measures associated with the pelvis and sternum. These findings suggest that the Microsoft Kinect™ can validly assess kinematic strategies of postural control. Given the potential benefits it could therefore become a useful tool for assessing postural control in the clinical setting. Copyright © 2012 Elsevier B.V. All rights reserved.

Photographic measurement of head and cervical posture when viewing mobile phone: a pilot study.

PubMed

Guan, Xiaofei; Fan, Guoxin; Wu, Xinbo; Zeng, Ying; Su, Hang; Gu, Guangfei; Zhou, Qi; Gu, Xin; Zhang, Hailong; He, Shisheng

2015-12-01

With the dramatic growth of mobile phone usage, concerns have been raised with regard to the adverse health effects of mobile phone on spinal posture. The aim of this study was to determine the head and cervical postures by photogrammetry when viewing the mobile phone screen, compared with those in neutral standing posture. A total of 186 subjects (81 females and 105 males) aged from 17 to 31 years old participated in this study. Subjects were instructed to stand neutrally and using mobile phone as in daily life. Using a photographic method, the sagittal head and cervical postures were assessed by head tilt angle, neck tilt angle, forward head shift and gaze angle. The photographic method showed a high intra-rater and inter-rater reliability in measuring the sagittal posture of cervical spine and gaze angle (ICCs ranged from 0.80 to 0.99). When looking at mobile phone, the head tilt angle significantly increased (from 74.55° to 95.22°, p = 0.000) and the neck angle decreased (from 54.68° to 38.77°, p = 0.000). The forward head posture was also confirmed by the significantly increased head shift (from 10.90 to 13.85 cm, p = 0.000). The posture assumed in mobile phone use was significantly correlated with neutral posture (p < 0.05). Males displayed a more forward head posture than females (p < 0.05). The head tilt angle was positively correlated with the gaze angle (r = 0.616, p = 0.000), while the neck tilt angle was negatively correlated with the gaze angle (r = -0.628, p = 0.000). Photogrammetry is a reliable, quantitative method to evaluate the head and cervical posture during mobile phone use. Compared to neutral standing, subjects display a more forward head posture when viewing the mobile phone screen, which is correlated with neutral posture, gaze angle and gender. Future studies will be needed to investigate a dose-response relationship between mobile phone use and assumed posture.

Mechanical Characteristics of Reflex Durign Upright Posture in Paralyzed Subjects

NASA Astrophysics Data System (ADS)

Kim, Yongchul; Youm, Youngil; Lee, Bumsuk; Kim, Youngho; Choi, Hyeonki

The characteristics of flexor reflexes have been investigated in the previous studies with human subjects who were seated or supine position. However, researchers did not describe how the spinal circuits are used in different hip angles for paralyzed subjects, such as the standing position with walker or cane. In upright posture the compatibility between a flexor reflex of leg and body balance is a special problem for lower limb injured subjects. Therefore, the purpose of this study was to investigate the effects of hip angle change on the flexor reflex evoked in standing paralyzed subjects supported by walker. In this study, six spinal cord injured and four stroke subjects were recruited through the inpatient physical therapy clinics of Korea national rehabilitation hospital. A single axis electronic goniometer was mounted on the lateral side of the hip joint of the impaired limb to record movements in the sagittal plane at this joint. The electronic goniometer was connected to a data acquisition system, through amplifiers to a computer. Since subject' posture influenced characteristics of the flexion reflex response, the subjects were supported in an upright posture by the help of parallelogram walder. Two series of tests were performed on each leg. The first series of the tests investigated the influence of hip angle during stationary standing posture on flexion reflex response. The hip angle was adjusted by the foot plate. The second examined the effect of the voluntary action of subject on swing motion during the gait. The electrically induced flexion reflex simultaneously produced the flexion of the hip, knee and dorsiflexion of the ankle enabling the swing phase of walking. Form the experimental results we observed that the reflex response of hip joint was largerwith the hip in the extended position than in the flexed position during standing posture. Under voluntary movement on flexion reflex during gaint, the peak hip angle induced by stimulation was

The Rim and the Ancient Mariner: The Nautical Horizon Affects Postural Sway in Older Adults

PubMed Central

Wade, Michael G.; Stergiou, Nick

2016-01-01

On land, the spatial magnitude of postural sway (i.e., the amount of sway) tends to be greater when participants look at the horizon than when they look at nearby targets. By contrast, on ships at sea, the spatial magnitude of postural sway in young adults has been greater when looking at nearby targets and less when looking at the horizon. Healthy aging is associated with changes in the movement patterns of the standing body sway, and these changes typically are interpreted in terms of age-related declines in the ability to control posture. To further elucidate the mechanisms associated with these changes we investigated control of posture in a setting that poses substantial postural challenges; standing on a ship at sea. In particular, we explored postural sway on a ship at sea when older adults looked at the horizon or at nearby targets. We evaluated the kinematics of the center of pressure in terms of spatial magnitude (i.e., the amount of sway) and multifractality (a measure of temporal dynamics). We found that looking at the horizon significantly affected the multifractality of standing body, but did not systematically influence the spatial magnitude of sway. We discuss the results in terms of age-related changes in the perception and control of dynamic body orientation. PMID:27973576

Effect of whole-body vibration on center-of-mass movement during standing in children and young adults.

PubMed

Liang, Huaqing; Beerse, Matthew; Ke, Xiang; Wu, Jianhua

2017-05-01

Whole body vibration (WBV) can affect postural control and muscular activation. The purpose of this study was to investigate the center-of-mass (COM) movement of children and young adults before, during, immediately after, and 5min after 40-s WBV in quiet standing. Fourteen young adults (mean age 24.5 years) and fourteen children (mean age 8.1 years) participated in the study. A full-body 35-marker set was placed on the participants and used to calculate COM. Forty-second standing trials were collected before, during, immediately after, and 5min after WBV with an frequency of 28Hz and an amplitude of <1mm. Two visual conditions were provided: eyes-open (EO) and eyes-closed (EC). COM variables included time-domain measures (average velocity, range, sway area and fractal dimension), frequency-domain measures (total power and median frequency), and detrended fluctuation analysis (DFA) scaling exponent in both anterior-posterior (AP) and medial-lateral (ML) directions. Results show that during WBV both children and adults increased average velocity and median frequency, but decreased range and the DFA scaling exponent. Immediately after WBV both groups increased the range, but showed pre-vibration values for most of the COM variables. Comparing to adults, children displayed a higher COM velocity, range, fractal dimension, and total power, but a lower DFA scaling exponent at all phases. The results suggest that both children and adults can quickly adapt their postural control system to WBV and maintain balance during and after vibration. Children display some adult-like postural control during and after WBV; however, their postural development continues into adolescence. Published by Elsevier B.V.

Postural control in man: the phylogenetic perspective.

PubMed

Gramsbergen, Albert

2005-01-01

Erect posture in man is a recent affordance from an evolutionary perspective. About eight million years ago, the stock from which modern humans derived split off from the ape family, and from around sixty-thousand years ago, modern man developed. Upright gait and manipulations while standing pose intricate cybernetic problems for postural control. The trunk, having an older evolutionary history than the extremities, is innervated by medially descending motor systems and extremity muscles by the more recent, laterally descending systems. Movements obviously require concerted actions from both systems. Research in rats has demonstrated the interdependencies between postural control and the development of fluent walking. Only 15 days after birth, adult-like fluent locomotion emerges and is critically dependent upon postural development. Vesttibular deprivation induces a retardation in postural development and, consequently, a retarded development of adult-like locomotion. The cerebellum obviously has an important role in mutual adjustments in postural control and extremity movements, or, in coupling the phylogenetic older and newer structures. In the human, the cerebellum develops partly after birth and therefore is vulnerable to adverse perinatal influences. Such vulnerability seems to justify focusing our scientific research efforts onto the development of this structure.

The relationship between sitting posture and seated-related upper quadrant musculoskeletal pain in computing South African adolescents: A prospective study.

PubMed

Brink, Yolandi; Louw, Quinette; Grimmer, Karen; Jordaan, Esmè

2015-12-01

There is evidence that consistent sitting for prolonged periods is associated with upper quadrant musculoskeletal pain (UQMP). It is unclear whether postural alignment is a significant risk factor. The aim of the prospective study (2010-2011) was to ascertain if three-dimensional sitting postural angles, measured in a real-life school computer classroom setting, predict seated-related UQMP. Asymptomatic Grade 10 high-school students, aged 15-17 years, undertaking Computer Application Technology, were eligible to participate. Using the 3D Posture Analysis Tool, sitting posture was measured while students used desk-top computers. Posture was reported as five upper quadrant angles (Head flexion, Neck flexion; Craniocervical angle, Trunk flexion and Head lateral bending). The Computer Usage Questionnaire measured seated-related UQMP and hours of computer use. The Beck Depression Inventory and the Multidimensional Anxiety Scale for Children assessed psychosocial factors. Sitting posture, computer use and psychosocial factors were measured at baseline. UQMP was measured at six months and one-year follow-up. 211, 190 and 153 students participated at baseline, six months and one-year follow-up respectively. 34.2% students complained of seated-related UQMP during the follow-up period. Increased head flexion (HF) predicted seated-related UQMP developing over time for a small group of students with pain scores greater than the 90th pain percentile, adjusted for age, gender, BMI, computer use and psychosocial factors (p = 0.003). The pain score increased 0.22 points per 1° increase in HF. Classroom ergonomics and postural hygiene should therefore focus on reducing large HF angles among computing adolescents. Copyright © 2015 Elsevier Ltd. All rights reserved.

Moving beyond quiet stance: applicability of the inverted pendulum model to stooping and crouching postures.

PubMed

Weaver, Tyler B; Glinka, Michal N; Laing, Andrew C

2014-11-07

Currently, it is unknown whether the inverted pendulum model is applicable to stooping or crouching postures. Therefore, the aim of this study was to determine the degree of applicability of the inverted pendulum model to these postures, via examination of the relationship between the centre of mass (COM) acceleration and centre of pressure (COP)-COM difference. Ten young adults held static standing, stooping and crouching postures, each for 20s. For both the anterior-posterior (AP) and medio-lateral (ML) directions, the time-varying COM acceleration and the COP-COM were computed, and the relationship between these two variables was determined using Pearson's correlation coefficients. Additionally, in both directions, the average absolute COM acceleration, average absolute COP-COM signal, and the inertial component (i.e., -I/Wh) were compared across postures. Pearson correlation coefficients revealed a significant negative relationship between the COM acceleration and COP-COM signal for all comparisons, regardless of the direction (p<0.001). While no effect of posture was observed in the AP direction (p=0.463), in the ML direction, the correlation coefficients for stooping were different (i.e., stronger) than standing (p=0.008). Regardless of direction, the average absolute COM acceleration for both the stooping and crouching postures was greater than standing (p<0.002). The high correlations indicate that the inverted pendulum model is applicable to stooping and crouching postures. Due to their importance in completing activities of daily living, there is merit in determining what type of motor strategies are used to control such postures and whether these strategies change with age. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

Cognitive tasks promote automatization of postural control in young and older adults.

PubMed

Potvin-Desrochers, Alexandra; Richer, Natalie; Lajoie, Yves

2017-09-01

Researchers looking at the effects of performing a concurrent cognitive task on postural control in young and older adults using traditional center-of-pressure measures and complexity measures found discordant results. Results of experiments showing improvements of stability have suggested the use of strategies such as automatization of postural control or stiffening strategy. This experiment aimed to confirm in healthy young and older adults that performing a cognitive task while standing leads to improvements that are due to automaticity of sway by using sample entropy. Twenty-one young adults and twenty-five older adults were asked to stand on a force platform while performing a cognitive task. There were four cognitive tasks: simple reaction time, go/no-go reaction time, equation and occurrence of a digit in a number sequence. Results demonstrated decreased sway area and variability as well as increased sample entropy for both groups when performing a cognitive task. Results suggest that performing a concurrent cognitive task promotes the adoption of an automatic postural control in young and older adults as evidenced by an increased postural stability and postural sway complexity. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of smart phone use on dynamic postural balance.

PubMed

Cho, Sung-Hak; Choi, Mun-Hee; Goo, Bong-Oh

2014-07-01

[Purpose] The present study investigated what kind of effect smart phone use has on dynamic postural balance. [Subjects] The study subjects were 30 healthy students in their 20's who were recruited from a University in Busan, Korea. [Methods] The present experiment was quasi-experimental research which measured the postural balance (Biodex) of subjects while they sent text messages via smart phones in the standing position with the eyes open, and while they used two-way SNS. [Results] There were significant differences between standing and the dual-task situations. Among dual tasks using smart phones, SNS using situations showed the highest instability. [Conclusion] The use of smart phones in less stable conditions such as while walking or in moving vehicles should be discouraged.

Measurement of hemodynamics during postural changes using a new wearable cephalic laser blood flowmeter.

PubMed

Fujikawa, Tetsuya; Tochikubo, Osamu; Kura, Naoki; Kiyokura, Takanori; Shimada, Junichi; Umemura, Satoshi

2009-10-01

Patients with orthostatic hypotension have pathologic hemodynamics related to changes in body posture. A new cephalic laser blood flowmeter that can be worn on the tragus to investigate the hemodynamics upon rising from a sitting or squatting posture was developed. The relationship between cephalic hemodynamics and cerebral ischemic symptoms in 63 subjects in a sitting, squatting, and standing positions using the new device was evaluated. Transient decrease in blood pressure within 15 s after rising to an erect position possibly causes dizziness, syncope, and fall. Subjects exhibiting dizziness upon standing showed a significant decrease in the cephalic blood flow (CBF) and indirect beat-to-beat systolic blood pressure, as monitored by the Finometer, and a significant correlation was observed between the drop ratio (drop value on rising/mean value in the squatting position) of CBF and that of systolic blood pressure. This new wearable CBF-meter is potentially useful for estimating cephalic hemodynamics and objectively diagnosing cerebral ischemic symptoms of subjects in a standing posture.

Evaluation of Myoelectric Activity of Paraspinal Muscles in Adolescents with Idiopathic Scoliosis during Habitual Standing and Sitting.

PubMed

Kwok, Garcia; Yip, Joanne; Cheung, Mei-Chun; Yick, Kit-Lun

2015-01-01

There is a number of research work in the literature that have applied sEMG biofeedback as an instrument for muscle rehabilitation. Therefore, sEMG is a good tool for this research work and is used to record the myoelectric activity in the paraspinal muscles of those with AIS during habitual standing and sitting. After the sEMG evaluation, the root-mean-square (RMS) sEMG values of the paraspinal muscles in the habitual postures reflect the spinal curvature situation of the PUMC Type Ia and IIc subjects. Both groups have a stronger average RMS sEMG value on the convex side of the affected muscle regions. Correction to posture as instructed by the physiotherapist has helped the subjects to achieve a more balanced RMS sEMG ratio in the trapezius and latissimus dorsi regions; the erector spinae in the thoracic region and/or erector spinae in the lumbar region. It is, therefore, considered that with regular practice of the suggested positions, those with AIS can use motor learning to achieve a more balanced posture. Consequently, the findings can be used in less intrusive early orthotic intervention and provision of care to those with AIS.

Postural transitions during activities of daily living could identify frailty status – Application of wearable technology to identify frailty during unsupervised condition

PubMed Central

Parvaneh, Saman; Mohler, Jane; Toosizadeh, Nima; Grewal, Gurtej Singh; Najafi, Bijan

2017-01-01

Background Impairment of physical function is a major indicator of frailty. Functional performance tests have been shown to be useful for identification of frailty in older adults. However, these tests are often not translatable into unsupervised and remote monitoring of frailty status at home and/or community settings. Objective In this study, we explored daily postural transition quantified using a chest-worn wearable technology to identify frailty in community-dwelling older adults. Methods Spontaneous daily physical activity was monitored over 24 hours in 120 community dwelling (age: 78±8 years) using an unobtrusive wearable sensor (PAMSys™, Biosensics LLC). Participants were classified as non-frail and pre-frail/frail using Fried’s criteria. A validated software was used to identify body postures and postural transition between each independent postural activities such as sit-to-stand, stand-to-sit, stand-to-walk, and walk-to-stand. Transition from walking to sitting was further classified as quick-sitting and cautious-sitting based on presence/absence of a standing-posture pause between sitting and walking. General linear model univariate test was used for between groups comparison. Pearson’s correlation was used to determine the association between sensor-derived parameters with age. Logistic regression model was used to identify independent predictors of frailty. Results According to Fried’s criteria, 63% of participants were pre-frail/frail. The total number of postural transitions, stand-to-walk, and walk-to-stand were, respectively, 25.2%, 30.2%, and 30.6% lower in the pre-frail/frail group when compared to non-frails (p<0.05, Cohen’s d=0.73–0.79). Furthermore, ratio of cautious-sitting was significantly higher by 6.2% in pre-frail/frail compared to non-frail (p=0.025, Cohen’s d=0.22). Total number of postural transitions and ratio of cautious-sitting also showed significant negative and positive correlations with age, respectively (r=-0

Temporal Structure of Support Surface Translations Drive the Temporal Structure of Postural Control During Standing

PubMed Central

Rand, Troy J.; Myers, Sara A.; Kyvelidou, Anastasia; Mukherjee, Mukul

2015-01-01

A healthy biological system is characterized by a temporal structure that exhibits fractal properties and is highly complex. Unhealthy systems demonstrate lowered complexity and either greater or less predictability in the temporal structure of a time series. The purpose of this research was to determine if support surface translations with different temporal structures would affect the temporal structure of the center of pressure (COP) signal. Eight healthy young participants stood on a force platform that was translated in the anteroposterior direction for input conditions of varying complexity: white noise, pink noise, brown noise, and sine wave. Detrended fluctuation analysis was used to characterize the long-range correlations of the COP time series in the AP direction. Repeated measures ANOVA revealed differences among conditions (P < .001). The less complex support surface translations resulted in a less complex COP compared to normal standing. A quadratic trend analysis demonstrated an inverted-u shape across an increasing order of predictability of the conditions (P < .001). The ability to influence the complexity of postural control through support surface translations can have important implications for rehabilitation. PMID:25994281

Static postural control among school-aged youth with Down syndrome: A systematic review.

PubMed

Maïano, Christophe; Hue, Olivier; Tracey, Danielle; Lepage, Geneviève; Morin, Alexandre J S; Moullec, Grégory

2018-05-01

Youth with Down syndrome are characterized by motor delays when compared to typically developing (TD) youth, which may be explained by a lower postural control or reduced postural tone. In the present article, we summarize research comparing the static postural control, assessed by posturography, between youth with Down syndrome and TD youth. A systematic literature search was performed in 10 databases and seven studies, published between 2001 and 2017, met our inclusion criteria. Based on the present reviewed findings, it is impossible to conclude that children with Down syndrome present significantly lower static postural control compared to TD children. In contrast, findings showed that adolescents with Down syndrome tended to present significantly lower static postural control compared to TD adolescents when visual and plantar cutaneous inputs were disturbed separately or simultaneously. The present findings should be interpreted with caution given the limitations of the small number of reviewed studies. Therefore, the static postural control among youth with Down syndrome should be further investigated in future rigorous studies examining the contribution of a range of sensory information. Copyright © 2018 Elsevier B.V. All rights reserved.

The spinal posture of computing adolescents in a real-life setting

PubMed Central

2014-01-01

Background It is assumed that good postural alignment is associated with the less likelihood of musculoskeletal pain symptoms. Encouraging good sitting postures have not reported consequent musculoskeletal pain reduction in school-based populations, possibly due to a lack of clear understanding of good posture. Therefore this paper describes the variability of postural angles in a cohort of asymptomatic high-school students whilst working on desk-top computers in a school computer classroom and to report on the relationship between the postural angles and age, gender, height, weight and computer use. Methods The baseline data from a 12 month longitudinal study is reported. The study was conducted in South African school computer classrooms. 194 Grade 10 high-school students, from randomly selected high-schools, aged 15–17 years, enrolled in Computer Application Technology for the first time, asymptomatic during the preceding month, and from whom written informed consent were obtained, participated in the study. The 3D Posture Analysis Tool captured five postural angles (head flexion, neck flexion, cranio-cervical angle, trunk flexion and head lateral bend) while the students were working on desk-top computers. Height, weight and computer use were also measured. Individual and combinations of postural angles were analysed. Results 944 Students were screened for eligibility of which the data of 194 students are reported. Trunk flexion was the most variable angle. Increased neck flexion and the combination of increased head flexion, neck flexion and trunk flexion were significantly associated with increased weight and BMI (p = 0.0001). Conclusions High-school students sit with greater ranges of trunk flexion (leaning forward or reclining) when using the classroom computer. Increased weight is significantly associated with increased sagittal plane postural angles. PMID:24950887

Pilates improves lower limbs strength and postural control during quite standing in a child with hemiparetic cerebral palsy: A case report study.

PubMed

Dos Santos, Adriana Neves; Serikawa, Simoni Sayuri; Rocha, Nelci Adriana Cicuto Ferreira

2016-08-01

To verify the effect of Pilates exercises in a child with cerebral palsy (CP) with mild functional impairment. We evaluated average peak torque of ankle and knee extensors/flexors using a Biodex System, using concentric active-assisted test. We also evaluated amplitude of anterior-posterior and of medial-lateral displacement of the CoP and area of oscillation during quite standing with a BERTEC platform. We applied Pilates exercises for eight weeks. Peak torque/body weight of ankle and knee extensors/flexors of both affected and unaffected limbs increased after Pilates. Also, all kinetic variables decreased after Pilates' intervention. After one-month follow-up, isokinetic variable values were higher while kinetic variable values were lower than baseline values. Pilates may be an important rehabilitation technique for children with CP that present mild deficits in motor structures and high functional level, especially when the aims are to improve muscle strength and postural control during quite standing.

Postural responses to unexpected perturbations of balance during reaching

PubMed Central

Trivedi, Hari; Leonard, Julia A.; Ting, Lena H.; Stapley, Paul J.

2014-01-01

To study the interaction between feedforward and feedback modes of postural control, we investigated postural responses during unexpected perturbations of the support surface that occurred during forward reaching in a standing position. We examined postural responses in lower limb muscles of 9 human subjects. Baseline measures were obtained when subjects executed reaching movements to a target placed in front of them (R condition) and during postural responses to forward and backward support-surface perturbations (no reaching, P condition) during quiet stance. Perturbations were also given at different delays after the onset of reaching movements (RP conditions) as well as with the arm extended in the direction of the target, but not reaching (P/AE condition). Results showed that during perturbations to reaching (RP), the initial automatic postural response, occurring around 100 ms after the onset of perturbations, was relatively unchanged in latency or amplitude compared to control conditions (P and P/AE). However, longer latency postural responses were modulated to aid in the reaching movements during forward perturbations but not during backward perturbations. Our results suggest that the nervous system prioritizes the maintenance of a stable postural base during reaching, and that later components of the postural responses can be modulated to ensure the performance of the voluntary task. PMID:20035321

Intermittent use of an "anchor system" improves postural control in healthy older adults.

PubMed

Freitas, Milena de Bem Zavanella; Mauerberg-deCastro, Eliane; Moraes, Renato

2013-07-01

Haptic information, provided by a non-rigid tool (i.e., an "anchor system"), can reduce body sway in individuals who perform a standing postural task. However, it was not known whether or not continuous use of the anchor system would improve postural control after its removal. Additionally, it was unclear as to whether or not frequency of use of the anchor system is related to improved control in older adults. The present study evaluated the effect of the prolonged use of the anchor system on postural control in healthy older individuals, at different frequencies of use, while they performed a postural control task (semi-tandem position). Participants were divided into three groups according to the frequency of the anchor system's use (0%, 50%, and 100%). Pre-practice phase (without anchor) was followed by a practice phase (they used the anchor system at the predefined frequency), and a post-practice phase (immediate and late-without anchor). All three groups showed a persistent effect 15min after the end of the practice phase (immediate post-practice phase). However, only the 50% group showed a persistent effect in the late post-practice phase (24h after finishing the practice phase). Older adults can improve their postural control by practicing the standing postural task, and use of the anchor system limited to half of their practice time can provide additional improvement in their postural control. Copyright © 2013 Elsevier B.V. All rights reserved.

Invariant density analysis: modeling and analysis of the postural control system using Markov chains.

PubMed

Hur, Pilwon; Shorter, K Alex; Mehta, Prashant G; Hsiao-Wecksler, Elizabeth T

2012-04-01

In this paper, a novel analysis technique, invariant density analysis (IDA), is introduced. IDA quantifies steady-state behavior of the postural control system using center of pressure (COP) data collected during quiet standing. IDA relies on the analysis of a reduced-order finite Markov model to characterize stochastic behavior observed during postural sway. Five IDA parameters characterize the model and offer physiological insight into the long-term dynamical behavior of the postural control system. Two studies were performed to demonstrate the efficacy of IDA. Study 1 showed that multiple short trials can be concatenated to create a dataset suitable for IDA. Study 2 demonstrated that IDA was effective at distinguishing age-related differences in postural control behavior between young, middle-aged, and older adults. These results suggest that the postural control system of young adults converges more quickly to their steady-state behavior while maintaining COP nearer an overall centroid than either the middle-aged or older adults. Additionally, larger entropy values for older adults indicate that their COP follows a more stochastic path, while smaller entropy values for young adults indicate a more deterministic path. These results illustrate the potential of IDA as a quantitative tool for the assessment of the quiet-standing postural control system.

Postural health in women: the role of physiotherapy.

PubMed

Britnell, S J; Cole, J V; Isherwood, L; Sran, M M; Britnell, N; Burgi, S; Candido, G; Watson, L

2005-05-01

To advise obstetric and gynaecology care providers of the physical, psychological, and environmental factors that affect women's posture throughout their lifespan, from adolescence to menopause. To outline the physiotherapy management of obstetrics, osteoporosis, and urinary incontinence in women and to identify recommendations for referral to a physiotherapist. Knowledge of abnormal postures, contributing factors and recommendations for physiotherapy management. MEDLINE, PEDro, and Cochrane Library Search from 1992 to 2003 for English-language articles and references from current textbooks related to posture and women's health conditions that are managed by physiotherapists. The evidence collected was reviewed by the authors and quantified using the evaluation of evidence guidelines developed by the Canadian Task Force on the Periodic Health Exam. 1. Pelvic floor muscle training with a physiotherapist is recommended to prevent urinary incontinence during pregnancy and after delivery (I-A). 2. Core stability training with a physiotherapist is recommended to prevent and treat back and pelvic pain during and following pregnancy (I-B). 3. Physiotherapist-prescribed exercises are recommended for women to elicit positive changes in bone mass and to reduce fall and fracture risk (I-A). 4. Pelvic floor muscle training with a physiotherapist is recommended for women with stress urinary incontinence (I-A). The Canadian Physiotherapy Association and Society of Obstetricians and Gynaecologists of Canada have developed this joint policy statement regarding posture in women's health that highlights the physical, psychological, and environmental factors that affect women's posture throughout their lifespan, from adolescence to menopause. This statement outlines the role of physiotherapy in the assessment and treatment of women's posture; outlines the physiotherapy management of obstetrics, osteoporosis, and urinary incontinence; and identifies recommendations for referral to a

Postural stability in the elderly during sensory perturbations and dual tasking: the influence of refractive blur.

PubMed

Anand, Vijay; Buckley, John G; Scally, Andy; Elliott, David B

2003-07-01

To determine the influence of refractive blur on postural stability during somatosensory and vestibular system perturbation and dual tasking. Fifteen healthy, elderly subjects (mean age, 71 +/- 5 years), who had no history of falls and had normal vision, were recruited. Postural stability during standing was assessed using a force platform, and was determined as the root mean square (RMS) of the center of pressure (COP) signal in the anterior-posterior (A-P) and medial-lateral directions collected over a 30-second period. Data were collected under normal standing conditions and with somatosensory and vestibular system perturbations. Measurements were repeated with an additional physical and/or cognitive task. Postural stability was measured under conditions of binocular refractive blur of 0, 1, 2, 4, and 8 D and with eyes closed. The data were analyzed with a population-averaged linear model. The greatest increases in postural instability were due to disruptions of the somatosensory and vestibular systems. Increasing refractive blur caused increasing postural instability, and its effect was greater when the input from the other sensory systems was disrupted. Performing an additional cognitive and physical task increased A-P RMS COP further. All these detrimental effects on postural stability were cumulative. The findings highlight the multifactorial nature of postural stability and indicate why the elderly, many of whom have poor vision and musculoskeletal and central nervous system degeneration, are at greater risk of falling. The findings also highlight that standing instability in both normal and perturbed conditions was significantly increased with refractive blur. Correcting visual impairment caused by uncorrected refractive error could be a useful intervention strategy to help prevent falls and fall-related injuries in the elderly.

Postural Analysis in Time and Frequency Domains in Patients with Ehlers-Danlos Syndrome

ERIC Educational Resources Information Center

Galli, Manuela; Rigoldi, Chiara; Celletti, Claudia; Mainardi, Luca; Tenore, Nunzio; Albertini, Giorgio; Camerota, Filippo

2011-01-01

The goal of this work is to analyze postural control in Ehlers-Danlos syndrome (EDS) participants in time and frequency domain. This study considered a pathological group composed by 22 EDS participants performing a postural test consisting in maintaining standing position over a force platform for 30 s in two conditions: open eyes (OE) and closed…

Influence of real and virtual heights on standing balance.

PubMed

Cleworth, Taylor W; Horslen, Brian C; Carpenter, Mark G

2012-06-01

Fear and anxiety induced by threatening scenarios, such as standing on elevated surfaces, have been shown to influence postural control in young adults. There is also a need to understand how postural threat influences postural control in populations with balance deficits and risk of falls. However, safety and feasibility issues limit opportunities to place such populations in physically threatening scenarios. Virtual reality (VR) has successfully been used to simulate threatening environments, although it is unclear whether the same postural changes can be elicited by changes in virtual and real threat conditions. Therefore, the purpose of this study was to compare the effects of real and virtual heights on changes to standing postural control, electrodermal activity (EDA) and psycho-social state. Seventeen subjects stood at low and high heights in both real and virtual environments matched in scale and visual detail. A repeated measures ANOVA revealed increases with height, independent of visual environment, in EDA, anxiety, fear, and center of pressure (COP) frequency, and decreases with height in perceived stability, balance confidence and COP amplitude. Interaction effects were seen for fear and COP mean position; where real elicited larger changes with height than VR. This study demonstrates the utility of VR, as simulated heights resulted in changes to postural, autonomic and psycho-social measures similar to those seen at real heights. As a result, VR may be a useful tool for studying threat related changes in postural control in populations at risk of falls, and to screen and rehabilitate balance deficits associated with fear and anxiety. Copyright © 2012 Elsevier B.V. All rights reserved.

The effects of trunk extensor and abdominal muscle fatigue on postural control and trunk proprioception in young, healthy individuals.

PubMed

Larson, Dennis J; Brown, Stephen H M

2018-02-01

The purpose of this study was to induce both trunk extensor and abdominal muscle fatigue, on separate occasions, and compare their effects on standing postural control and trunk proprioception, as well as look at the effects of a recovery period on these outcome measures. A total of 20 individuals participated, with 10 (5 males and 5 females) completing either a standing postural control or lumbar axial repositioning protocol. Participants completed their randomly assigned protocol on two occasions, separated by at least 4  days, with either their trunk extensor or abdominal muscles being fatigued on either day. Postural control centre of pressure variables and trunk proprioception errors were compared pre- and post-fatigue. Results showed that both trunk extensor and abdominal muscle fatigue significantly degraded standing postural control immediately post-fatigue, with recovery occurring within 2 min post-fatigue. In general, these degradative effects on postural control appeared to be greater when the trunk extensor muscles were fatigued compared to the abdominal muscles. No statistically significant changes in trunk proprioception were found after either fatigue protocol. The present findings demonstrate our body's ability to quickly adapt and reweight somatosensory information to maintain postural control and trunk proprioception, as well as illustrate the importance of considering the abdominal muscles, along with the trunk extensor muscles, when considering the impact of fatigue on trunk movement and postural control. Copyright © 2017 Elsevier B.V. All rights reserved.

Is sitting worse than static standing? How a gender analysis can move us toward understanding determinants and effects of occupational standing and walking.

PubMed

Messing, Karen; Stock, Susan; Côté, Julie; Tissot, France

2015-01-01

The Yant Award was established in 1964 to honor the contributions of William P. Yant, the first president of the American Industrial Hygiene Association. It is presented annually for outstanding contributions in industrial hygiene or allied fields to an individual residing outside the United States. The 2014 award recipient is Dr. Karen Messing, Professor emeritus, Department of Biological Sciences, Université du Québec à Montréal and Researcher, CINBIOSE Research Centre. Gender (socially determined) differences in occupations, employment, and working conditions, task assignments, and work methods that affect exposure to health risks are increasingly documented. Interactions of (biologically influenced) sex differences with workplace parameters may also influence exposure levels. During field studies, ergonomists learn a lot about gender and sex that can be important when generating and testing hypotheses about the mechanisms that link workplace exposures to health outcomes. Prolonged standing is common in North America; almost half (45%) of Québec workers spend more than three-quarters of their working time on their feet and 40% of these cannot sit at will. This posture has been linked to chronic back pain and musculoskeletal disorders (MSDs) in the lower limbs, but many health professionals suggest workers should stand rather than sit at work. We ask: (1) Given the fact that roughly the same proportion of men and women stand at work, what does a gender-sensitive analysis add to our ability to detect and thus prevent work-related MSDs?; (2) How does ergonomics research inform gender-sensitive analysis of occupational health data?; and (3) What do researchers need to know to orient interventions to improve general working postures? We have sought answers to these questions through collaborative research with specialists in epidemiology, occupational medicine, biomechanics, and physiology, carried out in partnership with public health organisations, community

M.I.T./Canadian vestibular experiments on the Spacelab-1 mission. V - Postural responses following exposure to weightlessness

NASA Technical Reports Server (NTRS)

Kenyon, R. V.; Young, L. R.

1986-01-01

The four science crewmembers of Spacelab-1 were tested for postural control before and after a 10 day mission in weightlessness. Previous reports have shown changes in astronaut postural behavior following a return to earth's 1-g field. This study was designed to identify changes in EMG latency and amplitudes that might explain the instabilities observed post-flight. Erect posture was tested having the subject stand on a pneumatically driven posture platform which pitched rapidly and unexpectedly about the ankles causing dorsi- and plantarflexion. Electromyographic (EMG) activity from the tibialis anterior and the gastrocnemius-soleus muscles was measured during eyes open and eyes closed trials. The early (pre 500 ms) EMG response characteristics (latency, amplitude) in response to a disturbance in the posture of the subject were apparently unchanged by the 10 days of weightlessness. However, the late (post 500 ms) response showed higher amplitudes than was found pre-flight. General postural control was quantitatively measured pre- and post-flight by a 'sharpened Romberg Rails test'. This test showed decrements in standing stability with eyes closed for several days post-flight.

Comparison of anti-siphon devices-how do they affect CSF dynamics in supine and upright posture?

PubMed

Gehlen, Manuel; Eklund, Anders; Kurtcuoglu, Vartan; Malm, Jan; Schmid Daners, Marianne

2017-08-01

Three different types of anti-siphon devices (ASDs) have been developed to counteract siphoning-induced overdrainage in upright posture. However, it is not known how the different ASDs affect CSF dynamics under the complex pressure environment seen in clinic due to postural changes. We investigated which ASDs can avoid overdrainage in upright posture best without leading to CSF accumulation. Three shunts each of the types Codman Hakim with SiphonGuard (flow-regulated), Miethke miniNAV with proSA (gravitational), and Medtronic Delta (membrane controlled) were tested. The shunts were compared on a novel in vitro setup that actively emulates the physiology of a shunted patient. This testing method allows determining the CSF drainage rates, resulting CSF volume, and intracranial pressure in the supine, sitting, and standing posture. The flow-regulated ASDs avoided increased drainage by closing their primary flow path when drainage exceeded 1.39 ± 0.42 mL/min. However, with intraperitoneal pressure increased in standing posture, we observed reopening of the ASD in 3 out of 18 experiment repetitions. The adjustable gravitational ASDs allow independent opening pressures in horizontal and vertical orientation, but they did not provide constant drainage in upright posture (0.37 ± 0.03 mL/min and 0.26 ± 0.03 mL/min in sitting and standing posture, respectively). Consequently, adaptation to the individual patient is critical. The membrane-controlled ASDs stopped drainage in upright posture. This eliminates the risk of overdrainage, but leads to CSF accumulation up to the volume observed without shunting when the patient is upright. While all tested ASDs reduced overdrainage, their actual performance will depend on a patient's specific needs because of the large variation in the way the ASDs influence CSF dynamics: while the flow-regulated shunts provide continuous drainage in upright posture, the gravitational ASDs allow and require additional adaptation, and the membrane

Feasibility of magnetic resonance imaging (MRI) in obtaining nucleus pulposus (NP) water content with changing postures.

PubMed

Nazari, Jalil; Pope, Malcolm H; Graveling, Richard A

2015-05-01

Opportunities to evaluate spinal loading in vivo are limited and a large majority of studies on the mechanical functions of the spine have been in vitro cadaveric studies and/or models based on many assumptions that are difficult to validate. The purpose of this study was to investigate the feasibility of magnetic resonance imaging (MRI) in obtaining nucleus pulposus (NP) water content measurements with changing postures. MRI studies were conducted on 25 healthy males with no history of low back pain (age 20-38). The L1 to S1 intradiscal levels were imaged in supine, sitting and standing postures using an upright 0.6 Tesla magnet, where a set of H2O: D2O7 phantoms were mounted on the back of the subjects. A calibration curve, provided from these phantoms, was applied to the absolute proton density image, yielding a pixel-by-pixel map of the water content of the NP. The NP at all levels showed a highly significant water loss (p<0.001) in sitting and standing postures compared with the supine posture. A trend towards higher levels of water was observed at all levels in the standing posture relative to sitting postures, however statistically significant differences were found only at L4-L5 and L5-S1 levels. This study demonstrates that variations in water content of the NP in different postures are in agreement with those determined from published invasive disc pressure measurements. The result of study demonstrates the feasibility of using MRI to determine the water content of the NP with changing postures and to use these data to evaluate spinal loading in these postures. This measurement method of water content by quantitative MR imaging could become a powerful tool for both clinical and ergonomic applications. The proposed methodology does not require invasive pressure measurement techniques. Copyright © 2015 Elsevier Inc. All rights reserved.

Motor Difficulties in Autism Spectrum Disorder: Linking Symptom Severity and Postural Stability

ERIC Educational Resources Information Center

Travers, Brittany G.; Powell, Patrick S.; Klinger, Laura G.; Klinger, Mark R.

2013-01-01

Postural stability is a fundamental aspect of motor ability that allows individuals to sustain and maintain the desired physical position of one's body. The present study examined postural stability in average-IQ adolescents and adults with Autism Spectrum Disorder (ASD). Twenty-six individuals with ASD and 26 age-and-IQ-matched individuals…

Differences in intermittent postural control between normal-weight and obese children.

PubMed

Villarrasa-Sapiña, Israel; García-Massó, Xavier; Serra-Añó, Pilar; Garcia-Lucerga, Consolación; Gonzalez, Luis-Millán; Lurbe, Empar

2016-09-01

The main objective of this study was to determine differences in postural control between obese and non-obese children. The study design was cross-sectional, prospective, between-subjects. Postural control variables were obtained from a group of obese children and a normal-weight control group under two different postural conditions: bipedal standing position with eyes open and bipedal standing with eyes closed. Variables were obtained for each balance condition using time domain and sway-density plot analysis of the center of pressure signals acquired by means of a force plate. Pairwise comparisons revealed significant differences between obese and normal-weight children in mean velocity in antero-posterior and medio-lateral directions, ellipse area and mean distance with both eyes open and eyes closed. Normal-weight subjects obtained lower values in all these variables than obese subjects. Furthermore, there were differences between both groups in mean peaks with eyes open and in mean time with eyes closed. Alterations were detected in the intermittent postural control in obese children. According to the results obtained, active anticipatory control produces higher center of pressure displacement responses in obese children and the periods during which balance is maintained by passive control and reflex mechanisms are of shorter duration. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of standing on neurohumoral responses and plasma volume in healthy subjects

NASA Technical Reports Server (NTRS)

Jacob, G.; Ertl, A. C.; Shannon, J. R.; Furlan, R.; Robertson, R. M.; Robertson, D.

1998-01-01

Upright posture leads to rapid pooling of blood in the lower extremities and shifts plasma fluid into surrounding tissues. This results in a decrease in plasma volume (PV) and in hemoconcentration. There has been no integrative evaluation of concomitant neurohumoral and PV shifts with upright posture in normal subjects. We studied 10 healthy subjects after 3 days of stable Na+ and K+ intake. PV was assessed by the Evans blue dye method and by changes in hematocrit. Norepinephrine (NE), NE spillover, epinephrine (Epi), vasopressin, plasma renin activity, aldosterone, osmolarity, and kidney response expressed by urine osmolality and by Na+ and K+ excretion of the subjects in the supine and standing postures were all measured. We found that PV fell by 13% (375 +/- 35 ml plasma) over approximately 14 min, after which time it remained relatively stable. There was a concomitant decrease in systolic blood pressure and an increase in heart rate that peaked at the time of maximal decrease in PV. Plasma Epi and NE increased rapidly to this point. Epi approached baseline by 20 min of standing. NE spillover increased 80% and clearance decreased 30% with 30 min of standing. The increase in plasma renin activity correlated with an increase in aldosterone. Vasopressin increased progressively, but there was no change in plasma osmolarity. The kidney response showed a significant decrease in Na+ and an increase in K+ excretion with upright posture. We conclude that a cascade of neurohumoral events occurs with upright posture, some of which particularly coincide with the decrease in PV. Plasma Epi levels may contribute to the increment in heart rate with maintained upright posture.

Postural orientation in microgravity depends on straightening up movement performed

NASA Astrophysics Data System (ADS)

Vaugoyeau, Marianne; Assaiante, Christine

2009-08-01

Whether the vertical body orientation depends on the initial posture and/or the type of straightening up movement is the main question raised in this paper. Another objective was to specify the compensatory role of visual input while adopting an erected posture during microgravity. The final body orientation was analysed in microgravity during parabolic flights. After either (1) straightening up movement from a crouching or (2) a sitting posture, with and without vision. The main results are the following: (1) a vertical erected final posture is correctly achieved after sit to stand movement, whereas all subjects were tilted forward after straightening up from a crouching posture and (2) vision may contribute to correct final posture. These results suggest the existence of a re-weighting of the remaining sensory information, visual information, contact cutaneous cues and proprioceptive information under microgravity condition. We can put forward the alternative hypothesis that the control of body orientation under microgravity condition may also be achieved on the basis of a postural body scheme, that seems to be dependant on the type of movement and/ or the initial position of the whole body.

The effects of upper and lower limb position on symmetry of vertical ground reaction force during sit-to-stand in chronic stroke subjects

PubMed Central

Lee, Jae Hong; Min, Dong Ki; Choe, Han Seong; Lee, Jin Hwan; Shin, So Hong

2018-01-01

[Purpose] The purpose of this study was to evaluate the influence of arm and leg posture elements on symmetrical weight bearing during Sit to Stand tasks in chronic stroke patients. [Subjects and Methods] The subjects were diagnosed with stroke and 22 patients (15 males and 7 females) participated in this study. All participants performed Sit to Stand tasks on three foot postures and two arm postures. Two force plates were used to measure peak of vertical ground reaction force and symmetrical ratio to peak Fz. The data were analyzed using independent t-test and two-way repeated ANOVA. [Results] The results of this study are as follows: 1) Peak Fz placed more weight in non-paretic leg during Sit to Stand. 2) A symmetrical ratio to Peak Fz indicated significant difference between foot and arm posture, and had non-paretic limb supported on a step and paretic at ground level (STP) and grasped arm posture that lock fingers together with shoulder flexion by 90°(GA) (0.79 ± 0.09). [Conclusion] These results suggest that STP posture of the legs and GA posture of the arms should be able to increase the use of the paretic side during Sit to Stand behavior and induce normal Sit to Stand mechanism through the anterior tilt of the hip in clinical practices, by which loads onto the knee joint and the ankle joint can be reduced, and the trunk righting response can be promoted by making the back fully stretched. The outcome of this study is expected to be a reference for exercise or prognosis of Sit to Stand in stroke patients. PMID:29545686

Standing postural instability in patients with schizophrenia: Relationships with psychiatric symptoms, anxiety, and the use of neuroleptic medications.

PubMed

Matsuura, Yukako; Fujino, Haruo; Hashimoto, Ryota; Yasuda, Yuka; Yamamori, Hidenaga; Ohi, Kazutaka; Takeda, Masatoshi; Imura, Osamu

2015-03-01

The purpose of this study was to assess postural instability in patients with schizophrenia using a pressure-sensitive platform and to examine the effects of anxiety, psychiatric symptoms, and the use of neuroleptic medications on postural sway. Participants were 23 patients with schizophrenia and 23 healthy controls. We found that the patients showed greater overall postural instability than the controls. Furthermore, they demonstrated greater instability when the test was performed with the eyes closed than with the eyes open. However, removal of visual input had less impact on the indices of postural instability in the patients than in the controls, suggesting that schizophrenia is associated with difficulties in integrating visual information and proprioceptive signals. Furthermore, in contrast to the controls, anxiety exacerbated postural instability in the patients. There were significant associations between postural stability and psychiatric symptoms in the patients without extrapyramidal symptoms, whereas medication dose did not significantly correlate with postural stability. Copyright © 2015 Elsevier B.V. All rights reserved.

Assessing Somatosensory Utilization during Unipedal Postural Control.

PubMed

Goel, Rahul; De Dios, Yiri E; Gadd, Nichole E; Caldwell, Erin E; Peters, Brian T; Reschke, Millard F; Bloomberg, Jacob J; Oddsson, Lars I E; Mulavara, Ajitkumar P

2017-01-01

Multisensory-visual, vestibular and somatosensory information is integrated for appropriate postural control. The primary goal of this study was to assess somatosensory utilization during a functional motor task of unipedal postural control, in normal healthy adults. Assessing individual bias in the utilization of individual sensory contributions during postural control may help customization of rehabilitation protocols. In this study, a test paradigm of unipedal stance control in supine orientation with and without vision was assessed. Postural control in this test paradigm was hypothesized to utilize predominantly contributions of somatosensory information from the feet and ankle joint, with minimal vestibular input. Fourteen healthy subjects "stood" supine on their dominant leg while strapped to a backpack frame that was freely moving on air-bearings, to remove available otolith tilt cues with respect to gravity that influences postural control when standing upright. The backpack was attached through a cable to a pneumatic cylinder that provided a gravity-like load. Subjects performed three trials each with Eyes-open (EO) and Eyes-closed (EC) while loaded with 60% body weight. There was no difference in unipedal stance time (UST) across the two conditions with EC condition challenging the postural control system greater than the EO condition. Stabilogram-diffusion analysis (SDA) indicated that the critical mean square displacement was significantly different between the two conditions. Vestibular cues, both in terms of magnitude and the duration for which relevant information was available for postural control in this test paradigm, were minimized. These results support our hypothesis that maintaining unipedal stance in supine orientation without vision, minimizes vestibular contribution and thus predominantly utilizes somatosensory information for postural control.

Assessing Somatosensory Utilization during Unipedal Postural Control

PubMed Central

Goel, Rahul; De Dios, Yiri E.; Gadd, Nichole E.; Caldwell, Erin E.; Peters, Brian T.; Reschke, Millard F.; Bloomberg, Jacob J.; Oddsson, Lars I. E.; Mulavara, Ajitkumar P.

2017-01-01

Multisensory—visual, vestibular and somatosensory information is integrated for appropriate postural control. The primary goal of this study was to assess somatosensory utilization during a functional motor task of unipedal postural control, in normal healthy adults. Assessing individual bias in the utilization of individual sensory contributions during postural control may help customization of rehabilitation protocols. In this study, a test paradigm of unipedal stance control in supine orientation with and without vision was assessed. Postural control in this test paradigm was hypothesized to utilize predominantly contributions of somatosensory information from the feet and ankle joint, with minimal vestibular input. Fourteen healthy subjects “stood” supine on their dominant leg while strapped to a backpack frame that was freely moving on air-bearings, to remove available otolith tilt cues with respect to gravity that influences postural control when standing upright. The backpack was attached through a cable to a pneumatic cylinder that provided a gravity-like load. Subjects performed three trials each with Eyes-open (EO) and Eyes-closed (EC) while loaded with 60% body weight. There was no difference in unipedal stance time (UST) across the two conditions with EC condition challenging the postural control system greater than the EO condition. Stabilogram-diffusion analysis (SDA) indicated that the critical mean square displacement was significantly different between the two conditions. Vestibular cues, both in terms of magnitude and the duration for which relevant information was available for postural control in this test paradigm, were minimized. These results support our hypothesis that maintaining unipedal stance in supine orientation without vision, minimizes vestibular contribution and thus predominantly utilizes somatosensory information for postural control. PMID:28443004

The Subjective Postural Vertical Determined in Patients with Pusher Behavior During Standing.

PubMed

Bergmann, Jeannine; Krewer, Carmen; Selge, Charlotte; Müller, Friedemann; Jahn, Klaus

2016-06-01

The subjective postural vertical (SPV), i.e., the perceived upright orientation of the body in relation to gravity, is disturbed in patients with pusher behavior. So far, the SPV has been measured only when these patients were sitting, and the results were contradictory as regards the side of the SPV deviation. The objective was to investigate the SPV in patients with different degrees of severity of pusher behavior while standing. Eight stroke patients with pusher behavior, ten age-matched stroke patients without pusher behavior, and ten age-matched healthy control subjects were included. The SPV (SPV error, SPV range) was assessed in the pitch and the roll planes. Pusher behavior was classified with the Burke Lateropulsion Scale (BLS). In the pitch plane, the SPV range was significantly larger in pusher patients than in patients without pusher behavior or healthy controls. The SPV error was similar for groups. In the roll plane, the SPV error and the SPV range were significantly larger and more ipsilesionally tilted in the pusher group than in the other two groups. There was a significant correlation between the SPV error in the roll plane and the BLS score. The study revealed that patients with pusher behavior had an ipsilesional SPV tilt that decreased with decreasing severity of the behavior. The large uncertainty in verticality estimation in both planes indicates that their sensitivity for the perception of verticality in space is generally disturbed. These findings emphasize the importance of specific rehabilitation approaches to recalibrate the impaired inner model of verticality.

Obesity Impact on the Attentional Cost for Controlling Posture

PubMed Central

Mignardot, Jean-Baptiste; Olivier, Isabelle; Promayon, Emmanuel; Nougier, Vincent

2010-01-01

Background This study investigated the effects of obesity on attentional resources allocated to postural control in seating and unipedal standing. Methods Ten non obese adults (BMI = 22.4±1.3, age = 42.4±15.1) and 10 obese adult patients (BMI = 35.2±2.8, age = 46.2±19.6) maintained postural stability on a force platform in two postural tasks (seated and unipedal). The two postural tasks were performed (1) alone and (2) in a dual-task paradigm in combination with an auditory reaction time task (RT). Performing the RT task together with the postural one was supposed to require some attentional resources that allowed estimating the attentional cost of postural control. 4 trials were performed in each condition for a total of 16 trials. Findings (1) Whereas seated non obese and obese patients exhibited similar centre of foot pressure oscillations (CoP), in the unipedal stance only obese patients strongly increased their CoP sway in comparison to controls. (2) Whatever the postural task, the additional RT task did not affect postural stability. (3) Seated, RT did not differ between the two groups. (4) RT strongly increased between the two postural conditions in the obese patients only, suggesting that body schema and the use of internal models was altered with obesity. Interpretation Obese patients needed more attentional resources to control postural stability during unipedal stance than non obese participants. This was not the case in a more simple posture such as seating. To reduce the risk of fall as indicated by the critical values of CoP displacement, obese patients must dedicate a strong large part of their attentional resources to postural control, to the detriment of non-postural events. Obese patients were not able to easily perform multitasking as healthy adults do, reflecting weakened psycho-motor abilities. PMID:21187914

The reliability and validity of the Saliba Postural Classification System.

PubMed

Collins, Cristiana Kahl; Johnson, Vicky Saliba; Godwin, Ellen M; Pappas, Evangelos

2016-07-01

To determine the reliability and validity of the Saliba Postural Classification System (SPCS). Two physical therapists classified pictures of 100 volunteer participants standing in their habitual posture for inter and intra-tester reliability. For validity, 54 participants stood on a force plate in a habitual and a corrected posture, while a vertical force was applied through the shoulders until the clinician felt a postural give. Data were extracted at the time the give was felt and at a time in the corrected posture that matched the peak vertical ground reaction force (VGRF) in the habitual posture. Inter-tester reliability demonstrated 75% agreement with a Kappa = 0.64 (95% CI = 0.524-0.756, SE = 0.059). Intra-tester reliability demonstrated 87% agreement with a Kappa = 0.8, (95% CI = 0.702-0.898, SE = 0.05) and 80% agreement with a Kappa = 0.706, (95% CI = 0.594-0818, SE = 0.057). The examiner applied a significantly higher (p < 0.001) peak vertical force in the corrected posture prior to a postural give when compared to the habitual posture. Within the corrected posture, the %VGRF was higher when the test was ongoing vs. when a postural give was felt (p < 0.001). The %VGRF was not different between the two postures when comparing the peaks (p = 0.214). The SPCS has substantial agreement for inter- and intra-tester reliability and is largely a valid postural classification system as determined by the larger vertical forces in the corrected postures. Further studies on the correlation between the SPCS and diagnostic classifications are indicated.

Postural threat influences vestibular-evoked muscular responses.

PubMed

Lim, Shannon B; Cleworth, Taylor W; Horslen, Brian C; Blouin, Jean-Sébastien; Inglis, J Timothy; Carpenter, Mark G

2017-02-01

Standing balance is significantly influenced by postural threat. While this effect has been well established, the underlying mechanisms of the effect are less understood. The involvement of the vestibular system is under current debate, and recent studies that investigated the effects of height-induced postural threat on vestibular-evoked responses provide conflicting results based on kinetic (Horslen BC, Dakin CJ, Inglis JT, Blouin JS, Carpenter MG. J Physiol 592: 3671-3685, 2014) and kinematic (Osler CJ, Tersteeg MC, Reynolds RF, Loram ID. Eur J Neurosci 38: 3239-3247, 2013) data. We examined the effect of threat of perturbation, a different form of postural threat, on coupling (cross-correlation, coherence, and gain) of the vestibulo-muscular relationship in 25 participants who maintained standing balance. In the "No-Threat" conditions, participants stood quietly on a stable surface. In the "Threat" condition, participants' balance was threatened with unpredictable mediolateral support surface tilts. Quiet standing immediately before the surface tilts was compared to an equivalent time from the No-Threat conditions. Surface EMG was recorded from bilateral trunk, hip, and leg muscles. Hip and leg muscles exhibited significant increases in peak cross-correlation amplitudes, coherence, and gain (1.23-2.66×) in the Threat condition compared with No-Threat conditions, and significant correlations were observed between threat-related changes in physiological arousal and medium-latency peak cross-correlation amplitude in medial gastrocnemius (r = 0.408) muscles. These findings show a clear threat effect on vestibular-evoked responses in muscles in the lower body, with less robust effects of threat on trunk muscles. Combined with previous work, the present results can provide insight into observed changes during balance control in threatening situations. This is the first study to show increases in vestibular-evoked responses of the lower body muscles under conditions

Regularity of center-of-pressure trajectories depends on the amount of attention invested in postural control

PubMed Central

Donker, Stella F.; Roerdink, Melvyn; Greven, An J.

2007-01-01

The influence of attention on the dynamical structure of postural sway was examined in 30 healthy young adults by manipulating the focus of attention. In line with the proposed direct relation between the amount of attention invested in postural control and regularity of center-of-pressure (COP) time series, we hypothesized that: (1) increasing cognitive involvement in postural control (i.e., creating an internal focus by increasing task difficulty through visual deprivation) increases COP regularity, and (2) withdrawing attention from postural control (i.e., creating an external focus by performing a cognitive dual task) decreases COP regularity. We quantified COP dynamics in terms of sample entropy (regularity), standard deviation (variability), sway-path length of the normalized posturogram (curviness), largest Lyapunov exponent (local stability), correlation dimension (dimensionality) and scaling exponent (scaling behavior). Consistent with hypothesis 1, standing with eyes closed significantly increased COP regularity. Furthermore, variability increased and local stability decreased, implying ineffective postural control. Conversely, and in line with hypothesis 2, performing a cognitive dual task while standing with eyes closed led to greater irregularity and smaller variability, suggesting an increase in the “efficiency, or “automaticity” of postural control”. In conclusion, these findings not only indicate that regularity of COP trajectories is positively related to the amount of attention invested in postural control, but also substantiate that in certain situations an increased internal focus may in fact be detrimental to postural control. PMID:17401553

Specificity of Postural Sway to the Demands of a Precision Task at Sea

ERIC Educational Resources Information Center

Chen, Fu-Chen; Stoffregen, Thomas A.

2012-01-01

Mariners actively adjust their body orientation in response to ship motion. On a ship at sea, we evaluated relations between standing postural activity and the performance of a precision aiming task. Standing participants (experienced mariners) maintained the beam from a handheld laser on a target. Targets were large or small, thereby varying the…

Bipedal distribution of human vestibular-evoked postural responses during asymmetrical standing

PubMed Central

Marsden, J F; Castellote, J; Day, B L

2002-01-01

Galvanic vestibular stimulation (GVS) evokes responses in muscles of both legs when bilateral stimuli are applied during normal stance. We have used this technique to assess whether asymmetrical standing alters the distribution of responses in the two legs. Subjects stood either asymmetrically with 75 % of their body weight on one leg or symmetrically with each leg taking 50 % of their body weight. The net response in each leg was taken from changes in ground reaction force measured from separate force plates under each foot. The net force profile consisted of a small initial force change that peaked at ∼200 ms followed by an oppositely directed larger component that peaked at ∼450 ms. We analysed the second force component since it was responsible for the kinematic response of lateral body sway and tilt towards the anode. In the horizontal plane, both legs produced lateral force responses that were in the same direction but larger in the leg ipsilateral to the cathodal ear. There were also vertical force responses that were of equal size in both legs but acted in opposite directions. When subjects stood asymmetrically the directions of the force responses remained the same but their magnitudes changed. The lateral force response became 2-3 times larger for the more loaded leg and the vertical forces increased 1.5 times on average for both legs. Control experiments showed that these changes could not be explained by either the consistent (< 5 deg) head tilt towards the side of the loaded leg or the changes in background muscle activity associated with the asymmetrical posture. We conclude that the redistribution of force responses in the two legs arises from a load-sensing mechanism. We suggest there is a central interaction between load-related afferent input from the periphery and descending motor signals from balance centres. PMID:12096073

The role of the antigravity musculature during quiet standing in man.

PubMed

Soames, R W; Atha, J

1981-01-01

The view that postural regulation is achieved by controlling the destabilising effects of gravity through myotatic reflex activity was examined using surface electromyography. Forty seconds of recordings were made of myograms from eighteen muscles in each of a sample of nine young adults. It was observed that antigravity muscular activity in standing is generally low and often absent, and that the myograms from the muscles of the right and left sides of the body differed appreciably, the two sides rarely working together. Some sudden and united bursts of antigravity muscle activity could be observed. These might well have been stretch reflex induced, but they were transient and rare. It is concluded that the view that postural control in quiet standing is continuously mediated in a simple way by stretch reflex mechanisms is probably not valid, and that other mechanisms for controlling posture remain to be identified.

Prevalence of frontal plane pelvic postural asymmetry--part 1.

PubMed

Juhl, John Henry; Ippolito Cremin, Tonya M; Russell, George

2004-10-01

Despite 80 years of study, questions of how leg length difference relates to recurrent pain and somatic dysfunction remain controversial. The authors hypothesize that a correlation exists between leg length inequality and back pain. They further hypothesize that if common compensatory patterns described in classic osteopathic medical literature exist, these patterns should interact with the pelvic postural asymmetry patterns of Lloyd and Eimerbrink in a predictable, most probable, and congruent fashion. This article reviews the osteopathic medical, as well as the allopathic medical and chiropractic literature for studies that meet criteria for evidence-based comparison. Using lumbar radiographic studies produced with subjects standing, the authors examined the prevalence of six types of pelvic postural asymmetry in a consecutive case series of 421 patients with low back pain. Establishing the frequency of pelvic postural asymmetry patterns is a necessary first step in creating an evidence-based foundation to further clarify postural compensatory patterns. Various correlations between and within these patterns are identified.

Effect of Social Stimuli on Postural Responses in Individuals with Autism Spectrum Disorder

ERIC Educational Resources Information Center

Ghanouni, Parisa; Memari, Amir-Hossein; Gharibzadeh, Shahriar; Eghlidi, Jandark; Moshayedi, Pouria

2017-01-01

This study was aimed to investigate the effects of social versus non-social stimuli on postural responses in 21 boys with autism spectrum disorder (ASD) (mean age of 11.6 ± 1.5) compared with 30 typically developing (TD) boys (mean age of 11.7 ± 1.8). Postural control of children was examined while they were standing on a force plate and viewing…

The lumbosacral segment as a vulnerable region in various postures

NASA Technical Reports Server (NTRS)

Rosemeyer, B.

1978-01-01

The lumbosacral region in man is exposed to special static and dynamic load. In a supine position, the disc size increases because of the absence of axial load. In a standing position, with physiological posture of the spine, strain discomfort occurs which is increased even more in the sitting position due to the curvature of the lumbar region of the spine and the irregular distribution of pressure in the discs as a result of this. This special problem of sitting posture can be confirmed by examinations.

Posture in ovo as a precursor of footedness in ostriches (Struthio camelus).

PubMed

Baciadonna, Luigi; Zucca, Paolo; Tommasi, Luca

2010-01-01

Two categories of behaviour involving lateralized posture were observed in semi-natural conditions in ostriches (Struthio camelus). Observing preferences for left or right foot, both in the forward foot posture (the foot standing in front at rest) and the starting foot used to initiate locomotion, a population-level right-foot preference was shown for the whole group and for each of the three age ranges considered (chick, young and adult). Ostriches are known to rely upon a lateralized behaviour during hatching (using their right foot to break the egg shell) suggesting the hypothesis that the precocious motor laterality observed at hatching might stand as a precursor of limb preference later in development, as already observed in other avian species. 2009 Elsevier B.V. All rights reserved.

The Effects of Slackline Balance Training on Postural Control in Older Adults.

PubMed

Thomas, Monika; Kalicinski, Michael

2016-07-01

The present study investigated whether slackline training enhances postural control in older adults. Twenty-four participants were randomized into an intervention and a control group. The intervention group received 6 weeks of slackline training, two times per week. Pre-post measurement included the time of different standing positions on a balance platform with and without an external disturbance and the acceleration of the balance platform. Results showed significantly improved standing times during one-leg stance without external disturbance and a significantly reduced acceleration of the balance platform for the intervention group after the training period during tandem stance with and without an external disturbance. We conclude that slackline training in older adults has a positive impact on postural control and thus on the reduction of fall risk.

The influence of a seated break on prolonged standing induced low back pain development.

PubMed

Gallagher, Kaitlin M; Campbell, Troy; Callaghan, Jack P

2014-01-01

With the recent attention to 'sitting disease', health practitioners and scientists are promoting standing in the workplace to decrease sedentary time, despite a high prevalence of low back pain (LBP) development during prolonged standing. The purpose of this study was to assess how a seated break inserted between bouts of prolonged standing would influence LBP development, posture and movement. A total of 20 participants stood for 45 minutes, sat for 15 minutes and repeated this sequence while lumbar and thoracic angles were measured, and LBP visual analogue scale reports were taken. Of the sample, 55% participants reported LBP in standing. A stand to sit ratio of 3:1 did not provide lasting recovery of LBP from standing and pain developers utilised a limited range of their lumbar spine angle and increased thoracic extension, resulting in static postures that caused tissue aggravation that was not resolved after 15 minutes of sitting. Prolonged standing in the workplace has the potential to result in LBP for some workers and alternate ways to reduce sedentary time should be investigated.

Posture, Flexibility and Grip Strength in Horse Riders

PubMed Central

Hobbs, Sarah Jane; Baxter, Joanna; Broom, Louise; Rossell, Laura-Ann; Sinclair, Jonathan; Clayton, Hilary M

2014-01-01

Since the ability to train the horse to be ambidextrous is considered highly desirable, rider asymmetry is recognized as a negative trait. Acquired postural and functional asymmetry can originate from numerous anatomical regions, so it is difficult to suggest if any is developed due to riding. The aim of this study was therefore to assess symmetry of posture, strength and flexibility in a large population of riders and to determine whether typical traits exist due to riding. 127 right handed riders from the UK and USA were categorized according to years riding (in 20 year increments) and their competition level (using affiliated test levels). Leg length, grip strength and spinal posture were measured and recorded by a physiotherapist. Standing and sitting posture and trunk flexibility were measured with 3-D motion capture technology. Right-left differences were explored in relation to years riding and rider competitive experience. Significant anatomical asymmetry was found for the difference in standing acromion process height for a competition level (−0.07±1.50 cm Intro/Prelim; 0.02±1.31 cm Novice; 0.43±1.27 cm Elementary+; p=0.048) and for sitting iliac crest height for years riding (−0.23±1.36 cm Intro/Prelim; 0.01±1.50 cm Novice; 0.86±0.41 cm Elementary+; p=0.021). For functional asymmetry, a significant interaction was found for lateral bending ROM for years riding x competition level (p=0.047). The demands on dressage riders competing at higher levels may predispose these riders to a higher risk of developing asymmetry and potentially chronic back pain rather than improving their symmetry. PMID:25414745

The reliability and validity of the Saliba Postural Classification System

PubMed Central

Collins, Cristiana Kahl; Johnson, Vicky Saliba; Godwin, Ellen M.; Pappas, Evangelos

2016-01-01

Objectives To determine the reliability and validity of the Saliba Postural Classification System (SPCS). Methods Two physical therapists classified pictures of 100 volunteer participants standing in their habitual posture for inter and intra-tester reliability. For validity, 54 participants stood on a force plate in a habitual and a corrected posture, while a vertical force was applied through the shoulders until the clinician felt a postural give. Data were extracted at the time the give was felt and at a time in the corrected posture that matched the peak vertical ground reaction force (VGRF) in the habitual posture. Results Inter-tester reliability demonstrated 75% agreement with a Kappa = 0.64 (95% CI = 0.524–0.756, SE = 0.059). Intra-tester reliability demonstrated 87% agreement with a Kappa = 0.8, (95% CI = 0.702–0.898, SE = 0.05) and 80% agreement with a Kappa = 0.706, (95% CI = 0.594–0818, SE = 0.057). The examiner applied a significantly higher (p < 0.001) peak vertical force in the corrected posture prior to a postural give when compared to the habitual posture. Within the corrected posture, the %VGRF was higher when the test was ongoing vs. when a postural give was felt (p < 0.001). The %VGRF was not different between the two postures when comparing the peaks (p = 0.214). Discussion The SPCS has substantial agreement for inter- and intra-tester reliability and is largely a valid postural classification system as determined by the larger vertical forces in the corrected postures. Further studies on the correlation between the SPCS and diagnostic classifications are indicated. PMID:27559288

Activation timing of postural muscles of lower legs and prediction of postural disturbance during bilateral arm flexion in older adults.

PubMed

Yaguchi, Chie; Fujiwara, Katsuo; Kiyota, Naoe

2017-12-22

Activation timings of postural muscles of lower legs and prediction of postural disturbance were investigated in young and older adults during bilateral arm flexion in a self-timing task and an oddball task with different probabilities of target presentation. Arm flexion was started from a standing posture with hands suspended 10 cm below the horizontal level in front of the body, in which postural control focused on the ankles is important. Fourteen young and 14 older adults raised the arms in response to the target sound signal. Three task conditions were used: 15 and 45% probabilities of the target in the oddball task and self-timing. Analysis items were activation timing of postural muscles (erector spinae, biceps femoris, and gastrocnemius) with respect to the anterior deltoid (AD), and latency and amplitude of the P300 component of event-related brain potential. For young adults, all postural muscles were activated significantly earlier than AD under each condition, and time of preceding gastrocnemius activation was significantly longer in the order of the self-timing, 45 and 15% conditions. P300 latency was significantly shorter, and P300 amplitude was significantly smaller under the 45% condition than under the 15% condition. For older adults, although all postural muscles, including gastrocnemius, were activated significantly earlier than AD in the self-timing condition, only activation timing of gastrocnemius was not significantly earlier than that of AD in oddball tasks, regardless of target probability. No significant differences were found between 15 and 45% conditions in onset times of all postural muscles, and latency and amplitude of P300. These results suggest that during arm movement, young adults can achieve sufficient postural preparation in proportion to the probability of target presentation in the oddball task. Older adults can achieve postural control using ankle joints in the self-timing task. However, in the oddball task, older adults

Reliability and concurrent validity of postural asymmetry measurement in adolescent idiopathic scoliosis

PubMed Central

Prowse, Ashleigh; Aslaksen, Berit; Kierkegaard, Marie; Furness, James; Gerdhem, Paul; Abbott, Allan

2017-01-01

AIM To investigate the reliability and concurrent validity of the Baseline® Body Level/Scoliosis meter for adolescent idiopathic scoliosis postural assessment in three anatomical planes. METHODS This is an observational reliability and concurrent validity study of adolescent referrals to the Orthopaedic department for scoliosis screening at Karolinska University Hospital, Stockholm, Sweden between March-May 2012. A total of 31 adolescents with idiopathic scoliosis (13.6 ± 0.6 years old) of mild-moderate curvatures (25° ± 12°) were consecutively recruited. Measurement of cervical, thoracic and lumbar curvatures, pelvic and shoulder tilt, and axial thoracic rotation (ATR) were performed by two trained physiotherapists in one day. The intraclass correlation coefficient (ICC) was used to determine the inter-examiner reliability (ICC2,1) and the intra-rater reliability (ICC3,3) of the Baseline® Body Level/Scoliosis meter. Spearman’s correlation analyses were used to estimate concurrent validity between the Baseline® Body Level/Scoliosis meter and Gold Standard Cobb angles from radiographs and the Orthopaedic Systems Inc. Scoliometer. RESULTS There was excellent reliability between examiners for thoracic kyphosis (ICC2,1 = 0.94), ATR (ICC2,1 = 0.92) and lumbar lordosis (ICC2,1 = 0.79). There was adequate reliability between examiners for cervical lordosis (ICC2,1 = 0.51), however poor reliability for pelvic and shoulder tilt. Both devices were reproducible in the measurement of ATR when repeated by one examiner (ICC3,3 0.98-1.00). The device had a good correlation with the Scoliometer (rho = 0.78). When compared with Cobb angle from radiographs, there was a moderate correlation for ATR (rho = 0.627). CONCLUSION The Baseline® Body Level/Scoliosis meter provides reliable transverse and sagittal cervical, thoracic and lumbar measurements and valid transverse plan measurements of mild-moderate scoliosis deformity. PMID:28144582

Reliability and concurrent validity of postural asymmetry measurement in adolescent idiopathic scoliosis.

PubMed

Prowse, Ashleigh; Aslaksen, Berit; Kierkegaard, Marie; Furness, James; Gerdhem, Paul; Abbott, Allan

2017-01-18

To investigate the reliability and concurrent validity of the Baseline ® Body Level/Scoliosis meter for adolescent idiopathic scoliosis postural assessment in three anatomical planes. This is an observational reliability and concurrent validity study of adolescent referrals to the Orthopaedic department for scoliosis screening at Karolinska University Hospital, Stockholm, Sweden between March-May 2012. A total of 31 adolescents with idiopathic scoliosis (13.6 ± 0.6 years old) of mild-moderate curvatures (25° ± 12°) were consecutively recruited. Measurement of cervical, thoracic and lumbar curvatures, pelvic and shoulder tilt, and axial thoracic rotation (ATR) were performed by two trained physiotherapists in one day. The intraclass correlation coefficient (ICC) was used to determine the inter-examiner reliability (ICC2,1) and the intra-rater reliability (ICC3,3) of the Baseline ® Body Level/Scoliosis meter. Spearman's correlation analyses were used to estimate concurrent validity between the Baseline ® Body Level/Scoliosis meter and Gold Standard Cobb angles from radiographs and the Orthopaedic Systems Inc. Scoliometer. There was excellent reliability between examiners for thoracic kyphosis (ICC2,1 = 0.94), ATR (ICC2,1 = 0.92) and lumbar lordosis (ICC2,1 = 0.79). There was adequate reliability between examiners for cervical lordosis (ICC2,1 = 0.51), however poor reliability for pelvic and shoulder tilt. Both devices were reproducible in the measurement of ATR when repeated by one examiner (ICC3,3 0.98-1.00). The device had a good correlation with the Scoliometer (rho = 0.78). When compared with Cobb angle from radiographs, there was a moderate correlation for ATR (rho = 0.627). The Baseline ® Body Level/Scoliosis meter provides reliable transverse and sagittal cervical, thoracic and lumbar measurements and valid transverse plan measurements of mild-moderate scoliosis deformity.

Analysis of WBV on standing and seated passengers during off-peak operation in KL monorail

NASA Astrophysics Data System (ADS)

Hasnan, K.; Bakhsh, Q.; Ahmed, A.; Ali, D.; Jamali, A. R.

2018-03-01

In this study, the Whole-Body Vibration (WBV) was analyzed on the standing and seated passenger during off-peak operating hours when train was on the track. The experiments were conducted on two car train at one constant location (bogie-1, which is near to driver’s cabin) during downward direction from KL sentral station towards Titiwangsa station. The aim of this study was to analyze that, in which posture of passenger’s exposures the maximum level of WBV. Since, one passenger was performed the whole journey in standing posture whereas, the other passenger was in seated posture. The result obtained from experiments for the RMS accelerations (Arms), maximum acceleration (Amax) and minimum acceleration (Amin) during the trip. As per standard ISO 2631-1, the daily vibration exposure (A8), Vibration Dose value (VDV) and Crest Factor (CF) of this trip for both standing and sitting orientations were calculated. Results shows that the seated passenger was exposed to longer periods of continuous vibration as compared to the standing passenger. Whereas, the Vibration Dose value (VDV) value was greater than the action value as per ISO 2631-1 and within the limit values. The study concluded that whole body vibration transmitted towards both passengers either standing or seated during their journey. But in overall results comparison of both orientations, the seated passengers gained higher vibration than the standing one.

The relationship beween posture and back muscle endurance in industrial workers with flexion-related low back pain.

PubMed

O'Sullivan, Peter B; Mitchell, Tim; Bulich, Paul; Waller, Rob; Holte, Johan

2006-11-01

This preliminary cross-sectional study was undertaken to determine if there were measurable relationships between posture, back muscle endurance and low back pain (LBP) in industrial workers with a reported history of flexion strain injury and flexion pain provocation. Clinical reports state that subjects with flexion pain disorders of the lumbar spine commonly adopt passive flexed postures such as slump sitting and present with associated dysfunction of the spinal postural stabilising musculature. However, to date there is little empirical evidence to support that patients with back pain, posture their spines differently than pain-free subjects. Subjects included 21 healthy industrial workers and 24 industrial workers with flexion-provoked LBP. Lifestyle information, lumbo-pelvic posture in sitting, standing and lifting, and back muscle endurance were measured. LBP subjects had significantly reduced back muscle endurance (P < 0.01). LBP subjects sat with less hip flexion, (P = 0.05), suggesting increased posterior pelvic tilt in sitting. LBP subjects postured their spines significantly closer to their end of range lumbar flexion in 'usual' sitting than the healthy controls (P < 0.05). Correlations between increased time spent sitting, physical inactivity and poorer back muscle endurance were also identified. There were no significant differences found between the groups for the standing and lifting posture measures. These preliminary results support that a relationship may exist between flexed spinal postures, reduced back muscle endurance, physical inactivity and LBP in subjects with a history of flexion injury and pain.

Three components of postural control associated with pushing in symmetrical and asymmetrical stance.

PubMed

Lee, Yun-Ju; Aruin, Alexander S

2013-07-01

A number of occupational and leisure activities that involve pushing are performed in symmetrical or asymmetrical stance. The goal of this study was to investigate early postural adjustments (EPAs), anticipatory postural adjustments (APAs), and compensatory postural adjustments (CPAs) during pushing performed while standing. Ten healthy volunteers stood in symmetrical stance (with feet parallel) or in asymmetrical stance (staggered stance with one foot forward) and were instructed to use both hands to push forward the handle of a pendulum attached to the ceiling. Bilateral EMG activity of the trunk and leg muscles and the center of pressure (COP) displacements in the anterior-posterior (AP) and medial-lateral (ML) directions were recorded and analyzed during the EPAs, APAs, and CPAs. The EMG activity and the COP displacement were different between the symmetrical and asymmetrical stance conditions. The COP displacements in the ML direction were significantly larger in staggered stance than in symmetrical stance. In staggered stance, the EPAs and APAs in the thigh muscles of the backward leg were significantly larger, and the CPAs were smaller than in the forward leg. There was no difference in the EMG activity of the trunk muscles between the stance conditions. The study outcome confirmed the existence of the three components of postural control (EPAs, APAs, and CPAs) in pushing. Moreover, standing asymmetrically was associated with asymmetrical patterns of EMG activity in the lower extremities reflecting the stance-related postural control during pushing. The study outcome provides a basis for studying postural control during other daily activities involving pushing.

Differences in body posture, strength and flexibility in schoolchildren with overweight and obesity: A quasi-experimental study.

PubMed

Schwanke, Natalí Lippert; Pohl, Hildegard Hedwig; Reuter, Cézane Priscila; Borges, Tássia Silvana; de Souza, Sonimar; Burgos, Miria Suzana

2016-04-01

Body posture and its components have been widely discussed, given the high prevalence of musculoskeletal disorders in children and adolescents. Among children and adolescents with overweight and obesity issues, these changes can be pronounced. This study sought to investigate whether a global exercise routine could result in positive changes in the angles and distances measured in postural assessments and in the number of abdominal and flexibility exercise repetitions performed by children and adolescents with overweight or obesity. A quasi-experimental design including an experimental group (EG) and a control group (CG) was used. The primary outcome variables included ratings of body posture (using SAPO software) and measures of abdominal muscle strength (number of sit-ups) and flexibility. The EG received an interdisciplinary intervention the included 48 sessions of global postural exercises performed three times a week. Of the 46 schoolchildren evaluated (EG, n = 23 and CG, n = 23), significant changes were observed in the EG from pre-to post-test in the thoracic angle (p = 0.001) and abdominal muscle strength (p = 0.016) for boys and in the thoracic angle (p = 0.010), abdominal muscle strength (p = 0.003) and flexibility (p = 0.010) for girls. Overall, the exercise program led to changes in the angle and distance measurements obtained in postural evaluations and contributed to increases in the number of repetitions of abdominal and flexibility exercises, indicating improvements in the EG group's body posture and health indicators. Copyright © 2015 Elsevier Ltd. All rights reserved.

Attenuated or absent HRV response to postural change in subjects with primary insomnia.

PubMed

Jiang, Xiao-ling; Zhang, Zheng-gang; Ye, Cui-ping; Lei, Ying; Wu, Lei; Zhang, Ying; Chen, Yuan-yuan; Xiao, Zhong-ju

2015-03-01

Previous studies have compared rest heart rate variability (HRV) between insomniacs and good sleepers, but the results have not been consistent. The altered HRV behavior in response to postural change was considered useful as another sensitive measure for evaluating the autonomic nervous function, however, to our knowledge, no study was found using HRV response to postural change in primary insomnia. Our study aimed to examine HRV response to postural change maneuver (PCM) in both primary insomniacs and controls between 22 and 39 years of age to gain insights into the characteristics of the autonomic nervous system (ANS) function in primary insomnia subjects. HRV was recorded for 5 min at seated rest, and then, the subjects quickly stood up from a seated position in up to 3s and remained standing for 15 min. HRV was recorded at the following times: seated rest and 0-5 min, 5-10 min and 10-15 min in the standing position. In primary insomnia subjects, attenuated or absent HRV response to postural change was identified, the increase in LF/HF ratio and the decrease in HF and SD1 from seated to standing were much slower than in the normal controls. In conclusion, this study provided evidence of the possible bi-directional relationship between insomnia and autonomic nervous system (ANS) function, which will move us closer to developing a new sensitive method for measuring autonomic impairment and early sympathetic damage in primary insomnia subjects. Copyright © 2015 Elsevier Inc. All rights reserved.

Postural synergies associated with a stepping task.

PubMed

Mercer, V S; Sahrmann, S A

1999-12-01

Synergistic relationships among multiple muscle components are thought to exist to simplify control of posture and movement. The purpose of this study was to examine the extent to which children, young adults, and older adults exhibit consistent sequences of postural muscle activation when lifting the right foot onto a step from a standing position. Twenty subjects without known impairments of the neuromuscular system (10 male, 10 female) in each of 3 age groups--children (8-12 years), young adults (25-35 years), and older adults (65-73 years)--participated. A pressure switch taped to the subject's right foot was used to determine movement onset and offset. Latencies of muscle activation were determined using surface electromyography. A preferred postural synergy was defined as the sequence of postural muscle activation observed during the majority of trials for each subject. Mean movement times did not differ among age groups. Although the left tibialis anterior (TA) muscle was the first of the postural muscles activated in 93% of the trials, subjects displayed considerable variability in the subsequent order of postural muscle activation. Across subjects, a total of 14 different preferred postural synergies were observed. Age groups did not differ in the number of different synergies. Early TA activation may reflect biomechanical constraints of the stepping task, producing forward displacement of the center of mass over the changing base of support. The fact that subjects of all ages were quite variable in the specific sequences of muscles activated subsequent to the TA suggests that, for this type of task, therapists should not focus their interventions on facilitating execution of particular synergy patterns.

Understanding balance differences in individuals with multiple sclerosis with mild disability: an investigation of differences in sensory feedback on postural control during a Romberg task.

PubMed

Denommé, Luke T; Mandalfino, Patricia; Cinelli, Michael E

2014-06-01

A major presenting symptom in 'individuals with multiple sclerosis with mild balance disability' (IwMS) is poor postural control, resulting from slowed spinal somatosensory conduction. Postural control deficits in IwMS are most apparent when vision is removed and the base of support is reduced such is the case during tandem and single support stances. The current study used center of pressure (COP) measurements to determine whether postural control differences exist between IwMS and either 'healthy age-matched individuals' (HAMI) or 'community-dwelling older adults' (OA). Postural control was evaluated using a Romberg standing task, which required participants to stand with their feet together and hands by their sides for 45 s with either their eyes open or closed. Results revealed that COP velocity root mean square was greater in IwMS and their COP position was closer to their self-selected maximum stability limits (e.g., greater Standing Index proportion) when vision was removed compared to HAMI. Conversely, IwMS displayed similar postural control characteristics to OA. The current study highlights two novel findings: (1) the utility of novel COP measurements to assess differences in the level of postural control in IwMS; and (2) the benefit of assessing postural control levels in IwMS to not only a population with a fully intact and functional postural control system (HAMI) but also to another population that is thought to experience postural control deficits (OA).

Postural Control Characteristics during Single Leg Standing of Individuals with a History of Ankle Sprain: Measurements Obtained Using a Gravicorder and Head and Foot Accelerometry.

PubMed

Abe, Yota; Sugaya, Tomoaki; Sakamoto, Masaaki

2014-03-01

[Purpose] This study aimed to validate the postural control characteristics of individuals with a history of ankle sprain during single leg standing by using a gravicorder and head and foot accelerometry. [Subjects] Twenty subjects with and 23 subjects without a history of ankle sprain (sprain and control groups, respectively) participated. [Methods] The anteroposterior, mediolateral, and total path lengths, as well as root mean square (RMS) of each length, were calculated using the gravicorder. The anteroposterior, mediolateral, and resultant acceleration of the head and foot were measured using accelerometers and were evaluated as the ratio of the acceleration of the head to the foot. [Results] There was no significant difference between the two groups in path length or RMS acceleration of the head and foot. However, the ratios of the mediolateral and resultant components were significantly higher in the sprain group than in the control group. [Conclusion] Our findings suggest that individuals with a history of ankle sprain have a higher head-to-foot acceleration ratio and different postural control characteristics than those of control subjects.

Spatial and temporal analysis center of pressure displacement during adolescence: Clinical implications of developmental changes.

PubMed

Quatman-Yates, Catherine; Bonnette, Scott; Gupta, Resmi; Hugentobler, Jason A; Wade, Shari L; Glauser, Tracy A; Ittenbach, Richard F; Paterno, Mark V; Riley, Michael A

2018-04-01

This study aimed to provide insight into the development of postural control abilities in youth. A total of 276 typically developing adolescents (155 males, 121 females) with a mean age of 13.23 years (range of 7.11-18.80) were recruited for participation. Subjects performed two-minute quiet standing trials in bipedal stance on a force plate. Center of pressure (COP) trajectories were quantified using Sample Entropy (SampEn) in the anterior-posterior direction (SampEn-AP), SampEn in the medial-lateral direction (SampEn-ML), and Path Length (PL) measures. Three separate linear regression analyses were conducted to predict the relationship between age and each of the response variables after adjusting for individuals' physical characteristics. Linear regression models showed an inverse relationship between age and entropy measures after adjusting for body mass index. Results indicated that chronological age was predictive of entropy and path length patterns. Specifically, older adolescents exhibited center of pressure displacement (smaller path length) and less complex, more regular center of pressure displacement patterns (lower SampEn-AP and SampEn-ML values) compared to the younger children. These findings support prior studies suggesting that developmental changes in postural control abilities may continue throughout adolescence and into adulthood. Copyright © 2018 Elsevier B.V. All rights reserved.

Postural Control in Bilateral Vestibular Failure: Its Relation to Visual, Proprioceptive, Vestibular, and Cognitive Input.

PubMed

Sprenger, Andreas; Wojak, Jann F; Jandl, Nico M; Helmchen, Christoph

2017-01-01

Patients with bilateral vestibular failure (BVF) suffer from postural and gait unsteadiness with an increased risk of falls. The aim of this study was to elucidate the differential role of otolith, semicircular canal (SSC), visual, proprioceptive, and cognitive influences on the postural stability of BVF patients. Center-of-pressure displacements were recorded by posturography under six conditions: target visibility; tonic head positions in the pitch plane; horizontal head shaking; sensory deprivation; dual task; and tandem stance. Between-group analysis revealed larger postural sway in BVF patients on eye closure; but with the eyes open, BVF did not differ from healthy controls (HCs). Head tilts and horizontal head shaking increased sway but did not differ between groups. In the dual task condition, BVF patients maintained posture indistinguishable from controls. On foam and tandem stance, postural sway was larger in BVF, even with the eyes open. The best predictor for the severity of bilateral vestibulopathy was standing on foam with eyes closed. Postural control of our BVF was indistinguishable from HCs once visual and proprioceptive feedback is provided. This distinguishes them from patients with vestibulo-cerebellar disorders or functional dizziness. It confirms previous reports and explains that postural unsteadiness of BVF patients can be missed easily if not examined by conditions of visual and/or proprioceptive deprivation. In fact, the best predictor for vestibular hypofunction (VOR gain) was examining patients standing on foam with the eyes closed. Postural sway in that condition increased with the severity of vestibular impairment but not with disease duration. In the absence of visual control, impaired otolith input destabilizes BVF with head retroflexion. Stimulating deficient SSC does not distinguish patients from controls possibly reflecting a shift of intersensory weighing toward proprioceptive-guided postural control. Accordingly, proprioceptive

Postural Control in Bilateral Vestibular Failure: Its Relation to Visual, Proprioceptive, Vestibular, and Cognitive Input

PubMed Central

Sprenger, Andreas; Wojak, Jann F.; Jandl, Nico M.; Helmchen, Christoph

2017-01-01

Patients with bilateral vestibular failure (BVF) suffer from postural and gait unsteadiness with an increased risk of falls. The aim of this study was to elucidate the differential role of otolith, semicircular canal (SSC), visual, proprioceptive, and cognitive influences on the postural stability of BVF patients. Center-of-pressure displacements were recorded by posturography under six conditions: target visibility; tonic head positions in the pitch plane; horizontal head shaking; sensory deprivation; dual task; and tandem stance. Between-group analysis revealed larger postural sway in BVF patients on eye closure; but with the eyes open, BVF did not differ from healthy controls (HCs). Head tilts and horizontal head shaking increased sway but did not differ between groups. In the dual task condition, BVF patients maintained posture indistinguishable from controls. On foam and tandem stance, postural sway was larger in BVF, even with the eyes open. The best predictor for the severity of bilateral vestibulopathy was standing on foam with eyes closed. Postural control of our BVF was indistinguishable from HCs once visual and proprioceptive feedback is provided. This distinguishes them from patients with vestibulo-cerebellar disorders or functional dizziness. It confirms previous reports and explains that postural unsteadiness of BVF patients can be missed easily if not examined by conditions of visual and/or proprioceptive deprivation. In fact, the best predictor for vestibular hypofunction (VOR gain) was examining patients standing on foam with the eyes closed. Postural sway in that condition increased with the severity of vestibular impairment but not with disease duration. In the absence of visual control, impaired otolith input destabilizes BVF with head retroflexion. Stimulating deficient SSC does not distinguish patients from controls possibly reflecting a shift of intersensory weighing toward proprioceptive-guided postural control. Accordingly, proprioceptive

Validity and Reliability of Gait and Postural Control Analysis Using the Tri-axial Accelerometer of the iPod Touch.

PubMed

Kosse, Nienke M; Caljouw, Simone; Vervoort, Danique; Vuillerme, Nicolas; Lamoth, Claudine J C

2015-08-01

Accelerometer-based assessments can identify elderly with an increased fall risk and monitor interventions. Smart devices, like the iPod Touch, with built-in accelerometers are promising for clinical gait and posture assessments due to easy use and cost-effectiveness. The aim of the present study was to establish the validity and reliability of the iPod Touch for gait and posture assessment. Sixty healthy participants (aged 18-75 years) were measured with an iPod Touch and stand-alone accelerometer while they walked under single- and dual-task conditions, and while standing in parallel and semi-tandem stance with eyes open, eyes closed and when performing a dual task. Cross-correlation values (CCV) showed high correspondence of anterior-posterior and medio-lateral signal patterns (CCV's ≥ 0.88). Validity of gait parameters (foot contacts, index of harmonicity, and amplitude variability) and standing posture parameters [root mean square of accelerations, median power frequency (MPF) and sway area] as indicated by intra-class correlation (ICC) was high (ICC = 0.85-0.99) and test-retest reliability was good (ICC = 0.81-0.97), except for MPF (ICC = 0.59-0.87). Overall, the iPod Touch obtained valid and reliable measures of gait and postural control in healthy adults of all ages under different conditions. Additionally, smart devices have the potential to be used for clinical gait and posture assessments.

The effects of muscle vibration on anticipatory postural adjustments.

PubMed

Slijper, Harm; Latash, Mark L

2004-07-23

The current study investigated the influence of changes in sensory information related to postural stability on anticipatory postural adjustments (APAs) in standing subjects. Subjects performed fast arm movements and a load release task while standing on a stable force platform or on an unstable board. We manipulated sensory information through vibration of the Achilles tendons and additional finger touch (contact forces under 1 N). Changes in the background activity of leg, trunk, and arm muscles and displacements of the center of pressure (COP) were quantified within time intervals typical for APAs. In the arm movement task, leg and trunk muscles showed a significant drop in the APAs with finger touch, while the vibration and standing on the unstable board each led to an increase in the APA magnitude. In the load release task, ventral muscles decreased their APA activity with touch, while dorsal muscles showed increased inhibition during APAs. During vibration, dorsal and ventral muscles showed increased excitation and inhibition during APAs, respectively. An additional analysis of APAs at a joint level, has shown that in both tasks, an index related to the co-activation of agonist-antagonist muscle pairs (C-index) was modulated with touch, vibration, and stability particularly in leg muscles. Small changes in the other index related to reciprocal activation (R-index) were found only in trunk muscles. Light touch and vibration induced opposing changes in the C-index, suggesting their opposite effects on the stabilization of a reference point or vertical. We conclude that the central nervous system deploys patterns of adjustments in which increased co-contraction of distal muscles and reciprocal adjustments in trunk muscles are modified to ensure equilibrium under postural instability.

The effect of vision on postural strategies in Prader-Willi patients.

PubMed

Cimolin, Veronica; Galli, Manuela; Vismara, Luca; Grugni, Graziano; Priano, Lorenzo; Capodaglio, Paolo

2011-01-01

The aim of this study was to quantify the role of visual contribution in patients with Prader-Willi syndrome (PWS) on balance maintenance using a force platform. We enrolled 14 individuals with PWS free from conditions associated with impaired balance, 44 obese (OG) and 20 healthy controls (CG). Postural sway was measured for 60s while standing on a force platform (Kistler, CH; acquisition frequency: 500 Hz) integrated with a video system. Patients maintained an upright standing position with Open Eyes (OE) and then with Closed Eyes (CE). The ratio between the value of the parameter under OE and CE conditions was measured. Under OE condition PWS and OG were characterized by higher postural instability than CG, with the PWS group showing poorer balance capacity than OG. The Romberg ratio showed that while OG and CG had lower balance without vision, PWS maintained the same performance changing from OE to CE. The integration of different sensory inputs appears similar in OG and CG with higher postural stability under OE than CE. Balance in PWS is not influenced by the elimination of visual input. Copyright © 2011 Elsevier Ltd. All rights reserved.

Improving Dual-Task Control With a Posture-Second Strategy in Early-Stage Parkinson Disease.

PubMed

Huang, Cheng-Ya; Chen, Yu-An; Hwang, Ing-Shiou; Wu, Ruey-Meei

2018-03-31

To examine the task prioritization effects on postural-suprapostural dual-task performance in patients with early-stage Parkinson disease (PD) without clinically observed postural symptoms. Cross-sectional study. Participants performed a force-matching task while standing on a mobile platform, and were instructed to focus their attention on either the postural task (posture-first strategy) or the force-matching task (posture-second strategy). University research laboratory. Individuals (N=16) with early-stage PD who had no clinically observed postural symptoms. Not applicable. Dual-task change (DTC; percent change between single-task and dual-task performance) of posture error, posture approximate entropy (ApEn), force error, and reaction time (RT). Positive DTC values indicate higher postural error, posture ApEn, force error, and force RT during dual-task conditions compared with single-task conditions. Compared with the posture-first strategy, the posture-second strategy was associated with smaller DTC of posture error and force error, and greater DTC of posture ApEn. In contrast, greater DTC of force RT was observed under the posture-second strategy. Contrary to typical recommendations, our results suggest that the posture-second strategy may be an effective dual-task strategy in patients with early-stage PD who have no clinically observed postural symptoms in order to reduce the negative effect of dual tasking on performance and facilitate postural automaticity. Copyright © 2018 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Effect of different types of exercise on postural balance in elderly women: a randomized controlled trial.

PubMed

de Oliveira, Marcio R; da Silva, Rubens A; Dascal, Juliana B; Teixeira, Denilson C

2014-01-01

Different types of exercise are indicated for the elderly to prevent functional capacity limitations due to aging and reduce the risk of falls. This study aimed to evaluate the effect of three different exercises (mini-trampoline, MT; aquatic gymnastics, AG and general floor gymnastics, GG) on postural balance in elderly women. Seventy-four physically independent elderly women, mean age 69±4 years, were randomly assigned to three intervention groups: (1) MT (n=23), (2) AG (n=28), and (3) GG (n=23). Each group performed physical training, including cardiorespiratory, muscular strength and endurance, flexibility and sensory-motor exercises for 12 weeks. To determine the effects on each intervention group, five postural balance tasks were performed on a force platform (BIOMEC 400): the two-legged stand with eyes open (TLEO) and two-legged stand with eyes closed (TLEC); the semi-tandem stand with eyes open (STEO) and semi-tandem stand with eyes closed (STEC) and the one-legged stand. Three trials were performed for each task (with 30s of rest between them) and the mean was used to compute balance parameters such as center of pressure (COP) sway movements. All modalities investigated such as the MT, AG and GG were significantly (P<0.05) efficient in improving the postural balance of elderly women after 12 weeks of training. These results provide further evidence concerning exercise and balance for promoting health in elderly women. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Specificity of postural sway to the demands of a precision task at sea.

PubMed

Chen, Fu-Chen; Stoffregen, Thomas A

2012-06-01

Mariners actively adjust their body orientation in response to ship motion. On a ship at sea, we evaluated relations between standing postural activity and the performance of a precision aiming task. Standing participants (experienced mariners) maintained the beam from a handheld laser on a target. Targets were large or small, thereby varying the difficulty of the aiming task. Targets were located in front of the participant or to the participant's right (requiring participants to look over the right shoulder), thereby varying the functional consequences (for the aiming task) of postural activity in different body axes. The torso was oriented toward the bow or toward the ship's side (athwartship), thereby varying the effects on postural activity of differential motion of the ship in its different axes. The weather was rough, producing high magnitudes of ship motion, which sometimes caused participants to step or stagger. Our manipulations influenced the magnitude and dynamics of head and torso movements, as well as the organization of movement in different axes. The results provide the first empirical confirmation that postural activity can be influenced by orientation of the torso relative to a ship. Despite powerful effects of ship motion, postural activity was influenced by variations in target location and in the difficulty of the aiming task, replicating subtle effects that have been observed on land. We discuss implications for hull design and the placement of workstations on ships.

The influence of an auditory-memory attention-demanding task on postural control in blind persons.

PubMed

Melzer, Itshak; Damry, Elad; Landau, Anat; Yagev, Ronit

2011-05-01

In order to evaluate the effect of an auditory-memory attention-demanding task on balance control, nine blind adults were compared to nine age-gender-matched sighted controls. This issue is particularly relevant for the blind population in which functional assessment of postural control has to be revealed through "real life" motor and cognitive function. The study aimed to explore whether an auditory-memory attention-demanding cognitive task would influence postural control in blind persons and compare this with blindfolded sighted persons. Subjects were instructed to minimize body sway during narrow base upright standing on a single force platform under two conditions: 1) standing still (single task); 2) as in 1) while performing an auditory-memory attention-demanding cognitive task (dual task). Subjects in both groups were required to stand blindfolded with their eyes closed. Center of Pressure displacement data were collected and analyzed using summary statistics and stabilogram-diffusion analysis. Blind and sighted subjects had similar postural sway in eyes closed condition. However, for dual compared to single task, sighted subjects show significant decrease in postural sway while blind subjects did not. The auditory-memory attention-demanding cognitive task had no interference effect on balance control on blind subjects. It seems that sighted individuals used auditory cues to compensate for momentary loss of vision, whereas blind subjects did not. This may suggest that blind and sighted people use different sensorimotor strategies to achieve stability. Copyright © 2010 Elsevier Ltd. All rights reserved.

Phase-dependent organization of postural adjustments associated with arm movements while walking.

PubMed

Nashner, L M; Forssberg, H

1986-06-01

This study examines the interactions between anteroposterior postural responses and the control of walking in human subjects. In the experimental paradigm, subjects walked upon a treadmill, gripping a rigid handle with one hand. Postural responses at different phases of stepping were elicited by rapid arm pulls or pushes against the handle. During arm movements, EMG's recorded the activity of representative arm, ankle, and thigh segment muscles. Strain gauges in the handle measured the force of the arm movement. A Selspot II system measured kinematics of the stepping movements. The duration of support and swing phases were marked by heel and toe switches in the soles of the subjects' shoes. In the first experiment, subjects were instructed to pull on the handle at their own pace. In these trials all subjects preferred to initiate pulls near heel strikes. Next, when instructed to pull as rapidly as possible in response to tone stimuli, reaction times were similar for all phases of the step cycle. Leg muscle responses associated with arm pulls and pushes, referred to as "postural activations," were directionally specific and preceded arm muscle activity. The temporal order and spatial distribution of postural activations in the muscles of the support leg were similar when arm pull movements occurred while the subject was standing in place and after heel strike while walking. Activations began in the ankle and radiated proximally to the thigh and then the arm. Activations of swing leg muscles were also directionally specific and involved flexion and forward or backward thrust of the limb. When arm movements were initiated during transitions from support by one leg to the other, patterns of postural activations were altered. Alterations usually occurred 10-20 ms before hell strikes and involved changes in the timing and sometimes the spatial structure of postural activations. Postural activation patterns are similar during in-place standing and during the support phase

Postural control and ventilatory drive during voluntary hyperventilation and carbon dioxide rebreathing.

PubMed

David, Pascal; Laval, David; Terrien, Jérémy; Petitjean, Michel

2012-01-01

The present study sought to establish links between hyperventilation and postural stability. Eight university students were asked to stand upright under two hyperventilation conditions applied randomly: (1) a metabolic hyperventilation induced by 5 min of hypercapnic-hyperoxic rebreathing (CO(2)-R); and, (2) a voluntary hyperventilation (VH) of 3 min imposed by a metronome set at 25 cycles per min. Recordings were obtained with eyes open, with the subjects standing on a force plate over 20-s periods. Ventilatory response, displacements in the centre of pressure in both the frontal and sagittal planes and fluctuations in the three planes of the ground reaction force were monitored in the time and frequency domains. Postural changes related to respiratory variations were quantified by coherence analysis. Myoelectric activities of the calf muscles were recorded using surface electromyography. Force plate measurements revealed a reduction in postural stability during both CO(2)-R and VH conditions, mainly in the sagittal plane. Coherence analysis provided evidence of a ventilatory origin in the vertical ground reaction force fluctuations during VH. Electromyographic analyses showed different leg muscles strategies, assuming the existence of links between the control of respiration and the control of posture. Our results suggest that the greater disturbing effects caused by voluntary hyperventilation on body balance are more compensated when respiration is under automatic control. These findings may have implications for understanding the organisation of postural and respiratory activities and suggest that stability of the body may be compromised in situations in which respiratory demand increases and requires voluntary control.

How proprioceptive impairments affect quiet standing in patients with multiple sclerosis.

PubMed

Rougier, P; Faucher, M; Cantalloube, S; Lamotte, D; Vinti, M; Thoumie, P

2007-01-01

To assess if multiple sclerosis patients with proprioceptive impairment are specifically affected during quiet standing with eyes open and how they can develop motor compensatory processes, 56 patients, classified from sensory clinical tests as ataxo-spastic (MS-AS) or only having spasticity (MS-S), were compared to 23 healthy adults matched for age. The postural strategies were assessed from the centre-of-pressure trajectories (CP), measured from a force platform in the eyes open standing condition for a single trial lasting 51.2 s. The vertical projection of the centre of gravity (CGv) and its vertical difference from the CP (CP-CGv) were then estimated through a biomechanical relationship. These two movements permit the characterization of the postural performance and the horizontal acceleration communicated to the CG and from that, the global energy expenditure, respectively. Both MS-AS and MS-S groups demonstrate larger CGv and CP-CGv movements than healthy individuals of the same age. Whilst similar CGv values are noticed in both MS subgroups, suggesting similar postural performances, statistically significant differences are observed for the CP-CGv component. Biomechanically, this feature expresses the necessity for the MS-AS group to develop augmented neuro-muscular means to control their body movements, as compared to the MS-S group. By demonstrating for both groups of patients similar postural performance accompanied by a varying degree of energy expenditure to maintain undisturbed upright stance, this study reveals that MS-AS patients which are affected by proprioceptive loss can compensate for this deficit with more efficient control strategies, when standing still with their eyes open.

Reaction to the sensory integration therapy in children with postural stability deficits.

PubMed

Maciaszek, Janusz; Kilan, Natalia; Bronikowski, Michal

2016-10-05

The goal was to examine the influence of sensory integration therapy (SIT) on one leg standing in children with deficits of the postural stability. 28 children 4 - 6 year old that could not stand on one leg for more than 20 seconds were randomly divided into control "C" and experimental "E" groups. Group "C" participated in standard classes in the kindergarten. Group "E" participated in sensory integration therapy (SIT) for 2 weeks, 5 times a week (additionally to the standard classes). Results of the experiment show that the skill of standing on one leg has significantly improved (p<0.01) in the group that underwent additional therapy. The change in time of standing on the right leg with eyes open in the E group was statistically and significantly higher than the changes observed in the same time in group C (F = 22.5, p = 0.001' η2 = 0.44). Similarly, significant changes in time of standing on the right leg with eyes closed were observed in group E. The foregoing changes were bigger in group E than in group C (F = 16. 1 , p = 0.004, η2 = 0.36). The analysis post hoc revealed that while there were no significant differences between the two groups on the pretest (p>0.05), there were significant differences between groups in right leg standing test with eyes open or closed on posttest. (p<0.05). Similar results were observed during on the one, left leg standing. The time of one leg standing with both eyes open and closed improved more significantly in group E than in group C (F = 20.4, p = 0.001, η2 = 0.42 respectively for the test with eyes open and F = 7.4, p = 0.010, η2 = 0.21 for the test with eyes closed). The analysis post hoc revealed that while there were no significant differences between the two groups on the pretest (p>0.05), there were significant differences between groups in left leg standing test with eyes open or closed on posttest. (p<0.05). Research conducted show that there is a positive influence of SIT on children with low level of postural

Quantitative Postural Analysis of Children With Congenital Visual Impairment.

PubMed

de Pádua, Michelle; Sauer, Juliana F; João, Silvia M A

2018-01-01

The aim of this study was to compare the postural alignment of children with visual impairment with that of children without visual impairment. The sample studied was 74 children of both sexes ages 5 to 12 years. Of these, 34 had visual impairment and 40 were control children. Digital photos from the standing position were used to analyze posture. Postural variables, such as tilt of the head, shoulder position, scapula position, lateral deviation of the spine, ankle position in the frontal plane and head posture, angle of thoracic kyphosis, angle of lumbar lordosis, pelvis position, and knee position in the frontal and sagittal planes, were measured with the Postural Assessment Software 0.63, version 36 (SAPO, São Paulo, Brazil), with markers placed in predetermined bony landmarks. The main results of this study showed that children with visual impairment have increased head tilt (P < .001), shoulder deviation in frontal plane (P = .004), lateral deviation of the spine (P < .001), changes in scapula position (P = .012), higher thoracic kyphosis (P = .004), and lower lumbar lordosis (P < .001). Visual impairment influences postural alignment. Children with visual impairment had increased head tilt, uneven shoulders, greater lateral deviation of the spine, thoracic kyphosis, lower lumbar lordosis, and more severe valgus deformities on knees. Copyright © 2017. Published by Elsevier Inc.

Effects of Levodopa on Postural Strategies in Parkinson's disease.

PubMed

Baston, Chiara; Mancini, Martina; Rocchi, Laura; Horak, Fay

2016-05-01

Altered postural control and balance are major disabling issues of Parkinson's disease (PD). Static and dynamic posturography have provided insight into PD's postural deficits; however, little is known about impairments in postural coordination. We hypothesized that subjects with PD would show more ankle strategy during quiet stance than healthy control subjects, who would include some hip strategy, and this stiffer postural strategy would increase with disease progression. We quantified postural strategy and sway dispersion with inertial sensors (one placed on the shank and one on the posterior trunk at L5 level) while subjects were standing still with their eyes open. A total of 70 subjects with PD, including a mild group (H&Y≤2, N=33) and a more severe group (H&Y≥3, N=37), were assessed while OFF and while ON levodopa medication. We also included a healthy control group (N=21). Results showed an overall preference of ankle strategy in all groups while maintaining balance. Postural strategy was significantly lower ON compared to OFF medication (indicating more hip strategy), but no effect of disease stage was found. Instead, sway dispersion was significantly larger in ON compared to OFF medication, and significantly larger in the more severe PD group compared to the mild. In addition, increased hip strategy during stance was associated with poorer self-perception of balance. Copyright © 2016 Elsevier B.V. All rights reserved.

Postural time-to-contact as a precursor of visually induced motion sickness.

PubMed

Li, Ruixuan; Walter, Hannah; Curry, Christopher; Rath, Ruth; Peterson, Nicolette; Stoffregen, Thomas A

2018-06-01

The postural instability theory of motion sickness predicts that subjective symptoms of motion sickness will be preceded by unstable control of posture. In previous studies, this prediction has been confirmed with measures of the spatial magnitude and the temporal dynamics of postural activity. In the present study, we examine whether precursors of visually induced motion sickness might exist in postural time-to-contact, a measure of postural activity that is related to the risk of falling. Standing participants were exposed to oscillating visual motion stimuli in a standard laboratory protocol. Both before and during exposure to visual motion stimuli, we monitored the kinematics of the body's center of pressure. We predicted that postural activity would differ between participants who reported motion sickness and those who did not, and that these differences would exist before participants experienced subjective symptoms of motion sickness. During exposure to visual motion stimuli, the multifractality of sway differed between the Well and Sick groups. Postural time-to-contact differed between the Well and Sick groups during exposure to visual motion stimuli, but also before exposure to any motion stimuli. The results provide a qualitatively new type of support for the postural instability theory of motion sickness.

The effect of methylphenidate on postural stability under single and dual task conditions in children with attention deficit hyperactivity disorder - a double blind randomized control trial.

PubMed

Jacobi-Polishook, Talia; Shorer, Zamir; Melzer, Itshak

2009-05-15

To investigate the effects of Methylphenidate (MPH) on postural stability in attention deficit hyperactivity disorder (ADHD) children in single and dual task conditions. A randomized controlled double-blind study analyzing postural stability in 24 ADHD children before and after MPH vs. placebo treatments, in three task conditions: (1) Single task, standing still; (2) dual task, standing still performing a memory-attention demanding task; (3) standing still listening to music. MPH resulted in a significant improvement in postural stability during the dual task condition and while listening to music, with no equivalent improvement in placebo controls. MPH improves postural stability in ADHD, especially when an additional task is performed. This is probably due to enhanced attention abilities, thus contributing to improved balance control during performance of tasks that require attention. MPH remains to be studied as a potential drug treatment to improve balance control and physical functioning in other clinical populations.

Influence of Input Hardware and Work Surface Angle on Upper Limb Posture in a Hybrid Computer Workstation.

PubMed

Kingston, David C; Riddell, Maureen F; McKinnon, Colin D; Gallagher, Kaitlin M; Callaghan, Jack P

2016-02-01

We evaluated the effect of work surface angle and input hardware on upper-limb posture when using a hybrid computer workstation. Offices use sit-stand and/or tablet workstations to increase worker mobility. These workstations may have negative effects on upper-limb joints by increasing time spent in non-neutral postures, but a hybrid standing workstation may improve working postures. Fourteen participants completed office tasks in four workstation configurations: a horizontal or sloped 15° working surface with computer or tablet hardware. Three-dimensional right upper-limb postures were recorded during three tasks: reading, form filling, and writing e-mails. Amplitude probability distribution functions determined the median and range of upper-limb postures. The sloped-surface tablet workstation decreased wrist ulnar deviation by 5° when compared to the horizontal-surface computer when reading. When using computer input devices (keyboard and mouse), the shoulder, elbow, and wrist were closest to neutral joint postures when working on a horizontal work surface. The elbow was 23° and 15° more extended, whereas the wrist was 6° less ulnar deviated, when reading compared to typing forms or e-mails. We recommend that the horizontal-surface computer configuration be used for typing and the sloped-surface tablet configuration be used for intermittent reading tasks in this hybrid workstation. Offices with mobile employees could use this workstation for alternating their upper-extremity postures; however, other aspects of the device need further investigation. © 2015, Human Factors and Ergonomics Society.

REVIEW: Restoring standing capabilities with feedback control of functional neuromuscular stimulation following spinal cord injury

PubMed Central

Nataraj, Raviraj; Audu, Musa L.; Triolo, Ronald J.

2017-01-01

This paper reviews the field of feedback control for neuroprosthesis systems that restore advanced standing function to individuals with spinal cord injury. Investigations into closed-loop control of standing by functional neuromuscular stimulation (FNS) have spanned three decades. The ultimate goal for FNS standing control systems is to facilitate hands free standing and enabling the user to perform manual functions at self-selected leaning positions. However, most clinical systems for home usage currently only provide basic upright standing using preprogrammed stimulation patterns. To date, online modulation of stimulation to produce advanced standing functions such as balance against postural disturbances or the ability to assume leaning postures have been limited to simulation and laboratory investigations. While great technological advances have been made in biomechanical sensing and interfaces for neuromuscular stimulation, further progress is still required for finer motor control by FNS. Another major challenge is the development of sophisticated control schemes that produce the necessary postural adjustments, adapt against accelerating muscle fatigue, and consider volitional actions of the intact upper-body of the user. Model-based development for novel control schemes are proven and sensible approaches to prototype and test the basic operating efficacy of potentially complex and multi-faceted control systems. The major considerations for further innovation of such systems are summarized in this paper prior to describing the evolution of closed-loop FNS control of standing from previous works. Finally, necessary emerging technologies to for implementing FNS feedback control systems for standing are identified. These technological advancements include novel electrodes that more completely and selectively activate paralyzed musculature and implantable sensors and stimulation modules for flexible neuroprosthesis system deployment. PMID:28215399

Foam pad of appropriate thickness can improve diagnostic value of foam posturography in detecting postural instability.

PubMed

Liu, Bo; Leng, Yangming; Zhou, Renhong; Liu, Jingjing; Liu, Dongdong; Liu, Jia; Zhang, Su-Lin; Kong, Wei-Jia

2018-04-01

The present study investigated the effect of foam thickness on postural stability in patients with unilateral vestibular hypofunction (UVH) during foam posturography. Static and foam posturography were performed in 33 patients (UVH group) and 30 healthy subjects (control group) with eyes open (EO) and closed (EC) on firm surface and on 1-5 foam pad(s). Sway velocity (SV) of center of pressure, standing time before falling (STBF) and falls reaction were recorded and analyzed. (1) SVs had an increasing tendency in both groups as the foam pads were added under EO and EC conditions. (2) STBFs, only in UVH group with EC, decreased with foam thickness increasing. (3) Significant differences in SV were found between the control and UVH group with EO (except for standing on firm surface, on 1 and 2 foam pad(s)) and with EC (all surface conditions). (4) Receiver operating characteristic curve analysis showed that the SV could better reflect the difference in postural stability between the two groups while standing on the 4 foam pads with EC. Our study showed that diagnostic value of foam posturography in detecting postural instability might be enhanced by using foam pad of right thickness.

Postural strategies assessed with inertial sensors in healthy and parkinsonian subjects

PubMed Central

Baston, Chiara; Mancini, Martina; Schoneburg, Bernadette; Horak, Fay; Rocchi, Laura

2015-01-01

The present study introduces a novel instrumented method to characterize postural movement strategies to maintain balance during stance (ankle and hip strategy), by means of inertial sensors, positioned on the legs and on the trunk. We evaluated postural strategies in subjects with2 types of parkinsonism: idiopathic Parkinson's disease (PD) and Progressive Supranuclear Palsy (PSP),and inage-matched control subjects standing under perturbed conditions implementedby the Sensory Organization Test (SOT).Coordination between the upper and lower segments of the body during postural sway was measured using a covariance index over time, by a sliding-window algorithm. Afterwards, a postural strategy index was computed. We also measuredthe amount of postural sway, as adjunctive information to characterize balance, by the root mean square of the horizontal trunk acceleration signal (RMS). Results showed that control subjects were able to change their postural strategy, whilst PSP and PD subjects persisted in use of an ankle strategy in all conditions.PD subjects had RMS values similar to control subjects even without changing postural strategy appropriately, whereas PSP subjects showed much larger RMS values than controls, resulting in several falls during the most challenging SOT conditions (5 and 6). Results are in accordance with the corresponding clinical literature describing postural behavior in the same kind of subjects. The proposed strategy index, based on the use ofinertial sensors on the upper and lower body segments, isa promising and unobtrusive toolto characterize postural strategies performed to attain balance. PMID:24656713

[Descending control of quiet standing and walking: a plausible neurophysiological basis of falls in elderly people].

PubMed

Nakajima, Masashi

2011-03-01

Quiet standing and walking are generally considered to be an automatic process regulated by sensory feedback. In our report "Astasia without abasia due to peripheral neuropathy," which was published in 1994, we proposed that forced stepping in patients lacking the ankle torque is a compensatory motor control in order to maintain an upright posture. A statistical-biomechanics approach to the human postural control system has revealed open-loop (descending) control as well as closed-loop (feedback) control in quiet standing, and fractal dynamics in stride-to-stride fluctuations of walking. The descending control system of bipedal upright posture and gait may have a functional link to cognitive domains. Increasing dependence on the descending control system with aging may play a role in falls in elderly people.

Restoring standing capabilities with feedback control of functional neuromuscular stimulation following spinal cord injury.

PubMed

Nataraj, Raviraj; Audu, Musa L; Triolo, Ronald J

2017-04-01

This paper reviews the field of feedback control for neuroprosthesis systems that restore advanced standing function to individuals with spinal cord injury. Investigations into closed-loop control of standing by functional neuromuscular stimulation (FNS) have spanned three decades. The ultimate goal for FNS standing control systems is to facilitate hands free standing and enabling the user to perform manual functions at self-selected leaning positions. However, most clinical systems for home usage currently only provide basic upright standing using preprogrammed stimulation patterns. To date, online modulation of stimulation to produce advanced standing functions such as balance against postural disturbances or the ability to assume leaning postures have been limited to simulation and laboratory investigations. While great technological advances have been made in biomechanical sensing and interfaces for neuromuscular stimulation, further progress is still required for finer motor control by FNS. Another major challenge is the development of sophisticated control schemes that produce the necessary postural adjustments, adapt against accelerating muscle fatigue, and consider volitional actions of the intact upper-body of the user. Model-based development for novel control schemes are proven and sensible approaches to prototype and test the basic operating efficacy of potentially complex and multi-faceted control systems. The major considerations for further innovation of such systems are summarized in this paper prior to describing the evolution of closed-loop FNS control of standing from previous works. Finally, necessary emerging technologies to for implementing FNS feedback control systems for standing are identified. These technological advancements include novel electrodes that more completely and selectively activate paralyzed musculature and implantable sensors and stimulation modules for flexible neuroprosthesis system deployment. Copyright © 2017 IPEM

Confounding compression: the effects of posture, sizing and garment type on measured interface pressure in sports compression clothing.

PubMed

Brophy-Williams, Ned; Driller, Matthew William; Shing, Cecilia Mary; Fell, James William; Halson, Shona Leigh; Halson, Shona Louise

2015-01-01

The purpose of this investigation was to measure the interface pressure exerted by lower body sports compression garments, in order to assess the effect of garment type, size and posture in athletes. Twelve national-level boxers were fitted with sports compression garments (tights and leggings), each in three different sizes (undersized, recommended size and oversized). Interface pressure was assessed across six landmarks on the lower limb (ranging from medial malleolus to upper thigh) as athletes assumed sitting, standing and supine postures. Sports compression leggings exerted a significantly higher mean pressure than sports compression tights (P < 0.001). Oversized tights applied significantly less pressure than manufacturer-recommended size or undersized tights (P < 0.001), yet no significant differences were apparent between different-sized leggings. Standing posture resulted in significantly higher mean pressure application than a seated posture for both tights and leggings (P < 0.001 and P = 0.002, respectively). Pressure was different across landmarks, with analyses revealing a pressure profile that was neither strictly graduated nor progressive in nature. The pressure applied by sports compression garments is significantly affected by garment type, size and posture assumed by the wearer.

Improvement of posture stability by vibratory stimulation following anterior cruciate ligament reconstruction.

PubMed

Brunetti, O; Filippi, G M; Lorenzini, M; Liti, A; Panichi, R; Roscini, M; Pettorossi, V E; Cerulli, G

2006-11-01

Surgical reconstruction of the anterior cruciate ligament (ACL) may reduce, but it does not always eliminate, knee and body instability because of a persisting proprioceptive deficit. In order to enhance body stability, a new protocol of treatment has been proposed consisting of mechanical vibration (100 Hz frequency and < 20 microm amplitude) of the quadriceps muscle in the leg that has undergone ACL reconstruction. In our trials, stimulation was performed when the quadriceps muscle was kept isometrically contracted. Treatment was started one month after surgery. Vibration was applied for short periods over three consecutive days. Nine months after treatment, postural stability was re-evaluated with the subjects standing on one leg with open and with closed eyes. The postural stability of the subjects having undergone vibration treatment, standing on the operated leg was significantly improved one day after treatment when evaluated as mean of speed and elliptic area of the center of pressure. The improvement persisted and increased during the following weeks. Peak torques of the operated leg extensor muscles also increased and reached values close to that of the leg, which had not been operated. Conversely, the balance of the untreated subjects standing on the operated leg did not improve and the restoration of the extensor muscle peak torque was poor. It is concluded that short lasting proprioceptive activation by vibration may lead to a faster and more complete equilibrium recovery probably by permanently changing the network controlling knee posture.

Assessment of postural asymmetry in mild to moderate Parkinson's disease.

PubMed

Geurts, A C H; Boonstra, T A; Voermans, N C; Diender, M G; Weerdesteyn, V; Bloem, B R

2011-01-01

Asymmetry of symptoms of Parkinson's disease is clinically most evident for appendicular impairments. For axial impairments such as freezing of gait, asymmetry is less obvious. To date, asymmetries in balance control in PD patients have seldom been studied. Therefore, in this study we investigated whether postural control can be asymmetrically affected in mild to moderate PD patients. Seventeen PD patients were instructed to stand as still and symmetrically as possible on a dual force-plate during two trials. Dynamic postural asymmetry was assessed by comparing the centre-of-pressure velocities between both legs. Results showed that four patients (24%) had dynamic postural asymmetry, even after correcting for weight-bearing asymmetry. Hence, this study suggests that postural control can be asymmetrical in early PD. However, future studies should investigate the prevalence of dynamic postural asymmetry, in a larger group of PD patients. It should also be further investigated whether this approach can be used as a tool to support the initial diagnosis or monitor disease progression, or as an outcome measure for interventions aimed at improving balance in PD. Copyright © 2010 Elsevier B.V. All rights reserved.

Preliminary evaluation of a commercially available videogame system as an adjunct therapeutic intervention for improving balance among children and adolescents with lower limb amputations.

PubMed

Andrysek, Jan; Klejman, Susan; Steinnagel, Bryan; Torres-Moreno, Ricardo; Zabjek, Karl F; Salbach, Nancy M; Moody, Kim

2012-02-01

To examine the safety, feasibility, and balance performance effects of a 4-week home-based balance therapy program using a commercially available videogame system. A pilot study involving a preintervention and postintervention design was conducted with measurements taken at baseline, immediately postintervention (week 5), and at follow-up (week 13) for retention. University hospital outpatient clinic and participants' places of residence. Children and adolescents with unilateral lower limb amputation (n=6; 3 transfemoral [TF] and 3 Van Ness) and age-matched, typically developing individuals (n=10) for baseline comparison. Two videogames involving weight shifting in standing were each played at home for 20 min/d, 4d/wk for a period of 4 weeks. A physical therapist provided initial instruction and monitoring. Postural control characteristics using center of pressure (COP) displacements during quiet standing; functional balance using the Community Balance and Mobility Scale (CB&M); and compliance, safety, and feasibility using custom questionnaires. Average playing times for the first 3 weeks ranged from 16.0 to 21.1 minutes for the 2 games. At baseline, the children and adolescents with TF amputation had substantially greater COP displacements than the Van Ness group and typically developing children and adolescents. Immediately postintervention, the COP displacements decreased in the TF amputees, resulting in values that were closer to those of the typically developing children. The average increase in CB&M score from baseline to follow-up was 6 points across participants. In-home, videogame-based balance training therapies can achieve excellent compliance in children and adolescents with lower limb amputation. With proper instructions and monitoring, the therapeutic intervention can be safely administered. Some improvements in postural control characteristics were seen in children and adolescents with balance deficits immediately postintervention, but long

Effects of emotional videos on postural control in children.

PubMed

Brandão, Arthur de Freitas; Palluel, Estelle; Olivier, Isabelle; Nougier, Vincent

2016-03-01

The link between emotions and postural control has been rather unexplored in children. The objective of the present study was to establish whether the projection of pleasant and unpleasant videos with similar arousal would lead to specific postural responses such as postural freezing, aversive or appetitive behaviours as a function of age. We hypothesized that postural sway would similarly increase with the viewing of high arousal videos in children and adults, whatever the emotional context. 40 children participated in the study and were divided into two groups of age: group 7-9 years (n=23; mean age=8 years ± 0.7) and group 10-12 years (n=17; mean age=11 years ± 0.7). 19 adults (mean age=25.8 years ± 4.4) also took part in the experiment. They viewed emotional videos while standing still on a force platform. Centre of foot pressure (CoP) displacements were analysed. Antero-posterior, medio-lateral mean speed and sway path length increased similarly with the viewing of high arousal movies in the younger, older children, and adults. Our findings suggest that the development of postural control is not influenced by the maturation of the emotional processing. Copyright © 2016 Elsevier B.V. All rights reserved.

Letter to the Editor: On "Advantages and disadvantages of stiffness instructions when studying postural control" by C.T. Bonnet: You just can't win: Advantages and disadvantages of the postural stability requirement.

PubMed

Lajoie, Y; Richer, N; Jehu, D A; Polskaia, N; Saunders, D

2016-05-01

In the examination of postural control, instructions to stand as still as possible are common and promote a relatively unnatural sway pattern. The validity of the stability requirement is discussed in the present commentary in response to the discussion initiated by Cedrick T. Bonnet. The advantages of using the stability requirement include: evaluating unbiased postural control, reducing variability in postural sway, manipulating focus of attention, examining the ability to maintain an upright stance, and ecological validity of testing. The disadvantages include: constraining natural postural sway, increasing the complexity of the control condition, promoting an internal focus of attention, and reducing the ability to detect exploratory behaviour. After evaluating the aforementioned advantages and disadvantages, the present commentary suggests that researchers should strive to provide specific instructions to maintain feet, arm and eye position without specifically requiring participants to reduce their postural sway. Copyright © 2015 Elsevier B.V. All rights reserved.

Analysis of the impact of a cognitive task on the posture of elderly subjects with depression compared with healthy elderly subjects.

PubMed

Casteran, Matthieu; Putot, Alain; Pfitzenmeyer, François; Thomas, Elizabeth; Manckoundia, Patrick

2016-11-01

While previous studies have demonstrated that depressive elderly subjects (DES) experience difficulties in the processing of simultaneous cognitive tasks, few have examined the coupling of cognitive tasks with seemingly 'automatic' tasks, such as standing upright. Current patient management focuses on pharmacological treatments and cognitive-behavioral therapies. Healthy elderly (HES) and non-treated DES were included. Postural sway in DES was compared with that in HES while in single-task and dual-task conditions. The single-task consisted of standing upright. For the dual-task, the subjects recalled various items from memory or counted while standing upright. Postural sway was evaluated by computing the center of pressure (CoP) area and path length. DES showed greater postural sway than HES in all conditions. The HES showed a greater CoP area in the dual-task than in the single-task conditions. In DES, the CoP area in the single-task condition was similar to that in the dual-task condition. The greater postural sway observed in DES may be a cause of a greater risk of falls. We showed that even seemingly automatic tasks, such as maintaining an upright posture, are affected by depression. These results are important for the management of DES. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Effects of transcranial direct current stimulation (tDCS) on multiscale complexity of dual-task postural control in older adults.

PubMed

Zhou, Diange; Zhou, Junhong; Chen, Hu; Manor, Brad; Lin, Jianhao; Zhang, Jue

2015-08-01

Transcranial direct current stimulation (tDCS) targeting the prefrontal cortex reduces the size and speed of standing postural sway in younger adults, particularly when performing a cognitive dual task. Here, we hypothesized that tDCS would alter the complex dynamics of postural sway as quantified by multiscale entropy (MSE). Twenty healthy older adults completed two study visits. Center-of-pressure (COP) fluctuations were recorded during single-task (i.e., quiet standing) and dual-task (i.e., standing while performing serial subtractions) conditions, both before and after a 20-min session of real or sham tDCS. MSE was used to estimate COP complexity within each condition. The percentage change in complexity from single- to dual-task conditions (i.e., dual-task cost) was also calculated. Before tDCS, COP complexity was lower (p = 0.04) in the dual-task condition as compared to the single-task condition. Neither real nor sham tDCS altered complexity in the single-task condition. As compared to sham tDCS, real tDCS increased complexity in the dual-task condition (p = 0.02) and induced a trend toward improved serial subtraction performance (p = 0.09). Moreover, those subjects with lower dual-task COP complexity at baseline exhibited greater percentage increases in complexity following real tDCS (R = -0.39, p = 0.05). Real tDCS also reduced the dual-task cost to complexity (p = 0.02), while sham stimulation had no effect. A single session of tDCS targeting the prefrontal cortex increased standing postural sway complexity with concurrent non-postural cognitive task. This form of noninvasive brain stimulation may be a safe strategy to acutely improve postural control by enhancing the system's capacity to adapt to stressors.

The effect of transcutaneous electrical nerve stimulation on postural sway on fatigued dorsi-plantar flexor.

PubMed

Yu, JaeHo; Lee, SoYeon; Kim, HyongJo; Seo, DongKwon; Hong, JiHeon; Lee, DongYeop

2014-01-01

The application of transcutaneous electrical nerve stimulation (TENS) enhances muscle weakness and static balance by muscle fatigue. It was said that TENS affects decrease of the postural sway. On the other hand, the applications of TENS to separate dorsi-plantar flexor and the comparison with and without visual input have not been studied. Thus, the aim of this study was to compare the effects of TENS on fatigued dorsi-plantar flexor with and without visual input. 13 healthy adult males and 12 females were recruited and agreed to participate as the subject (mean age 20.5 ± 1.4, total 25) in this study after a preliminary research. This experiment was a single group repeated measurements design in three days. The first day, after exercise-induced fatigue, the standing position was maintained for 30 minutes and then the postural sway was measured on eyes open(EO) and eyes closed(EC). The second, TENS was applied to dorsi flexor in standing position for 30 minutes after conducting exercise-induced fatigue. On the last day, plantar flexor applied by TENS was measured to the postural sway on EO and EC after same exercise-induced fatigue. The visual input was not statistically difference between the groups. However, when compared of dorsi-plantar flexor after applied to TENS without visual input, the postural sway of plantar flexor was lower than the dorsi flexor (p< 0.05). As the result, the application of TENS in GCM clinically decreases the postural sway with visual input it helps to stable posture control and prevent to falling down.

Altered Timing of Postural Reflexes Contributes to Falling in Persons with Chronic Stroke

PubMed Central

Marigold, Daniel S.; Eng, Janice J.

2011-01-01

The purpose of this study was to determine differences in the timing of postural reflexes and changes in kinematics between those who fell (Fallers) in response to standing platform translations and those who did not (Non-fallers). Forty-four persons with stroke were exposed to unexpected forward and backward platform translations while standing. Surface electromyography from bilateral tibialis anterior, gastrocnemius, rectus femoris, and biceps femoris were recorded along with kinematic data. Those that fell in response to the translations were compared to those who did not fall in terms of (1) postural reflex onset latency, (2) the time interval between the activation of distal and proximal muscles (i.e. intralimb coupling), and (3) changes in joint angles and trunk motion. Approximately 85% of falls occurred in response to the forward translations. Postural reflex onset latencies were delayed and intralimb coupling durations were longer in the Faller versus Non-faller group. At the time that the platform completed the translating motion (300 ms), the Faller group demonstrated higher trunk velocity, greater change in paretic ankle angle, and the trunk was further behind the ankle compared to the Non-faller group. This study suggests that following platform translations, delays in the timing of postural reflexes and disturbed intralimb coupling result in changes in kinematics, which contribute to falls in persons with stroke. PMID:16418855

Energy Cost of Standing in a Multi-Ethnic Cohort: Are Energy-Savers a Minority or the Majority?

PubMed Central

Monnard, Cathríona R.

2017-01-01

Background The disease risks associated with sedentary behavior are now firmly established, and consequently there is much interest in methods of increasing low-intensity physical activity. In this context, it is a widely held belief that altering posture allocation can modify energy expenditure (EE) to impact upon body weight regulation and health. However, we recently showed the existence of two distinct phenotypes pertaining to the energy cost of standing–with the majority of a Caucasian cohort showing no sustained increase in EE during standing relative to sitting. Here we investigated whether this phenomenon is also observed across a multi-ethnic male cohort. Objective To determine the magnitude and time-course of changes in EE and respiratory quotient (RQ) during steady-state standing versus sitting, and to explore inter-individual variability in these responses across 4 ethnic groups (European, Indian, Chinese, African) Design Min-by-min monitoring using posture-adapted ventilated-hood indirect calorimetry was conducted in 35 healthy, men (20–43 years) during 10 min of steady-state standing versus sitting comfortably. Results 69% of subjects showed little or no increase (<5%) in EE during standing compared to sitting (energy savers). Furthermore, the proportion of energy savers did not significantly differ between ethnic groups, despite ethnic differences in anthropometry; with body weight as the primary predictor of the energy cost of standing maintenance (r2 = 0.30, p = 0.001). Conclusion Our results indicate that the majority of individuals in a multi-ethnic cohort display a postural energy-saver phenotype. The mechanisms by which the large majority of individuals appear to maintain sitting and standing postures at the same energetic cost remains to be elucidated but is of considerable importance to our understanding of the spontaneous physical activity compartment of EE and its potential as a target for weight regulation. PMID:28056094

A comparison of trunk biomechanics, musculoskeletal discomfort and productivity during simulated sit-stand office work.

PubMed

Karakolis, Thomas; Barrett, Jeff; Callaghan, Jack P

2016-10-01

Sedentary office work has been shown to cause low back discomfort and potentially cause injury. Prolonged standing work has been shown to cause discomfort. The implementation of a sit-stand paradigm is hypothesised to mitigate discomfort and prevent injury induced by prolonged exposure to each posture in isolation. This study explored the potential of sit-stand to reduce discomfort and prevent injury, without adversely affecting productivity. Twenty-four participants performed simulated office work in three different conditions: sitting, standing and sit-stand. Variables measured included: perceived discomfort, L4-L5 joint loading and typing/mousing productivity. Working in a sit-stand paradigm was found to have the potential to reduce discomfort when compared to working in a sitting or standing only configuration. Sit-stand was found to be associated with reduced lumbar flexion during sitting compared to sitting only. Increasing lumbar flexion during prolonged sitting is a known injury mechanism. Therefore, sit-stand exhibited a potentially beneficial response of reduced lumbar flexion that could have the potential to prevent injury. Sit-stand had no significant effect on productivity. Practitioner Summary: This study has contributed foundational elements to guide usage recommendations for sit-stand workstations. The sit-stand paradigm can reduce discomfort; however, working in a sit-stand ratio of 15:5 min may not be the most effective ratio. More frequent posture switches may be necessary to realise the full benefit of sit-stand.

Neural Control of Posture in Individuals with Persisting Postconcussion Symptoms.

PubMed

Helmich, Ingo; Berger, Alisa; Lausberg, Hedda

2016-12-01

Postural instability has been shown to characterize individuals who suffered from long-term symptoms after mild traumatic brain injury. However, recordings of neural processes during postural control are difficult to realize with standard neuroimaging techniques. Thus, we used functional nearinfrared spectroscopy to investigate brain oxygenation of individuals with persistent postconcussion symptoms (pPCS) during postural control in altered environments. We compared brain oxygenation and postural sway during balance control in three groups: individuals suffering from pPCS, individuals with a history of mild traumatic brain injury but without pPCS, and healthy controls. Individuals were investigated during postural control tasks with six different conditions: i) eyes opened, ii) eyes closed, and iii) blurred visual input, each while standing a) on a stable and b) an unstable surface. In all groups, during the eyes closed/unstable surface condition as compared with the other conditions, the postural sway increased as well as the brain oxygenation in frontal brain cortices. In the most difficult balance condition, as compared with the other two groups, subjects with pPCS applied more force over time to keep balance as measured by the force plate system with a significantly greater activation in frontopolar/orbitofrontal areas of the right hemisphere. As subjects with pPCS applied more force over time to control balance, we propose that with regard to cognitive processes, the increase of cerebral activation in these individuals indicates an increase of attention-demanding processes during postural control in altered environments.

Postural Instability Induced by Visual Motion Stimuli in Patients With Vestibular Migraine

PubMed Central

Lim, Yong-Hyun; Kim, Ji-Soo; Lee, Ho-Won; Kim, Sung-Hee

2018-01-01

Patients with vestibular migraine are susceptible to motion sickness. This study aimed to determine whether the severity of posture instability is related to the susceptibility to motion sickness. We used a visual motion paradigm with two conditions of the stimulated retinal field and the head posture to quantify postural stability while maintaining a static stance in 18 patients with vestibular migraine and in 13 age-matched healthy subjects. Three parameters of postural stability showed differences between VM patients and controls: RMS velocity (0.34 ± 0.02 cm/s vs. 0.28 ± 0.02 cm/s), RMS acceleration (8.94 ± 0.74 cm/s2 vs. 6.69 ± 0.87 cm/s2), and sway area (1.77 ± 0.22 cm2 vs. 1.04 ± 0.25 cm2). Patients with vestibular migraine showed marked postural instability of the head and neck when visual stimuli were presented in the retinal periphery. The pseudo-Coriolis effect induced by head roll tilt was not responsible for the main differences in postural instability between patients and controls. Patients with vestibular migraine showed a higher visual dependency and low stability of the postural control system when maintaining quiet standing, which may be related to susceptibility to motion sickness. PMID:29930534

Postural Instability Induced by Visual Motion Stimuli in Patients With Vestibular Migraine.

PubMed

Lim, Yong-Hyun; Kim, Ji-Soo; Lee, Ho-Won; Kim, Sung-Hee

2018-01-01

Patients with vestibular migraine are susceptible to motion sickness. This study aimed to determine whether the severity of posture instability is related to the susceptibility to motion sickness. We used a visual motion paradigm with two conditions of the stimulated retinal field and the head posture to quantify postural stability while maintaining a static stance in 18 patients with vestibular migraine and in 13 age-matched healthy subjects. Three parameters of postural stability showed differences between VM patients and controls: RMS velocity (0.34 ± 0.02 cm/s vs. 0.28 ± 0.02 cm/s), RMS acceleration (8.94 ± 0.74 cm/s 2 vs. 6.69 ± 0.87 cm/s 2 ), and sway area (1.77 ± 0.22 cm 2 vs. 1.04 ± 0.25 cm 2 ). Patients with vestibular migraine showed marked postural instability of the head and neck when visual stimuli were presented in the retinal periphery. The pseudo-Coriolis effect induced by head roll tilt was not responsible for the main differences in postural instability between patients and controls. Patients with vestibular migraine showed a higher visual dependency and low stability of the postural control system when maintaining quiet standing, which may be related to susceptibility to motion sickness.

Postural disorders and spatial neglect in stroke patients: a strong association.

PubMed

Pérennou, Dominic

2006-01-01

In this paper we analyse the arguments for a strong association between spatial neglect and postural disorders and attempt to better understand the mechanisms which underlie that. We first provide a general overview of the available tools for a rational assessment of postural control in a clinical context. We then analyse the arguments in favour of a close relationship, although not necessarily causal, between spatial neglect and: 1) body orientation with respect to gravity (including verticality perception i.e. the visual vertical, the haptic vertical, and the postural vertical); 2) body stabilisation with respect to the base of support; 3) posturographic features of stroke patients; 4) and finally their postural disability in daily life. This second part of the paper is based both on the literature review and on results of our current research. Neglect patients show a dramatic postural disability, due both to problems in body orientation with respect to gravity and to problems in body stabilisation. It might be that these problems are partly caused by a neglect phenomenon bearing on graviceptive (somaesthetic > vestibular) and visual information serving postural control. This could correspond to a kind of postural neglect involving both the bodily and nonbodily domains of spatial neglect. The existence of distorsion(s) in the body scheme are also probably involved, especially to explain the weight-bearing asymmetry in standing, and probably an impaired multisegmental postural coordination leading to an impaired body stabilisation. The present paper explains why neglect patients show longer/worse recovery of postural-walking autonomy than other stroke patients.

Postural strategies assessed with inertial sensors in healthy and parkinsonian subjects.

PubMed

Baston, Chiara; Mancini, Martina; Schoneburg, Bernadette; Horak, Fay; Rocchi, Laura

2014-01-01

The present study introduces a novel instrumented method to characterize postural movement strategies to maintain balance during stance (ankle and hip strategy), by means of inertial sensors, positioned on the legs and on the trunk. We evaluated postural strategies in subjects with 2 types of Parkinsonism: idiopathic Parkinson's disease (PD) and Progressive Supranuclear Palsy (PSP), and in age-matched control subjects standing under perturbed conditions implemented by the Sensory Organization Test (SOT). Coordination between the upper and lower segments of the body during postural sway was measured using a covariance index over time, by a sliding-window algorithm. Afterwards, a postural strategy index was computed. We also measured the amount of postural sway, as adjunctive information to characterize balance, by the root mean square of the horizontal trunk acceleration signal (RMS). showed that control subjects were able to change their postural strategy, whilst PSP and PD subjects persisted in use of an ankle strategy in all conditions. PD subjects had RMS values similar to control subjects even without changing postural strategy appropriately, whereas PSP subjects showed much larger RMS values than controls, resulting in several falls during the most challenging SOT conditions (5 and 6). Results are in accordance with the corresponding clinical literature describing postural behavior in the same kind of subjects. The proposed strategy index, based on the use of inertial sensors on the upper and lower body segments, is a promising and unobtrusive tool to characterize postural strategies performed to attain balance. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of Achilles tendon vibration on postural orientation.

PubMed

Ceyte, Hadrien; Cian, Corinne; Zory, Raphael; Barraud, Pierre-Alain; Roux, Alain; Guerraz, Michel

2007-04-06

Vibration applied to the Achilles tendon is well known to induce in freely standing subjects a backward body displacement and in restrained subjects an illusory forward body tilt. The purpose of the present experiment was to evaluate the effect of Achilles tendon vibration (90Hz) on postural orientation in subjects free of equilibrium constraints. Subjects (n=12) were strapped on a backboard that could be rotated in the antero-posterior direction with the axis of rotation at the level of the ankles. They stood on a rigid horizontal floor with the soles of their feet parallel to the ground. They were initially positioned 7 degrees backward or forward or vertical and were required to adjust their body (the backboard) to the vertical orientation via a joystick. Firstly, results showed that in response to Achilles tendon vibration, subjects adjusted their body backward compared to the condition without vibration. This backward body adjustment likely cancel the appearance of an illusory forward body tilt. It was also observed that the vibratory stimulus applied to the Achilles tendon elicited in restrained standing subjects an increased EMG activity in both the gastrocnemius lateralis and the soleus muscles. Secondly, this vibration effect was more pronounced when passive displacement during the adjustment phase was congruent with the simulated elongation of calf muscles. These results indicated that the perception of body orientation is coherent with the postural response classically observed in freely standing subjects although the relationship between these two responses remains to be elucidated.

Effects of Levodopa on Postural Strategies in Parkinson’s disease

PubMed Central

Mancini, Martina; Rocchi, Laura; Horak, Fay

2017-01-01

Altered postural control and balance are major disabling issues of Parkinson’s disease (PD). Static and dynamic posturography have provided insight into PD’s postural deficits; however, little is known about impairments in postural coordination. We hypothesized that subjects with PD would show more ankle strategy during quiet stance than healthy control subjects, who would include some hip strategy, and this stiffer postural strategy would increase with disease progression. We quantified postural strategy and sway dispersion with inertial sensors (one placed on the shank and one on the posterior trunk at L5 level) while subjects were standing still with their eyes open. A total of 70 subjects with PD, including a mild group (H&Y≤2, N=33) and a more severe group (H&Y≥3, N=37), were assessed while OFF and while ON levodopa medication. We also included a healthy control group (N=21). Results showed an overall preference of ankle strategy in all groups while maintaining balance. Postural strategy was significantly lower ON compared to OFF medication (indicating more hip strategy), but no effect of disease stage was found. Instead, sway dispersion was significantly larger in ON compared to OFF medication, and significantly larger in the more severe PD group compared to the mild. In addition, increased hip strategy during stance was associated with poorer self-perception of balance. PMID:27131172

A test of fixed and moving reference point control in posture.

PubMed

Lee, I-Chieh; Pacheco, Matheus M; Newell, Karl M

2017-01-01

This study investigated two contrasting assumptions of the regulation of posture: namely, fixed and moving reference point control. These assumptions were tested in terms of time-dependent structure and data distribution properties when stability is manipulated. Fifteen male participants performed a tightrope simulated balance task that is, maintaining a tandem stance while holding a pole. Pole length (and mass) and the standing support surface (fixed surface/balance board) were manipulated so as to mechanically change the balance stability. The mean and standard deviation (SD) of COP length were reduced with pole length increment but only in the balance board surface condition. Also, the SampEn was lower with greater pole length for the balance board but not the fixed surface. More than one peak was present in the distribution of COP in the majority of trials. Collectively, the findings provide evidence for a moving reference point in the maintenance of postural stability for quiet standing. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of a clinical static and dynamic standing balance measurement tool appropriate for use in adolescents.

PubMed

Emery, Carolyn A; Cassidy, J David; Klassen, Terry P; Rosychuk, Rhonda J; Rowe, Brian B

2005-06-01

There is a need in sports medicine for a static and dynamic standing balance measure to quantify balance ability in adolescents. The purposes of this study were to determine the test-retest reliability of timed static (eyes open) and dynamic (eyes open and eyes closed) unipedal balance measurements and to examine factors associated with balance. Adolescents (n=123) were randomly selected from 10 Calgary high schools. This study used a repeated-measures design. One rater measured unipedal standing balance, including timed eyes-closed static (ECS), eyes-open dynamic (EOD), and eyes-closed dynamic (ECD) balance at baseline and 1 week later. Dynamic balance was measured on a foam surface. Reliability was examined using both intraclass correlation coefficients (ICCs) and Bland and Altman statistical techniques. Multiple linear regressions were used to examine other potentially influencing factors. Based on ICCs, test-retest reliability was adequate for ECS, EOD, and ECD balance (ICC=.69, .59, and .46, respectively). The results of Bland and Altman methods, however, suggest that caution is required in interpreting reliability based on ICCs alone. Although both ECS balance and ECD balance appear to demonstrate adequate test-retest reliability by ICC, Bland and Altman methods of agreement demonstrate sufficient reliability for ECD balance only. Thirty percent of the subjects reached the 180-second maximum on EOD balance, suggesting that this test is not appropriate for use in this population. Balance ability (ECS and ECD) was better in adolescents with no past history of lower-extremity injury. Timed ECD balance is an appropriate and reliable clinical measurement for use in adolescents and is influenced by previous injury.

Performing saccadic eye movements or blinking improves postural control.

PubMed

Rougier, Patrice; Garin, Mélanie

2007-07-01

To determine the relationship between eye movement and postural control on an undisturbed upright stance maintenance protocol, 15 young, healthy individuals were tested in various conditions. These conditions included imposed blinking patterns and horizontal and vertical saccadic eye movements. The directions taken by the center of pressure (CP) were recorded via a force platform on which the participants remained in an upright position. The CP trajectories were used to estimate, via a low-pass filter, the vertically projected movements of the center of gravity (CGv) and consequently the difference CP-CGv. An analysis of the frequency shows that regular bilateral blinking does not produce a significant change in postural control. In contrast, performing saccadic eye movements induces some reduced amplitude for both basic CGv and CP-CGv movements principally along the antero-posterior axis. The present result supports the theory that some ocular movements may modify postural control in the maintenance of the upright standing position in human participants.

Mechanical effort predicts the selection of ankle over hip strategies in nonstepping postural responses

PubMed Central

Jonkers, Ilse; De Schutter, Joris; De Groote, Friedl

2016-01-01

Experimental studies have shown that a continuum of ankle and hip strategies is used to restore posture following an external perturbation. Postural responses can be modeled by feedback control with feedback gains that optimize a specific objective. On the one hand, feedback gains that minimize effort have been used to predict muscle activity during perturbed standing. On the other hand, hip and ankle strategies have been predicted by minimizing postural instability and deviation from upright posture. It remains unclear, however, whether and how effort minimization influences the selection of a specific postural response. We hypothesize that the relative importance of minimizing mechanical work vs. postural instability influences the strategy used to restore upright posture. This hypothesis was investigated based on experiments and predictive simulations of the postural response following a backward support surface translation. Peak hip flexion angle was significantly correlated with three experimentally determined measures of effort, i.e., mechanical work, mean muscle activity and metabolic energy. Furthermore, a continuum of ankle and hip strategies was predicted in simulation when changing the relative importance of minimizing mechanical work and postural instability, with increased weighting of mechanical work resulting in an ankle strategy. In conclusion, the combination of experimental measurements and predictive simulations of the postural response to a backward support surface translation showed that the trade-off between effort and postural instability minimization can explain the selection of a specific postural response in the continuum of potential ankle and hip strategies. PMID:27489362

Closed loop kinesthetic feedback for postural control rehabilitation.

PubMed

Vérité, Fabien; Bachta, Wael; Morel, Guillaume

2014-01-01

Postural control rehabilitation may benefit from the use of smart devices providing biofeedback. This approach consists of increasing the patients perception of their postural state. Namely, postural state is monitored and fed back in real time to the patients through one or more sensory channels. This allows implementing rehabilitation exercises where the patients control their posture with the help of additional sensory inputs. In this paper, a closed loop control of the Center-Of-Pressure (CoP) based on kinesthetic feedback is proposed as a new form of biofeedback. The motion of a one Degree of Freedom (DoF) translational device, lightly touched by the patient's forefinger, is servoed to the patient's CoP position extracted from the measurements of a force plate on which he/she stands. As a result, the patient's CoP can be controllably displaced. A first set of experiments is used to prove the feasibility of this closed-loop control under ideal conditions favoring the perception of the kinesthetic feedback, while the subject is totally unaware of the context. A second set of experiments is then proposed to evaluate the robustness of this approach under experimental conditions that are more realistic with regards to the clinical context of a rehabilitation program involving biofeedback-based exercises.

Postural and Spatial Orientation Driven by Virtual Reality

PubMed Central

Keshner, Emily A.; Kenyon, Robert V.

2009-01-01

Orientation in space is a perceptual variable intimately related to postural orientation that relies on visual and vestibular signals to correctly identify our position relative to vertical. We have combined a virtual environment with motion of a posture platform to produce visual-vestibular conditions that allow us to explore how motion of the visual environment may affect perception of vertical and, consequently, affect postural stabilizing responses. In order to involve a higher level perceptual process, we needed to create a visual environment that was immersive. We did this by developing visual scenes that possess contextual information using color, texture, and 3-dimensional structures. Update latency of the visual scene was close to physiological latencies of the vestibulo-ocular reflex. Using this system we found that even when healthy young adults stand and walk on a stable support surface, they are unable to ignore wide field of view visual motion and they adapt their postural orientation to the parameters of the visual motion. Balance training within our environment elicited measurable rehabilitation outcomes. Thus we believe that virtual environments can serve as a clinical tool for evaluation and training of movement in situations that closely reflect conditions found in the physical world. PMID:19592796

Competing effects of pain and fear of pain on postural control in low back pain?

PubMed

Mazaheri, Masood; Heidari, Elham; Mostamand, Javid; Negahban, Hossein; van Dieen, Jaap H

2014-12-01

A cross-sectional, observational study. To determine whether pain and fear of pain have competing effects on postural sway in patients with low back pain (LBP). Competing effects of pain and pain-related fear on postural control can be proposed as the likely explanation for inconsistent results regarding postural sway in the LBP literature. We hypothesized that although pain might increase postural sway, fear of pain might reduce sway through an increased cognitive effort or increased cocontraction to restrict body movement. The cognitive strategy would be less effective under dual-task conditions and the cocontraction strategy was expected to be less effective when standing on a narrow base of support surface. Postural sway was measured in combined conditions of base of support (full and narrow) and cognitive loading (single and dual tasks) in 3 experimental groups with current LBP, recent LBP, and no LBP. Sway amplitude, path length, mean power frequency, and sample entropy were extracted from center-of-pressure data. The current-LBP group and recent-LBP group reported significantly different levels of pain, but similar levels of pain catastrophizing and kinesiophobia. The current-LBP group tended to display larger sway amplitudes in the anteroposterior direction compared with the other 2 groups. Mean power frequency values in mediolateral direction were lower in patients with the current LBP compared with recent LBP. Smaller sample entropy was found in the current-LBP group than the other groups in most experimental conditions, particularly when standing on a narrow base of support. Alterations of postural sway are mostly mediated by pain but not pain-related fear. LBP tends to increase sway amplitude, which seems to be counteracted by increased effort invested in postural control leading to decreased frequency and increased regularity of sway particularly under increased task demands. Cross-sectional study.

Clinical correlates of between-limb synchronization of standing balance control and falls during inpatient stroke rehabilitation.

PubMed

Mansfield, Avril; Mochizuki, George; Inness, Elizabeth L; McIlroy, William E

2012-01-01

Stroke-related sensorimotor impairment potentially contributes to impaired balance. Balance measures that reveal underlying limb-specific control problems, such as a measure of the synchronization of both lower limbs to maintain standing balance, may be uniquely informative about poststroke balance control. This study aimed to determine the relationships between clinical measures of sensorimotor control, functional balance, and fall risk and between-limb synchronization of balance control. The authors conducted a retrospective chart review of 100 individuals with stroke admitted to inpatient rehabilitation. Force plate-based measures were obtained while standing on 2 force plates, including postural sway (root mean square of anteroposterior and mediolateral center of pressure [COP]), stance load asymmetry (percentage of body weight borne on the less-loaded limb), and between-limb synchronization (cross-correlation of the COP recordings under each foot). Clinical measures obtained were motor impairment (Chedoke-McMaster Stroke Assessment), plantar cutaneous sensation, functional balance (Berg Balance Scale), and falls experienced in rehabilitation. Synchronization was significantly related to motor impairment and prospective falls, even when controlling for other force plate-based measures of standing balance control (ie, postural sway and stance load symmetry). Between-limb COP synchronization for standing balance appears to be a uniquely important index of balance control, independent of postural sway and load symmetry during stance.

Effects of sensory augmentation on postural control and gait symmetry of transfemoral amputees: a case description.

PubMed

Pagel, Anna; Arieta, Alejandro Hernandez; Riener, Robert; Vallery, Heike

2016-10-01

Despite recent advances in leg prosthetics, transfemoral amputees still experience limitations in postural control and gait symmetry. It has been hypothesized that artificial sensory information might improve the integration of the prosthesis into the human sensory-motor control loops and, thus, reduce these limitations. In three transfemoral amputees, we investigated the effect of Electrotactile Moving Sensation for Sensory Augmentation (EMSSA) without training and present preliminary findings. Experimental conditions included standing with open/closed eyes on stable/unstable ground as well as treadmill walking. For standing conditions, spatiotemporal posturographic measures and sample entropy were derived from the center of pressure. For walking conditions, step length and stance duration were calculated. Conditions without feedback showed effects congruent with findings in the literature, e.g., asymmetric weight bearing and step length, and validated the collected data. During standing, with EMSSA a tendency to influence postural control in a negative way was found: Postural control was less effective and less efficient and the prosthetic leg was less involved. Sample entropy tended to decrease, suggesting that EMSSA demanded increased attention. During walking, with EMSSA no persistent positive effect was found. This contrasts the positive subjective assessment and the positive effect on one subject's step length.

Vibrotactile Feedback Alters Dynamics Of Static Postural Control In Persons With Parkinson's Disease But Not Older Adults At High Fall Risk.

PubMed

High, Carleigh M; McHugh, Hannah F; Mills, Stephen C; Amano, Shinichi; Freund, Jane E; Vallabhajosula, Srikant

2018-06-01

Aging and Parkinson's disease are often associated with impaired postural control. Providing extrinsic feedback via vibrotactile sensation could supplement intrinsic feedback to maintain postural control. We investigated the postural control response to vibrotactile feedback provided at the trunk during challenging stance conditions in older adults at high fall risk and individuals with Parkinson's disease compared to healthy older adults. Nine older adults at high fall risk, 9 persons with Parkinson's disease and 10 healthy older adults performed 30s quiet standing on a force platform under five challenging stance conditions with eyes open/closed and standing on firm/foam surface with feet together, each with and without vibrotactile feedback. During vibrotactile feedback trials, feedback was provided when participants swayed >10% over the center of their base of support. Participants were instructed vibrations would be in response to their movement. Magnitude of postural sway was estimated using center of pressure path length, velocity, and sway area. Dynamics of individuals' postural control was evaluated using detrended fluctuation analysis. Results showed that vibrotactile feedback induced a change in postural control dynamics among persons with Parkinson's disease when standing with intact intrinsic visual input and altered intrinsic somatosensory input, but there was no change in sway magnitude. However, use of vibrotactile feedback did not significantly alter dynamics of postural control in older adults with high risk of falling or reduce the magnitude of sway. Considering the effects of vibrotactile feedback were dependent on the population and stance condition, designing an optimal therapeutic regimen for balance training should be carefully considered and be specific to a target population. Furthermore, our results suggest that explicit instructions on how to respond to the vibrotactile feedback could affect training outcome. Copyright © 2018 The

What triggers the continuous muscle activity during upright standing?

PubMed

Masani, Kei; Sayenko, Dimitry G; Vette, Albert H

2013-01-01

The ankle extensors play a dominant role in controlling the equilibrium during bipedal quiet standing. Their primary role is to resist the gravity toppling torque that pulls the body forward. The purpose of this study was to investigate whether the continuous muscle activity of the anti-gravity muscles during standing is triggered by the joint torque requirement for opposing the gravity toppling torque, rather than by the vertical load on the lower limbs. Healthy adults subjects stood on a force plate. The ankle torque, ankle angle, and electromyograms from the right lower leg muscles were measured. A ground-fixed support device was used to support the subject at his/her knees, without changing the posture from the free standing one. During the supported condition, which eliminates the ankle torque requirement while maintaining both the vertical load on the lower limbs and the natural upright standing posture, the plantarflexor activity was attenuated to the resting level. Also, this attenuated plantarflexor activity was found only in one side when the ipsilateral leg was supported. Our results suggest that the vertical load on the lower limb is not determinant for inducing the continuous muscle activity in the anti-gravity muscles, but that it depends on the required joint torque to oppose the gravity toppling torque. Copyright © 2012 Elsevier B.V. All rights reserved.

Trunk Accelerometry Reveals Postural Instability in Untreated Parkinson's Disease

PubMed Central

Mancini, Martina; Horak, Fay B.; Zampieri, Cris; Carlson-Kuhta, Patricia; Nutt, John G.; Chiari, Lorenzo

2017-01-01

While several studies have shown that subjects with advanced Parkinson's disease (PD) exhibit abnormalities in sway parameters during quiet standing, abnormalities of postural sway associated with untreated PD have not been reported. Although not clinically apparent, we hypothesized that spontaneous sway in quiet stance is abnormal in people with untreated PD. We examined 13 subjects, recently diagnosed with PD, who were not yet taking any anti-parkinsonian medications and 12 healthy, age-matched control subjects. Postural sway was measured with a linear accelerometer on the posterior trunk (L5 level) and compared with traditional forceplate measures of sway. Subjects stood for two minutes under two conditions: eyes open (EO) and eyes closed (EC). One of the most discriminative measures of postural changes in subjects with untreated PD was the increased ‘JERK’ of lower trunk in the EO condition, measured with the accelerometer. Root mean square and the frequency dispersion of postural sway in the EO condition also discriminated sway in untreated PD subjects compared to controls subjects. We conclude that accelerometer-based sway metrics could be used as objective measures of postural instability in untreated PD. Accelerometer-based analysis of spontaneous sway may provide a powerful tool for early clinical trials and for monitoring the effects of treatment of balance disorders in subjects with PD. PMID:21641263

An interview technique for recording work postures in epidemiological studies. Music-Norrtälje Study Group.

PubMed

Wiktorin, C; Selin, K; Ekenvall, L; Alfredsson, L

1996-02-01

The aim of the study was to present and evaluate a work-task-oriented interview technique focusing on the placement of the hands relative to the body and assessing per cent time spent in five standard work postures during a working day. The reproducibility of estimated time spent in each work posture was tested by the test-retest method in 32 subjects; 16 were interviewed by the same interviewer and 16 were interviewed by another one at the retest. The validity concerning estimated time spent in th five standard work postures was tested in relation to observations in 58 male blue-collar workers. The mean registration (assessment) time was 6 hours and 15 minutes. No evident differences in the reproducibility depending on same or different interviewers at test and retest could be observed. The linear relationship between times estimated by the interview and by observations was high for four of the work postures: 'sitting' (r = 0.86), 'standing with hands above shoulder level' (r = 0.87), 'between shoulder and knuckle level' (r = 0.75), and 'below knuckle level' (r = 0.93). When the work posture 'standing with hands between shoulder and knuckle level' was divided into 'hands fixed' (r = 0.62) and 'hands not fixed' (r = 0.50) the correlations were weak. Current musculoskeletal complaints did not influence the accuracy of the estimations. The present task-oriented interview technique may be the best available method to estimate these work postures in a way that requires few resources compared to observations and technical measurements.

Postural Control in Children, Teenagers and Adults with Down Syndrome

ERIC Educational Resources Information Center

Rigoldi, Chiara; Galli, Manuela; Mainardi, Luca; Crivellini, Marcello; Albertini, Giorgio

2011-01-01

The goal of this work was to analyze postural control in Down syndrome (DS) participants considering three different groups composed by children, teenagers and adults with DS. An analysis of the centre of pressure (COP) displacement during standing position was therefore performed for the three groups of subjects. The obtained signal of COP was…

Associations between Tactile Sensory Threshold and Postural Performance and Effects of Healthy Aging and Subthreshold Vibrotactile Stimulation on Postural Outcomes in a Simple Dual Task

PubMed Central

Dettmer, Marius; Pourmoghaddam, Amir; Lee, Beom-Chan; Layne, Charles S.

2016-01-01

Specific activities that require concurrent processing of postural and cognitive tasks may increase the risk for falls in older adults. We investigated whether peripheral receptor sensitivity was associated with postural performance in a dual-task and whether an intervention in form of subthreshold vibration could affect performance. Ten younger (age: 20–35 years) and ten older adults (70–85 years) performed repeated auditory-verbal 1-back tasks while standing quietly on a force platform. Foot sole vibration was randomly added during several trials. Several postural control and performance measures were assessed and statistically analyzed (significance set to α-levels of .05). There were moderate correlations between peripheral sensitivity and several postural performance and control measures (r = .45 to .59). Several postural performance measures differed significantly between older and younger adults (p < 0.05); addition of vibration did not affect outcome measures. Aging affects healthy older adults' performance in dual-tasks, and peripheral sensitivity may be a contributor to the observed differences. A vibration intervention may only be useful when there are more severe impairments of the sensorimotor system. Hence, future research regarding the efficacy of sensorimotor interventions in the form of vibrotactile stimulation should focus on older adults whose balance is significantly affected. PMID:27143967

Postural imbalance and falls in PSP correlate with functional pathology of the thalamus.

PubMed

Zwergal, A; la Fougère, C; Lorenzl, S; Rominger, A; Xiong, G; Deutschenbaur, L; Linn, J; Krafczyk, S; Dieterich, M; Brandt, T; Strupp, M; Bartenstein, P; Jahn, K

2011-07-12

To determine how postural imbalance and falls are related to regional cerebral glucose metabolism (PET) and functional activation of the cerebral postural network (fMRI) in patients with progressive supranuclear palsy (PSP). Sixteen patients with PSP, who had self-monitored their frequency of falls, underwent a standardized clinical assessment, posturographic measurement of balance during modified sensory input, and a resting [¹⁸F]FDG-PET. In addition, patients performed an fMRI paradigm using mental imagery of standing. Results were compared to healthy controls (n = 16). The frequency of falls/month in patients (range 1-40) correlated with total PSP rating score (r = 0.90). Total sway path in PSP significantly correlated with frequency of falls, especially during modulated sensory input (eyes open: r = 0.62, eyes closed: r = 0.67, eyes open/head extended: r = 0.84, eyes open/foam-padded platform: r = 0.87). Higher sway path values and frequency of falls were associated with decreased regional glucose metabolism (rCGM) in the thalamus (sway path: r = -0.80, falls: r = -0.64) and increased rCGM in the precentral gyrus (sway path: r = 0.79, falls: r = 0.64). Mental imagery of standing during fMRI revealed a reduced activation of the mesencephalic brainstem tegmentum and the thalamus in patients with postural imbalance and falls. The new and clinically relevant finding of this study is that imbalance and falls in PSP are closely associated with thalamic dysfunction. Deficits in thalamic postural control get most evident when balance is assessed during modified sensory input. The results are consistent with the hypothesis that reduced thalamic activation via the ascending brainstem projections may cause postural imbalance in PSP.

The effect of foot posture on capacity to apply free moments to the ground: implications for fighting performance in great apes

PubMed Central

Cunningham, Christopher

2017-01-01

ABSTRACT In contrast to most other primates, great apes have feet in which the heel supports body weight during standing, walking and running. One possible advantage of this plantigrade foot posture is that it may enhance fighting performance by increasing the ability to apply free moments (i.e. force couples) to the ground. We tested this possibility by measuring performance of human subjects when performing from plantigrade and digitigrade (standing on the ball of the foot and toes) postures. We found that plantigrade posture substantially increased the capacity to apply free moments to the ground and to perform a variety of behaviors that are likely to be important to fighting performance in great apes. As predicted, performance in maximal effort lateral striking and pushing was strongly correlated with free moment magnitude. All else being equal, these results suggest species that can adopt plantigrade posture will be able to apply larger free moments to the ground than species restricted to digitigrade or unguligrade foot posture. Additionally, these results are consistent with the suggestion that selection for physical competition may have been one of the factors that led to the evolution of the derived plantigrade foot posture of great apes. PMID:28202470

The effect of foot posture on capacity to apply free moments to the ground: implications for fighting performance in great apes.

PubMed

Carrier, David R; Cunningham, Christopher

2017-02-15

In contrast to most other primates, great apes have feet in which the heel supports body weight during standing, walking and running. One possible advantage of this plantigrade foot posture is that it may enhance fighting performance by increasing the ability to apply free moments (i.e. force couples) to the ground. We tested this possibility by measuring performance of human subjects when performing from plantigrade and digitigrade (standing on the ball of the foot and toes) postures. We found that plantigrade posture substantially increased the capacity to apply free moments to the ground and to perform a variety of behaviors that are likely to be important to fighting performance in great apes. As predicted, performance in maximal effort lateral striking and pushing was strongly correlated with free moment magnitude. All else being equal, these results suggest species that can adopt plantigrade posture will be able to apply larger free moments to the ground than species restricted to digitigrade or unguligrade foot posture. Additionally, these results are consistent with the suggestion that selection for physical competition may have been one of the factors that led to the evolution of the derived plantigrade foot posture of great apes. © 2017. Published by The Company of Biologists Ltd.

Postural correction reduces hip pain in adult with acetabular dysplasia: A case report.

PubMed

Lewis, Cara L; Khuu, Anne; Marinko, Lee N

2015-06-01

Developmental dysplasia of the hip is often diagnosed in infancy, but less severe cases of acetabular dysplasia are being detected in young active adults. The purpose of this case report is to present a non-surgical intervention for a 31-year-old female with mild acetabular dysplasia and an anterior acetabular labral tear. The patient presented with right anterior hip and groin pain, and she stood with the trunk swayed posterior to the pelvis (swayback posture). The hip pain was reproduced with the anterior impingement test. During gait, the patient maintained the swayback posture and reported 6/10 hip pain. Following correction of the patient's posture, the patient's pain rating was reduced to a 2/10 while walking. The patient was instructed to maintain the improved posture. At the 1 year follow-up, she demonstrated significantly improved posture in standing and walking. She had returned to recreational running and was generally pain-free. The patient demonstrated improvement on self-reported questionnaires for pain, function, and activity. These findings suggest that alteration of posture can have an immediate and lasting effect on hip pain in persons with structural abnormality and labral pathology. Copyright © 2015 Elsevier Ltd. All rights reserved.

Postural correction reduces hip pain in adult with acetabular dysplasia: a case report

PubMed Central

Lewis, Cara L.; Khuu, Anne; Marinko, Lee

2015-01-01

Developmental dysplasia of the hip is often diagnosed in infancy, but less severe cases of acetabular dysplasia are being detected in young active adults. The purpose of this case report is to present a non-surgical intervention for a 31-year-old female with mild acetabular dysplasia and an anterior acetabular labral tear. The patient presented with right anterior hip and groin pain, and she stood with the trunk swayed posterior to the pelvis (swayback posture). The hip pain was reproduced with the anterior impingement test. During gait, the patient maintained the swayback posture and reported 6/10 hip pain. Following correction of the patient’s posture, the patient’s pain rating was reduced to a 2/10 while walking. The patient was instructed to maintain the improved posture. At the 1 year follow-up, she demonstrated significantly improved posture in standing and walking. She had returned to recreational running and was generally pain-free. The patient demonstrated improvement on self-reported questionnaires for pain, function and activity. These findings suggest that alteration of posture can have an immediate and lasting effect on hip pain in persons with structural abnormality and labral pathology. PMID:25731688

Vertical Heterophoria and Postural Control in Nonspecific Chronic Low Back Pain

PubMed Central

Matheron, Eric; Kapoula, Zoï

2011-01-01

The purpose of this study was to test postural control during quiet standing in nonspecific chronic low back pain (LBP) subjects with vertical heterophoria (VH) before and after cancellation of VH; also to compare with healthy subjects with, and without VH. Fourteen subjects with LBP took part in this study. The postural performance was measured through the center of pressure displacements with a force platform while the subjects fixated on a target placed at either 40 or 200 cm, before and after VH cancellation with an appropriate prism. Their postural performance was compared to that of 14 healthy subjects with VH and 12 without VH (i.e. vertical orthophoria) studied previously in similar conditions. For LBP subjects, cancellation of VH with a prism improved postural performance. With respect to control subjects (with or without VH), the variance of speed of the center of pressure was higher, suggesting more energy was needed to stabilize their posture in quiet upright stance. Similarly to controls, LBP subjects showed higher postural sway when they were looking at a target at a far distance than at a close distance. The most important finding is that LBP subjects with VH can improve their performance after prism-cancellation of their VH. We suggest that VH reflects mild conflict between sensory and motor inputs involved in postural control i.e. a non optimal integration of the various signals. This could affect the performance of postural control and perhaps lead to pain. Nonspecific chronic back pain may results from such prolonged conflict. PMID:21479210

[Effects of sports and media consumption on the trunk muscle strength, posture and flexibility of the spine in 12- to 14- year-old adolescents].

PubMed

Küster, M

2004-06-01

Back pain and posture deficits get more common in childhood and adolescents. Lack of movement, insufficient physical education and high amounts of TV and PC are known as risk factors for chronic low back pain in later life. In a cross-sectional study, trunk muscle strength, posture and spinal flexibility were assessed in 200 untrained schoolchildren (117 girls, 83 boys). Independent variables, collected by a standardized questionnaire: age, height, weight, gender, weekly scope of TV, PC and sports (conditional, conditional-coordinative, coordinative). spinal parameter, tested by the Zebris CMS-System and IPN Back Check. PC and TV-consumption had negative effects on the spinal parameter, whereas esp. conditional-coordinative sports correlated positively. For general health and preventive reasons, children need a daily minimum of 30 minutes of movement. Conditional-coordinative sports are suited best because of their multifactorial load.

SEMG analysis of astronaut upper arm during isotonic muscle actions with normal standing posture

NASA Astrophysics Data System (ADS)

Qianxiang, Zhou; Chao, Ma; Xiaohui, Zheng

sEMG analysis of astronaut upper arm during isotonic muscle actions with normal standing posture*1 Introduction Now the research on the isotonic muscle actions by using Surface Electromyography (sEMG) is becoming a pop topic in fields of astronaut life support training and rehabilitations. And researchers paid more attention on the sEMG signal processes for reducing the influence of noise which is produced during monitoring process and the fatigue estimation of isotonic muscle actions with different force levels by using the parameters which are obtained from sEMG signals such as Condition Velocity(CV), Median Frequency(MDF), Mean Frequency(MNF) and so on. As the lucubrated research is done, more and more research on muscle fatigue issue of isotonic muscle actions are carried out with sEMG analysis and subjective estimate system of Borg scales at the same time. In this paper, the relationship between the variable for fatigue based on sEMG and the Borg scale during the course of isotonic muscle actions of the upper arm with different contraction levels are going to be investigated. Methods 13 young male subjects(23.4±2.45years, 64.7±5.43Kg, 171.7±5.41cm) with normal standing postures were introduced to do isotonic actions of the upper arm with different force levels(10% MVC, 30%MVC and 50%MVC). And the MVC which means maximal voluntary contraction was obtained firstly in the experiment. Also the sEMG would be recorded during the experiments; the Borg scales would be recorded for each contraction level. By using one-third band octave method, the fatigue variable (p) based on sEMG were set up and it was expressed as p = i g(fi ) · F (fi ). And g(fi ) is defined as the frequent factor which was 0.42+0.5 cos(π fi /f0 )+0.08 cos(2π fi /f0 ), 0 < FI fi 0, orf0 ≤> f0 . According to the equations, the p could be computed and the relationship between variable p and the Borg scale would be investigated. Results In the research, three kinds of fitted curves between

The neuropathic postural tachycardia syndrome

NASA Technical Reports Server (NTRS)

Jacob, G.; Costa, F.; Shannon, J. R.; Robertson, R. M.; Wathen, M.; Stein, M.; Biaggioni, I.; Ertl, A.; Black, B.; Robertson, D.

2000-01-01

BACKGROUND: The postural tachycardia syndrome is a common disorder that is characterized by chronic orthostatic symptoms and a dramatic increase in heart rate on standing, but that does not involve orthostatic hypotension. Several lines of evidence indicate that this disorder may result from sympathetic denervation of the legs. METHODS: We measured norepinephrine spillover (the rate of entry of norepinephrine into the venous circulation) in the arms and legs both before and in response to exposure to three stimuli (the cold pressor test, sodium nitroprusside infusion, and tyramine infusion) in 10 patients with the postural tachycardia syndrome and in 8 age- and sex-matched normal subjects. RESULTS: At base line, the mean (+/-SD) plasma norepinephrine concentration in the femoral vein was lower in the patients with the postural tachycardia syndrome than in the normal subjects (135+/-30 vs. 215+/-55 pg per milliliter [0.80+/-0.18 vs. 1.27+/-0.32 nmol per liter], P=0.001). Norepinephrine spillover in the arms increased to a similar extent in the two groups in response to each of the three stimuli, but the increases in the legs were smaller in the patients with the postural tachycardia syndrome than in the normal subjects (0.001+/-0.09 vs. 0.12+/-0.12 ng per minute per deciliter of tissue [0.006+/-0.53 vs. 0.71+/-0.71 nmol per minute per deciliter] with the cold pressor test, P=0.02; 0.02+/-0.07 vs. 0.23+/-0.17 ng per minute per deciliter [0.12+/-0.41 vs. 1.36+/-1.00 nmol per minute per deciliter] with nitroprusside infusion, P=0.01; and 0.008+/-0.09 vs. 0.19+/-0.25 ng per minute per deciliter [0.05+/-0.53 vs. 1.12+/-1.47 nmol per minute per deciliter] with tyramine infusion, P=0.04). CONCLUSIONS: The neuropathic postural tachycardia syndrome results from partial sympathetic denervation, especially in the legs.

Postural habits of young adults and possibilities of modification.

PubMed

Nowotny-Czupryna, Olga; Czupryna, Krzysztof; Bąk, Krzysztof; Wróblewska, Ewa; Rottermund, Jerzy

2013-01-01

The aim of the study was to assess postural habits in young, healthy people, identify correlations between postural errors and pain and attempt to modify bad habits. 144 people, aged 18-23 were enrolled. The intervention consisted of 4 stages: Stage 1 - identification of postural habits, description of responses to stress, back pain frequency and intensity (Jackson & Moskowitz); Stage 2 - correction of habitual position with the help of a physiotherapist, briefing about ergonomic everyday behaviours and consequences of continued non-ergonomic behaviours, Stage 3 - follow-up examination: self-assessment of changes, evaluation of the effects of modifications, determination of causes for discontinuing the behaviour modification programme, where applicable; and Stage 4 - final examination, assessment of results. Correlations were sought between inappropriate postural behaviour in various positions and between non-ergonomic postural behaviour and pain location and response to stress. Statistical analysis was carried out with Excel and Statistica v. 7.1. A non-parametric χ(2) test was used at p<0.005. All participants presented poor postural patterns in the standing, sitting and recumbent position. Back pain was reported by half of the participants. Statistically significant relationships between pain and habitual positions were noted with regard to the cervical and lumbar spine and also for abdominal pain as a response to stress in people with excessive thoracic kyphosis. Behaviour modifications caused or intensified lumbar pain or thigh muscle pain. Positive outcomes included better urination and/or defecation and greater comfort in assuming the different positions and performing activities of daily living in these positions. Some examinees discontinued behaviour modification during the first month after the initial instruction and the majority did so over the next three months. 1. Non-ergonomic postural behaviours are common among young people. 2. Changing the body

Relationship between Spectral Characteristics of Spontaneous Postural Sway and Motion Sickness Susceptibility.

PubMed

Laboissière, Rafael; Letievant, Jean-Charles; Ionescu, Eugen; Barraud, Pierre-Alain; Mazzuca, Michel; Cian, Corinne

2015-01-01

Motion sickness (MS) usually occurs for a narrow band of frequencies of the imposed oscillation. It happens that this frequency band is close to that which are spontaneously produced by postural sway during natural stance. This study examined the relationship between reported susceptibility to motion sickness and postural control. The hypothesis is that the level of MS can be inferred from the shape of the Power Spectral Density (PSD) profile of spontaneous sway, as measured by the displacement of the center of mass during stationary, upright stance. In Experiment 1, postural fluctuations while standing quietly were related to MS history for inertial motion. In Experiment 2, postural stability measures registered before the onset of a visual roll movement were related to MS symptoms following the visual stimulation. Study of spectral characteristics in postural control showed differences in the distribution of energy along the power spectrum of the antero-posterior sway signal. Participants with MS history provoked by exposure to inertial motion showed a stronger contribution of the high frequency components of the sway signal. When MS was visually triggered, sick participants showed more postural sway in the low frequency range. The results suggest that subject-specific PSD details may be a predictor of the MS level. Furthermore, the analysis of the sway frequency spectrum provided insight into the intersubject differences in the use of postural control subsystems. The relationship observed between MS susceptibility and spontaneous posture is discussed in terms of postural sensory weighting and in relation to the nature of the provocative stimulus.

Balance and postural skills in normal-weight and overweight prepubertal boys.

PubMed

Deforche, Benedicte I; Hills, Andrew P; Worringham, Charles J; Davies, Peter S W; Murphy, Alexia J; Bouckaert, Jacques J; De Bourdeaudhuij, Ilse M

2009-01-01

This study investigated differences in balance and postural skills in normal-weight versus overweight prepubertal boys. Fifty-seven 8-10-year-old boys were categorized overweight (N = 25) or normal-weight (N = 32) according to the International Obesity Task Force cut-off points for overweight in children. The Balance Master, a computerized pressure plate system, was used to objectively measure six balance skills: sit-to-stand, walk, step up/over, tandem walk (walking on a line), unilateral stance and limits of stability. In addition, three standardized field tests were employed: standing on one leg on a balance beam, walking heel-to-toe along the beam and the multiple sit-to-stand test. Overweight boys showed poorer performances on several items assessed on the Balance Master. Overweight boys had slower weight transfer (p < 0.05), lower rising index (p < 0.05) and greater sway velocity (p < 0.001) in the sit-to-stand test, greater step width while walking (p < 0.05) and lower speed when walking on a line (p < 0.01) compared with normal-weight counterparts. Performance on the step up/over test, the unilateral stance and the limits of stability were comparable between both groups. On the balance beam, overweight boys could not hold their balance on one leg as long (p < 0.001) and had fewer correct steps in the heel-to-toe test (p < 0.001) than normal-weight boys. Finally, overweight boys were slower in standing up and sitting down five times in the multiple sit-to-stand task (p < 0.01). This study demonstrates that when categorised by body mass index (BMI) level, overweight prepubertal boys displayed lower capacity on several static and dynamic balance and postural skills.

Evaluation of Work-Related Musculoskeletal Disorders and Postural Stress of Female "Jari" Workers.

PubMed

Pal, Amitava; Dhara, Prakash C

2017-01-01

The present investigation was aimed to assess the postural stress and the prevalence of musculoskeletal disorders (MSDs) of the "Jari" (golden thread) workers. This cross-sectional study was carried out on 156 female workers in different areas of the Purba Medinipur, Paschim Medinipur, and Howrah districts of West Bengal, India. The MSDs of the workers were evaluated by modified Nordic questionnaire method. The postural pattern during work was assessed by direct observation method. The posture of Jari workers has been analyzed by OWAS, REBA, and RULA methods. The joint angle in normal and working posture was observed. The prevalence of MSDs was very high among the workers. The major locations of body pains in Jari workers were lower back, upper back, neck, wrist, thigh, and shoulder. The occurrence of MSDs was higher in lower and higher age group than that of the middle age group. The total work shift of the workers was approximately 13 h including rest pause. The dominant postures adopted by the workers were sitting on the floor with stretched legs, sitting on the floor with folded knees, and kneeling posture. From the results of the postural analysis, the postures of the Jari workers had been categorized as stressful. There were a significant deviation between normal standing angles and working angles. From the overall study, it may be concluded that adoption of stressful postures for longer duration might be the cause of MSDs in different body parts of the Jari workers.

Remote monitoring of soldier safety through body posture identification using wearable sensor networks

NASA Astrophysics Data System (ADS)

Biswas, Subir; Quwaider, Muhannad

2008-04-01

differentiation between low activity postures such as sitting and standing. We develop a wearable sensor network that monitors relative proximity using Radio Signal Strength indication (RSSI), and then construct a HMM system for posture identification in the presence of sensing errors. Controlled experiments using human subjects were carried out for evaluating the accuracy of the HMM identified postures compared to a naÃve threshold based mechanism, and its variations over different human subjects. A large spectrum of target human postures, including lie down, sit (straight and reclined), stand, walk, run, sprint and stair climbing, are used for validating the proposed system.

A procedure to detect abnormal sensorimotor control in adolescents with idiopathic scoliosis.

PubMed

Pialasse, Jean-Philippe; Mercier, Pierre; Descarreaux, Martin; Simoneau, Martin

2017-09-01

This work identifies, among adolescents with idiopathic scoliosis, those demonstrating impaired sensorimotor control through a classification procedure comparing the amplitude of their vestibular-evoked postural responses. The sensorimotor control of healthy adolescents (n=17) and adolescents with idiopathic scoliosis (n=52) with either mild (Cobb angle≥15° and ≤30°) or severe (Cobb angle >30°) spine deformation was assessed through galvanic vestibular stimulation. A classification procedure sorted out adolescents with idiopathic scoliosis whether the amplitude of their vestibular-evoked postural response was dissimilar or similar to controls. Compared to controls, galvanic vestibular stimulation evoked larger postural response in adolescents with idiopathic scoliosis. Nonetheless, the classification procedure revealed that only 42.5% of all patients showed impaired sensorimotor control. Consequently, identifying patients with sensorimotor control impairment would allow to apply personalized treatments, help clinicians to establish prognosis and hopefully improve the condition of patients with adolescent idiopathic scoliosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Step-Initiation Deficits in Children with Faulty Posture Diagnosed with Neurodevelopmental Disorders during Infancy.

PubMed

Stania, Magdalena; Sarat-Spek, Alina; Blacha, Teresa; Kazek, Beata; Słomka, Kajetan J; Emich-Widera, Ewa; Juras, Grzegorz

2017-01-01

Early detection of movement deficits during step initiation will facilitate the selection of the optimal physiotherapy management strategy. The main aim of the study was to assess potential differences in step initiation between 5- and 6-year-old children with faulty posture who had been diagnosed with neurodevelopmental disorders during infancy and healthy children. The experimental group consisted of 19 children aged 5-6 years with faulty posture, who had been diagnosed with neurodevelopmental disorders during infancy and were given physiotherapy in the first year of their lives. The control group comprised 19 nursery school children aged 5-6 years with no postural defects, no history of postural control or movement deficits, and no physiotherapy interventions in the first year of their lives. Step initiation was performed on force platforms under various conditions, i.e., with and without an obstacle, stepping up onto a platform placed at a higher level, stepping down onto a platform placed on a lower level. The recording of center of foot pressure (COP) displacements was divided into three phases: phase 1 (P1)-quiet standing before step initiation, phase 2 (P2)-transit, phase 3 (P3)-quiet standing until measurement completion. The Tukey post hoc test showed that the means of sway range (raCOP) and mean velocity (vCOP) in sagittal ( AP ) plane for phase 1 and vCOP in frontal ( ML ) plane for phase 3 registered in the step-up trial were significantly higher ( p  < 0.05) in children with faulty posture compared to children with typical development. P1vCOP ML , P3vCOP AP , P3raCOP ML , and P3vCOP ML of the step-down trial were also significantly higher in children with faulty posture ( p  < 0.05). Inclusion of functional movement exercises (stair-walking tasks) in physiotherapy interventions for children with postural defects seems well justified.The trial was registered in the Australian and New Zealand Clinical Trials Registry (no. ACTRN12617001068358).

Influences of arm proprioception and degrees of freedom on postural control with light touch feedback.

PubMed

Rabin, Ely; DiZio, Paul; Ventura, Joel; Lackner, James R

2008-02-01

Lightly touching a stable surface with one fingertip strongly stabilizes standing posture. The three main features of this phenomenon are fingertip contact forces maintained at levels too low to provide mechanical support, attenuation of postural sway relative to conditions without fingertip touch, and center of pressure (CP) lags changes in fingertip shear forces by approximately 250 ms. In the experiments presented here, we tested whether accurate arm proprioception and also whether the precision fingertip contact afforded by the arm's many degrees of freedom are necessary for postural stabilization by finger contact. In our first experiment, we perturbed arm proprioception and control with biceps brachii vibration (120-Hz, 2-mm amplitude). This degraded postural control, resulting in greater postural sway amplitudes. In a second study, we immobilized the touching arm with a splint. This prevented precision fingertip contact but had no effect on postural sway amplitude. In both experiments, the correlation and latency of fingertip contact forces to postural sway were unaffected. We conclude that postural control is executed based on information about arm orientation as well as tactile feedback from light touch, although precision fingertip contact is not essential. The consistent correlation and timing of CP movement and fingertip forces across conditions in which postural sway amplitude and fingertip contact are differentially disrupted suggests posture and the fingertip are controlled in parallel with feedback from the fingertip in this task.

Sit-stand desks in call centres: associations of use and ergonomics awareness with sedentary behavior.

PubMed

Straker, Leon; Abbott, Rebecca A; Heiden, Marina; Mathiassen, Svend Erik; Toomingas, Allan

2013-07-01

To investigate whether or not use of sit-stand desks and awareness of the importance of postural variation and breaks are associated with the pattern of sedentary behavior in office workers. The data came from a cross-sectional observation study of Swedish call centre workers. Inclinometers recorded 'seated' or 'standing/walking' episodes of 131 operators over a full work shift. Differences in sedentary behavior based on desk type and awareness of the importance of posture variation and breaks were assessed by non-parametric analyses. 90 (68.7%) operators worked at a sit-stand desk. Working at a sit-stand desk, as opposed to a sit desk, was associated with less time seated (78.5 vs 83.8%, p = 0.010), and less time taken to accumulate 5 min of standing/walking (36.2 vs 46.3 min, p = 0.022), but no significant difference to sitting episode length or the number of switches between sitting and standing/walking per hour. Ergonomics awareness was not associated with any sedentary pattern variable among those using a sit-stand desk. Use of sit-stand desks was associated with better sedentary behavior in call centre workers, however ergonomics awareness did not enhance the effect. Copyright © 2012 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Frequency of postural changes during sitting whilst using a desktop computer--exploring an analytical methodology.

PubMed

Niekerk, Sjan-Mari van; Louw, Quinette Abigail; Grimmer-Sommers, Karen

2014-01-01

Dynamic movement whilst sitting is advocated as a way to reduce musculoskeletal symptoms from seated activities. Conventionally, in ergonomics research, only a 'snapshot' of static sitting posture is captured, which does not provide information on the number or type of movements over a period of time. A novel approach to analyse the number of postural changes whist sitting was employed in order to describe the sitting behaviour of adolescents whilst undertaking computing activities. A repeated-measures observational study was conducted. A total of 12 high school students were randomly selected from a conveniently selected school. Fifteen minutes of 3D posture measurements were recorded to determine the number of postural changes whilst using computers. Data of 11 students were able to be analysed. Large intra-subject variation of the median and IQR was observed, indicating frequent postural changes whilst sitting. Better understanding of usual dynamic postural movements whilst sitting will provide new insights into causes of musculoskeletal symptoms experienced by computer users.

Improvement in automatic postural coordination following alexander technique lessons in a person with low back pain.

PubMed

Cacciatore, Timothy W; Horak, Fay B; Henry, Sharon M

2005-06-01

The relationship between abnormal postural coordination and back pain is unclear. The Alexander Technique (AT) aims to improve postural coordination by using conscious processes to alter automatic postural coordination and ongoing muscular activity, and it has been reported to reduce low back pain. This case report describes the use of the AT with a client with low back pain and the observed changes in automatic postural responses and back pain. The client was a 49-year-old woman with a 25-year history of left-sided, idiopathic, lumbrosacral back pain. Automatic postural coordination was measured using a force plate during horizontal platform translations and one-legged standing. The client was tested monthly for 4 months before AT lessons and for 3 months after lessons. Before lessons, she consistently had laterally asymmetric automatic postural responses to translations. After AT lessons, the magnitude and asymmetry of her responses and balance improved and her low back pain decreased. Further research is warranted to study whether AT lessons improve low back pain-associated abnormalities in automatic postural coordination and whether improving automatic postural coordination helps to reduce low back pain.

Influence of musical groove on postural sway.

PubMed

Ross, Jessica M; Warlaumont, Anne S; Abney, Drew H; Rigoli, Lillian M; Balasubramaniam, Ramesh

2016-03-01

Timescales of postural fluctuation reflect underlying neuromuscular processes in balance control that are influenced by sensory information and the performance of concurrent cognitive and motor tasks. An open question is how postural fluctuations entrain to complex environmental rhythms, such as in music, which also vary on multiple timescales. Musical groove describes the property of music that encourages auditory-motor synchronization and is used to study voluntary motor entrainment to rhythmic sounds. The influence of groove on balance control mechanisms remains unexplored. We recorded fluctuations in center of pressure (CoP) of standing participants (N = 40) listening to low and high groove music and during quiet stance. We found an effect of musical groove on radial sway variability, with the least amount of variability in the high groove condition. In addition, we observed that groove influenced postural sway entrainment at various temporal scales. For example, with increasing levels of groove, we observed more entrainment to shorter, local timescale rhythmic musical occurrences. In contrast, we observed more entrainment to longer, global timescale features of the music, such as periodicity, with decreasing levels of groove. Finally, musical experience influenced the amount of postural variability and entrainment at local and global timescales. We conclude that groove in music and musical experience can influence the neural mechanisms that govern balance control, and discuss implications of our findings in terms of multiscale sensorimotor coupling. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

[Postural control disorders in initial phases of whiplash].

PubMed

Pleguezuelos Cobo, Eulogio; García-Alsina, Joan; García Almazán, Concepción; Ortiz Fandiño, Javier; Pérez Mesquida, M Engracia; Guirao Cano, Lluis; Samitier Pastor, Beatriz; Perucho Pont, Cristina; Coll Serra, Estel; Matarrubias, Carlos; Reveron, Genoveva

2009-05-02

Dizziness of variable intensity is a frequent complaint in patients who suffered whiplash and largely documented balance disturbances. The objective of the study was to identify balance disorders in early stage of whiplash after road traffic accidents. Ninety nine women were included in the study. Fifty four women had suffered whiplash within two weeks and 45 were included in a healthy control group. Static posturography on a force platform was carried out in all study participants, by means of the Romberg test in four sequential phases, using the postural sway area (SA) as a dependent variable. Visual Analogic Scale (VAS) and Northwick Park Neck Pain Questionnaire (NPH) were used to evaluate pain and function. Postural sway area increased significantly in each of the consecutive phases in both groups. The differences of the means of the postural sway area were statistically significant in all Romberg phases (p=.009 to P=.000). No correlation was found between SA and VAS or NPH scores. There was a positive correlation between the postural sway area standing on a thick foam cushion placed over the plate with closed eyes and the number of days of transitory incapacity (r=0.414; P=.009). Patients with recent whiplash show a postural control disturbance revealed trough a sequential static posturography analysis. This suggests that the balance disorder is not only a consequence of late whiplash syndrome evolution. Therefore, we should promote early instauration of a specific therapeutic approach if and when the patient refers dizziness and related symptoms.

Ankle and hip postural strategies defined by joint torques

NASA Technical Reports Server (NTRS)

Runge, C. F.; Shupert, C. L.; Horak, F. B.; Zajac, F. E.; Peterson, B. W. (Principal Investigator)

1999-01-01

Previous studies have identified two discrete strategies for the control of posture in the sagittal plane based on EMG activations, body kinematics, and ground reaction forces. The ankle strategy was characterized by body sway resembling a single-segment-inverted pendulum and was elicited on flat support surfaces. In contrast, the hip strategy was characterized by body sway resembling a double-segment inverted pendulum divided at the hip and was elicited on short or compliant support surfaces. However, biomechanical optimization models have suggested that hip strategy should be observed in response to fast translations on a flat surface also, provided the feet are constrained to remain in contact with the floor and the knee is constrained to remain straight. The purpose of this study was to examine the experimental evidence for hip strategy in postural responses to backward translations of a flat support surface and to determine whether analyses of joint torques would provide evidence for two separate postural strategies. Normal subjects standing on a flat support surface were translated backward with a range of velocities from fast (55 cm/s) to slow (5 cm/s). EMG activations and joint kinematics showed pattern changes consistent with previous experimental descriptions of mixed hip and ankle strategy with increasing platform velocity. Joint torque analyses revealed the addition of a hip flexor torque to the ankle plantarflexor torque during fast translations. This finding indicates the addition of hip strategy to ankle strategy to produce a continuum of postural responses. Hip torque without accompanying ankle torque (pure hip strategy) was not observed. Although postural control strategies have previously been defined by how the body moves, we conclude that joint torques, which indicate how body movements are produced, are useful in defining postural control strategies. These results also illustrate how the biomechanics of the body can transform discrete control

Development of adaptive sensorimotor control in infant sitting posture.

PubMed

Chen, Li-Chiou; Jeka, John; Clark, Jane E

2016-03-01

A reliable and adaptive relationship between action and perception is necessary for postural control. Our understanding of how this adaptive sensorimotor control develops during infancy is very limited. This study examines the dynamic visual-postural relationship during early development. Twenty healthy infants were divided into 4 developmental groups (each n=5): sitting onset, standing alone, walking onset, and 1-year post-walking. During the experiment, the infant sat independently in a virtual moving-room in which anterior-posterior oscillations of visual motion were presented using a sum-of-sines technique with five input frequencies (from 0.12 to 1.24 Hz). Infants were tested in five conditions that varied in the amplitude of visual motion (from 0 to 8.64 cm). Gain and phase responses of infants' postural sway were analyzed. Our results showed that infants, from a few months post-sitting to 1 year post-walking, were able to control their sitting posture in response to various frequency and amplitude properties of the visual motion. Infants showed an adult-like inverted-U pattern for the frequency response to visual inputs with the highest gain at 0.52 and 0.76 Hz. As the visual motion amplitude increased, the gain response decreased. For the phase response, an adult-like frequency-dependent pattern was observed in all amplitude conditions for the experienced walkers. Newly sitting infants, however, showed variable postural behavior and did not systemically respond to the visual stimulus. Our results suggest that visual-postural entrainment and sensory re-weighting are fundamental processes that are present after a few months post sitting. Sensorimotor refinement during early postural development may result from the interactions of improved self-motion control and enhanced perceptual abilities. Copyright © 2016 Elsevier B.V. All rights reserved.

Age-related effects on postural control under multi-task conditions.

PubMed

Granacher, Urs; Bridenbaugh, Stephanie A; Muehlbauer, Thomas; Wehrle, Anja; Kressig, Reto W

2011-01-01

Changes in postural sway and gait patterns due to simultaneously performed cognitive (CI) and/or motor interference (MI) tasks have previously been reported and are associated with an increased risk of falling in older adults. The objectives of this study were to investigate the effects of a CI and/or MI task on static and dynamic postural control in young and elderly subjects, and to find out whether there is an association between measures of static and dynamic postural control while concurrently performing the CI and/or MI task. A total of 36 healthy young (n = 18; age: 22.3 ± 3.0 years; BMI: 21.0 ± 1.6 kg/m(2)) and elderly adults (n = 18; age: 73.5 ± 5.5 years; BMI: 24.2 ± 2.9 kg/m(2)) participated in this study. Static postural control was measured during bipedal stance, and dynamic postural control was obtained while walking on an instrumented walkway. Irrespective of the task condition, i.e. single-task or multiple tasks, elderly participants showed larger center-of-pressure displacements and greater stride-to-stride variability than younger participants. Associations between measures of static and dynamic postural control were found only under the single-task condition in the elderly. Age-related deficits in the postural control system seem to be primarily responsible for the observed results. The weak correlations detected between static and dynamic measures could indicate that fall-risk assessment should incorporate dynamic measures under multi-task conditions, and that skills like erect standing and walking are independent of each other and may have to be trained complementarily. Copyright © 2010 S. Karger AG, Basel.

Creative Dance Practice Improves Postural Control in a Child With Cerebral Palsy.

PubMed

Stribling, Kate; Christy, Jennifer

2017-10-01

To investigate the effect of creative dance instruction on postural control and balance in an 11-year-old with spastic triplegic cerebral palsy, Gross Motor Function Classification Scale level II. We conducted 1-hour dance interventions twice weekly for 8 weeks, with a focus on somatosensory awareness and movement in all planes of motion. Computerized dynamic posturography using the SMART Balance Master/EquiTest (NeuroCom) was used to assess postural control and balance reactions before the first class and following the final class. Gains in standing stability, balance recovery, directional control, and endpoint excursion of movement were found. Participation in creative dance lessons appears to improve somatosensory effectiveness and postural control in a child with cerebral palsy. Dance is a fun way to improve balance and coordination. These interventions could be easily implemented into programs for children with cerebral palsy.

Postural stability and ankle sprain history in athletes compared to uninjured controls.

PubMed

Huurnink, Arnold; Fransz, Duncan P; Kingma, Idsart; Verhagen, Evert A L M; van Dieën, Jaap H

2014-02-01

Diminished postural stability is a risk factor for ankle sprain occurrence and ankle sprains result in impaired postural stability. To date, ankle sprain history has not been taken into account as a determinant of postural stability, while it could possibly specify subgroups of interest. Postural stability was compared between 18 field hockey athletes who had recovered from an ankle sprain (mean (SD); 3.6 (1.5) months post-injury), and 16 uninjured controls. Force plate and kinematics parameters were calculated during single-leg standing: mean center of pressure speed, mean absolute horizontal ground reaction force, mean absolute ankle angular velocity, and mean absolute hip angular velocity. Additionally, cluster analysis was applied to the 'injured' participants, and the cluster with diminished postural stability was compared to the other participants with respect to ankle sprain history. MANCOVA showed no significant difference between groups in postural stability (P = 0.68). A self-reported history of an (partial) ankle ligament rupture was typically present in the cluster with diminished postural stability. Subsequently, a 'preceding rupture' was added as a factor in the MANCOVA, which showed a significant association between diminished postural stability and a 'preceding rupture' (P = 0.01), for all four individual parameters (P: 0.001-0.029; Cohen's d: 0.96-2.23). Diminished postural stability is not apparent in all previously injured athletes. However, our analysis suggests that an (mild) ankle sprain with a preceding severe ankle sprain is associated with impaired balance ability. Therefore, sensorimotor training may be emphasized in this particular group and caution is warranted in return to play decisions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of epidural blood injection on upright posture intolerance in patients with headaches due to intracranial hypotension: A prospective study.

PubMed

Qureshi, Adnan I; Kherani, Danish; Waqas, Muhammad A; Qureshi, Mushtaq H; Raja, Faisal M; Wallery, Shawn S

2018-06-19

We performed a prospective study to quantify changes in various aspects of upright posture intolerance in patients with intracranial hypotension. Six patients were provided a standard questionnaire before, immediately after epidural blood patch injection and at follow-up visit within 1 month after epidural blood injection inquiring: (a) How long can they stand straight without any support? (b) Do they feel any sense of sickness when they sit or lie down after standing? (c) How long do they have to wait before they are comfortable standing again after they have stood straight? (d) How effectively and fast can they get up from sitting or lying position to stand straight? and (e) Rate their activities in upright posture without support on a standard vertical visual analogue scale between 100 (can do everything) and 0 (cannot do anything). All patients responded that they could not stand straight for ≥30 min (four responding <5 min) on pretreatment evaluation. All patients reported improvement in this measure immediately postprocedure with two reporting ≥30 min. At follow-up, three patients reported further improvement and one patient reported worsening in this measure. The magnitude of improvement ranged from 10 to 80 points increase immediately postprocedure in their ability to perform activities, while they are standing without any support on visual analogue scale. At follow-up, four patient reported additional improvement in their ability to perform activities, while they are standing without any support (ranged from 10 to 20 points increase compared with immediately postprocedure rating). We present semiquantitative data on various aspects of upright posture intolerance in patients with intracranial hypotension before and after epidural blood injection. © 2018 The Authors. Brain and Behavior published by Wiley Periodicals, Inc.

Sport Skill-Specific Expertise Biases Sensory Integration for Spatial Referencing and Postural Control.

PubMed

Thalassinos, Michalis; Fotiadis, Giorgos; Arabatzi, Fotini; Isableu, Brice; Hatzitaki, Vassilia

2017-09-15

The authors asked how sport expertise modulates visual field dependence and sensory reweighting for controlling posture. Experienced soccer athletes, ballet dancers, and nonathletes performed (a) a Rod and Frame test and (b) a 100-s bipedal stance task during which vision and proprioception were successively or concurrently disrupted in 20-s blocks. Postural adaptation was assessed in the mean center of pressure displacement, root mean square of center of pressure velocity and ankle muscles integrated electromyography activity. Soccer athletes were more field dependent than were nonathletes. During standing, dancers were more destabilized by vibration and required more time to reweigh sensory information compared with the other 2 groups. These findings reveal a sport skill-specific bias in the reweighing of sensory inputs for spatial orientation and postural control.

Cardiovascular responses to postural changes: differences with age for women and men

NASA Technical Reports Server (NTRS)

Frey, M. A.; Tomaselli, C. M.; Hoffler, W. G.

1994-01-01

The cardiovascular responses to postural change, and how they are affected by aging, are inadequately described in women. Therefore, the authors examined the influence of age and sex on the responses of blood pressure, cardiac output, heart rate, and other variables to change in posture. Measurements were made after 10 minutes each in the supine, seated, and standing positions in 22 men and 25 women who ranged in age from 21 to 59 years. Several variables differed, both by sex and by age, when subjects were supine. On rising, subjects' diastolic and mean arterial pressures, heart rate, total peripheral resistance (TPR), and thoracic impedance increased; cardiac output, stroke volume, and mean stroke ejection rate decreased; and changes in all variables, except heart rate, were greater from supine to sitting than sitting to standing. The increase in heart rate was greater in the younger subjects, and increases in TPR and thoracic impedance were greater in the older subjects. Stroke volume decreased less, and TPR and thoracic impedance increased more, in the women than in the men. The increase in TPR was particularly pronounced in the older women. These studies show that the cardiovascular responses to standing differ, in some respects, between the sexes and with age. The authors suggest that the sex differences are, in part, related to greater decrease of thoracic blood volume with standing in women than in men, and that the age differences result, in part, from decreased responsiveness of the high-pressure baroreceptor system.

A Correlation-based Framework for Evaluating Postural Control Stochastic Dynamics

PubMed Central

Hernandez, Manuel E.; Snider, Joseph; Stevenson, Cory; Cauwenberghs, Gert; Poizner, Howard

2016-01-01

The inability to maintain balance during varying postural control conditions can lead to falls, a significant cause of mortality and serious injury among older adults. However, our understanding of the underlying dynamical and stochastic processes in human postural control have not been fully explored. To further our understanding of the underlying dynamical processes, we examine a novel conceptual framework for studying human postural control using the center of pressure (COP) velocity autocorrelation function (COP-VAF) and compare its results to Stabilogram Diffusion Analysis (SDA). Eleven healthy young participants were studied under quiet unipedal or bipedal standing conditions with eyes either opened or closed. COP trajectories were analyzed using both the traditional posturographic measure SDA and the proposed COP-VAF. It is shown that the COP-VAF leads to repeatable, physiologically meaningful measures that distinguish postural control differences in unipedal versus bipedal stance trials with and without vision in healthy individuals. More specifically, both a unipedal stance and lack of visual feedback increased initial values of the COP-VAF, magnitude of the first minimum, and diffusion coefficient, particularly in contrast to bipedal stance trials with open eyes. Use of a stochastic postural control model, based on an Ornstein-Uhlenbeck process that accounts for natural weight-shifts, suggests an increase in spring constant and decreased damping coefficient when fitted to experimental data. This work suggests that we can further extend our understanding of the underlying mechanisms behind postural control in quiet stance under varying stance conditions using the COP-VAF and provides a tool for quantifying future neurorehabilitative interventions. PMID:26011886

Personality traits and individual differences predict threat-induced changes in postural control.

PubMed

Zaback, Martin; Cleworth, Taylor W; Carpenter, Mark G; Adkin, Allan L

2015-04-01

This study explored whether specific personality traits and individual differences could predict changes in postural control when presented with a height-induced postural threat. Eighty-two healthy young adults completed questionnaires to assess trait anxiety, trait movement reinvestment (conscious motor processing, movement self-consciousness), physical risk-taking, and previous experience with height-related activities. Tests of static (quiet standing) and anticipatory (rise to toes) postural control were completed under low and high postural threat conditions. Personality traits and individual differences significantly predicted height-induced changes in static, but not anticipatory postural control. Individuals less prone to taking physical risks were more likely to lean further away from the platform edge and sway at higher frequencies and smaller amplitudes. Individuals more prone to conscious motor processing were more likely to lean further away from the platform edge and sway at larger amplitudes. Individuals more self-conscious about their movement appearance were more likely to sway at smaller amplitudes. Evidence is also provided that relationships between physical risk-taking and changes in static postural control are mediated through changes in fear of falling and physiological arousal. Results from this study may have indirect implications for balance assessment and treatment; however, further work exploring these factors in patient populations is necessary. Copyright © 2015 Elsevier B.V. All rights reserved.

Decorticate posture

MedlinePlus

Abnormal posturing - decorticate posture; Traumatic brain injury - decorticate posture ... Brain problem due to drugs, poisoning, or infection Traumatic brain injury Brain problem due to liver failure Increased pressure ...

Effect of footwear on standing balance in healthy young adult males.

PubMed

Alghadir, Ahmad H; Zafar, Hamayun; Anwer, Shahnawaz

2018-03-01

The present study aimed to evaluate the effect of footwear on standing balance in healthy young adult males. Thirty healthy male participants aged 20-30 years were tested for standing balance on the Balance Master on three occasions, including wearing a sandal, standard shoe, or no footwear (barefoot). The tests of postural stability include; "Modified Clinical Test of Sensory Interaction on Balance" (mCTSIB), "Unilateral Stance" (US), and the "Limits of Stability" (LOS). The balance scores (mCTSIB, US, and LOS) was analyzed. There was a significant effect between footwear conditions for mCTIB with eye closed on a firm surface (p=0.002). There was a significant effect between footwear conditions for the US with eye open and closed (p⟨0.05). There was a significant effect between footwear conditions for LOS reaction time during forward movement (p=0.02). Similarly, there was a significant effect between footwear conditions for LOS reaction time during left side movement (p=0.01). Wearing sandals compared to bare feet significantly increased postural sway and reduced stability in healthy young adult males. However, wearing a standard shoe compared to bare feet did not significantly affect balance scores in standing.

Postural stability and the influence of concurrent muscle activation--Beneficial effects of jaw and fist clenching.

PubMed

Ringhof, Steffen; Leibold, Timo; Hellmann, Daniel; Stein, Thorsten

2015-10-01

Recent studies reported on the potential benefits of submaximum clenching of the jaw on human postural control in upright unperturbed stance. However, it remained unclear whether these effects might also be observed among active controls. The purpose of the present study, therefore, was to comparatively examine the influence of concurrent muscle activation in terms of submaximum clenching of the jaw and submaximum clenching of the fists on postural stability. Posturographic analyses were conducted with 17 healthy young adults on firm and foam surfaces while either clenching the jaw (JAW) or clenching the fists (FIST), whereas habitual standing served as the control condition (CON). Both submaximum tasks were performed at 25% maximum voluntary contraction, assessed, and visualized in real time by means of electromyography. Statistical analyses revealed that center of pressure (COP) displacements were significantly reduced during JAW and FIST, but with no differences between both concurrent clenching activities. Further, a significant increase in COP displacements was observed for the foam as compared to the firm condition. The results showed that concurrent muscle activation significantly improved postural stability compared with habitual standing, and thus emphasize the beneficial effects of jaw and fist clenching for static postural control. It is suggested that concurrent activities contribute to the facilitation of human motor excitability, finally increasing the neural drive to the distal muscles. Future studies should evaluate whether elderly or patients with compromised postural control might benefit from these physiological responses, e.g., in the form of a reduced risk of falling. Copyright © 2015 Elsevier B.V. All rights reserved.

Foot anatomy specialization for postural sensation and control

PubMed Central

Ivanenko, Y. P.; Gurfinkel, V. S.

2012-01-01

Anthropological and biomechanical research suggests that the human foot evolved a unique design for propulsion and support. In theory, the arch and toes must play an important role, however, many postural studies tend to focus on the simple hinge action of the ankle joint. To investigate further the role of foot anatomy and sensorimotor control of posture, we quantified the deformation of the foot arch and studied the effects of local perturbations applied to the toes (TOE) or 1st/2nd metatarsals (MT) while standing. In sitting position, loading and lifting a 10-kg weight on the knee respectively lowered and raised the foot arch between 1 and 1.5 mm. Less than 50% of this change could be accounted for by plantar surface skin compression. During quiet standing, the foot arch probe and shin sway revealed a significant correlation, which shows that as the tibia tilts forward, the foot arch flattens and vice versa. During TOE and MT perturbations (a 2- to 6-mm upward shift of an appropriate part of the foot at 2.5 mm/s), electromyogram (EMG) measures of the tibialis anterior and gastrocnemius revealed notable changes, and the root-mean-square (RMS) variability of shin sway increased significantly, these increments being greater in the MT condition. The slow return of RMS to baseline level (>30 s) suggested that a very small perturbation changes the surface reference frame, which then takes time to reestablish. These findings show that rather than serving as a rigid base of support, the foot is compliant, in an active state, and sensitive to minute deformations. In conclusion, the architecture and physiology of the foot appear to contribute to the task of bipedal postural control with great sensitivity. PMID:22157121

Older adults prioritize postural stability in the anterior-posterior direction to regain balance following volitional lateral step.

PubMed

Porter, Shaun; Nantel, Julie

2015-02-01

Postural control in the medial-lateral (ML) direction is of particular interest regarding the assessment of changes in postural control, as it is highly related to the risk of falling. To determine the postural strategies used to regain balance following a voluntary lateral step and compare these strategies between young and older adults. Sixteen older adults (60-90 years) and 14 young adults (20-40 years) were asked to stand quietly for 30s, walk in place and then take a lateral step and stand quietly (30s). Balance Post was divided into 10s intervals. Center of pressure displacement (CoP) and velocity (VCoP) in the anterio-posterior (AP) and ML directions were analyzed. In both groups, CoP and VCoP in AP and ML increased in Post1 compared to Pre (P<0.001). Dissimilar to young adults, VCoP-Post2, Post3 ML were larger than Pre (P=0.01) in older adults. Age correlated with all VCoP (Pre and Post) in both ML (P<0.05) and AP directions (P<0.01). Dissimilar to young adults, older adults use different postural strategies in ML and AP directions and prioritized postural stability in the AP direction to recover balance after completing a lateral step. In the ML direction, older adults took up to 30s to regain balance. Considering that age was related to larger CoP displacement and velocity, the AP strategy to recover postural balance following a lateral step could become less efficient as older adults age and therefore increasing the risk of falls. Copyright © 2015 Elsevier B.V. All rights reserved.

Impact of visual and somatosensory deprivation on dynamic balance in adolescent idiopathic scoliosis.

PubMed

Kuo, Fang-Chuan; Wang, Nai-Hwei; Hong, Chang-Zern

2010-11-01

A cross-sectional study of balance control in adolescents with idiopathic scoliosis (AIS). To investigate the impact of visual and somatosensory deprivation on the dynamic balance in AIS patients and to discuss electromyographic (EMG) and posture sway findings. Most studies focus on posture sway in quiet standing controls with little effort on examining muscle-activated patterns in dynamic standing controls. Twenty-two AIS patients and 22 age-matched normal subjects were studied. To understand how visual and somatosensory information could modulate standing balance, balance tests with the Biodex stability system were performed on a moving platform under 3 conditions: visual feedback provided (VF), eyes closed (EC), and standing on a sponge pad with visual feedback provided (SV). Muscular activities of bilateral lumbar multifidi, gluteus medii, and gastrocnemii muscles were recorded with a telemetry EMG system. AIS patients had normal balance index and amplitude and duration of EMG similar to those of normal subjects in the balance test. However, the onset latency of right gastrocnemius was earlier in AIS patients than in normal subjects. In addition, body-side asymmetry was noted on muscle strength and onset latency in AIS subjects. Under EC condition, lumbar multifidi, and gluteus medii activities were higher than those under SV and VF conditions (P < 0.05). Under SV condition, the medial-lateral tilting angle was less than that under VF and EC conditions. In addition, the active duration of right gluteus medius was shorter under SV condition (P < 0.05). The dynamic balance control is particularly disruptive under visual deprivation with increasing lumbar multifidi and gluteus medii activities for compensation. Sponge pad can cause decrease in frontal plane tilting and gluteus medii effort. The asymmetric muscle strength and onset timing are attributed to anatomic deformation as opposed to neurologic etiological factors.

Development of posture-specific computational phantoms using motion capture technology and application to radiation dose-reconstruction for the 1999 Tokai-Mura nuclear criticality accident

NASA Astrophysics Data System (ADS)

Vazquez, Justin A.; Caracappa, Peter F.; Xu, X. George

2014-09-01

The majority of existing computational phantoms are designed to represent workers in typical standing anatomical postures with fixed arm and leg positions. However, workers found in accident-related scenarios often assume varied postures. This paper describes the development and application of two phantoms with adjusted postures specified by data acquired from a motion capture system to simulate unique human postures found in a 1999 criticality accident that took place at a JCO facility in Tokai-Mura, Japan. In the course of this accident, two workers were fatally exposed to extremely high levels of radiation. Implementation of the emergent techniques discussed produced more accurate and more detailed dose estimates for the two workers than were reported in previous studies. A total-body dose of 6.43 and 26.38 Gy was estimated for the two workers, who assumed a crouching and a standing posture, respectively. Additionally, organ-specific dose estimates were determined, including a 7.93 Gy dose to the thyroid and 6.11 Gy dose to the stomach for the crouching worker and a 41.71 Gy dose to the liver and a 37.26 Gy dose to the stomach for the standing worker. Implications for the medical prognosis of the workers are discussed, and the results of this study were found to correlate better with the patient outcome than previous estimates, suggesting potential future applications of such methods for improved epidemiological studies involving next-generation computational phantom tools.

Development of posture-specific computational phantoms using motion capture technology and application to radiation dose-reconstruction for the 1999 Tokai-Mura nuclear criticality accident.

PubMed

Vazquez, Justin A; Caracappa, Peter F; Xu, X George

2014-09-21

The majority of existing computational phantoms are designed to represent workers in typical standing anatomical postures with fixed arm and leg positions. However, workers found in accident-related scenarios often assume varied postures. This paper describes the development and application of two phantoms with adjusted postures specified by data acquired from a motion capture system to simulate unique human postures found in a 1999 criticality accident that took place at a JCO facility in Tokai-Mura, Japan. In the course of this accident, two workers were fatally exposed to extremely high levels of radiation. Implementation of the emergent techniques discussed produced more accurate and more detailed dose estimates for the two workers than were reported in previous studies. A total-body dose of 6.43 and 26.38 Gy was estimated for the two workers, who assumed a crouching and a standing posture, respectively. Additionally, organ-specific dose estimates were determined, including a 7.93 Gy dose to the thyroid and 6.11 Gy dose to the stomach for the crouching worker and a 41.71 Gy dose to the liver and a 37.26 Gy dose to the stomach for the standing worker. Implications for the medical prognosis of the workers are discussed, and the results of this study were found to correlate better with the patient outcome than previous estimates, suggesting potential future applications of such methods for improved epidemiological studies involving next-generation computational phantom tools.

The Short-Term Effects of Lying, Sitting and Standing on Energy Expenditure in Women

PubMed Central

POPP, COLLIN J.; BRIDGES, WILLIAM C.; JESCH, ELLIOT D.

2018-01-01

The deleterious health effects of too much sitting have been associated with an increased risk for overweight and obesity. Replacing sitting with standing is the proposed intervention to increase daily energy expenditure (EE). The purpose of this study was to determine the short-term effects of lying, sitting, and standing postures on EE, and determine the magnitude of the effect each posture has on EE using indirect calorimetry (IC). Twenty-eight healthy females performed three separate positions (lying, sitting, standing) in random order. Inspired and expired gases were collected for 45-minutes (15 minutes for each position) using breath-by-breath indirect calorimetry. Oxygen consumption (VO2) and carbon dioxide production (VCO2) were measured to estimate EE. Statistical analyses used repeat measures ANOVA to analyze all variables and post hoc t-tests. Based on the ANOVA the individual, time period and order term did not result in a statistically significant difference. Lying EE and sitting EE were not different from each other (P = 0.56). However, standing EE (kcal/min) was 9.0 % greater than lying EE (kcal/min) (P = 0.003), and 7.1% greater than sitting EE (kcal/min) (P = 0.02). The energetic cost of standing was higher compared to lying and sitting. While this is statistically significant, the magnitude of the effect of standing when compared to sitting was small (Cohen’s d = 0.31). Short-term standing does not offer an energetic advantage when compared to sitting.

Postural sway and regional cerebellar volume in adults with attention-deficit/hyperactivity disorder