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Sample records for adolescent standing postural

  1. The effect of backpack weight on the standing posture and balance of schoolgirls with adolescent idiopathic scoliosis and normal controls.

    PubMed

    Chow, Daniel H K; Kwok, Monica L Y; Cheng, Jack C Y; Lao, Miko L M; Holmes, Andrew D; Au-Yang, Alexander; Yao, Fiona Y D; Wong, M S

    2006-10-01

    Concerns have been raised regarding the effect of carrying a backpack on adolescent posture and balance, but the effect of backpack loading combined with other factors affecting balance, such as adolescent idiopathic scoliosis (AIS), has not been determined. This study examines the effects of backpack load on the posture and balance of schoolgirls with AIS and normal controls. The standing posture of 26 schoolgirls with mild AIS (mean age 13, Cobb angle 10-25 degrees ) and 20 age-matched normal schoolgirls were recorded without a backpack and while carrying a standard dual-strap backpack loaded at 7.5%, 10%, 12.5% and 15% of the subject's bodyweight (BW). Kinematics of the pelvis, trunk and head were recorded using a motion analysis system and centre of pressure (COP) data were recorded using a force platform. Reliable COP data could only be derived for 13 of the subjects with AIS. Increasing backpack load causes a significantly increased flexion of the trunk in relation to the pelvis and extension of the head in relation to the trunk, as well as increased antero-posterior range of COP motion. While backpack load appears to affect balance predominantly in the antero-posterior direction, differences between groups were more evident in the medio-lateral direction, with AIS subjects showing poor balance in this direction. Overall, carrying a backpack causes similar sagittal plane changes in posture and balance in both normal and AIS groups. Load size or subject group did not influence balance, but the additive effect of backpack carrying and AIS on postural control alters the risk of fall in this population. Therefore, load limit recommendations based on normal subjects should not be applicable to subjects with AIS.

  2. Pelvic Morphology, Body Posture and Standing Balance Characteristics of Adolescent Able-Bodied and Idiopathic Scoliosis Girls

    PubMed Central

    Stylianides, Georgios A.; Dalleau, Georges; Begon, Mickaël; Rivard, Charles-Hilaire; Allard, Paul

    2013-01-01

    The purpose of this study was to determine how pelvic morphology, body posture, and standing balance variables of scoliotic girls differ from those of able-bodied girls, and to classify neuro-biomechanical variables in terms of a lower number of unobserved variables. Twenty-eight scoliotic and twenty-five non-scoliotic able-bodied girls participated in this study. 3D coordinates of ten anatomic body landmarks were used to describe pelvic morphology and trunk posture using a Flock of Birds system. Standing balance was measured using a force plate to identify the center of pressure (COP), and its anteroposterior (AP) and mediolateral (ML) displacements. A multivariate analysis of variance (MANOVA) was performed to determine differences between the two groups. A factor analysis was used to identify factors that best describe both groups. Statistical differences were identified between the groups for each of the parameter types. While spatial orientation of the pelvis was similar in both groups, five of the eight trunk postural variables of the scoliotic group were significantly different that the able-bodied group. Also, five out of the seven standing balance variables were higher in the scoliotic girls. Approximately 60% of the variation is supported by 4 factors that can be associated with a set of variables; standing balance variables (factor 1), body posture variables (factor 2), and pelvic morphology variables (factors 3 and 4). Pelvic distortion, body posture asymmetry, and standing imbalance are more pronounced in scoliotic girls, when compared to able-bodied girls. These findings may be beneficial when addressing balance and ankle proprioception exercises for the scoliotic population. PMID:23875021

  3. A New Standing Posture Detector to Enable People with Multiple Disabilities to Control Environmental Stimulation by Changing Their Standing Posture through a Commercial Wii Balance Board

    ERIC Educational Resources Information Center

    Shih, Ching-Hsiang; Shih, Ching-Tien; Chiang, Ming-Shan

    2010-01-01

    This study assessed whether two persons with multiple disabilities would be able to control environmental stimulation using body swing (changing standing posture) and a Wii Balance Board with a newly developed standing posture detection program (i.e. a new software program turns a Wii Balance Board into a precise standing posture detector). The…

  4. 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.

  5. Postural stability in children with hemiplegia estimated for three postural conditions: standing, sitting and kneeling.

    PubMed

    Szopa, Andrzej; Domagalska-Szopa, Małgorzata

    2015-04-01

    Postural control deficit is one of the most important problems in children with cerebral palsy (CP). The purpose of the presented study was to compare the effects of body posture asymmetry alone (i.e., in children with mild scoliosis) with the effects of body posture impairment (i.e., in children with hemiplegia) on postural stability. Forty-five outpatients with hemiplegia and 51 children with mild scoliosis were assessed using a posturography device. The examination comprised two parts: (1) analysis of the static load distribution; and (2) a posturographic test (CoP measurements) conducted in three postural conditions: standing, sitting and kneeling. Based on the asymmetry index of the unaffected/affected body sides while standing, the children with hemiplegia were divided into two different postural patterns: a pro-gravitational postural pattern (PGPP) and an anti-gravitational postural pattern (AGPP) (Domagalska-Szopa & Szopa (2013). BioMed Research International, 2013, 462094; (2014). Therapeutics and Clinical Risk Management, 10, 113). The group of children with mild scoliosis, considered as a standard for static body weight distribution, was used as the reference group. The results of present study only partially confirmed that children with hemiplegia have increased postural instability. Strong weight distribution asymmetry was found in children with an AGPP, which induced larger lateral-medial CoP displacements compared with children with scoliosis. In children with hemiplegia, distinguishing between their postural patterns may be useful to improve the guidelines for early therapy children with an AGPP before abnormal patterns of weight-bearing asymmetry are fully established.

  6. The Control of Posture in Newly Standing Infants is Task Dependent

    ERIC Educational Resources Information Center

    Claxton, Laura J.; Melzer, Dawn K.; Ryu, Joong Hyun; Haddad, Jeffrey M.

    2012-01-01

    The postural sway patterns of newly standing infants were compared under two conditions: standing while holding a toy and standing while not holding a toy. Infants exhibited a lower magnitude of postural sway and more complex sway patterns when holding the toy. These changes suggest that infants adapt postural sway in a manner that facilitates…

  7. Relationship between morphologic somatotypes and standing posture equilibrium.

    PubMed

    Allard, P; Nault, M L; Hinse, S; LeBlanc, R; Labelle, H

    2001-01-01

    Previous studies have identified height and weight as important factors affecting quiet standing stability but studies have not addressed body morphology as a global factor. Using anthropometric measurements, the morphologic somatotypes were defined in terms of body composition and structure. The aim of this study was to test the hypothesis that morphologic somatotypes were related to standing posture equilibrium in able-bodied girls. A total of 43 able-bodied girls having a mean age of 13.8 +/- 2.2 years participated in this study. Somatotype measurements were taken to determine their endomorphic, mesomorphic or ectomorphic components. Then, subjects were asked to stand still on a force platform for 64 s with their eyes opened, feet about 23 cm apart and arms aligned with the trunk. Afterwards, subjects were grouped based on the highest value of their somatotype component. There was no statistical difference in age, height and weight among the groups. The surface area of an ellipse delineated by the displacement of the centre of pressure (COP) was statistically larger (236.9 +/- 134.3 mm2) for the ectomorphs than for the endomorphs 137.7 +/- 71.4 mm2). The minor axis was longer (8.1 +/- 2.9 mm) for the ectomorphs than for the endomorphs (5.7 +/- 2.2 mm). The decrease in standing posture stability of the ectomorphic group was attributed to a relatively low muscle component, a high height weight ratio and an elevated position of the body centre of mass in this population of girls. Somatotypes should be considered when assessing standing posture in both able-bodied subjects and patients.

  8. Both anticipatory and compensatory postural adjustments are adapted while catching a ball in unstable standing posture.

    PubMed

    Scariot, Vanessa; Rios, Jaqueline L; Claudino, Renato; dos Santos, Eloá C; Angulski, Hanna B B; dos Santos, Marcio J

    2016-01-01

    The main objective of this study was to analyze the role of balance exercises on anticipatory (APA) and compensatory (CPA) postural adjustments in different conditions of postural stability. Sixteen subjects were required to catch a ball while standing on rigid floor, trampoline and foam cushion surfaces. Electromyographic activities (EMG) of postural muscles were analyzed during time windows typical for APAs and CPAs. Overall there were a reciprocal activation of the muscles around the ankle and co-activations between ventral and dorsal muscles of the thigh and trunk during the catching a ball task. Compared to the rigid floor, the tibialis anterior activation was greater during the trampoline condition (CPA: p = 0.006) and the soleus muscle inhibition was higher during foam cushion condition (APA: p = 0.001; CPA: p = 0.007). Thigh and trunk muscle activities were similar across the conditions. These results advance the knowledge in postural control during body perturbations standing on unstable surfaces.

  9. Postural support by a standing aid alleviating subjective discomfort among cooks in a forward-bent posture during food preparation.

    PubMed

    Iwakiri, Kazuyuki; Kunisue, Reiko; Sotoyama, Midori; Udo, Hiroshi

    2008-01-01

    In this study, we evaluated the effects on subjective discomfort among cooks during food preparation through use of a standing aid that we developed to alleviate the workload on the low back in the forward-bent posture. Twelve female cooks who worked in a kitchen in a nursing home were asked to prepare foods in 2 working postures: (a) supported by the standing aid (Aid) and (b) without the aid (No aid). They were instructed to evaluate discomfort in 13-body regions during food preparation and the degree of fatigue at the day's end and to enter their ratings after the end of the workday. Since a significant correlation was observed between body height and the improvement effect of discomfort through use of the standing aid, cooks were divided into two groups according to the height, and ratings were analyzed in each group. Among the tall cooks, subjective discomfort in the low back and the front and back of thighs was significantly less with the Aid posture than with the No aid posture. However, in short cooks these values tended to increase in the Aid posture compared with the No aid posture. The results suggest that the standing aid was effective in alleviating tall cooks' workload on the low back in the forward-bent posture.

  10. Does increased muscular tension along the torso impair postural equilibrium in a standing posture?

    PubMed

    Hamaoui, Alain; Friant, Yola; Le Bozec, Serge

    2011-10-01

    This paper focused on the relationship between active muscular tension along the torso and postural equilibrium while standing. Eleven healthy male subjects underwent a posturographic examination associated with a bimanual compression of a dynamometric bar, which was used to set the torso muscular activity at three different levels (0MVC, 20MVC, 40MVC). Electromyographic pre-tests identified the main superficial muscles of the compressive load as: pectoralis major, latissimus dorsi, thoracic and lumbar erector spinae. Kinematics of the chest wall was recorded by means of two sensing belts, in order to assess the respiratory component of the center of pressure (CP) signal. The analysis of time-domain stabilometric parameters showed that CP displacements were larger and faster in 40MVC that in 20MVC, with no variation between 0MVC and 20MVC. The respiratory component of the CP signal was not sensitive to the compressive load. It was concluded that increased muscular tension along the torso is likely to disturb postural equilibrium, but only when it exceeds a given level.

  11. Postural and cortical responses following visual occlusion in standing and sitting tasks.

    PubMed

    Goh, Kwang Leng; Morris, Susan; Lee, Wee Lih; Ring, Alexander; Tan, Tele

    2017-03-16

    Perturbation-evoked responses (PERs) to a physical perturbation of postural stability have been detected using electroencephalography (EEG). Components of these responses are hypothesized to demonstrate the detection (P1) and evaluation (N1) of postural instability. Despite the important contribution of the visual system to postural control, PERs to a visual perturbation of posture have yet to be reported. Ten healthy young adults were exposed to unpredictable visual occlusion mediated through liquid crystal glasses under two conditions of postural demand: quiet standing and quiet sitting. The participants' PERs and postural responses were recorded and differences between conditions assessed using Wilcoxon signed-rank tests. In response to unpredictable visual occlusion, both P1 and N1 components of the PER were observed in both postural conditions. The amplitude of the P1 response remained consistent between postural conditions ([Formula: see text], [Formula: see text]), whereas N1 amplitude and postural responses were significantly smaller in the sitting condition ([Formula: see text], [Formula: see text]). This is the first study to demonstrate cortical responses to visual perturbation of posture. The responses to postural perturbation by sudden visual occlusion are similar in nature to that seen in relation to a physical perturbation. In addition, the amplitude of the N1 response is not only consistent with the relative magnitude of the perturbation, but also the underlying postural set, with a larger N1 seen in standing relative to sitting. The study informs the relative importance of vision to postural stability, postural set and provides a protocol to objectively assess sensory-based postural disorders.

  12. 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.

  13. 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…

  14. Effect of masticating chewing gum on postural stability during upright standing.

    PubMed

    Kushiro, Keisuke; Goto, Fumiyuki

    2011-01-07

    The purpose of this study was to investigate the effect of masticating chewing gum on postural stability during upright standing. To address this issue, 12 healthy subjects performed quiet standing on a force platform for the posturography study. The subjects were instructed to stand as stable as possible on the force platform in order to record the trajectory of the center-of-pressure (COP). After measuring the postural sway in the initial condition (pre-condition), the subjects were asked to stand while masticating chewing gum (gum-condition). Following the gum-condition, quiet standing without mastication was evaluated (post-condition) to ensure the effect of masticating chewing gum on postural stability. The trajectory and velocity of the COP were analyzed for each condition. We found that the postural stability tended to enhance during mastication of chewing gum. The rectangle area of the COP trajectory significantly diminished in the gum-condition and significantly enlarged in the post-condition. A similar effect was observed in the maximum velocity and standard deviation (SD) of the fore-aft amplitude of the COP trajectory. The values were significantly smaller in the gum-condition compared to those in the post-condition. These findings suggest that mastication of chewing gum affects the postural control by enhancing the postural stability during upright standing.

  15. Foot sole skin vibration perceptual thresholds are elevated in a standing posture compared to sitting.

    PubMed

    Mildren, Robyn L; Strzalkowski, Nicholas D J; Bent, Leah R

    2016-01-01

    Foot sole sensitivity is commonly assessed while individuals are seated or prone; however the primary role of foot sole cutaneous feedback is for the control of upright stance and gait. The aim of this study was to compare vibration perceptual thresholds across the foot sole between sitting and standing postures. Vibration perceptual thresholds were measured in sitting and standing postures in 18 healthy participants (8 male) using a custom vibration device. Two foot sole locations (heels and metatarsals) were tested at four vibration frequencies (3, 15, 40, and 250Hz) selected to target different cutaneous afferent populations. At each frequency, perceptual thresholds across the foot sole were significantly higher in the standing posture compared to the sitting posture; this is indicative of lower sensitivity while standing. In addition, threshold differences between the heels and metatarsals for lower frequency vibratory stimuli were more pronounced while standing, with higher thresholds observed at the heels. Our results demonstrate that standing significantly alters sensitivity across the foot sole. Therefore, conducting perceptual tests at the foot sole during stance could potentially provide more direct information about the ability of cutaneous afferents to signal tactile information in a state where this feedback can contribute to postural control.

  16. "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.

  17. Intra- and inter-foot coordination in quiet standing: footwear and posture effects.

    PubMed

    Kilby, Melissa C; Newell, Karl M

    2012-03-01

    Intra-foot coordination between center of pressure (COP) of the ball and heel of the foot in single leg standing and inter-foot coordination of the right and left foot during bipedal stance was examined as a function of postural stance (two legs, one leg, and toe postures), footwear (barefoot, different area based high heel shoes) and postural training (ballet group and regular exercising group). Young adult females performed three 20s trials in each postural condition. In general, the traditional variability measures of COPnet motion increased under the less stable postural support conditions and ballet dancers had better balance in single leg standing. Regularity analysis revealed a negative relation between the variability of foot coupling (both intra- and inter-foot) and the standard deviation of COPnet that was mediated by the interaction of shoe support and postural stance. The findings show that shoe support and postural stance modulate collective postural motion (COPnet) through the adaptability of the coupling of foot dynamics.

  18. Human body area factors for radiation exchange analysis: standing and walking postures.

    PubMed

    Park, Sookuk; Tuller, Stanton E

    2011-09-01

    Effective radiation area factors (f (eff)) and projected area factors (f (p)) of unclothed Caucasians' standing and walking postures used in estimating human radiation exchange with the surrounding environment were determined from a sample of adults in Canada. Several three-dimensional (3D) computer body models were created for standing and walking postures. Only small differences in f (eff) and f (p) values for standing posture were found between gender (male or female) and body type (normal- or over-weight). Differences between this study and previous studies were much larger: ≤0.173 in f (p) and ≤0.101 in f (eff). Directionless f (p) values for walking posture also had only minor differences between genders and positions in a stride. However, the differences of mean directional f (p) values of the positions dependent on azimuth angles were large enough, ≤0.072, to create important differences in modeled radiation receipt. Differences in f (eff) values were small: 0.02 between the normal-weight male and female models and up to 0.033 between positions in a stride. Variations of directional f (p) values depending on solar altitudes for walking posture were narrower than those for standing posture. When both standing and walking postures are considered, the mean f (eff) value, 0.836, of standing (0.826) and walking (0.846) could be used. However, f (p) values should be selected carefully because differences between directional and directionless f (p) values were large enough that they could influence the estimated level of human thermal sensation.

  19. Parkinsonian deficits in context-dependent regulation of standing postural control.

    PubMed

    Brown, Lesley A; Doan, Jon B; Whishaw, Ian Q; Suchowersky, Oksana

    2007-05-18

    This study explored whether patients with Parkinson's disease alter the regulation of upright standing according to constraints imposed by the environmental context. The provision of context-dependent adaptations was inferred from the presence of adjustments to standing postural control that would serve to reduce fall risk when balance was challenged by a threatening environmental context. Participants were asked to stand as still as possible in two environmental context conditions that differed in the level of imposed postural threat: LOW threat and HIGH threat. Eight levodopa dependent patients with Parkinson's disease (PD) and eight age-matched control subjects (CTRL) provided the subject sample. PD patients were tested following a 12-h withdrawal of anti-Parkinsonian medications and approximately 1h post-medication. The CTRL group showed altered postural control in the HIGH threat condition, in a manner that was indicative of appropriate context-dependent regulation of standing. PD patients, in the non-medicated or medicated states, did not modify stance regulation when the environmental context heightened postural threat. Our results extend the current understanding of Parkinsonian deficits in the context-dependent regulation of postural control to include upright standing.

  20. Not just standing there: the use of postural coordination to aid visual tasks.

    PubMed

    Smart, L James; Mobley, Brandy S; Otten, Edward W; Smith, Dean L; Amin, Maryse R

    2004-04-01

    Postural control is an integral part of all physical behavior. Recent research has indicated that postural control functions in a manner that facilitates other higher order (suprapostural) tasks. These studies, while showing that postural sway is modulated in a task specific manner, have not examined the form of postural coordination that allows for the achievement of these higher behavioral goals. The current study examined the relation between visual task constraints (viewing distance), environmental constraints (changes in the surface of support), and the postural coordination employed to complete the task. Thirty-one participants were asked to perform a reading task while standing on various surfaces. Postural motion was recorded from the head, cervico-thoracic spine, sacrum (hip), and ankle. It was found that body segment coordination changed as a function of surface characteristics and task constraints. Additionally, the overall pattern of postural sway (head motion) replicated that which was found by Stoffregen et al. [J. Exp. Psychol. Human Percep. Perform. 25 (6) (1999) 1641]. These findings suggest that postural adaptation involves more than basic reduction or increase of motion; it involves the functional coordination of body segments to achieve a particular goal. The data further suggest that there is a need to examine postural control in the absence of external perturbations.

  1. [Functional characteristics of gait and standing posture in poststroke patients in residual period].

    PubMed

    Batysheva, T T; Rusina, L R; Skvortsov, D V; Boĭko, A N

    2004-01-01

    Using biomechanic method, gait and standing posture were studied in 17 stroke patients in a remote poststroke period. The locomotor system was found to have non-specific compensatory changes to optimize motor functions and reduce functional disturbances. Symptoms of the triceps surae muscle insufficiency as well as a balance deficit at standing posture and displacement of the center of pressure towards the non-affected side were characteristic of the given stage of rehabilitation stroke period that should be taken into account during the rehabilitation treatment.

  2. Both standing and postural threat decrease Achilles tendon reflex inhibition from tendon electrical stimulation.

    PubMed

    Horslen, Brian C; Inglis, J Timothy; Blouin, Jean-Sébastien; Carpenter, Mark G

    2017-03-22

    Golgi tendon organ Ib reflexes are thought to contribute to standing balance control, but it is unknown if they are modulated when people are exposed to a postural threat. We used a novel application of tendon electrical stimulation (TStim) to elicit Ib inhibitory reflexes in the medial gastrocnemius, while actively engaged in upright standing balance, to examine a) how Ib reflexes to TStim are influenced by upright stance, and b) the effects of height-induced postural threat on Ib reflexes during standing. TStim evoked short-latency (<47 ms) inhibition apparent in trigger-averaged rectified EMG, which was quantified in terms of area, duration, and mean amplitude of inhibition. In order to validate the use of TStim in a standing model, TStim-Ib inhibition was compared from conditions where participants were laying prone vs. standing upright. TStim evoked Ib inhibition in both conditions, however significant reductions in Ib inhibition area (42.2%) and duration (32.9%) were observed during stance. Postural threat, manipulated by having participants stand at LOW (0.8 m high, 0.6 m from edge) and HIGH (3.2 m, at edge) elevated surfaces, significantly reduced Ib inhibition area (32.4%), duration (16.4%) and amplitude (24.8%) in the HIGH, compared to LOW threat condition. These results demonstrate TStim is a viable technique for investigating Ib reflexes in standing, and confirm Ib reflexes are modulated with postural orientation. The novel observation of reduced Ib inhibition with elevated postural threat reveals that human Ib reflexes are context-dependent, and the human Ib reflex pathways are modulated by threat or emotional processing centres of the CNS. This article is protected by copyright. All rights reserved.

  3. 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.

  4. Relation between postural sway magnitude and metabolic energy cost during upright standing on a compliant surface.

    PubMed

    Houdijk, Han; Brown, Starr E; van Dieën, Jaap H

    2015-09-15

    Postural control performance is often described in terms of postural sway magnitude, assuming that lower sway magnitude reflects better performance. However, people do not typically minimize sway magnitude when performing a postural control task. Possibly, other criteria are satisfied when people select the amount of sway they do. Minimal metabolic cost has been suggested as such a criterion. The aim of this study was to experimentally test the relation between sway magnitude and metabolic cost to establish whether metabolic cost could be a potential optimization criterion in postural control. Nineteen healthy subjects engaged in two experiments in which different magnitudes of sway were evoked during upright standing on a foam surface while metabolic energy expenditure, center of pressure (CoP) excursion, and muscle activation were recorded. In one experiment, sway was manipulated by visual feedback of CoP excursion. The other experiment involved verbal instructions of standing still, natural or relaxed. In both experiments, metabolic cost changed with sway magnitude in an asymmetric parabolic fashion, with a minimum around self-selected sway magnitudes and a larger increase at small compared with large sway magnitudes. This metabolic response was paralleled by a change in tonic and phasic EMG activity in the major leg muscles. It is concluded that these results are in line with the notion that metabolic cost can be an optimization criterion used to set postural control and as such could account for the magnitude of naturally occurring postural sway in healthy individuals, although the pathway remains to be elucidated.

  5. 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…

  6. 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

  7. Bioceramic fabrics improve quiet standing posture and handstand stability in expert gymnasts.

    PubMed

    Cian, C; Gianocca, V; Barraud, P A; Guerraz, M; Bresciani, J P

    2015-10-01

    Bioceramic fabrics have been claimed to improve blood circulation, thermoregulation and muscle relaxation, thereby also improving muscular activity. Here we tested whether bioceramic fabrics have an effect on postural control and contribute to improve postural stability. In Experiment 1, we tested whether bioceramic fabrics contribute to reduce body-sway when maintaining standard standing posture. In Experiment 2, we measured the effect of bioceramic fabrics on body-sway when maintaining a more instable posture, namely a handstand hold. For both experiments, postural oscillations were measured using a force platform with four strain gauges that recorded the displacements of the center of pressure (CoP) in the horizontal plane. In half of the trials, the participants wore a full-body second skin suit containing a bioceramic layer. In the other half of the trials, they wore a 'placebo' second skin suit that had the same cut, appearance and elasticity as the bioceramic suit but did not contain the bioceramic layer. In both experiments, the surface of displacement of the CoP was significantly smaller when participants were wearing the bioceramic suit than when they were wearing the placebo suit. The results suggest that bioceramic fabrics do have an effect on postural control and improve postural stability.

  8. 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.

  9. Effects of preparatory period on anticipatory postural control and contingent negative variation associated with rapid arm movement in standing posture.

    PubMed

    Maeda, Kaoru; Fujiwara, Katsuo

    2007-01-01

    We investigated CNS motor preparation state and anticipatory postural muscle activation while subjects performed bilateral rapid arm movement at various intervals between warning and response stimulus (preparatory period) during standing. Motor preparation state was evaluated by integrated values of the late components of the contingent negative variation (late CNV), obtained by averaging electroencephalograms during the last 100ms of the preparatory period. For quantifying anticipatory postural muscle activation, we measured the onset of burst activity in postural muscles (lumbar paraspinal, biceps femoris, and gastrocnemius) with respect to anterior deltoid activity and integrated values of preceding activation. Subjects performed the arm movement with minimal delay in the warning stimulus-response stimulus-motor response paradigm under preparatory periods of 2.0, 3.0 and 3.5s. Late CNV did not differ between the 2.0-s and 3.0-s period, but was significantly smaller in the 3.5-s period than in the 2.0-s period, suggesting difficulty in predicting response timing in the 3.5-s period. No change was found on integrated values of preceding activations of postural muscles. Burst onset of all postural muscles significantly preceded anterior deltoid activation in all periods. Burst activity for gastrocnemius only occurred earlier in the 3.5-s period than in the 2.0-s and 3.0-s periods. Weak correlations were observed between late CNV and onset time of gastrocnemius activity. It is suggested that earlier activation of gastrocnemius is a strategy adopted when response stimulus timing is relatively difficult to predict.

  10. 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.

  11. Effect of three different jaw positions on postural stability during standing

    PubMed Central

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

    2015-01-01

    Summary Studies in the literature show that jaw and neck regions are linked anatomically, biomechanically and neurologically. Voluntary clenching has been shown to improve muscle strength and performance of various motor tasks. Information from the neck sensory-motor system is reported to be important for posture. Hence it is reasonable to believe that activation of the jaw sensory-motor system has the potential to modulate posture. In a sample of 116 healthy subjects, we compared center of gravity (COG) velocity during quiet standing on a foam surface during three test positions: i) resting jaw, ii) open jaw, and iii) clenching; these were tested in two conditions: with eyes open and with eyes closed. The COG velocity decreased significantly during clenching in comparison to both open and resting jaw positions (p<0.0001). This suggests that the jaw sensory-motor system can modulate postural mechanisms. We conclude that jaw clenching can enhance postural stability during standing on an unstable surface in both the presence and absence of visual input in healthy adults and suggest that this should be taken into consideration in treatment and rehabilitation planning for patients with postural instability. PMID:26329542

  12. Low-frequency force steadiness practice in plantar flexor muscle reduces postural sway during quiet standing.

    PubMed

    Oshita, Kazushige; Yano, Sumio

    2011-01-01

    The purpose of this study was to assess the effect of low-frequency force steadiness practice in the plantar flexor muscles on postural sway during quiet standing. Healthy young 21 men (21±1 yrs) were randomly assigned to a practice group (n=14) and a nonexercising control group (n=7). Practice groups were divided by frequency of practice: 7 participants practiced once a week, and the other 7 twice a week, for 4 weeks. Steadiness practice required practice group to 5 sets of 60-s contraction at levels corresponding to 10% and 20% maximal voluntary contraction (MVC) in the plantar flexor muscles. The 4-week-long practice period reduced the force fluctuations (assessed as the standard deviation (SD) of the outputted force during steady isometric plantar flexion) and postural sway (assessed as SD of the center of mass velocity during quiet standing). However, these practice effects were not significantly affected by the practice frequencies (1 vs. 2 sessions per week) examined in this study. Further, a linear regression analysis revealed the association between prepractice postural sway and the relative change in postural sway by the practice (r=-0.904) in the practice group. These results suggest that the steadiness practice in plantar flexor muscles improves postural stability during quiet standing, even though the practice is low-frequency (once a week) and low-intensity (within 20% MVC). These practice effects are dependent on prepractice postural stability. Further, the present results have provided the functional significance of force fluctuation in lower limb muscles.

  13. A photographic method for multi-plane assessment of adolescent posture.

    PubMed

    Puglisi, Filadelfio; Donati, Paolo; Marini, Mirca; Romeo, Loris; Scidone, Stefano; Ferrari, Robert

    2014-01-01

    To date there have been no photographic methods reported for assessing the standing postural alignment in a manner that can be used in large scale populations. The purpose of this study was to describe a photographic, multi-plane postural measurement method in a pilot group of subjects in a school setting. A total of 83 healthy male adolescents, volunteered for the study, were photographed. The mean age was 14.5 +/- 0.7 years (range 14-16). The mean height was 170.7 +/- 3.5 cm, (range 155-187), and the mean weight was 63.2 +/- 13.9 kg (range 37-110). During procedure, subjects stood on a platform, with specific markers placed on landmarks that could be identified photographically. Photography was accomplished from above, below, each side, and front and back. These six photographs permit views to be projected onto the six sides of an ideal parallelepiped enclosing the body. Five angles were calculated and reported to describe the alignments of the head, shoulders, torso, and pelvis. As expected the means of each of the five angles were small, the absolute value varying from 0 to 7 degrees. This paper describes the results of a simple, practical, and effective way to gather data concerning standing postural alignment in adolescents using a photographic technique. This technique will be used to form a normative database by large-scale studies. Using this approach, a number of angles can be calculated and eventually models can be developed, relating these angles to sitting posture measurements and to symptoms.

  14. Influence of Transcranial Direct Current Stimulation to the Cerebellum on Standing Posture Control

    PubMed Central

    Inukai, Yasuto; Saito, Kei; Sasaki, Ryoki; Kotan, Shinichi; Nakagawa, Masaki; Onishi, Hideaki

    2016-01-01

    Damage to the vestibular cerebellum results in dysfunctional standing posture control. Patients with cerebellum dysfunction have a larger sway in the center of gravity while standing compared with healthy subjects. Transcranial direct current stimulation (tDCS) is a noninvasive technique for selectively exciting or inhibiting specific neural structures with potential applications in functional assessment and treatment of neural disorders. However, the specific stimulation parameters for influencing postural control have not been assessed. In this study, we investigated the influence of tDCS when applied over the cerebellum on standing posture control. Sixteen healthy subjects received tDCS (20 min, 2 mA) over the scalp 2 cm below the inion. In Experiment 1, all 16 subjects received tDCS under three stimulus conditions, Sham, Cathodal, and Anodal, in a random order with the second electrode placed on the forehead. In Experiment 2, five subjects received cathodal stimulation only with the second electrode placed over the right buccinator muscle. Center of gravity sway was measured twice for 60 s before and after tDCS in a standing posture with eyes open and legs closed, and average total locus length, locus length per second, rectangular area, and enveloped area were calculated. In Experiment 1, total locus length and locus length per second decreased significantly after cathodal stimulation but not after anodal or sham stimulation, while no tDCS condition influenced rectangular or enveloped areas. In Experiment 2, cathodal tDCS again significantly reduced total locus length and locus length per second but not rectangular and enveloped areas. The effects of tDCS on postural control are polarity-dependent, likely reflecting the selective excitation or inhibition of cerebellar Purkinje cells. Cathodal tDCS to the cerebellum of healthy subjects can alter body sway (velocity). PMID:27458358

  15. 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;…

  16. 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

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

    PubMed Central

    2012-01-01

    Background 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. Methods 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. Results 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. Conclusions 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

  18. 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

  19. Quantification of the postural and technical errors in asymptomatic adults using direct 3D whole body scan measurements of standing posture.

    PubMed

    Tomkinson, Grant R; Shaw, Linda G

    2013-02-01

    Measurement repeatability has important decision-making implications for clinicians and researchers when assessing individuals. The aims of this study were to quantify: (a) the repeatability of direct measurements of standing posture using three dimensional (3D) whole body scanning, and (b) the magnitude of the postural and technical errors involved. Fifty-two asymptomatic adults were scanned twice, 24h apart, using the Vitus Smart 3D whole body scanner. Eleven clinically relevant standing postural measurements were calculated from scan-extracted data. The process was repeated with 10 shop mannequins. Systematic error was expressed as absolute changes in means and as standardised effect sizes, with random (within-subject) error expressed as the typical error. Technical error was calculated as the typical error in the measurement of mannequins; total error as the typical error in the measurement of subjects; and postural error as the square root of the difference between the squared total error and the squared technical error. Most standing postural measurements demonstrated good repeatability, with median (95% CI) systematic and random errors of -0.1° (1.1°) and 2.8° (1.9°), respectively. However, head and neck postures demonstrated poor repeatability due to large random errors brought about by large postural errors. Overall, most of the error was due to postural error rather than technical error. The relatively small technical errors highlight that this 3D measurement process is generally repeatable, while the relatively large postural errors related to the head and neck suggest that these postures probably lack the precision to be clinically useful using this procedure.

  20. Shape and thickness of cushion in a standing aid to support a forward bending posture: effects on posture, muscle activities and subjective discomfort.

    PubMed

    Iwakiri, Kazuyuki; Sotoyama, Midori; Mori, Ippei; Jonai, Hiroshi; Saito, Susumu

    2004-01-01

    In order to prevent low back pain (LBP) during dishwashing, we developed three types of aid with a thick cushion for supporting the shins and evaluated the effects of the standing aid on the subjective discomfort and muscle activities. Nine female volunteers were asked to wash plates in each of four working postures: (a) without the standing aid, (b) with the round type of aid, (c) with the small rectangular type of aid, and (d) with the large rectangular type of aid. With the three types of aid, the subjects were instructed to support the shins with the standing aid and to support the abdomen with the edge of a kitchen counter. In the three postures with the standing aid, 21.5 +/- 10.0% of the weight was supported with the standing aid and the kitchen counter. The subjective discomfort was milder and the muscle activity level in the low back was lower in the three postures with the standing aid than in the posture without the aid. It was thought that the round type of aid would be more effective in decreasing the discomfort in many of body regions and the muscle load on the low back than either of the rectangular types of aid. Therefore, it was suggested that the standing aid had the desired effect in decreasing discomfort and muscle load on the low back during dishwashing.

  1. Age-gender differences in the postural sway during squat and stand-up movement.

    PubMed

    Kim, Ji-Won; Kwon, Yuri; Ho, Yeji; Jeon, Hyeong-Min; Bang, Min-Jung; Jun, Jae-Hoon; Eom, Gwang-Moon; Park, Byung Kyu; Cho, Yeong Bin

    2014-01-01

    Incidence of falling among elderly female has been reported to be much higher than that of elderly male. Although the gender differences in the elderly were reported for the static postural sway, there has been no investigation of the gender difference for the dynamic postural sway. This study investigates how age and gender affect the postural sway during dynamic squat and stand-up movement. 124 subjects (62 subjects for each of young and elderly) performed consecutive squat and stand-up movement, 2 times in one session, and 2 sessions per subject. Center of pressure (COP) was measured using force platform during the test. Outcome measures included peak-to-peak sways of the COP (COP sway) in the sagittal plane (anteroposterior) and frontal plane (mediolateral) and also those normalized by body height. Two-way ANOVA and post-hoc comparisons were performed for the outcome measures with the independent factors of age and gender. All outcome measures, excluding mediolateral COP sway, showed significant interaction of age and gender (p<0.05). Post-hoc test revealed that only female showed increase in COP sway with age. When normalized by height, increase in COP sways (both directions) with age significant only in women resulted in greater sways in elderly female than elderly male. This may be related to the greater fall rate of elderly female than that of elderly men while performing dynamic activities.

  2. 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.

  3. 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.

  4. Effects of transporting an infant on the posture of women during walking and standing still.

    PubMed

    Junqueira, Lúcia Desideri; Amaral, Lia Queiroz; Iutaka, Alexandre Sadao; Duarte, Marcos

    2015-03-01

    We investigated the effects on women of carrying an infant in front, focusing on the pelvic and spinal posture and the displacement of the body's center of gravity. For such, we compared mothers to non-mothers not carrying anything or carrying the same load (a doll) and the mothers carrying their infants. Twenty mothers and 44 women who did not have children were analyzed for their movement and posture during walking and standing still with a motion capture system. Walking while carrying a load was slower and with a shorter stride length than while not carrying a load. The mothers' group walked slower and with a shorter stride length than the non-mothers' group. During walking and standing still, the women decreased their angle of pelvic anteversion, increased lumbar lordosis, increased thoracic kyphosis, and increased trunk backward inclination while carrying a load in comparison with not carrying anything. In addition, we observed some small differences in the spinal angles of mothers when carrying their infants compared to when carrying a doll. When standing still, the women carrying a load displaced backwards their vertical projection of the center of gravity to exactly compensate the destabilizing load at the front that resulted in no net change of the body-plus-load center of gravity. In general, these changes are qualitatively similar to the ones observed during pregnancy.

  5. The impact of localized fatigue on contralateral tremor and muscle activity is exacerbated by standing posture.

    PubMed

    Morrison, S; Sosnoff, J J

    2010-12-01

    Physiological tremor is an inherent feature of the motor system that is influenced by intrinsic (neuromuscular) and/or extrinsic (task) factors. Given that tremor must be accounted for during the performance of many fine motor skills; there is a requirement to clarify how different factors interact to influence tremor. This study was designed to assess the impact localized fatigue of a single arm and stance position had on bilateral physiological tremor and forearm muscle activity. Results demonstrated that unilateral fatigue produced bilateral increases in tremor and wrist extensor activity. For example, fatigue resulted in increases in extensor activity across both exercised (increased 8-10% MVC) and the non-exercised arm (increased 3-7% MVC). The impact of fatigue was not restricted to changes in tremor/EMG amplitude, with altered hand-finger coupling observed within both arms. Within the exercised arm, cross-correlation values decreased (pre-exercise r=0.62-0.64; post-exercise r=0.37-0.43) while coupling increased within the non-exercised arm (pre-exercise r=0.51-0.55; post-exercise r=0.62-0.67). While standing posture alone had no significant impact on tremor/EMG dynamics, the tremor and muscle increases seen with fatigue were more pronounced when standing. Together these results demonstrate that the combination of postural and fatigue factors can influence both tremor/EMG outputs and the underlying coordinative coupling dynamics.

  6. Perceptual inhibition is associated with sensory integration in standing postural control among older adults.

    PubMed

    Redfern, Mark S; Jennings, J Richard; Mendelson, David; Nebes, Robert D

    2009-09-01

    In older adults, maintaining balance and processing information typically interfere with each other, suggesting that executive functions may be engaged for both. We investigated associations between measures of inhibitory processes and standing postural control in healthy young and older adults. Perceptual and motor inhibition was measured using a protocol adapted from Nassauer and Halperin (2003, Dissociation of perceptual and motor inhibition processes through the use of novel computerized conflict tasks. Journal of the International Neuropsychological Society, 9, 25-30). These measures were then correlated to postural sway during standing conditions that required resolving various levels of sensory conflict, for example, world-fixed versus sway-referenced floor and visual scene. In the older adults, perceptual inhibition was positively correlated with sway amplitude on a sway-referenced floor and with a fixed visual scene (r = .68, p < .001). Motor inhibition was not correlated with sway on either group. Perceptual inhibition may be a component of the sensory integration process important for maintaining balance in older adults.

  7. 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.

  8. Body metabolic rate and electromyographic activities of antigravitational muscles in supine and standing postures.

    PubMed

    Rubini, Alessandro; Paoli, Antonio; Parmagnani, Andrea

    2012-06-01

    We measured metabolic (oxygen uptake, carbon dioxide production, respiratory ratio), cardio-circulatory (heart rate, systolic and diastolic arterial blood pressure, rate-pressure product, an index of myocardial oxygen consumption calculated by multiplying heart rate by systolic pressure) and electromyographic (integrated electromyographic activities of two antigravitational muscles of the lower limb, soleus and gastrocnemius) variables on 12 young healthy subjects in supine and standing positions at rest. We found statistically significant increments of oxygen uptake, carbon dioxide production, heart rate and integrated electromyographic activities in standing versus supine position. Rate-pressure product increased but not significantly, and no other significant changes were detected. We conclude that postural changes influence metabolic rate, antigravitational muscle reflex activities, and heart rate. A significant positive correlation was found between oxygen uptake and carbon dioxide production and integrated electromyographic activities of antigravitational muscles, while the same was not found for cardio-circulatory variables. These results suggest that the increased metabolic rate in standing position is, at least in part, due to antigravitational muscle tone.

  9. Early Adolescent Romantic Partner Status, Peer Standing, and Problem Behaviors

    ERIC Educational Resources Information Center

    Miller, Shari; Lansford, Jennifer E.; Costanzo, Philip; Malone, Patrick S.; Golonka, Megan; Killeya-Jones, Ley A.

    2009-01-01

    This study examined associations among early adolescent romantic relationships, peer standing, problem behaviors, and gender as a moderator of these associations, in a sample of 320 seventh-grade students. Popular and controversial status youth were more likely to have a romantic partner, whereas neglected status youth were less likely to have a…

  10. Studying the relationship between low back pain and working postures among those who stand and those who sit most of the working day.

    PubMed

    Tissot, F; Messing, K; Stock, S

    2009-11-01

    A relationship between low back pain (LBP) and prolonged standing or prolonged sitting at work has not been clearly shown, despite its biological plausibility. Because sitting and standing postures vary as to duration and freedom to alternate postures, and standing postures vary as to mobility, associations between specific working postures and LBP were explored using multiple logistic regression. Associations between work factors and self-reported LBP during the previous 12 months that interfered with usual activities were examined among 4493 standing workers and 3237 sitting workers interviewed in the 1998 Quebec Health and Social Survey; 24.5% reported significant LBP. Since the same conditions can correspond to different physiological demands for sitting compared with standing workers, analyses were performed separately for the two groups. Standing without freedom to sit was associated with LBP. Different occupational physical and psychosocial factors were associated with LBP in sitting compared with standing populations.

  11. Thoracic and lumbar posture behaviour in sitting tasks and standing: Progressing the biomechanics from observations to measurements.

    PubMed

    Claus, Andrew P; Hides, Julie A; Moseley, G Lorimer; Hodges, Paul W

    2016-03-01

    Few studies quantify spinal posture behaviour at both the thoracolumbar and lumbar spinal regions. This study compared spontaneous spinal posture in 50 asymptomatic participants (21 males) during three conditions: 10-min computer task in sitting (participants naïve to the measure), during their perceived 'correct' sitting posture, and standing. Three-dimensional optical tracking quantified surface spinal angles at the thoracolumbar and lumbar regions, and spinal orientation with respect to the vertical. Despite popular belief that lordotic lumbar angles are 'correct' for sitting, this was rarely adopted for 10-min sitting. In 10-min sitting, spinal angles flexed 24(7-9)deg at lumbar and 12(6-8)deg at thoracolumbar regions relative to standing (P < 0.001). When participants 'corrected' their sitting posture, their thoracolumbar angle -2(7)deg was similar to the angle in standing -1(6)deg (P = 1.00). Males were flexed at the lumbar angle relative to females for 10-min sitting, 'correct' sitting and standing, but showed no difference at the thoracolumbar region.

  12. Lower extremity preference during gross and fine motor skills performed in sitting and standing postures.

    PubMed

    Beling, J; Wolfe, G A; Allen, K A; Boyle, J M

    1998-12-01

    The evaluation of lower limb preference in physical therapy practice is critical in order for the clinician to assist patients with functional retraining tasks. No studies in the physical therapy literature present a systematic approach to determine the criteria needed to identify the preferred limb. This research was designed to present a series of tests for effectiveness in determining limb preference. The purpose of this study was to determine whether lower limb preference existed in a group of recreationally athletic women when performing either stability or dynamic skills with the lower extremities while sitting or standing. The relationship of such a preference to handedness was also determined. Forty female recreational athletes, 20 right-handed subjects and 20 left-handed subjects, who ranged in age from 21 to 35 years, participated in this study. Subjects performed three repetitions of the following tests in both sitting and standing: kick a ball, swing a leg over a box, pick up a marble with the toes, and trace a triangle with the toes. The subjects were also asked to stand on one leg. The order of performing the tests was randomized. The results indicated that right-handed subjects performed activities more consistently with one lower extremity when compared with left-handed subjects, regardless of posture (sitting or standing). The difference in limb choice between right- and left-handed subjects was significant for all activities (p < .05). The considerable sensitivity of foot and leg performance following neurological insult renders the assessment of foot and leg preference very important for purposes of clinical rehabilitation.

  13. 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

  14. Risk Factors for Postural Tachycardia Syndrome in Children and Adolescents

    PubMed Central

    Li, Xueying; Ochs, Todd; Zhao, Juan; Zhang, Xi; Yang, Jinyan; Liu, Ping; Xiong, Zhenyu; Gai, Yong; Tang, Chaoshu; Du, Junbao; Jin, Hongfang

    2014-01-01

    Background Postural tachycardia syndrome (POTS) is prevalent in children and adolescents and has a great impact on health. But its risk factors have not been fully understood. This study aimed to explore possible risk factors for children and adolescents with POTS. Methods and Findings 600 children and adolescents (test group) aged 7–18 (11.9±3.0) years old, 259 males and 341 females, were recruited for identifying its risk factors. Another 197 subjects aged from 7 to 18 (11.3±2.3) years old were enrolled in the validation group. Heart rate (HR) and blood pressure (BP) were monitored during upright test. Risk factors were analyzed and sensitivity and specificity for predicting POTS were tested via receiver operating characteristic curve. Among 600 subjects, 41 were confirmed with POTS patients (6.8%) based on clinical manifestation and upright test. The results showed a significant difference in daily water intake, the daily sleeping hours, supine HR, HR increment and maximum HR during upright test between POTS and the unaffected children (P<0.05). Likelihood of POTS would increase by 1.583 times if supine HR was increased by 10 beats/min (95%CI 1.184 to 2.116, P<0.01), by 3.877 times if a child's water intake was less than 800 ml/day (95%CI 1.937 to 7.760, P<0.001), or by 5.905 times (95%CI 2.972 to 11.733, P<0.001) if sleeping hours were less than 8 hours/day. Supine HR, daily water intake and sleeping hours showed the capability of predicting POTS in children and adolescents with an AUC of 83.9% (95% CI: 78.6%–89.1%), sensitivity of 80.5% and specificity of 75%. Furthermore, in validation group, predictive sensitivity and specificity were 73.3% and 72.5%. Conclusion Faster supine HR, less water intake and shorter sleeping hours were identified as risk factors for POTS. PMID:25474569

  15. Association of force steadiness of plantar flexor muscles and postural sway during quiet standing by young adults.

    PubMed

    Oshita, Kazushige; Yano, Sumio

    2012-08-01

    This study was conducted to assess the relations of force fluctuations during isometric plantar-flexion and postural sway during quiet standing. Twelve healthy men (M age = 21 yr., SD = 1) performed unilateral plantar flexion measured by a strain gauge force transducer. Participants performed force-matching tasks; sustained plantar flexion for 20 sec. at levels corresponding to 10% and 20% of maximum voluntary contraction with the visual feedback. Also, participants were asked to stand quietly with their eyes open, and then the center of mass displacement and velocity in the anteroposterior were measured. In analysis, postural sway was associated with force fluctuation at only 10% of maximum voluntary contraction. The statistically significant correlation between variables was found only at corresponding contraction intensities for plantar-flexor muscles. From this one may infer neural strategies in plantar-flexor muscles during quiet standing may be characteristics similar to those controlling the plantar-flexion force in young adults.

  16. A Quiet Standing Index for Testing the Postural Sway of Healthy and Diabetic Adults Across a Range of Ages

    PubMed Central

    Bollt, Erik M.; Fulk, George D.; Skufca, Joseph D.; Al-Ajlouni, Ahmad F.; Robinson, Charles J.

    2010-01-01

    A quietstanding index is developed for tracking the postural sway of healthy and diabetic adults over a range of ages. Several postural sway features are combined into a single composite feature C that increases with age a. Sway features are ranked based on the r2 -values of their linear regression models, and the composite feature is a weighted sum of selected sway features with optimal weighting coefficients determined using principal component analysis. A performance index based on both reliability and sensitivity is used to determine the optimal number of features. The features used to form C include power and distance metrics. The quiet standing index is a scalar that compares the composite feature C to a linear regression model f (a) using C′ (a) = C/f (a). For a motionless subject, C′ = 0, and when the composite feature exactly matches the healthy control (HC) model, C′ = 1. Values of C′ ≫ 1 represent excessive postural sway and may indicate impaired postural control. Diabetic neurologically intact subjects, nondiabetic peripheral neuropathy subjects (PN), and diabetic PN subjects (DPN) were evaluated. The quiet standing indexes of the PN and DPN groups showed statistically significant increases over the HC group. Changes in the quiet standing index over time may be useful in identifying people with impaired balance who may be at an increased risk of falling. PMID:19342327

  17. Inclination of standing posture due to the presentation of tilted view through an immersive head-mounted display

    PubMed Central

    Ohmura, Yuji; Yano, Shiro; Katsuhira, Junji; Migita, Masato; Yozu, Arito; Kondo, Toshiyuki

    2017-01-01

    [Purpose] The purpose of the present study is to clarify whether tilted scenery presented through an immersive head-mounted display (HMD) causes the inclination of standing posture. [Subjects and Methods] Eleven healthy young adult males who provided informed consent participated in the experiment. An immersive HMD and a stereo camera were employed to develop a visual inclination system. The subjects maintained a standing posture twice for 5s each while wearing the visual inclination system. They performed this task under two conditions: normal view and 20° leftward tilted view. A three-dimensional motion analysis system was used to measure the subjects’ postures, and two force plates were used to measure the vertical component of the floor reaction force of each leg. [Results] In the 20° leftward tilted view, the head and trunk angles in the frontal plane were similarly inclined toward the left, and the vertical component of the floor reaction force increased in the left leg, whereas it decreased in the right leg. [Conclusion] When the view in the immersive HMD was tilted, the participants’ trunk side bent toward the same side as that of the view. This visual inclination system seems to be a simple intervention for changing standing posture. PMID:28265145

  18. The effect of foam surface properties on postural stability assessment while standing.

    PubMed

    Patel, M; Fransson, P A; Lush, D; Gomez, S

    2008-11-01

    A common assessment of postural control often involves subjects standing on a compliant surface, such as a foam block, to make balance tests more challenging. However, the physical properties of the foam block used by different researchers can vary considerably. The objective of this study was to provide an initial approach for investigating whether two of the foam properties, i.e. density and elastic modulus, influenced recorded anteroposterior and lateral torque variance with eyes open and eyes closed. Thirty healthy adults (mean age 22.5 years) were assessed with posturography using three different types of foam block placed on a force platform. These blocks were categorised: firm foam, medium foam and soft foam by their elastic modulus. To investigate the spectral characteristics of recorded body movements, variance values were calculated for total movements, movements <0.1Hz and movements >0.1Hz. Results showed that anteroposterior and lateral torque variances >0.1Hz were larger when standing on the firm foam compared with medium and soft foam and in turn were larger on the medium foam compared with the soft foam with eyes closed. Moreover, GLM and correlation analysis demonstrated that the properties of the foam blocks affected anteroposterior torque variance >0.1Hz and lateral torque variance in all frequency ranges. In addition, the stabilising effect of vision in the anteroposterior direction had a greater influence when the subjects' stability was increasingly challenged by the support surface, as illustrated by the higher torque variance values. In conclusion, caution should be taken when analysing balance deficits with foam test setups, because the foam properties may influence the recorded body movements.

  19. High flow variant postural orthostatic tachycardia syndrome amplifies the cardiac output response to exercise in adolescents.

    PubMed

    Pianosi, Paolo T; Goodloe, Adele H; Soma, David; Parker, Ken O; Brands, Chad K; Fischer, Philip R

    2014-08-01

    Postural orthostatic tachycardia syndrome (POTS) is characterized by chronic fatigue and dizziness and affected individuals by definition have orthostatic intolerance and tachycardia. There is considerable overlap of symptoms in patients with POTS and chronic fatigue syndrome (CFS), prompting speculation that POTS is akin to a deconditioned state. We previously showed that adolescents with postural orthostatic tachycardia syndrome (POTS) have excessive heart rate (HR) during, and slower HR recovery after, exercise - hallmarks of deconditioning. We also noted exaggerated cardiac output during exercise which led us to hypothesize that tachycardia could be a manifestation of a high output state rather than a consequence of deconditioning. We audited records of adolescents presenting with long-standing history of any mix of fatigue, dizziness, nausea, who underwent both head-up tilt table test and maximal exercise testing with measurement of cardiac output at rest plus 2-3 levels of exercise, and determined the cardiac output () versus oxygen uptake () relationship. Subjects with chronic fatigue were diagnosed with POTS if their HR rose ≥40 beat·min(-1) with head-up tilt. Among 107 POTS patients the distribution of slopes for the , relationship was skewed toward higher slopes but showed two peaks with a split at ~7.0 L·min(-1) per L·min(-1), designated as normal (5.08 ± 1.17, N = 66) and hyperkinetic (8.99 ± 1.31, N = 41) subgroups. In contrast, cardiac output rose appropriately with in 141 patients with chronic fatigue but without POTS, exhibiting a normal distribution and an average slope of 6.10 ± 2.09 L·min(-1) per L·min(-1). Mean arterial blood pressure and pulse pressure from rest to exercise rose similarly in both groups. We conclude that 40% of POTS adolescents demonstrate a hyperkinetic circulation during exercise. We attribute this to failure of normal regional vasoconstriction during exercise, such that patients must increase flow through an

  20. Postural responses to various frequencies of vibration of the triceps surae and forefoot sole during quiet standing.

    PubMed

    Naka, Masami; Fujiwara, Katsuo; Kiyota, Naoe

    2015-01-01

    The purpose of this study was to determine the role of somatosensory input to the sensory reference system in quiet standing. We applied vibration (0.5 mm amplitude, 1-60 Hz) to the triceps surae and the forefoot sole to stimulate the muscle spindles and the mechanoreceptors, respectively, and evaluated postural responses. Thirteen young healthy adults who showed backward-lean and forward-lean responses to vibration at high and low frequencies, respectively, participated in the full experiment. The lowest vibration frequencies inducing backward-lean responses (B-LF) were 15-55 Hz for the triceps surae and 16-60 Hz for the forefoot sole. The highest frequencies inducing forward-lean responses (F-HF) were 3-18 Hz for the triceps surae and 1-20 Hz for the forefoot sole. When vibration was simultaneously applied to the triceps surae and forefoot sole at F-HF, no response was induced in 70% of trials. A forward-lean response was induced in the remaining 30% of trials. Simultaneous vibration of the triceps surae and forefoot sole at B-LF induced backward-lean responses in all trials. All postural responses occurred 0.5-4.3 s after vibration onset. Postural responses to high-frequency vibration conceivably occur as a compensatory movement to the illusionary perception that standing position is deviating forward from quiet standing, which must be a reference position. Postural responses to low-frequency vibration possibly occur to equalize the positional information that is received from the triceps surae and the forefoot sole. Both postural responses are likely to involve the sensory reference system, which is located in the supraspinal nervous system.

  1. 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

  2. Effects of neck flexion on contingent negative variation and anticipatory postural control during arm movement while standing.

    PubMed

    Fujiwara, Katsuo; Tomita, Hidehito; Maeda, Kaoru; Kunita, Kenji

    2009-02-01

    We investigated the effects of neck flexion on contingent negative variation (CNV) and anticipatory postural control using an arm flexion task in standing. CNV was adopted to evaluate the state of activation of brain areas related to anticipatory postural control. Subjects were required to flex the arms in response to a sound stimulus preceded by a warning sound stimulus. Two different intervals (2.0 and 3.5s) between these two stimuli were used in neck position in quiet standing (neck resting) and neck position at 80% angle of maximal neck flexion. The mean amplitude of CNV 100-ms before the response stimulus, recorded from a Cz electrode, was calculated. Onset timing of activation of the postural muscles (lumbar paraspinal, biceps femoris and gastrocnemius) with respect to the anterior deltoid was analyzed. Reaction time at the anterior deltoid was significantly shorter in the 2.0s period than in the 3.5s period, and in the neck flexion than in the neck resting in both periods. In the 2.0s, but not in the 3.5s period, neck flexion resulted in an increased CNV amplitude and an increased duration of preceding activation of the postural muscles, and the correlation between these increases was significant.

  3. Functionality level and its relation to postural control during sitting-to-stand movement in children with cerebral palsy.

    PubMed

    Pavão, Silvia Leticia; Dos Santos, Adriana Neves; de Oliveira, Ana Beatriz; Rocha, Nelci Adriana Cicuto Ferreira

    2014-02-01

    In this study we studied functional performance and functional balance in children with cerebral palsy (CP) and typically developing (TD) children. The relationship between these components and postural control during sit-to-stand movement (STS) was also investigated. Ten children with CP (GMFCS I and II) and 27 TD children, ages 5-12 years, were included in the study. The Pediatric Evaluation of Disability Inventory (PEDI) and the Pediatric Balance Scale (PBS) were used to measure functional performance and functional balance, respectively. Postural control during STS was assessed by means of a force plate. Participants were asked to stand from a chair with feet over a force plate. Children with CP exhibited lower scores than TD children in the PBS and in the mobility Functional Skills and Caregiver Assistance domains of the PEDI (p≤0.05). In both groups postural control during STS movement was correlated with mobility Caregiver Assistance scores of the PEDI. The results demonstrate that although the participants had mild to moderate motor impairment, they exhibit deficits in their level of functional performance and functional balance compared to typical children. Moreover, it was observed that impairments in postural control during the STS movement are related to functional performance in both groups. This result demonstrates the importance of the structure and function components to the level of activity in children.

  4. Difference in Postural Control during Quiet Standing between Young Children and Adults: Assessment with Center of Mass Acceleration.

    PubMed

    Oba, Naoko; Sasagawa, Shun; Yamamoto, Akio; Nakazawa, Kimitaka

    2015-01-01

    The development of upright postural control has often been investigated using time series of center of foot pressure (COP), which is proportional to the ankle joint torque (i.e., the motor output of a single joint). However, the center of body mass acceleration (COMacc), which can reflect joint motions throughout the body as well as multi-joint coordination, is useful for the assessment of the postural control strategy at the whole-body level. The purpose of the present study was to investigate children's postural control during quiet standing by using the COMacc. Ten healthy children and 15 healthy young adults were instructed to stand upright quietly on a force platform with their eyes open or closed. The COMacc as well as the COP in the anterior-posterior direction was obtained from ground reaction force measurement. We found that both the COMacc and COP could clearly distinguish the difference between age groups and visual conditions. We also found that the sway frequency of COMacc in children was higher than that in adults, for which differences in biomechanical and/or neural factors between age groups may be responsible. Our results imply that the COMacc can be an alternative force platform measure for assessing developmental changes in upright postural control.

  5. Influence of dual-task on sit-to-stand-to-sit postural control in Parkinson's disease.

    PubMed

    Fernandes, Ângela; Sousa, Andreia S P; Couras, Joana; Rocha, Nuno; Tavares, João Manuel R S

    2015-11-01

    Postural control deficits are the most disabling aspects of Parkinson's disease (PD), resulting in decreased mobility and functional independence. The aim of this study was to assess the postural control stability, revealed by variables based on the centre of pressure (CoP), in individuals with PD while performing a sit-to-stand-to-sit sequence under single- and dual-task conditions. An observational, analytical and cross-sectional study was performed. The sample consisted of 9 individuals with PD and 9 healthy controls. A force platform was used to measure the CoP displacement and velocity during the sit-to-stand-to-sit sequence. The results were statistically analysed. Individuals with PD required greater durations for the sit-to-stand-to-sit sequence than the controls (p < 0.05). The anteroposterior and mediolateral CoP displacement were higher in the individuals with PD (p < 0.05). However, only the anteroposterior CoP velocity in the stand-to-sit phase (p = 0.006) was lower in the same individuals. Comparing the single- and dual-task conditions in both groups, the duration, the anteroposterior CoP displacement and velocity were higher in the dual-task condition (p < 0.05). The individuals with PD presented reduced postural control stability during the sit-to-stand-to-sit sequence, especially when under the dual-task condition. These individuals have deficits not only in motor performance, but also in cognitive performance when performing the sit-to-stand-to-sit sequence in their daily life tasks. Moreover, both deficits tend to be intensified when two tasks are performed simultaneously.

  6. Quantitative postural analysis and pain in children and adolescents victims of burns

    PubMed Central

    Valenciano, Paola Janeiro; Itakussu, Edna Yukimi; Trelha, PhD, Celita Salmaso; Fujisawa, PhD, Dirce Shizuko

    2015-01-01

    [Purpose] This study aimed to quantitatively assess postural alignment in both frontal and sagittal planes, as well as pain in children and adolescents victims of burn injuries. [Subjects and Methods] This cross-sectional study included 21 victims of burns, nine children (age [mean ± SD], 7.3 ± 1.1 yrs) and 12 adolescents (12,0 ± 1.4 yrs), classified as medium and large burns, being investigated on pain and postural alignment evaluated by photogrammetry. Pain intensity was assessed by face scales and postural examination included the assessment of global and thoraco-lumbo-pelvic alignment by previously designed protocols. [Results] Only two adolescents reported mild pain associated with burn injuries, whereas deviations of the projection of the gravity center; forward head posture, and scapular asymmetry were observed in both groups. In the analysis of the thoraco-lumbo-pelvic alignment, children tended to have anterior inclination trunk, increased thoracic kyphosis and lumbar lordosis, while in adolescents, increased thoracic kyphosis and lumbar lordosis were observed. [Conclusion] The results indicate that due to the postural alterations and asymmetries in both frontal and sagittal planes, there is an increased risk of developing scoliosis and possible future pain. Thus, physiotherapy is indicated and should be maintained until complete growth is reached. PMID:26834321

  7. Dynamic Response of the Standing Human Body Exposed to Vertical Vibration: Influence of Posture and Vibration Magnitude

    NASA Astrophysics Data System (ADS)

    Matsumoto, Y.; Griffin, M. J.

    1998-04-01

    The influence of the posture of the legs and the vibration magnitude on the dynamic response of the standing human body exposed to vertical whole-body vibration has been investigated. Motions were measured on the body surface at the first and eighth thoracic and fourth lumbar vertebrae (T1, T8 and L4), at the right and left iliac crests and at the knee. Twelve subjects took part in the experiment with three leg postures (normal, legs bent and one leg), and five magnitudes of random vibration (0·125-2·0 ms-2r.m.s.) in the frequency range from 0[msde]5-30 Hz. The main resonance frequencies of the apparent masses at 1·0 ms-2r.m.s. differed between postures: 5·5 Hz in the normal posture, 2·75 Hz in the legs bent posture and 3·75 Hz in the one leg posture. In the normal posture, the transmissibilities to L4 and the iliac crests showed a similar trend to the apparent mass at low frequencies. With the legs straight, no resonance was observed in the legs at frequencies below 15 Hz. In the legs bent posture, a bending motion of the legs at the knee and a pitching or bending motion of the upper-body appeared to contribute to the resonance of the whole body as observed in the apparent mass, with attenuation of vibration transmission to the upper body at high frequencies. In the one leg posture, coupled rotational motion of the whole upper-body about the hip joint may have contributed to the resonance observed in the apparent mass at low frequencies and the attenuation of vertical vibration transmission at high frequencies. The resonance frequency of the apparent mass in the normal posture decreased from 6·75-5·25 Hz with increasing vibration magnitude from 0·125 to 2·0 ms-2r.m.s. This “softening” effect was also found in the transmissibilities to many parts of the body that showed resonances.

  8. Influence of Cervical Spine Mobility on the Focal and Postural Components of the Sit-to-Stand Task

    PubMed Central

    Hamaoui, Alain; Alamini-Rodrigues, Caroline

    2017-01-01

    The aim of this study was to determine the influence of cervical spine mobility on the focal and postural components of the sit-to-stand transition, which represent the preparatory and execution phases of the task, respectively. Sixteen asymptomatic female participants (22 ± 3 years, 163 ± 0,06 cm, 57,5 ± 5 kg), free of any neurological or musculoskeletal disorders, performed six trials of the sit-to-stand task at maximum speed, in four experimental conditions varying the mobility of the cervical spine by means of three different splints. A six-channel force plate, which collected the reaction forces and moments applied at its top surface, was used to calculate the center of pressure displacements along the anterior-posterior and medial-lateral axes. The local accelerations of the head, spine, and pelvis, were assessed by three pairs of accelerometers, oriented along the vertical and anterior-posterior axes. Restriction of cervical spine mobility resulted in an increased duration of the focal movement, associated with longer and larger postural adjustments. These results suggest that restricted cervical spine mobility impairs the posturo-kinetic capacity during the sit-to-stand task, leading to a lower motor performance and a reorganization of the anticipatory postural adjustments. In a clinical context, it might be assumed that preserving the articular free play of the cervical spine might be useful to favor STS performance and autonomy.

  9. 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.

  10. Vestibulo-spinal and vestibulo-ocular reflexes are modulated when standing with increased postural threat.

    PubMed

    Naranjo, E N; Cleworth, T W; Allum, J H J; Inglis, J T; Lea, J; Westerberg, B D; Carpenter, M G

    2016-02-01

    We investigated how vestibulo-spinal reflexes (VSRs) and vestibulo-ocular reflexes (VORs) measured through vestibular evoked myogenic potentials (VEMPs) and video head impulse test (vHIT) outcomes, respectively, are modulated during standing under conditions of increased postural threat. Twenty-five healthy young adults stood quietly at low (0.8 m from the ground) and high (3.2 m) surface height conditions in two experiments. For the first experiment (n = 25) VEMPs were recorded with surface EMG from inferior oblique (IO), sternocleidomastoid (SCM), trapezius (TRP), and soleus (SOL) muscles in response to 256 air-conducted short tone bursts (125 dB SPL, 500 Hz, 4 ms) delivered via headphones. A subset of subjects (n = 19) also received horizontal and vertical head thrusts (∼150°/s) at each height in a separate session, comparing eye and head velocities by using a vHIT system for calculating the functional VOR gains. VEMP amplitudes (IO, TRP, SOL) and horizontal and vertical vHIT gains all increased with high surface height conditions (P < 0.05). Changes in IO and SCM VEMP amplitudes as well as horizontal vHIT gains were correlated with changes in electrodermal activity (ρ = 0.44-0.59, P < 0.05). VEMP amplitude for the IO also positively correlated with fear (ρ = 0.43, P = 0.03). Threat-induced anxiety, fear, and arousal have significant effects on VSR and VOR gains that can be observed in both physiological and functional outcome measures. These findings provide support for a potential central modulation of the vestibular nucleus complex through excitatory inputs from neural centers involved in processing fear, anxiety, arousal, and vigilance.

  11. External landmark, body surface, and volume data of a mid-sized male in seated and standing postures.

    PubMed

    Gayzik, F S; Moreno, D P; Danelson, K A; McNally, C; Klinich, K D; Stitzel, Joel D

    2012-09-01

    The purpose of this study was to acquire external landmark, undeformed surface, and volume data from a pre-screened individual representing a mid-sized male (height 174.9 cm, weight 78.6 ± 0.77 kg) in the seated and standing postures. The individual matched the 50th percentile value of 15 measures of external anthropometry from previous anthropometric studies with an average deviation of 3%. As part of a related study, a comprehensive full body medical image data set was acquired from the same individual on whom landmark data were collected. Three dimensional bone renderings from this data were used to visually verify the landmark and surface results. A total of 54 landmarks and external surface data were collected using a 7-axis digitizer. A seat buck designed in-house with removable back and seat pan panels enabled collection of undeformed surface contours of the back, buttocks, and posterior thigh. Eight metrics describing the buck positioning are provided. A repeatability study was conducted with three trials to assess intra-observer variability. Total volume and surface area of the seated model were found to be 75.8 × 10(3) cm(3) and 18.6 × 10(3) cm(2) and match the volume and surface area of the standing posture within 1%. Root mean squared error values from the repeatability study were on average 5.9 and 6.6 mm for the seated and standing postures respectively. The peak RMS error as a percentage of the centroid size of the landmark data sets were 3% for both the seated and standing trials. The data were collected as part of a global program on the development of an advanced human body model for blunt injury simulation. In addition, the reported data can be used for many diverse applications of biomechanical research such as ergonomics and morphometrics studies.

  12. Simulating the restoration of standing balance at leaning postures with functional neuromuscular stimulation following spinal cord injury

    PubMed Central

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

    2015-01-01

    In this simulation study, we present and examine methods to develop a feedback controller for a neuroprosthesis that restores forward and side leaning function during standing following complete, thoracic-level spinal cord injury. Achieving leaning postures away from erect stance with functional neuromuscular stimulation (FNS) would allow users to extend their reaching capabilities. Utilizing a 3-D computer model of human stance, an FNS control system based on total-body center of mass (CoM) kinematics (position, acceleration) is developed and tested in simulation. CoM kinematics drive an artificial neural network to modulate muscle excitations and reduce the upper extremity loading, presumably against a walker or similar support surface, required to resist the effects of postural perturbations. Furthermore, a novel method to robustly estimate the feedback kinematics for standing applications is also presented while assuming 3-D accelerometer signals at locations consistent with a proposed implantable networked neuroprosthesis system. For shifting and balance at leaning postures, respectively, center of mass position and acceleration could be approximated to within 20% of the maximum value, with strong correlations (R>0.9) between values estimated by the proposed method and the true values derived from model dynamics. When utilizing the estimated feedback kinematics for FNS control, standing performance in terms of maximum upper extremity loading was still significantly reduced (p<0.001) compared to conventionally applying constant and maximal stimulation. In the future, these simulation-based methods will be employed to develop experimental approaches for restoring leaning standing function by FNS. PMID:26324246

  13. 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.

  14. Spino-pelvic postural changes between the standing and sitting human position: proposal of a method for its systematic analysis.

    PubMed

    Berthonnaud, E; Hilmi, R; Labelle, H; Dimnet, J

    2011-09-01

    This study presents numerical tools, based on biplanar radiography, allowing to analyze the 3D changes in position and length of the various spinal segments with respect to the pelvis which occur between the standing and sitting positions. Three asymptomatic adult subjects and twelve adult patients with low back pain or scoliosis had biplanar calibrated radiographs in the erect posture and sitting position. The 3D points of the spinal curve were then reconstructed from their plane projections using a standard photogrammetric technique. A technical data form has been formulated to present and summarize the complex 3D spino-pelvic changes occurring between both postures. The spine and pelvis are displayed as a chain of linear articulated segments, in their plane of maximum curvature, allowing users to compare both postures and to assess the global and local spinal mobility between the two fixed postures. Examples of asymptomatic volunteers and of subjects with low back pain or scoliosis demonstrate that different strategies can be adopted to perform this simple task and are presented to illustrate these new techniques and their clinical potential to discriminate between and within normal and pathological conditions.

  15. 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

  16. Is there an association between variables of postural control and strength in adolescents?

    PubMed

    Granacher, Urs; Gollhofer, Albert

    2011-06-01

    Is there an association between variables of postural control and strength in adolescents? The risk of sustaining sport injuries is particularly high in adolescents. Deficits in postural control and muscle strength represent 2 important intrinsic injury risk factors. Therefore, the purpose of this study was to investigate the relationship between variables of static and dynamic postural control and isometric and dynamic muscle strength and to find out whether there is an association between measures of postural control and muscle strength. Twenty-eight adolescents participated in this study (age 16.8 ± 0.6 years; body mass index 20.5 ± 1.8 kg · m(-2)). Biomechanic tests included the measurements of maximal isometric leg extension force (MIF) and rate of force development (RFDmax) of the leg extensors on a leg press with the feet resting on a force platform, vertical jumping force, and height (countermovement jump [CMJ]) on a force plate and the assessment of static (1-legged stance on a balance platform) and dynamic (mediolateral perturbation impulse on a balance platform) postural control. The significance level was set at p < 0.05. No significant associations were observed between measures of static and dynamic postural control. Significant positive correlations were detected between variables of isometric and dynamic muscle strength with r-values ranging from 0.441 to 0.779 (p < 0.05). Based on these models, a 100-N increase in MIF of the leg extensors was associated with 3.9, 4.2, and 6.5% better maximal CMJ force, CMJ height, and RFDmax, respectively. No significant correlations were observed between variables of postural control and muscle strength. The nonsignificant correlation between static/dynamic postural control and muscle strength implies that primarily dynamic measures of postural control should be incorporated in injury risk assessment and that postural control and muscle strength are independent of each other and may have to be trained

  17. 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.

  18. 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

  19. 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

  20. The effects of foot position and orientation on inter- and intra-foot coordination in standing postures: a frequency domain PCA analysis.

    PubMed

    Wang, Zheng; Molenaar, Peter C M; Molenaar, Peter M C; Newell, Karl M

    2013-09-01

    We investigated the effect of foot position and foot orientation on asymmetrical body weight loading and the inter- and intra-foot coordination dynamics of standing postures. The participants were instructed to stand with the feet side-by-side and in staggered and tandem positions with the right foot oriented at different angles (30, 60 and 90°). The results showed that the participants naturally loaded more on their left foot when positioned with their right foot forward. As the orientation of the right foot was changed from 90 to 30°, they loaded a significantly large proportion of their body weight on their left foot and the degree of coordination of the 4 COP time series increased. Foot position, constrains both the area of the base of support and the loading of the feet, played an important role differentiating the contribution of each COP to the postural control system. In particular, when postural stance was challenged by the limitation of the base of support, the COPs in the unstable plane (inter-foot coordination) showed larger factor weightings. In contrast, when standing posture was not challenged by the base of support boundary, the COPs of the more loaded foot (intra-foot coordination) dominated foot coordination in postural control. These findings show that the mechanical constraints of foot position and orientation interact to channel different patterns of inter- and intra-foot coordination dynamics of standing postures.

  1. The Vestibular-Evoked Postural Response of Adolescents with Idiopathic Scoliosis Is Altered

    PubMed Central

    Pialasse, Jean-Philippe; Descarreaux, Martin; Mercier, Pierre; Blouin, Jean; Simoneau, Martin

    2015-01-01

    Adolescent idiopathic scoliosis is a multifactorial disorder including neurological factors. A dysfunction of the sensorimotor networks processing vestibular information could be related to spine deformation. This study investigates whether feed-forward vestibulomotor control or sensory reweighting mechanisms are impaired in adolescent scoliosis patients. Vestibular evoked postural responses were obtained using galvanic vestibular stimulation while participants stood with their eyes closed and head facing forward. Lateral forces under each foot and lateral displacement of the upper body of adolescents with mild (n = 20) or severe (n = 16) spine deformation were compared to those of healthy control adolescents (n = 16). Adolescent idiopathic scoliosis patients demonstrated greater lateral displacement and net lateral forces than controls both during and immediately after vestibular stimulation. Altered sensory reweighting of vestibular and proprioceptive information changed balance control of AIS patients during and after vestibular stimulation. Therefore, scoliosis onset could be related to abnormal sensory reweighting, leading to altered sensorimotor processes. PMID:26580068

  2. 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

    2016-03-15

    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.

  3. Early Adolescent Romantic Partner Status, Peer Standing, and Problem Behaviors.

    PubMed

    Miller, Shari; Lansford, Jennifer E; Costanzo, Philip; Malone, Patrick S; Golonka, Megan; Killeya-Jones, Ley A

    2009-12-01

    This study examined associations among early adolescent romantic relationships, peer standing, problem behaviors, and gender as a moderator of these associations, in a sample of 320 seventh-grade students. Popular and controversial status youth were more likely to have a romantic partner, whereas neglected status youth were less likely to have a romantic partner. Similarly, youth perceived as conventional and unconventional leaders were also more likely to have a romantic partner than were non-leaders. Youth who had a romantic partner drank more alcohol and were more aggressive than were youth who did not have a romantic partner. Among those youth who had romantic partners, those who reported having more deviance-prone partners were themselves more likely to use alcohol and to be more aggressive, and those who engaged in deviant behavior with their partners used more alcohol. However, these associations varied somewhat by gender. These findings underscore the salience of early romantic partner relationships in the adjustment of early adolescents.

  4. Increasing speed to improve arm movement and standing postural control in Parkinson's disease patients when catching virtual moving balls.

    PubMed

    Su, Kuei-Jung; Hwang, Wen-Juh; Wu, Ching-yi; Fang, Jing-Jing; Leong, Iat-Fai; Ma, Hui-Ing

    2014-01-01

    Research has shown that moving targets help Parkinson's disease (PD) patients improve their arm movement while sitting. We examined whether increasing the speed of a moving ball would also improve standing postural control in PD patients during a virtual reality (VR) ball-catching task. Twenty-one PD patients and 21 controls bilaterally reached to catch slow-moving and then fast-moving virtual balls while standing. A projection-based VR system connected to a motion-tracking system and a force platform was used. Dependent measures included the kinematics of arm movement (movement time, peak velocity), duration of anticipatory postural adjustments (APA), and center of pressure (COP) movement (movement time, maximum amplitude, and average velocity). When catching a fast ball, both PD and control groups made arm movements with shorter movement time and higher peak velocity, longer APA, as well as COP movements with shorter movement time and smaller amplitude than when catching a slow ball. The change in performance from slow- to fast-ball conditions was not different between the PD and control groups. The results suggest that raising the speed of virtual moving targets should increase the speed of arm and COP movements for PD patients. Therapists, however, should also be aware that a fast virtual moving target causes the patient to confine the COP excursion to a smaller amplitude. Future research should examine the effect of other task parameters (e.g., target distance, direction) on COP movement and examine the long-term effect of VR training.

  5. Spherical lenses and prisms lead to postural instability in both dyslexic and non dyslexic adolescents.

    PubMed

    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 improve their

  6. Postural Stability During Standing Balance and Sit-to-Stand in Master Athlete Runners Compared With Non-Athletic Old and Young Adults.

    PubMed

    Leightley, Daniel; Yap, Moi Hoon; Coulson, Jessica; Piasecki, Mathew; Cameron, James; Barnouin, Yoann; Tobias, Jon; McPhee, Jamie S

    2016-10-21

    The aim of this study was to compare postural sway during a series of static balancing tasks and during five chair rises between healthy young (mean (SEM) age 26(1) yrs), healthy old (age 67(1) yrs) and master athlete runners (age 67(1) yrs; competing and training for the previous 51(5) yrs) using the Microsoft Kinect One. The healthy old had more sway than young in all balance tasks. The master athletes had similar sway to young during two-leg balancing and one leg standing with eyes open. When balancing on one-leg with eyes closed, both the healthy old and the master athletes had around 17-fold more sway than young. The healthy old and master athletes also had less anterio-posterior movement during chair rising compared with young. These results suggest that masters runners are not spared from the age-associated decline in postural stability and may benefit from specific balance training.

  7. Anticipatory postural muscle activity associated with bilateral arm flexion while standing in individuals with spastic diplegic cerebral palsy: A pilot study.

    PubMed

    Tomita, Hidehito; Fukaya, Yoshiki; Honma, Shota; Ueda, Tomomi; Yamamoto, Yoshiji; Shionoya, Katsuyoshi

    2010-07-26

    Compared to automatic postural responses to external perturbation, little is known about anticipatory postural adjustments in individuals with spastic diplegic cerebral palsy. In this study, we examined whether anticipatory activation of postural muscles would be observed before voluntary arm movement while standing in individuals with spastic diplegia. Seven individuals with spastic diplegia (SDCP(group), 12-22 years) and 7 age- and gender-matched individuals without disability (Control(group)) participated in this study. Participants performed bilateral arm flexion at maximum speed at their own timing while standing, during which electromyographic (EMG) activities of focal and postural muscles were recorded. In both groups, the erector spinae (ES) and medial hamstring (MH) muscles were activated in advance of the anterior deltoid muscle (AD), which is a focal muscle of arm flexion. Although start times of ES and MH with respect to AD were similar in the 2 groups, increases in EMG amplitudes of ES and MH in the anticipatory range from -150ms to +50ms, with respect to burst onset of AD, were significantly smaller in the SDCP(group) than in the Control(group). These findings suggest that individuals with spastic diplegia have the ability to anticipate the effects of disturbance of posture and equilibrium caused by arm movement and to activate postural muscles in advance of focal muscles. However, it is likely that the anticipatory increase in postural muscle activity is insufficient in individuals with spastic diplegia.

  8. Relation between the Sensory and Anthropometric Variables in the Quiet Standing Postural Control: Is the Inverted Pendulum Important for the Static Balance Control?

    PubMed Central

    Alonso, Angélica C.; Mochizuki, Luis; Silva Luna, Natália Mariana; Ayama, Sérgio; Canonica, Alexandra Carolina; Greve, Júlia M. D. A.

    2015-01-01

    The aim of this study was to evaluate the relation between the sensory and anthropometric variables in the quiet standing. Methods. One hundred individuals (50 men, 50 women; 20–40 years old) participated in this study. For all participants, the body composition (fat tissue, lean mass, bone mineral content, and bone mineral density) and body mass, height, trunk-head length, lower limb length, and upper limb length were measured. The center of pressure was measured during the quiet standing posture, the eyes opened and closed with a force platform. Correlation and regression analysis were run to analyze the relation among body composition, anthropometric data, and postural sway. Results. The correlation analysis showed low relation between postural sway and anthropometric variables. The multiple linear regression analyses showed that the height explained 12% of the mediolateral displacement and 11% of the center of pressure area. The length of the trunk head explained 6% of displacement in the anteroposterior postural sway. During eyes closed condition, the support basis and height explained 18% of mediolateral postural sway. Conclusion. The postural control depends on body composition and dimension. This relation is mediated by the sensory information. The height was the anthropometric variable that most influenced the postural sway. PMID:26539550

  9. Postural stability with exhaustive repetitive sit-to-stand exercise in young adults.

    PubMed

    Bryanton, Megan A; Bilodeau, Martin

    2016-10-01

    Previous research has indicated that muscle fatigue due to repeated bouts of physical activity can have negative residual effects on balance; however investigations using multi-joint forms of exercise involved in everyday settings and determination of how control of posture is altered during the physical activity itself are limited. The purpose of this investigation was to evaluate alterations in postural stability before, during, and after prolonged multi-joint STS exercise in healthy young adults. Center of pressure (COP) acquisitions were collected during repetitive STS exercise, while voluntary limits of stability (LOS) testing was performed before, immediately after, and 10min after STS exercise. By 50% total STS exercise time, fatigue resulted in increased anterio-posterior (y) and medio-lateral (x) COP path lengths (p=0.003 and p=0.018 respectively) and an anterior shift of COP at seat-off towards the mid-foot (p=0.010). No significant change in LOS mean amplitude was found after STS exercise; however a significant fatigue effect resulted in increased COPy sway velocity at maximal lean positions (p=0.006), but returned to PRE values after 10min of rest. Declines in postural stability during repetitive STS exercise was associated with reduced control of COP, as well as a reduced ability to stably control COP at extreme postural limits; however, 10min was adequate in young adults for recovery. These results may have important implications for monitoring fall risk due to acute bouts of exercise induced muscle fatigue from repetitive multi-joint activities such as the STS.

  10. Craniofacial and cervical morphology related to sagittal spinal posture in children and adolescents.

    PubMed

    Segatto, Emil; Segatto, Angyalka; Braunitzer, Gábor; Kirschneck, Christian; Fanghänel, Jochen; Danesh, Gholamreza; Lippold, Carsten

    2014-01-01

    Studies on the relationship between body posture and craniofacial parameters often focus on the cervical spine. Thus, less attention has been paid to the morphology of the vertebra C2 that serves as both a structural and functional link between the craniofacial area and the other part of the spine. The objective of this study was to assess the relation of craniofacial features to certain morphological and positional characteristics of the cervical vertebrae and the spine during growth. We determined body posture indices for 69 children and adolescents by means of a radiation-free method (rasterstereography). The morphological and positional analysis of the craniofacial area and the cervical vertebrae was based on standardized lateral X-ray cephalograms. Medium to strong correlations were found between body posture, C2 morphology, and craniofacial parameters. We found significant correlations between the C2 dens axis height and maxillary indices as well as between the C2 dens axis inclination and cephalometrical values of the mandibular area. Similarly the correlation between the C2 dens axis inclination and the postural index flèche cervicale was highly significant (P < 0.05, r = 0.333). These results suggest that morphological features of the odontoid process may serve as valuable predictive markers in interdisciplinary orthopedic-orthodontic diagnostics.

  11. Craniofacial and Cervical Morphology Related to Sagittal Spinal Posture in Children and Adolescents

    PubMed Central

    Segatto, Angyalka; Braunitzer, Gábor

    2014-01-01

    Studies on the relationship between body posture and craniofacial parameters often focus on the cervical spine. Thus, less attention has been paid to the morphology of the vertebra C2 that serves as both a structural and functional link between the craniofacial area and the other part of the spine. The objective of this study was to assess the relation of craniofacial features to certain morphological and positional characteristics of the cervical vertebrae and the spine during growth. We determined body posture indices for 69 children and adolescents by means of a radiation-free method (rasterstereography). The morphological and positional analysis of the craniofacial area and the cervical vertebrae was based on standardized lateral X-ray cephalograms. Medium to strong correlations were found between body posture, C2 morphology, and craniofacial parameters. We found significant correlations between the C2 dens axis height and maxillary indices as well as between the C2 dens axis inclination and cephalometrical values of the mandibular area. Similarly the correlation between the C2 dens axis inclination and the postural index flèche cervicale was highly significant (P < 0.05, r = 0.333). These results suggest that morphological features of the odontoid process may serve as valuable predictive markers in interdisciplinary orthopedic-orthodontic diagnostics. PMID:25276804

  12. One- or Two-Legged Standing: What Is the More Suitable Protocol to Assess the Postural Effects of the Rigid Ankle Orthosis?

    ERIC Educational Resources Information Center

    Rougier, Patrice; Genthon, Nicolas; Gallois-Montbrun, Thibault; Brugiere, Steve; Bouvat, Eric

    2009-01-01

    To highlight the capacity of one- and two-legged standing protocols when assessing postural behavior induced by a rigid ankle orthosis, 14 healthy individuals stood upright barefoot and wore either an elastic stocking on the preferred leg or a rigid orthosis with or without additional taping in one- or two-legged (TL) conditions. Traditional…

  13. Heterogeneity in the Energy Cost of Posture Maintenance during Standing Relative to Sitting: Phenotyping According to Magnitude and Time-Course

    PubMed Central

    Miles-Chan, Jennifer L.; Sarafian, Delphine; Montani, Jean-Pierre; Schutz, Yves; Dulloo, Abdul

    2013-01-01

    Background Reducing sitting-time may decrease risk of disease and increase life-span. In the search for approaches to reduce sitting-time, research often compares sitting to standing and ambulation, but the energetic cost of standing alone versus sitting is equivocal, with large variation in reported mean values (0% to >20% increase in energy expenditure (EE) during standing). Objective To determine the magnitude and time-course of changes in EE and respiratory quotient (RQ) during steady-state standing versus sitting. Design Min-by-min monitoring using a posture-adapted ventilated-hood indirect calorimetry system was conducted in 22 young adults with normal BMI during 10 min of steady-state standing versus sitting comfortably. Results This study reveals three distinct phenotypes based on the magnitude and time-course of the EE response to steady-state standing. One-third of participants (8/22) showed little or no change in EE during standing relative to sitting (ΔEE <5%; below first quartile). Of the 14 responders (ΔEE 7–21%), 4 showed sustained, elevated EE during standing, while 10 decreased their EE to baseline sitting values during the second half of the standing period. These EE phenotypes were systematically mirrored by alterations in RQ (a proxy of substrate oxidation), with ΔEE inversely correlated with ΔRQ (r = 0.6–0.8, p<0.01). Conclusion This study reveals different phenotypes pertaining to both energy cost and fuel utilization during standing, raising questions regarding standing as a strategy to increase EE and thermogenesis for weight control, and opening new avenues of research towards understanding the metabolic and psychomotor basis of variability in the energetics of standing and posture maintenance. PMID:23741514

  14. What Makes a Bystander Stand By? Adolescents and Bullying

    ERIC Educational Resources Information Center

    Chapin, John; Brayack, Michael

    2016-01-01

    The current study sheds some light on the extent to which adolescents say they are experiencing bullying, what they think they would do when confronted with bullies, and what they have actually done in the past when witnessing bullying. Results from a survey of 1,742 adolescents indicates even young adolescents have already experienced verbal,…

  15. Effect of frequency, magnitude and direction of translational and rotational oscillation on the postural stability of standing people

    NASA Astrophysics Data System (ADS)

    Nawayseh, Naser; Griffin, Michael J.

    2006-12-01

    Oscillatory motions can cause injury in transport when standing passengers or crew lose balance and fall. To predict the loss of balance of standing people, a model is required of the relationship between the input motion and the stability of the human body. This experimental study investigated the effect of frequency, magnitude and direction of oscillation on the postural stability of standing subjects and whether response to rotational oscillation can be predicted from knowledge of response to translational oscillation. Twelve male subjects stood on a floor that oscillated in either horizontal (fore-and-aft or lateral) or rotational (pitch or roll) directions. The oscillations were one-third octave bands of random motion centred on five preferred octave centre frequencies (0.125, 0.25, 0.5, 1.0, and 2.0 Hz). The horizontal motions were presented at each of four velocities (0.04, 0.062, 0.099, and 0.16 ms -1 rms) and the rotational motions were presented at each of four rotational angles (0.73, 1.46, 2.92, and 5.85° rms) corresponding to four accelerations (0.125, 0.25, 0.5, and 1.0 ms -2 rms), where the acceleration is that caused by rotation through the gravitational vector. Postural stability was determined by subjective methods and by measuring the displacement of the centre of pressure at the feet during horizontal oscillation. During horizontal oscillation, increases in motion magnitude increased instability and, with the same velocity at all frequencies from 0.125 to 2.0 Hz, most instability occurred in the region of 0.5 Hz. Fore-and-aft oscillation produced more instability than lateral oscillation, although displacements of the centre of pressure were similar in both directions. With the same angular displacement at all frequencies from 0.125 to 2.0 Hz, pitch oscillation caused more instability than roll oscillation, but in both directions instability increased with increased frequency of oscillation. Frequency weightings for acceleration in the plane of

  16. [Influence of Achilles tendon vibration on the human vertical posture during standing with asymmetrical leg loading].

    PubMed

    Kazennikov, O V; Kireeva, T B; Shlykov, V Iu

    2014-01-01

    The shift of center of pressure (CP) of body and CP of each leg was studied during Achilles tendon vibration of one or both legs while subject was standing with symmetrical load on the legs or with the load transferred on one leg. The CP shift of standing subject during unilateral Achilles tendon vibration depended both on the side of the tendon vibration and on the leg load. When standing with a load transferred on one leg the shift of common CP was larger than when the vibration was applied to the loaded leg. The CP shift of one leg was greater if the vibration, and the load was applied to it. Vibration of unloaded leg caused a CP shift in the contralateral loaded leg. In this case, the vibration of left unloaded leg caused no noticeable CP shift of left leg, while the vibration of the unloaded right leg caused CP shift of right foot. In the same conditions of load and vibration the CP displacement of right leg was larger than the CP shift of left foot. It can be assumed that the change in the load on the leg and unilateral vibration of leg muscles change of the internal representation of the vertical body axis, which affects the CP position of one leg during the muscles vibration.

  17. Postural control during sit-to-stand movement and its relationship with upright position in children with hemiplegic spastic cerebral palsy and in typically developing children

    PubMed Central

    Pavão, Silvia L.; Santos, Adriana N.; Oliveira, Ana B.; Rocha, Nelci A. C. F.

    2015-01-01

    OBJECTIVE: The purpose of this study was to compare postural control in typically developing (TD) children and children with cerebral palsy (CP) during the sit-to-stand (STS) movement and to assess the relationship between static (during static standing position) and dynamic postural control (during STS movement) in both groups. METHOD: The center of pressure (CoP) behavior of 23 TD children and 6 children with spastic hemiplegic CP (Gross Motor Function Classification System [GMFCS] I and II) was assessed during STS movement performance and during static standing conditions with the use of a force plate. The data obtained from the force plate were used to calculate CoP variables: anteroposterior (AP) and mediolateral (ML) amplitudes of CoP displacement and the area and velocity of CoP oscillation. RESULTS: According to the Mann-Whitney test, children with CP exhibited higher CoP values in all of the analyzed variables during the beginning of STS movement. Pearson's correlation verified a positive correlation between the CoP variables during both static conditions and the performance of STS movement. CONCLUSIONS: Children with spastic hemiplegic CP present major postural oscillations during the beginning of STS movement compared with typical children. Moreover, the observed relationship between postural control in static and dynamic conditions reveals the importance of body control in the static position for the performance of functional activities that put the body in motion, such as STS movement. PMID:25651131

  18. Reliability and Validity Measurement of Sagittal Lumbosacral Quiet Standing Posture with a Smartphone Application in a Mixed Population of 183 College Students and Personnel

    PubMed Central

    Nikoloudaki, Maria; Thacheth, Sara; Zagli, Kalliroi; Bitrou, Konstantina; Nigritinos, Andreas; Botton, Leon

    2016-01-01

    Accurate recording of spinal posture with simple and accessible measurement devices in clinical practice may lead to spinal loading optimization in occupations related to prolonged sitting and standing postures. Therefore, the purpose of this study was to establish the level of reliability of sagittal lumbosacral posture in quiet standing and the validity of the method in differentiating between male and female subjects, establishing in parallel a normative database. 183 participants (83 males and 100 females), with no current low back or pelvic pain, were assessed using the “iHandy Level” smartphone application. Intrarater reliability (3 same-day sequential measurements) was high for both the lumbar curve (ICC2,1: 0.96, SEM: 2.13°, and MDC95%: 5.9°) and the sacral slope (ICC2,1: 0.97, SEM: 1.61°, and MDC95%: 4.46°) sagittal alignment. Data analysis for each gender separately confirmed equally high reliability for both male and female participants. Correlation between lumbar curve and sacral slope was high (Pearson's r = 0.86, p < 0.001). Between-gender comparisons confirmed the validity of the method to differentiate between male and female lumbar curve and sacral slope angles, with females generally demonstrating greater lumbosacral values (p < 0.001). The “iHandy Level” application is a reliable and valid tool in the measurement of lumbosacral quiet standing spinal posture in the sagittal plane. PMID:27843650

  19. Effect of Experimentally-Induced Trunk Muscular Tensions on the Sit-to-Stand Task Performance and Associated Postural Adjustments.

    PubMed

    Hamaoui, Alain; Alamini-Rodrigues, Caroline

    2017-01-01

    It has been shown that increased muscular activity along the trunk is likely to impair body balance, but there is little knowledge about its consequences on more dynamic tasks. The purpose of this study was to determine the effect of unilateral and bilateral increases of muscular tension along the trunk on the sit-to-stand task (STS) performance and associated anticipatory postural adjustments (APAs). Twelve healthy females (23 ± 3 years, 163 ± 0.06 cm, 56 ± 9 kg), free of any neurological or musculoskeletal disorders, performed six trials of the STS at maximum speed, in seven experimental conditions varying the muscular tension along each side of the trunk, using a specific bimanual compressive load paradigm. A six-channel force plate was used to calculate the coordinates of the center of pressure (CP) along the anterior-posterior and medial-lateral axes, and the kinematics of the head, spine and pelvis, were estimated using three pairs of uni-axial accelerometers. The postural and focal components of the task were assessed using three biomechanical parameters calculated from CP signals: the duration and magnitude of APAs, and the duration of focal movement (dFM). Results showed that beyond a given level, higher muscular tension along the trunk results in longer APAs, but with a stable duration of the focal movement. In addition, no significant variation of APAs and FM parameters was found between bilateral and unilateral increases of muscular tension. It was suggested that restricted mobility due to higher muscular tension along the trunk requires an adaptation of the programming of APAs to keep the same level of performance in the STS task. These findings may have implications in treatment strategies aimed at preserving functional autonomy in pathologies including a rise of muscular tension.

  20. Effect of Experimentally-Induced Trunk Muscular Tensions on the Sit-to-Stand Task Performance and Associated Postural Adjustments

    PubMed Central

    Hamaoui, Alain; Alamini-Rodrigues, Caroline

    2017-01-01

    It has been shown that increased muscular activity along the trunk is likely to impair body balance, but there is little knowledge about its consequences on more dynamic tasks. The purpose of this study was to determine the effect of unilateral and bilateral increases of muscular tension along the trunk on the sit-to-stand task (STS) performance and associated anticipatory postural adjustments (APAs). Twelve healthy females (23 ± 3 years, 163 ± 0.06 cm, 56 ± 9 kg), free of any neurological or musculoskeletal disorders, performed six trials of the STS at maximum speed, in seven experimental conditions varying the muscular tension along each side of the trunk, using a specific bimanual compressive load paradigm. A six-channel force plate was used to calculate the coordinates of the center of pressure (CP) along the anterior-posterior and medial-lateral axes, and the kinematics of the head, spine and pelvis, were estimated using three pairs of uni-axial accelerometers. The postural and focal components of the task were assessed using three biomechanical parameters calculated from CP signals: the duration and magnitude of APAs, and the duration of focal movement (dFM). Results showed that beyond a given level, higher muscular tension along the trunk results in longer APAs, but with a stable duration of the focal movement. In addition, no significant variation of APAs and FM parameters was found between bilateral and unilateral increases of muscular tension. It was suggested that restricted mobility due to higher muscular tension along the trunk requires an adaptation of the programming of APAs to keep the same level of performance in the STS task. These findings may have implications in treatment strategies aimed at preserving functional autonomy in pathologies including a rise of muscular tension. PMID:28220064

  1. What COP and Kinematic Parameters Better Characterize Postural Control in Standing Balance Tasks?

    PubMed

    Caballero, Carla; Barbado, David; Moreno, Francisco Javier

    2015-01-01

    The authors' aim was to determine which variables allow for the characterization of motor balance behavior. Traditional measures and nonlinear measures of center of pressure (COP; n = 30) and kinematics (n = 10) were tested in their absolute and relative consistency in a 30-s standing balance task protocol under stable and unstable conditions. Regarding COP variables, mean velocity (mVel), permutation entropy (PE) and detrended fluctuation analysis (DFA) exhibited high consistency between trials and ranked individuals more accurately compare with other metrics. In the kinematic signal mVel, PE and DFA had good intrasession reliability values in unstable conditions. Overall, the intrasession reliability values were better in the unstable condition than in the stable condition and the measures calculated using derived data had better intrasession reliability values. In conclusion, mVel, PE, and DFA allow for the good characterization of motor balance behavior in a simplified protocol where velocity time series are analyzed.

  2. Interpreting the posture and locomotion of Australopithecus afarensis: where do we stand?

    PubMed

    Ward, Carol V

    2002-01-01

    , but still do not falsify the null hypothesis. Disaptation, or negative selection, should result in a trait being reduced or lost. To infer the behaviors of a fossil species, we must first determine its adaptations, use this to make hypotheses about its behavior, and test these hypotheses using epigenetically sensitive traits that are modified by an individual's activity pattern. When the A. afarensis data are evaluated using this framework, it is clear that these hominins had undergone selection for habitual bipedality, but the null hypothesis of nonaptation to explain the retention of primitive, ape-like characters cannot be falsified at present. The apparent stasis in Australopithecus postcranial form is currently the strongest evidence for stabilizing selection maintaining its primitive features. Evidence from features affected by individual behaviors during ontogeny shows that A. afarensis individuals were habitually traveling bipedally, but evidence presented for arboreal behavior so far is not conclusive. By clearly identifying the questions we are asking about early hominin fossils, refining our knowledge about character polarities, and elucidating the factors influencing morphology, we will be able to progress in our understanding of the posture and locomotion of A. afarensis and all early hominins.

  3. 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

  4. 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.

  5. Leg and trunk muscle coordination and postural sway during increasingly difficult standing balance tasks in young and older adults.

    PubMed

    Donath, Lars; Kurz, Eduard; Roth, Ralf; Zahner, Lukas; Faude, Oliver

    2016-09-01

    Ageing impairs body balance and increases older adults' fall risk. Balance training can improve intrinsic fall risk factors. However, age comparisons of muscle activity responses during balance tasks are lacking. This study investigated relative muscle activity, muscle coordination and postural sway during various recommended static balance training tasks. Muscle activity (%MVC), amplitude ratios (AR) and co-activity (CAI) were determined during standing tasks for 30s (1: double limb stance on a foam surface, eyes open; 2: double limb stance on firm ground, eyes closed; 3: double limb stance, feet in step position on a foam surface, eyes open; 4: double limb stance, feet in step position on firm ground, eyes closed; 5: single limb stance on firm ground, eyes open) in 20 healthy young adults (24±2 y) and 20 older adults (73±6 y). Surface electromyography (SEMG) was applied (SENIAM guidelines) to ankle (tibialis anterior, soleus, medial gastrocnemius, peroneus longus) and thigh (vastus lateralis, vastus medialis, biceps femoris, semitendinosus) muscles (non-dominant leg). Electrodes over trunk (multifidus and internal oblique) muscles were applied bilaterally. Two- to six-fold higher levels of relative muscle activity were found in older adults for ankle (0.0002

  6. Reliability and concurrent validity of the Microsoft Xbox One Kinect for assessment of standing balance and postural control.

    PubMed

    Clark, Ross A; Pua, Yong-Hao; Oliveira, Cristino C; Bower, Kelly J; Thilarajah, Shamala; McGaw, Rebekah; Hasanki, Ksaniel; Mentiplay, Benjamin F

    2015-07-01

    The Microsoft Kinect V2 for Windows, also known as the Xbox One Kinect, includes new and potentially far improved depth and image sensors which may increase its accuracy for assessing postural control and balance. The aim of this study was to assess the concurrent validity and reliability of kinematic data recorded using a marker-based three dimensional motion analysis (3DMA) system and the Kinect V2 during a variety of static and dynamic balance assessments. Thirty healthy adults performed two sessions, separated by one week, consisting of static standing balance tests under different visual (eyes open vs. closed) and supportive (single limb vs. double limb) conditions, and dynamic balance tests consisting of forward and lateral reach and an assessment of limits of stability. Marker coordinate and joint angle data were concurrently recorded using the Kinect V2 skeletal tracking algorithm and the 3DMA system. Task-specific outcome measures from each system on Day 1 and 2 were compared. Concurrent validity of trunk angle data during the dynamic tasks and anterior-posterior range and path length in the static balance tasks was excellent (Pearson's r>0.75). In contrast, concurrent validity for medial-lateral range and path length was poor to modest for all trials except single leg eyes closed balance. Within device test-retest reliability was variable; however, the results were generally comparable between devices. In conclusion, the Kinect V2 has the potential to be used as a reliable and valid tool for the assessment of some aspects of balance performance.

  7. 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…

  8. Effects of foot position of the nonparetic side during sit-to-stand training on postural balance in patients with stroke.

    PubMed

    Han, Jintae; Kim, Youngmi; Kim, Kyung

    2015-08-01

    [Purpose] We aimed to investigate postural balance after sit-to-stand (STS) training with different nonparetic foot positions in stroke patients. [Subjects] Thirty-six subjects who experienced a stroke (21 males, 15 females) participated and were divided into the symmetric foot position (SYMM), asymmetric foot position (ASYM), and step foot (STEP) groups. [Methods] Each group performed repetitive sit-to-stand training 5 times a week for 6 weeks. The timed up-and-go test (TUG), functional reach test (FRT), and F-mat system correcting the anterior/posterior (A-P) and medial/lateral (M-L) distance of the center of pressure (COP) were used to measure the static and dynamic postural balance pre- and postintervention. ANCOVA was used to analyze differences among groups, and preintervention variables were used as covariates. [Results] The TUG, FRT, and A-P and M-L distance of the COP in the ASYM and STEP groups were significantly decreased after intervention compared with the SYMM group. All parameters in the STEP group were lower than those in the ASYM group, without a significant difference. [Conclusion] The asymmetric foot position during STS is a good intervention to improve the static and dynamic postural balance in stroke patients. Especially, using a step to change the foot position is effective in improving STS performance.

  9. Effects of foot position of the nonparetic side during sit-to-stand training on postural balance in patients with stroke

    PubMed Central

    Han, Jintae; Kim, Youngmi; Kim, Kyung

    2015-01-01

    [Purpose] We aimed to investigate postural balance after sit-to-stand (STS) training with different nonparetic foot positions in stroke patients. [Subjects] Thirty-six subjects who experienced a stroke (21 males, 15 females) participated and were divided into the symmetric foot position (SYMM), asymmetric foot position (ASYM), and step foot (STEP) groups. [Methods] Each group performed repetitive sit-to-stand training 5 times a week for 6 weeks. The timed up-and-go test (TUG), functional reach test (FRT), and F-mat system correcting the anterior/posterior (A-P) and medial/lateral (M-L) distance of the center of pressure (COP) were used to measure the static and dynamic postural balance pre- and postintervention. ANCOVA was used to analyze differences among groups, and preintervention variables were used as covariates. [Results] The TUG, FRT, and A-P and M-L distance of the COP in the ASYM and STEP groups were significantly decreased after intervention compared with the SYMM group. All parameters in the STEP group were lower than those in the ASYM group, without a significant difference. [Conclusion] The asymmetric foot position during STS is a good intervention to improve the static and dynamic postural balance in stroke patients. Especially, using a step to change the foot position is effective in improving STS performance. PMID:26356809

  10. Early adolescents' social standing in peer groups: behavioral correlates of stability and change.

    PubMed

    Lansford, Jennifer E; Killeya-Jones, Ley A; Miller, Shari; Costanzo, Philip R

    2009-09-01

    Sociometric nominations, social cognitive maps, and self-report questionnaires were completed in consecutive years by 327 students (56% girls) followed longitudinally from grade 7 to grade 8 to examine the stability of social standing in peer groups and correlates of changes in social standing. Social preference, perceived popularity, network centrality, and leadership were moderately stable from grade 7 to grade 8. Alcohol use and relational aggression in grade 7 predicted changes in social preference and centrality, respectively, between grade 7 and grade 8, but these effects were moderated by gender and ethnicity. Changes in social standing from grade 7 to grade 8 were unrelated to grade 8 physical aggression, relational aggression, and alcohol use after controlling for the grade 7 corollaries of these behaviors. Results are discussed in terms of their implications for understanding links between social standing and problem behaviors during adolescence.

  11. The Complexity of Standing Postural Control in Older Adults: A Modified Detrended Fluctuation Analysis Based upon the Empirical Mode Decomposition Algorithm

    PubMed Central

    Liu, Dongdong; Hu, Kun; Zhang, Jue; Fang, Jing

    2013-01-01

    Human aging into senescence diminishes the capacity of the postural control system to adapt to the stressors of everyday life. Diminished adaptive capacity may be reflected by a loss of the fractal-like, multiscale complexity within the dynamics of standing postural sway (i.e., center-of-pressure, COP). We therefore studied the relationship between COP complexity and adaptive capacity in 22 older and 22 younger healthy adults. COP magnitude dynamics were assessed from raw data during quiet standing with eyes open and closed, and complexity was quantified with a new technique termed empirical mode decomposition embedded detrended fluctuation analysis (EMD-DFA). Adaptive capacity of the postural control system was assessed with the sharpened Romberg test. As compared to traditional DFA, EMD-DFA more accurately identified trends in COP data with intrinsic scales and produced short and long-term scaling exponents (i.e., αShort, αLong) with greater reliability. The fractal-like properties of COP fluctuations were time-scale dependent and highly complex (i.e., αShort values were close to one) over relatively short time scales. As compared to younger adults, older adults demonstrated lower short-term COP complexity (i.e., greater αShort values) in both visual conditions (p>0.001). Closing the eyes decreased short-term COP complexity, yet this decrease was greater in older compared to younger adults (p<0.001). In older adults, those with higher short-term COP complexity exhibited better adaptive capacity as quantified by Romberg test performance (r2 = 0.38, p<0.001). These results indicate that an age-related loss of COP complexity of magnitude series may reflect a clinically important reduction in postural control system functionality as a new biomarker. PMID:23650518

  12. 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.

  13. 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

  14. 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…

  15. Interaction between the oculomotor and postural systems during a dual-task: Compensatory reductions in head sway following visually-induced postural perturbations promote the production of accurate double-step saccades in standing human adults.

    PubMed

    Boulanger, Mathieu; Giraudet, Guillaume; Faubert, Jocelyn

    2017-01-01

    Humans routinely scan their environment for useful information using saccadic eye movements and/or coordinated movements of the eyes and other body segments such the head and the torso. Most previous eye movement studies were conducted with seated subject and showed that single saccades and sequences of saccades (e.g. double-step saccades) made to briefly flashed stimuli were equally accurate and precise. As one can easily appreciate, most gaze shifts performed daily by a given person are not produced from a seated position, but rather from a standing position either as subjects perform an action from an upright stance or as they walk from one place to another. In the experiments presented here, we developed a new dual-task paradigm in order to study the interaction between the gaze control system and the postural system. Healthy adults (n = 12) were required to both maintain balance and produce accurate single-step and double-step eye saccades from a standing position. Visually-induced changes in head sway were evoked using wide-field background stimuli that either moved in the mediolateral direction or in the anteroposterior direction. We found that, as in the seated condition, single- and double-step saccades were very precise and accurate when made from a standing position, but that a tighter control of head sway was necessary in the more complex double-step saccades condition for equivalent results to be obtained. Our perturbation results support the "common goal" hypothesis that state that if necessary, as was the case during the more complex oculomotor task, context-dependent modulations of the postural system can be triggered to reduced instability and therefore support the accomplishment of a suprapostural goal.

  16. Interaction between the oculomotor and postural systems during a dual-task: Compensatory reductions in head sway following visually-induced postural perturbations promote the production of accurate double-step saccades in standing human adults

    PubMed Central

    Giraudet, Guillaume; Faubert, Jocelyn

    2017-01-01

    Humans routinely scan their environment for useful information using saccadic eye movements and/or coordinated movements of the eyes and other body segments such the head and the torso. Most previous eye movement studies were conducted with seated subject and showed that single saccades and sequences of saccades (e.g. double-step saccades) made to briefly flashed stimuli were equally accurate and precise. As one can easily appreciate, most gaze shifts performed daily by a given person are not produced from a seated position, but rather from a standing position either as subjects perform an action from an upright stance or as they walk from one place to another. In the experiments presented here, we developed a new dual-task paradigm in order to study the interaction between the gaze control system and the postural system. Healthy adults (n = 12) were required to both maintain balance and produce accurate single-step and double-step eye saccades from a standing position. Visually-induced changes in head sway were evoked using wide-field background stimuli that either moved in the mediolateral direction or in the anteroposterior direction. We found that, as in the seated condition, single- and double-step saccades were very precise and accurate when made from a standing position, but that a tighter control of head sway was necessary in the more complex double-step saccades condition for equivalent results to be obtained. Our perturbation results support the “common goal” hypothesis that state that if necessary, as was the case during the more complex oculomotor task, context-dependent modulations of the postural system can be triggered to reduced instability and therefore support the accomplishment of a suprapostural goal. PMID:28296958

  17. The influence of seat heights and foot placement positions on postural control in children with cerebral palsy during a sit-to-stand task.

    PubMed

    Medeiros, Daiane Lazzeri de; Conceição, Josilene Souza; Graciosa, Maylli Daiani; Koch, Deyse Borges; Santos, Marcio Jose Dos; Ries, Lilian Gerdi Kittel

    2015-01-01

    This paper aimed to analyze, from both a kinetic and kinematic perspective, the postural control of children with cerebral palsy (CP) able to independently perform the sit-to-stand (STS) task (ICP) and children who needed support (SCP) typically developing children during the STS; and also investigate the influence of seats heights and foot placement positions on postural control of these children. Fourteen children with CP and fourteen typically developing controls were recruited. Based on the Gross Motor Function Classification System (GMFCS) the children with CP were divided into ICP (level I) and SCP (levels II and III). Balance was assessed using the Pediatric Balance Scale. Motor function was rated using the GMFCS. Kinematic and kinetic data were recorded and analyzed during the STS task at two different seat heights and foot placement positions. The SCP exhibited significantly less balance according to the PBS and smaller displacement of their center of pressure (COP) in anteroposterior (COPAP) and mediolateral (COPML) direction relative to the other two groups. ICP demonstrated significant greater in the COPML displacement than the other groups. Children with CP required more time to complete the STS than controls. Those in the SCP group had lower linear displacement of the shoulder and knee than others during the STS task. During the high bench condition, the linear displacements of the shoulder and knee were reduced also. We conclude that the SCP has less COPAP and COPML oscillation, what means the better postural control during STS than the other two groups, which may be related to the support provided. The ICP exhibited greater COPML oscillations than controls, suggesting that they utilized different strategies in the frontal plane during the STS task. The seat height and foot placement did not influence postural control in children with CP, at least in terms of kinetic parameters. Seat height influenced the kinematic variables, with a high bench

  18. 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.

  19. 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.

  20. Smart garment to help children improve posture.

    PubMed

    Lou, E; Moreau, M J; Hill, D L; Raso, V J; Mahood, J K

    2006-01-01

    Many of the aches and pains of adults are the result not of injuries, but of the long-term effects of distortions in posture or alignment. Postural kyphosis in adolescence may be one of the effects of poor standing and sitting habits. Kyphosis is an excessive rounding of the upper spine. A smart garment that can monitor and provide vibration feedback to children has been developed to investigate an alternative treatment possibility. Laboratory tests verified that the accuracy of the system was +/-2 degrees within the full 180 degrees range. A clinical trial has been conducted and it showed that the system can aid subjects to improve by 20% the proportion of time in a more balanced posture. The long term effect is still under investigation.

  1. 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

  2. Electromyographic responses of erector spinae and lower limb's muscles to dynamic postural perturbations in patients with adolescent idiopathic scoliosis.

    PubMed

    Farahpour, Nader; Ghasemi, Safoura; Allard, Paul; Saba, Mohammad Sadegh

    2014-10-01

    The aim of this study was to evaluate electromyographic (EMG) responses of erector spinae (ES) and lower limbs' muscles to dynamic forward postural perturbation (FPP) and backward postural perturbation (BPP) in patients with adolescent idiopathic scoliosis (AIS) and in a healthy control group. Ten right thoracic AIS patients (Cobb=21.6±4.4°) and 10 control adolescents were studied. Using bipolar surface electrodes, EMG activities of ES muscle at T10 (EST10) and L3 (ESL3) levels, biceps femoris (BF), gastrocnemius lateralis (G) and rectus femoris (RF) muscles in the right and the left sides during FPP and BPP were evaluated. Muscle responses were measured over a 1s time window after the onset of perturbation. In FPP test, the EMG responses of right EST10, ESL3 and BF muscles in the scoliosis group were respectively about 1.40 (p=0.035), 1.43 (p=0.07) and 1.45 (p=0.01) times greater than those in control group. Also, in BPP test, at right ESL3 muscle of the scoliosis group the EMG activity was 1.64 times higher than that in the control group (p=0.01). The scoliosis group during FPP displayed asymmetrical muscle responses in EST10 and BF muscles. This asymmetrical muscle activity in response to FPP is hypothesized to be a possible compensatory strategy rather than an inherent characteristic of scoliosis.

  3. Reduced postural differences between phobic postural vertigo patients and healthy subjects during a postural threat.

    PubMed

    Holmberg, Johan; Tjernström, Fredrik; Karlberg, Mikael; Fransson, Per Anders; Magnusson, Måns

    2009-08-01

    Phobic postural vertigo is characterized by subjective imbalance and dizziness while standing or walking, despite normal values for clinical balance tests. Patients with phobic postural vertigo exhibit an increased high-frequency sway in posturographic tests. Their postural sway, however, becomes similar to the sway of healthy subjects during difficult balance tasks. Posturographic recordings of 30 s of quiet stance was compared to recordings of 30 s of quiet stance during a postural threat, which consisted of the knowledge of forthcoming vibratory calf muscle stimulation, in 37 consecutive patients with phobic postural vertigo and 24 healthy subjects. During quiet stance without the threat of forthcoming vibratory stimulation, patients with phobic postural vertigo exhibited a postural sway containing significantly more high-frequency sway than the healthy subjects. During the quiet stance with forthcoming vibratory stimulation, i.e., anticipation of a postural threat, the significant differences between groups disappeared for all variables except sagittal high-frequency sway. During postural threat, healthy subjects seemed to adopt a postural strategy that was similar to that exhibited by phobic postural vertigo patients. The lack of additional effects facing a postural threat among phobic postural vertigo patients may be due to an already maximized postural adaptation. Deviant postural reactions among patients with phobic postural vertigo may be considered as an avoidant postural response due to a constant fear of losing postural control.

  4. Identification and experimental validation of damping ratios of different human body segments through anthropometric vibratory model in standing posture.

    PubMed

    Gupta, T C

    2007-08-01

    A 15 degrees of freedom lumped parameter vibratory model of human body is developed, for vertical mode vibrations, using anthropometric data of the 50th percentile US male. The mass and stiffness of various segments are determined from the elastic modulii of bones and tissues and from the anthropometric data available, assuming the shape of all the segments is ellipsoidal. The damping ratio of each segment is estimated on the basis of the physical structure of the body in a particular posture. Damping constants of various segments are calculated from these damping ratios. The human body is modeled as a linear spring-mass-damper system. The optimal values of the damping ratios of the body segments are estimated, for the 15 degrees of freedom model of the 50th percentile US male, by comparing the response of the model with the experimental response. Formulating a similar vibratory model of the 50th percentile Indian male and comparing the frequency response of the model with the experimental response of the same group of subjects validate the modeling procedure. A range of damping ratios has been considered to develop a vibratory model, which can predict the vertical harmonic response of the human body.

  5. Standing footprint diagnostic method

    NASA Astrophysics Data System (ADS)

    Fan, Y. F.; Fan, Y. B.; Li, Z. Y.; Newman, T.; Lv, C. S.; Fan, Y. Z.

    2013-10-01

    Center of pressure is commonly used to evaluate standing balance. Even though it is incomplete, no better evaluation method has been presented. We designed our experiment with three standing postures: standing with feet together, standing with feet shoulder width apart, and standing with feet slightly wider than shoulder width. Our platform-based pressure system collected the instantaneous plantar pressure (standing footprint). A physical quantity of instantaneous standing footprint principal axis was defined, and it was used to construct an index to evaluate standing balance. Comparison between results from our newly established index and those from the center of pressure index to evaluate the stability of different standing postures revealed that the standing footprint principal axis index could better respond to the standing posture change than the existing one. Analysis indicated that the insensitive response to the relative position between feet and to the standing posture change from the center of pressure could be better detected by the standing footprint principal axis index. This predicts a wide application of standing footprint principal axis index when evaluating standing balance.

  6. Foot-type analysis and plantar pressure differences between obese and nonobese adolescents during upright standing.

    PubMed

    Cimolin, Veronica; Capodaglio, Paolo; Cau, Nicola; Galli, Manuela; Pau, Massimiliano; Patrizi, Alessandra; Tringali, Gabriella; Sartorio, Alessandro

    2016-03-01

    This study aimed to characterize the effect of obesity on foot-type and plantar pressure distribution in adolescents. Ten obese adolescents (obese group; BMI: 35.45±4.73 kg/m) and eight normal-weighted adolescents (control group; BMI: 18.67±2.46 kg/m) were recruited. Both groups were evaluated while standing using the Pedar-X in-shoe system. Foot-ground contact was characterized using contact area, peak of force and pressure calculated for the subareas of the foot. The analysis showed that obese participants had significantly higher area of contact in forefoot and midfoot (only in medial area) regions in comparison with the control group, whereas no statistically significant differences were observed for the rearfoot region. As far as the maximum pressure and force was concerned, similar results were obtained for both groups. Obese participants showed higher values for all the regions, with the exception of medial rearfoot area, for which the values were similar between the two groups. The analysis of foot-type distribution displayed that in the obese group high percentage of participants presented flat foot (70%) respect to cavus foot (20%) and normal foot (10%); on the contrary, in the control group, foot-types were markedly different, with 25% of participants with flat foot, 25% with cavus foot and 50% with normal foot. These results are important from a clinical perspective to develop and enhance the rehabilitative options in these patients and to avoid a worsening of their foot abnormalities. Untreated flat foot can in fact be disabling and over time can result in significant difficulties for the patient.

  7. Effects of Balance Training on Postural Sway, Leg Extensor Strength, and Jumping Height in Adolescents

    ERIC Educational Resources Information Center

    Granacher, Urs; Gollhofer, Albert; Kriemler, Susi

    2010-01-01

    Deficits in strength of the lower extremities and postural control have been associated with a high risk of sustaining sport-related injuries. Such injuries often occur during physical education (PE) classes and mostly affect the lower extremities. Thus, the objectives of this study were to investigate the effects of balance training on postural…

  8. The Effect of Somatosensory and Cognitive-motor Tasks on the Paretic Leg of Chronic Stroke Patients in the Standing Posture

    PubMed Central

    Ju, Sung-kwang; Yoo, Won-gyu

    2014-01-01

    [Purpose] The purpose of this study was to investigate how different standing surfaces alter somatosensory input and how postural control is affected by these changes during the performance of a dual task with a cognitive-motor aspect. [Subjects] The subjects were 20 chronic stroke patients: 18 males, 2 females. [Methods] COP total distance, sway velocity, and the weight load on the paretic leg were measured while subjects performed the following three tasks (somatosensory task, cognitive-motor task, and dual task). [Results] Both COP total distance and sway velocity significantly decreased during the performance of all tasks. COP total distance and sway velocity significantly decreased during the somatosensory task and the dual task. The weight load significantly increased during performance of the somatosensory task and the dual task. [Conclusion] Compensatory mechanisms in the non-paretic leg were limited by placing it on an air cushion, and we observed an increase in somatosensory input from the paretic leg due to an enhanced weight load. PMID:25540484

  9. The effect of foot orthoses on standing foot posture and gait of young children with Down syndrome.

    PubMed

    Selby-Silverstein, L; Hillstrom, H J; Palisano, R J

    2001-01-01

    The purpose of this study was to determine if foot orthoses (FOs) immediately affected gait of children with Down Syndrome (DS) and excessively pronated feet. Subjects were 3--6 years old; 16 with DS and 10 without disabilities. Gait of children with DS wearing sneakers was compared with and without FOs and compared to gait of children without disabilities. Ankle moment, walking speed during stance phase, sneaker prints, center of pressure, and transverse plane foot angles were collected and compared. In standing, heel eversion was reduced when the children wore FOs (p=0.000). During gait the transverse plane foot angle decreased indicating more internal rotation with FOs (p=0.000). Trial-to-trial variability of pronation-supination index (p=0.0001), foot length contact (p=0.0001), transverse plane foot angle (p=0.0003), and walking speed (p=0.0001) all decreased with FO use. Trial-to-trial variability of normalized peak ankle moment (p=0.0001), and of phase of peak ankle moment (p=0.0001) increased when the children wore FOs.

  10. Comparison of Standing Posture Bioelectrical Impedance Analysis with DXA for Body Composition in a Large, Healthy Chinese Population

    PubMed Central

    Chen, Kuen-Tsann; Chen, Yu-Yawn; Wang, Chia-Wei; Chuang, Chih-Lin; Chiang, Li-Ming; Lai, Chung-Liang; Lu, Hsueh-Kuan; Dwyer, Gregory B.; Chao, Shu-Ping; Shih, Ming-Kuei; Hsieh, Kuen-Chang

    2016-01-01

    Bioelectrical impedance analysis (BIA) is a common method for assessing body composition in research and clinical trials. BIA is convenient but when compared with other reference methods, the results have been inconclusive. The level of obesity degree in subjects is considered to be an important factor affecting the accuracy of the measurements. A total of 711 participants were recruited in Taiwan and were sub-grouped by gender and levels of adiposity. Regression analysis and Bland-Altman analysis were used to evaluate the agreement of the measured body fat percentage (BF%) between BIA and DXA. The BF% measured by the DXA and BIA methods (Tanita BC-418) were expressed as BF%DXA and BF%BIA8, respectively. A one-way ANOVA was used to test the differences in BF% measurements by gender and levels of adiposity. The estimated BF%BIA8 and BF%DXA in the all subjects, male and female groups were all highly correlated (r = 0.934, 0.901, 0.916, all P< 0.001). The average estimated BF%BIA8 (22.54 ± 9.48%) was significantly lower than the average BF%DXA (26.26 ± 11.18%). The BF%BIA8 was overestimated in the male subgroup (BF%DXA< 15%), compared to BF%DXA by 0.45%, respectively. In the other subgroups, the BF%BIA8 values were all underestimated. Standing BIA estimating body fat percentage in Chinese participants have a high correlation, but underestimated on normal and high obesity degree in both male and female subjects. PMID:27467065

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

    PubMed Central

    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. PMID:26583151

  12. 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.

  13. Influence of pelvic asymmetry and idiopathic scoliosis in adolescents on postural balance during sitting.

    PubMed

    Jung, Ji-Yong; Cha, Eun-Jong; Kim, Kyung-Ah; Won, Yonggwan; Bok, Soo-Kyung; Kim, Bong-Ok; Kim, Jung-Ja

    2015-01-01

    The effects of pelvic asymmetry and idiopathic scoliosis on postural balance during sitting were studied by measuring inclination angles, pressure distribution, and electromyography. Participants were classified into a control group, pelvic asymmetry group, scoliosis group, and scoliosis with pelvic asymmetry and then performed anterior, posterior, left, and right pelvic tilting while sitting on the unstable board for 5 seconds to assess their postural balance. Inclination and obliquity angles between the groups were measured by an accelerometer located on the unstable board. Pressure distribution (maximum force and peak pressure) was analyzed using a capacitive seat sensor. In addition, surface electrodes were attached to the abdominal and erector spinae muscles of each participant. Inclination and obliquity angles increased more asymmetrically in participants with both pelvic asymmetry and scoliosis than with pelvic asymmetry or scoliosis alone. Maximum forces and peak pressures of each group showed an asymmetrical pressure distribution caused by the difference in height between the left and right pelvis and curve type of the patients' spines when performing anterior, posterior, left, and right pelvic tilting while sitting. Muscle contraction patterns of external oblique, thoracic erector spinae, lumbar erector spinae, and lumbar multifidus muscles may be influenced by spine curve type and region of idiopathic scoliosis. Asymmetrical muscle activities were observed on the convex side of scoliotic patients and these muscle activity patterns were changed by the pelvic asymmetry. From these results, it was confirmed that pelvic asymmetry and idiopathic scoliosis cause postural asymmetry, unequal weight distribution, and muscular imbalance during sitting.

  14. Perception-Action and Adaptation in Postural Control of Children and Adolescents with Cerebral Palsy

    ERIC Educational Resources Information Center

    Barela, Jose A.; Focks, Grietje M. Jaspers; Hilgeholt, Toke; Barela, Ana M. F.; Carvalho, Raquel de P.; Savelsbergh, Geert J. P.

    2011-01-01

    The aim of this study was to examine the coupling between visual information and body sway and the adaptation in this coupling of individuals with cerebral palsy (CP). Fifteen children with and 15 without CP, 6-15 years old, were required to stand upright inside of a moving room. All children first performed two trials with no movement of the room…

  15. 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…

  16. Anticipatory control of center of mass and joint stability during voluntary arm movement from a standing posture: interplay between active and passive control.

    PubMed

    Patla, Aftab E; Ishac, Milad G; Winter, David A

    2002-04-01

    Anticipatory control of upright posture is the focus of this study that combines experimental and modeling work. Individuals were asked to raise or lower their arms from two initial postures such that the final posture of the arm was at 90 degrees with respect to the body. Holding different weights in the hand varied the magnitude of perturbation to postural stability generated by the arm movement. Whole body kinematics and ground reaction forces were measured. Inverse dynamic analysis was used to determine the internal joint moments at the shoulder, hip, knee and ankle, and reaction forces at the shoulder. Center of mass (COM) of the arm, posture (rest of the body without the arms) and whole body (net COM) were also determined. Changes in joint moment at the hip, knee and ankle revealed a significant effect of the direction of movement. The polarities of the joint moment response were appropriate for joint stabilization. Net COM change showed a systematic effect of the direction of movement even though the arm COM was displaced by the same amount and in the same direction for both arm raising and lowering conditions. In order to determine the effects of the passive forces and moments on the posture COM, the body was modeled as an inverted pendulum. The model was customized for each participant; the relevant model parameters were estimated from data obtained from each trial. The ankle joint stiffness and viscosity were adjusted to ensure postural equilibrium prior to arm movement. Joint reactive forces and moments generated by the arm movements were applied at the shoulder level of this inverted pendulum; these were the only inputs and no active control was included. The posture COM profile from the model simulation was calculated. Results show that simulated posture COM profile and measured posture COM profile are identical for about 200 ms following the onset of arm movement and then they deviate. Therefore, the initial control of COM is passive in nature and the

  17. Early Adolescents' Social Standing in Peer Groups: Behavioral Correlates of Stability and Change

    ERIC Educational Resources Information Center

    Lansford, Jennifer E.; Killeya-Jones, Ley A.; Miller, Shari; Costanzo, Philip R.

    2009-01-01

    Sociometric nominations, social cognitive maps, and self-report questionnaires were completed in consecutive years by 327 students (56% girls) followed longitudinally from grade 7 to grade 8 to examine the stability of social standing in peer groups and correlates of changes in social standing. Social preference, perceived popularity, network…

  18. Relationships between Task-Oriented Postural Control and Motor Ability in Children and Adolescents with Down Syndrome

    ERIC Educational Resources Information Center

    Wang, Hui-Yi; Long, I-Man; Liu, Mei-Fang

    2012-01-01

    Individuals with Down syndrome (DS) have been characterized by greater postural sway in quiet stance and insufficient motor ability. However, there is a lack of studies to explore the properties of dynamic postural sway, especially under conditions of task-oriented movement. The purpose of this study was to investigate the relationships between…

  19. Reliability of upright posture measurements in primary school children

    PubMed Central

    McEvoy, Maureen P; Grimmer, Karen

    2005-01-01

    Background Correct upright posture is considered to be a measure of good musculoskeletal health. Little is known about the usual variability of children's upright standing posture. The aim of this study was to assess differences between repeated measures of upright posture in a group of primary school children. Methods Sagittal plane photographs of usual, relaxed upright standing posture of 38 boys and girls aged 5–12 years were taken twice within an hour. Reflective markers were placed over the canthus, tragus, C7 spinous process, greater trochanter and lateral malleolus. Digitising software was used to calculate the x,y plane coordinates, from which five postural angles were calculated (trunk, neck, gaze, head on neck, lower limb). Height, weight, motor control estimates (as measured by the Brace Tests) and presence of recent pain were recorded for each child, and the association between the first test measure of posture angles and these factors was assessed using linear regression and ANOVA models. Multiple ANOVA models were applied to analyse the effect of repeated testing, and significant predictors on the angles. Results Four of the five postural angles (trunk, neck, head on neck, lower limb) were significantly influenced by age. As age was strongly associated with height (r2 = 0.84) and moderately associated with weight and motor control (r2 = 0.67, 0.56 respectively), these developmental parameters may well explain the age effect on angles. There was no relationship between age and pain reported on either the testing day, or recently, and there was no gender influence on any angle. There was no significant effect of repeated testing on any angle (ICC>0.93). None of the hypothesized predictors were associated with differences in angles from repeated testing. Conclusion This study outlined the variability of relaxed upright standing posture of children aged 5–12 years, when measured twice in an hour. Age influenced the size of the angles but not the

  20. Perception-action and adaptation in postural control of children and adolescents with cerebral palsy.

    PubMed

    Barela, José A; Focks, Grietje M Jaspers; Hilgeholt, Toke; Barela, Ana M F; Carvalho, Raquel de P; Savelsbergh, Geert J P

    2011-01-01

    The aim of this study was to examine the coupling between visual information and body sway and the adaptation in this coupling of individuals with cerebral palsy (CP). Fifteen children with and 15 without CP, 6-15 years old, were required to stand upright inside of a moving room. All children first performed two trials with no movement of the room and eyes open or closed, then four trials in which the room oscillated at 0.2 or 0.5 Hz (peak velocity of 0.6 cm/s), one trial in which the room oscillated at 0.2 Hz (peak velocity of 3.5 cm/s), and finally two other trials in which the room oscillated again at 0.2 Hz (peak velocity of 0.6 cm/s). Participants with CP coupled body sway to visual information provided by the moving room, comparable to the coupling of participants without CP. However, participants with CP exhibited larger body sway in maintaining upright position and more variable sway when body sway was induced by visual manipulation. They showed adaptive sensory motor coupling, e.g. down-weighting visual influence when a larger stimulus was provided, but not with the same magnitude as typically developing participants. This indicates that participants with CP have less capability of adaptation.

  1. Effects of rehabilitative horse riding on the Sit-to-Stand action of the adolescent with brain lesions

    PubMed Central

    Lee, Jang Won; Han, A-reum; Kim, Kihong

    2014-01-01

    The purpose of this study was to investigate the balance abilities of the adolescent girl with brain lesions by Sit-to-Stand (STS) action analysis before and after the rehabilitative horse riding of 16 week program. The subject aged 16 yr old who had the disabilities of spasticity and hemiplegia was recruited with the consent approval. The equilibrium abilities of the subject were tested by Sit-to-Stand examination with Weight Transfer Time (WTT), Mean Rising Index (MRI), Mean Weight Asymmetry (MWA), Max Trunk Flexion Velocity (MTFV), and Max Trunk Extension Velocity (MTEV). Research was designed by AB single subject study with baseline of 3 times of measurement and rehabilitative horse riding treatments. In the results, the enhancement of the subject’s equilibrium ability was shown from the comparisons between baseline and treatment by the STS test that WTT was 2.37 sec faster, MRI was 6.64 N/kg higher, and MWA was 8.12% lower, and MTFV was 0.57°/sec larger than all those means of baseline. It suggested that the subject showed her enhanced balance ability while in sitting and standing after the rehabilitative horse riding treatments. PMID:24678502

  2. "A Chance to Stand Back": Parenting Programmes for Parents of Adolescents

    ERIC Educational Resources Information Center

    Clarke, Karen; Churchill, Harriet

    2012-01-01

    Parenting interventions were an important feature of New Labour's policies to combat social exclusion. This paper critically examines parenting programmes for families with adolescents, assessing national and local policy aims against the perspectives of women who took part in a parenting course, which was the subject of a local evaluation. The…

  3. Deficits in anticipatory inhibition of postural muscle activity associated with load release while standing in individuals with spastic diplegic cerebral palsy.

    PubMed

    Tomita, Hidehito; Fukaya, Yoshiki; Totsuka, Kenji; Tsukahara, Yuri

    2013-04-01

    This study aimed to determine whether individuals with spastic diplegic cerebral palsy (SDCP) have deficits in anticipatory inhibition of postural muscle activity. Nine individuals with SDCP (SDCP group, 3 female and 6 male, 13-24 yr of age) and nine age- and sex-matched individuals without disability (control group) participated in this study. Participants stood on a force platform, which was used to measure the position of the center of pressure (CoP), while holding a light or heavy load in front of their bodies. They then released the load by abducting both shoulders. Surface electromyograms were recorded from the rectus abdominis, erector spinae (ES), rectus femoris (RF), medial hamstring (MH), tibialis anterior (TA), and gastrocnemius (GcM) muscles. In the control group, anticipatory inhibition before load release and load-related modulation of the inhibition were observed in all the dorsal muscles recorded (ES, MH, and GcM). In the SDCP group, similar results were obtained in the trunk muscle (ES) but not in the lower limb muscles (MH and GcM), although individual differences were seen, especially in MH. Anticipatory activation of the ventral lower limb muscles (RF and TA) and load-related modulation of the activation were observed in both participant groups. CoP path length during load release was longer in the SDCP group than in the control group. The present findings suggest that individuals with SDCP exhibit deficits in anticipatory inhibition of postural muscles at the dorsal part of the lower limbs, which is likely to result in a larger disturbance of postural equilibrium.

  4. Correlation between rounded shoulder posture, neck disability indices, and degree of forward head posture

    PubMed Central

    Kim, Eun-Kyung; Kim, Jin Seop

    2016-01-01

    [Purpose] The present study aimed to examine the correlation between rounded shoulder posture, neck disability indices and the degree of forward head posture. [Subjects and Methods] Subjects aged 19–24 years were selected for this study, and the craniovertebral angle was used to measure the degree of forward head posture in the standing and seated positions. Vernier calipers were used to measure rounded shoulder posture in the supine position, and neck pain and functional disability were assessed using neck disability indices. [Results] Angle and neck disability indices in both standing and sitting posture positions exhibited a significant inverse relationship. However, no significant correlation was detected between the craniovertebral angle and rounded shoulder posture for the standing and sitting posture positions. [Conclusion] In conclusion, it was demonstrated in the present study that, depending on the degree of forward head posture, changes were detected in the neck disability indices. However, even an increase in the forward head tilt angle did not lead to rounded shoulder posture. Therefore, maintaining proper posture may prevent postural pain syndrome, functional disability, and postural deformity. PMID:27821964

  5. Sagittal Spinal Morphology in Highly Trained Adolescent Tennis Players

    PubMed Central

    Muyor, José M.; Sánchez-Sánchez, Estefanía; Sanz-Rivas, David; López-Miñarro, Pedro A.

    2013-01-01

    Sports with a predominance of forward-bending and extension postures have been associated with alterations in the sagittal spinal curvatures and greater risk of spinal injury. Because, the tennis players adopt these postures, the aims of this study were: 1) to describe spinal curvatures and pelvic tilt in male and female highly trained adolescent tennis players during relaxed standing posture and with thoracic spine corrected (in prone lying on the floor); and 2) to determine the frequency of thoracic hyperkyphosis and lumbar hypo/hyper lordosis in these postures. Forty adolescent tennis players (24 male and 16 female) aged 13-18 years, participated voluntarily in this study. The Spinal Mouse system was used to measure sagittal spinal curvatures and pelvic tilt. The mean values in the relaxed standing posture were 43.83° ± 7.87° (thoracic kyphosis), - 27.58° ± 7.01° (lumbar lordosis), and 13.38° ± 5.57° (pelvic tilt) for male tennis players, respectively; and 36.13° ± 6.69° (thoracic kyphosis), - 32.69° ± 5.06° (lumbar lordosis), 20.94° ± 5.36° (pelvic tilt) for female tennis players (p < 0.05 between genders in all spinal parameters). The male and female tennis players showed a frequency of 62.5% and 93.8% (p = 0.032) for neutral thoracic kyphosis, and 83.3% and 93.8% (p = 0.062) in neutral lumbar lordosis, respectively. In conclusion, due to the high percentage of neutral spinal curvatures in both male and female tennis players, to practice tennis in these levels does not alter sagittal spinal morphology in the relaxed standing posture in adolescent highly trained tennis players. Key Points This study evaluated thoracic and lumbar spinal curvatures and pelvic tilt during several postures in young highly trained tennis players. Female tennis players showed statistically significant greater anterior pelvic tilt, lumbar lordosis and lower thoracic kyphosis than male tennis players. The high percentage of neutral thoracic kyphosis and lumbar

  6. 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)

  7. An effect of posture on anticipatory anxiety.

    PubMed

    Lipnicki, Darren M; Byrne, Don G

    2008-02-01

    This study investigated the effects of body posture on state anxiety and psychological stress. Twenty normal adults performed a demanding mental arithmetic task in both standing and supine conditions, with subjective measures of anxiety and stress obtained before, immediately, and 10 min after the task. Participants were found to experience anticipatory anxiety when standing, although not when supine. The mechanism underlying this effect remains to be determined, although it could involve a postural difference in baroreceptor load.

  8. The effect of asymmetry of posture on anticipatory postural adjustments.

    PubMed

    Aruin, Alexander S

    2006-06-19

    The study investigates the effect of body asymmetry on anticipatory postural adjustments (APAs). Subjects performed a task involving a standard load release induced by a shoulder abduction movement while standing symmetrically or in an asymmetrical stance with either their right or left leg in 45 degrees of external rotation. EMG activities of trunk and leg muscles were recorded during the postural perturbation and were quantified within the time intervals typical of APAs. Anticipatory postural adjustments were observed in all experimental conditions. It was found that asymmetrical body positioning was associated with significant asymmetrical patterns of APAs seen in the right and left distal muscles. These APA asymmetries were dependant upon the side in which the body asymmetry was induced: reduced APAs were observed in the leg muscles on the side of leg rotation, while increased APAs were seen in the muscles on the contralateral side. These findings stress the important role that body asymmetries play in the control of upright posture.

  9. 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.

  10. A model of postural control in quiet standing: robust compensation of delay-induced instability using intermittent activation of feedback control.

    PubMed

    Asai, Yoshiyuki; Tasaka, Yuichi; Nomura, Kunihiko; Nomura, Taishin; Casadio, Maura; Morasso, Pietro

    2009-07-08

    The main purpose of this study is to compare two different feedback controllers for the stabilization of quiet standing in humans, taking into account that the intrinsic ankle stiffness is insufficient and that there is a large delay inducing instability in the feedback loop: 1) a standard linear, continuous-time PD controller and 2) an intermittent PD controller characterized by a switching function defined in the phase plane, with or without a dead zone around the nominal equilibrium state. The stability analysis of the first controller is carried out by using the standard tools of linear control systems, whereas the analysis of the intermittent controllers is based on the use of Poincaré maps defined in the phase plane. When the PD-control is off, the dynamics of the system is characterized by a saddle-like equilibrium, with a stable and an unstable manifold. The switching function of the intermittent controller is implemented in such a way that PD-control is 'off' when the state vector is near the stable manifold of the saddle and is 'on' otherwise. A theoretical analysis and a related simulation study show that the intermittent control model is much more robust than the standard model because the size of the region in the parameter space of the feedback control gains (P vs. D) that characterizes stable behavior is much larger in the latter case than in the former one. Moreover, the intermittent controller can use feedback parameters that are much smaller than the standard model. Typical sway patterns generated by the intermittent controller are the result of an alternation between slow motion along the stable manifold of the saddle, when the PD-control is off, and spiral motion away from the upright equilibrium determined by the activation of the PD-control with low feedback gains. Remarkably, overall dynamic stability can be achieved by combining in a smart way two unstable regimes: a saddle and an unstable spiral. The intermittent controller exploits the

  11. 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.

  12. Coupling of postural and manual tasks in expert performers.

    PubMed

    Amado, A C; Palmer, C J; Hamill, J; van Emmerik, R E A

    2016-04-01

    The purpose of this study was to investigate the integration of bimanual rhythmic movements and posture in expert marching percussionists. Participants (N=11) performed three rhythmic manual tasks [1:1, 2:3, and 2:3-F (2:3 rhythm played faster at a self-selected tempo)] in one of three postures: sitting, standing on one foot, and standing on two feet. Discrete relative phase, postural time-to-contact, and coherence analysis were used to analyze the performance of the manual task, postural control, and the integration between postural and manual performance. Across all three rhythms, discrete relative phase mean and variability results showed no effects of posture on rhythmic performance. The complexity of the manual task (1:1 vs. 2:3) had no effect on postural time-to-contact. However, increasing the tempo of the manual task (2:3 vs. 2:3-F) did result in a decreased postural time-to-contact in the two-footed posture. Coherence analysis revealed that the coupling between the postural and manual task significantly decreased as a function of postural difficulty (going from a two-footed to a one-footed posture) and rhythmic complexity (1:1 vs. 2:3). Taken together, these results demonstrate that expert marching percussionists systematically decouple postural and manual fluctuations in order to preserve the performance of the rhythmic movement task.

  13. Use of an allostatic neurotechnology by adolescents with postural orthostatic tachycardia syndrome (POTS) is associated with improvements in heart rate variability and changes in temporal lobe electrical activity.

    PubMed

    Fortunato, John E; Tegeler, Catherine L; Gerdes, Lee; Lee, Sung W; Pajewski, Nicholas M; Franco, Meghan E; Cook, Jared F; Shaltout, Hossam A; Tegeler, Charles H

    2016-03-01

    Autonomic dysregulation and heterogeneous symptoms characterize postural orthostatic tachycardia syndrome (POTS). This study evaluated the effect of high-resolution, relational, resonance-based, electroencephalic mirroring (HIRREM(®)), a noninvasive, allostatic neurotechnology for relaxation and auto-calibration of neural oscillations, on heart rate variability, brain asymmetry, and autonomic symptoms, in adolescents with POTS. Seven subjects with POTS (three males, ages 15-18) underwent a median of 14 (10-16) HIRREM sessions over 13 (8-17) days. Autonomic function was assessed from 10-min continuous heart rate and blood pressure recordings, pre- and post-HIRREM. One-minute epochs of temporal high-frequency (23-36 Hz) brain electrical activity data (T3 and T4, eyes closed) were analyzed from baseline HIRREM assessment and subsequent sessions. Subjects rated autonomic symptoms before and after HIRREM. Four of seven were on fludrocortisone, which was stopped before or during their sessions. Heart rate variability in the time domain (standard deviation of the beat-to-beat interval) increased post-HIRREM (mean increase 51%, range 10-143, p = 0.03), as did baroreflex sensitivity (mean increase in high-frequency alpha 65%, range -6 to 180, p = 0.05). Baseline temporal electrical asymmetry negatively correlated with change in asymmetry from assessment to the final HIRREM session (p = 0.01). Summed high-frequency amplitudes at left and right temporal lobes decreased a median of 3.8 μV (p = 0.02). There was a trend for improvements in self-reported symptoms related to the autonomic nervous system. Use of HIRREM was associated with reduced sympathetic bias in autonomic cardiovascular regulation, greater symmetry and reduced amplitudes in temporal lobe high-frequency electrical activity, and a trend for reduced autonomic symptoms. Data suggest the potential for allostatic neurotechnology to facilitate increased flexibility in autonomic cardiovascular regulation, possibly

  14. 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.

  15. Transfer of dynamic learning across postures.

    PubMed

    Ahmed, Alaa A; Wolpert, Daniel M

    2009-11-01

    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.

  16. 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

  17. Postural behavior in children born preterm.

    PubMed

    Fallang, Bjørg; Hadders-Algra, Mijna

    2005-01-01

    The present paper presents clinical and neurophysiological data of postural behavior in preterm children without CP. Clinical follow-up studies of preterm infants until toddler and school age have reported that low-risk preterm infants may have atypical postural behavior in terms of reduced amount of rotation during crawling, delayed dynamic balance, delayed onset of and a poor quality of early walking behavior. At school age, dysfunctions such as problems in standing on one leg and poor hopping are reported. Neurophysiological data of postural control at early age indicated the presence of a dysfunction in the capacity to modulate postural activity, and the postural activity has been characterized by temporal disorganization of EMG responses. Postural responses to goal-directed reaching in supine lying have been recorded and analyzed in terms of the total body center of pressure. In this study, preterm infants show less mobile postural behavior compared with full-term infants. In infancy, the less mobile postural behavior seemed to be adequate as it was related to better goal-directed reaching quality, but the results indicated that the relatively immobile postural behavior during reaching in early age was related to less favorable neuromotor behavior in school-age.

  18. Impaired Synergic Control of Posture in Parkinson’s Patients without Postural Instability

    PubMed Central

    Falaki, Ali; Huang, Xuemei; Lewis, Mechelle M.; Latash, Mark L.

    2015-01-01

    Background Postural instability is one of most disabling motor symptoms in Parkinson’s disease. Indices of multi-muscle synergies are new measurements of movement and postural stability. Objectives Multi-muscle synergies stabilizing vertical posture were studied in Parkinson’s disease patients without clinical symptoms of postural instability (Hoehn-Yahr- ≤ II) and age-matched controls. We tested the hypothesis that both synergy indices during quiet standing and synergy adjustments to self-triggered postural perturbations would be reduced in patients. Methods Eleven Parkinson’s disease patients and 11 controls performed whole-body tasks while standing. Surface electromyography was used to quantify synergy indices stabilizing center of pressure shifts in the anterior-posterior direction during a load-release task. Results Parkinson’s disease patients showed a significantly lower percentage of variance in the muscle activation space accounted for by the first four principal components, significantly reduced synergy indices during steady state, and significantly reduced anticipatory synergy adjustments (a drop in the synergy index prior to the self-triggered unloading). Conclusions The study demonstrates for the first time that impaired synergic control in Parkinson’s disease can be quantified in postural tasks, even in patients without clinical manifestations of postural instability. Synergy measurements may provide a biomarker sensitive for early problems with postural stability in Parkinson’s disease. PMID:27004660

  19. 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.…

  20. 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.…

  1. Standing between Two Worlds in Harlem: A Developmental Psychopathology Perspective of Perinatally Acquired Human Immunodeficiency Virus and Adolescence

    ERIC Educational Resources Information Center

    Kang, Ezer; Mellins, Claude Ann; Ng, Warren Yiu Kee; Robinson, Lisa-Gaye; Abrams, Elaine J.

    2008-01-01

    Perinatal HIV infection in the US continues to evolve from a fatal pediatric illness to a chronic medical condition of childhood and adolescence. Although navigating this period is influenced by multi-leveled deprivations commonly experienced by low-income minority families, HIV alters the timing and experience of developmental milestones for many…

  2. Determining postural stability

    NASA Technical Reports Server (NTRS)

    Lieberman, Erez (Inventor); Forth, Katharine E. (Inventor); Paloski, William H. (Inventor)

    2011-01-01

    A method for determining postural stability of a person can include acquiring a plurality of pressure data points over a period of time from at least one pressure sensor. The method can also include the step of identifying a postural state for each pressure data point to generate a plurality of postural states. The method can include the step of determining a postural state of the person at a point in time based on at least the plurality of postural states.

  3. Posture Training for Special Needs Students.

    ERIC Educational Resources Information Center

    James, Terrance N.; And Others

    1986-01-01

    Educable mentally handicapped adolescents with and without additional health problems (N=24) participated in a three-month fitness intervention program. Pre- and post-measures revealed a high incidence of poor posture in both groups. Related topics discussed include subsequent biomechanical interventions, subjective symptomatology, and the need…

  4. 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.

  5. 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.

  6. Relationship between Postural Sway and Dynamic Balance in Stroke Patients.

    PubMed

    Cho, Kihun; Lee, Kyoungsuk; Lee, Byungjoon; Lee, Hwangjae; Lee, Wanhee

    2014-12-01

    [Purpose] The purpose of the current study was to investigate the relationship between postural sway and dynamic balance in post stroke patients. [Subjects] Thirty-one stroke patients (20 men and 11 women; age 64.25 years; stroke duration 12.70 months; MMSE-K score 26.35) participated in this study. [Methods] This study applied a cross-sectional design. A Good Balance system was used for measurement of the postural sway velocity (anteroposterior and mediolateral) and velocity moment of subjects under the eyes open and eyes closed conditions in a standing posture. The postural sway of subjects was measured under two surface conditions (stable and unstable surfaces). [Results] On the unstable surface (foam), no significant correlation was observed between postural sway and dynamic balance except for the berg balance scale (BBS) score and anteroposterior postural sway velocity under the eyes open condition, anteroposterior postural sway velocity under the eyes closed condition, and postural sway velocity moment. In addition, in the stable condition, no significant correlation was observed between postural sway and dynamic balance. [Conclusion] Our results indicate that a decrease in postural sway does not necessarily reflect improvement of dynamic balance ability. We believe that this finding may be useful in balance rehabilitation for prevention of falls after a stroke.

  7. Postural Control in Man: The Phylogenetic Perspective

    PubMed Central

    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 phyiogenetic 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. PMID:16097476

  8. [Risks of awkward posture].

    PubMed

    Bazzini, G; Capodaglio, E; Panigazzi, M; Prestifilippo, E; Vercesi, C

    2010-01-01

    For posture we mean the position of the body in the space and the relationship with its segments. The correct posture is determined by neurophysiological, biomechanical, emotional, psychological and relation factors, enabling us to perform daily and working activities with the lowest energy expenditure. When possible we suggest during posture variation, a preventive measure where there are prolonged fixed activities.

  9. Postural orthostatic tachycardia syndrome (POTS).

    PubMed

    Sidhu, Bharat; Obiechina, Nonyelum; Rattu, Noman; Mitra, Shanta

    2013-09-16

    Postural orthostatic tachycardia syndrome (POTS) is a heterogeneous group of conditions characterised by autonomic dysfunction and an exaggerated sympathetic response to assuming an upright position. Up till recently, it was largely under-recognised as a clinical entity. There is now consensus about the definition of POTS as a greater than 30/min heart rate increase on standing from a supine position (greater than 40/min increase in 12-19-year-old patients) or an absolute heart rate of greater than 120/min within 10 min of standing from a supine position and in the absence of hypotension, arrhythmias, sympathomimetic drugs or other conditions that cause tachycardia. We present two cases of POTS, followed by a discussion of its pathogenesis, pathophysiology, epidemiology and management.

  10. 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

  11. Clinical evaluation of a new biofeedback standing balance training device.

    PubMed

    Lee, M Y; Wong, M K; Tang, F T

    1996-01-01

    For patients with neurological damage of the central nervous system, such as that due to cerebrovascular accident (CVA), standing balance training is a critical therapeutic procedure to be undertaken before walking and self-care training. The identification and characterization of neurological disorder in postural steadiness will enhance our understanding of the postural control system, and help to identify patients at risk of falls in the CVA population. This paper discusses the design and clinical evaluation of a new biofeedback training device for static (postural steadiness) performance of the standing balance system. The device includes a height adjustable standing table, an instrumented force sensing platform, an on-line weight bearing audio/visual biofeedback system, a postural correction mirror, and a belt suspension system for the upper extremities. A quantitative evaluation protocol of bilateral asymmetries in weight distribution and postural sway to characterize standing balance with the force sensing platform is discussed. Finally, the clinical evaluation results of sixty patients with hemiplegia from acute stroke for a period of four weeks are discussed. With this economic standing training device, the static standing steadiness can be trained effectively through weight bearing biofeedback and a postural correction mirror in the clinical and home caring environments.

  12. Transfer of postural adaptation depends on context of prior exposure.

    PubMed

    Pienciak-Siewert, Alison; Barletta, Anthony J; Ahmed, Alaa A

    2014-04-01

    Postural control is significantly affected by the postural base of support; however, the effects on postural adaptation are not well understood. Here we investigated how adaptation and transfer of anticipatory postural control are affected by stance width. Subjects made reaching movements in a novel dynamic environment while holding the handle of a force-generating robotic arm. Each subject initially adapted to the dynamics while standing in a wide stance and then switched to a narrow stance, or vice versa. Our hypothesis is that anticipatory postural control, reflected in center of pressure (COP) movement, is not affected by stance width, as long as the control remains within functional limits; therefore we predicted that subjects in either stance would show similar COP movement by the end of adaptation and immediately upon transfer to the other stance. We found that both groups showed similar adaptation of postural control, by using different muscle activation strategies to account for the differing stance widths. One group, after adapting in wide stance, transferred similar postural control to narrow stance, by modifying their muscle activity to account for the new stance. Interestingly, the other group showed an increase in postural control when transferring from narrow to wide stance, associated with no change in muscle activity. These results confirm that adaptation of anticipatory postural control is not affected by stance width, as long as the control remains within biomechanical limits. However, transfer of control between stance widths is affected by the initial context in which the task is learned.

  13. 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.

  14. The role of anticipatory postural adjustments in compensatory control of posture: 1. Electromyographic analysis.

    PubMed

    Santos, Marcio J; Kanekar, Neeta; Aruin, Alexander S

    2010-06-01

    Anticipatory (APAs) and compensatory (CPAs) postural adjustments are the two principal mechanisms that the central nervous system uses to maintain equilibrium while standing. We studied the role of APAs in compensatory postural adjustments. Eight subjects were exposed to external predictable and unpredictable perturbations induced at the shoulder level, while standing with eyes open and closed. Electrical activity of leg and trunk muscles was recorded and analyzed during four epochs representing the time duration typical for anticipatory and compensatory postural control. No anticipatory activity of the trunk and leg muscles was seen in the case of unpredictable perturbations; instead, significant compensatory activation of muscles was observed. When the perturbations were predictable, strong anticipatory activation was seen in all the muscles: such APAs were associated with significantly smaller compensatory activity of muscles and COP displacements after the perturbations. The outcome of the study highlights the importance of APAs in control of posture and points out the existence of a relationship between the anticipatory and the compensatory components of postural control. It also suggests a possibility to enhance balance control by improving the APAs responses during external perturbations.

  15. Can Smartwatches Replace Smartphones for Posture Tracking?

    PubMed Central

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

    2015-01-01

    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. PMID:26506354

  16. 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.

  17. Take a Stand for Standing

    ERIC Educational Resources Information Center

    Labandz, Stephenie

    2010-01-01

    As a school-based physical therapist, the author sees children with a wide variety of diagnoses affecting their mobility and motor function. Supported standing is an important part of the routines of those who are unable to stand independently due to issues affecting the neuromuscular system. Being eye-to-eye with their peers and interacting with…

  18. 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.

  19. [Pyridostigmine in the treatment of postural orthostatic tachycardia syndrome].

    PubMed

    Can, Ilknur; Tholakanahalli, Venkatakrishna

    2014-09-01

    A 34-year-old female patient was admitted with the complaints of inability to stand upright, palpitations, dizziness, and fatigue in the upright posture for the last one year. She was found to stand upright for less than one minute without symptoms. Tilt table testing showed that, compared to baseline her heart rate increased 55 beats/min in the fifth minute of the test with the symptoms of palpitations, fatigue and sweating without any significant change in her blood pressure. Postural orthostatic tachycardia syndrome was diagnosed, and pyridostigmine treatment was started. Four months after treatment her symptoms were relieved so that she was able to function as a nurse.

  20. Oculomotor tasks affect differently postural control in healthy children.

    PubMed

    Bucci, Maria Pia; Ajrezo, Layla; Wiener-Vacher, Sylvette

    2015-11-01

    Eye movements affect postural stability in children. The present study focuses on the effect of different types of eye movements on postural stability in healthy children. Both eye movements and postural stability have been recorded in 51 healthy children from 6.3 to 15.5 years old. Eye movements were recorded binocularly with a video oculography (MobilEBT(®)), and postural stability was measured while child was standing on a force platform (TechnoConcept(®)). Children performed three oculomotor tasks: saccades, pursuits and reading a text silently. We measured the number of saccades made in the three oculomotor tasks, the number of words read, and the surface area, the length and mean velocity of the center of pressure (CoP). According to previous studies, postural control improves with age until 10-12 years. Saccades toward a target as well as during a reading task reduce significantly the CoP displacement and its velocity, while during pursuit eye movements all children increase postural parameters (i.e., the surface area, the length and mean velocity of the CoP). These results suggest the presence of an interaction between the oculomotor control and the postural system. Visual attention to perform saccades (to stationary targets or to words) influences postural stability more than the frequency of saccade triggering does.

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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…

  6. (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…

  7. Social Postural Coordination

    ERIC Educational Resources Information Center

    Varlet, Manuel; Marin, Ludovic; Lagarde, Julien; Bardy, Benoit G.

    2011-01-01

    The goal of the current study was to investigate whether a visual coupling between two people can produce spontaneous interpersonal postural coordination and change their intrapersonal postural coordination involved in the control of stance. We examined the front-to-back head displacements of participants and the angular motion of their hip and…

  8. The relationship between dynamic balancing ability and posture-related modulation of the soleus H-reflex.

    PubMed

    Kawaishi, Yu; Domen, Kazuhisa

    2016-02-01

    Soleus H-reflex reveals down modulation with increased postural difficulty. Role of this posture-related reflex modulation is thought to shift movement control toward higher motor centers in order to facilitate more precise postural control. Present study hypothesized that the ability to modulate H-reflex is related to one's ability to dynamically balance while in an unstable posture. This study examined the relationship between dynamic balancing ability and soleus H-reflex posture-related modulation. Thirty healthy adults participated. The soleus maximal H-reflex (Hmax), motor response (Mmax), and background EMG activity (bEMG) were obtained during three postural conditions: prone, open-legged standing, and closed-legged standing. Hmax/Mmax ratios were normalized via the corresponding bEMG in order to remove the effects of background muscle activity from the obtained H-reflex. Reflex modulation was calculated as the ratio of the normalized Hmax/Mmax ratios in one postural condition to another posture in a more difficult condition. Dynamic balancing ability was assessed by testing stability while standing on a wobble board. A significant negative correlation was observed between balancing scores and reflex modulation from open-legged standing to closed-legged standing. This suggests that the ability to modulate monosynaptic stretch reflex excitability in response to a changing posture is a significant factor for dynamic balancing.

  9. Effects of temporal and spatial cueing on anticipatory postural control in a rapid interceptive task.

    PubMed

    Huntley, Andrew H; Zettel, John L

    2015-04-10

    Balance disruptions induced by voluntary focal arm actions are accommodated via anticipatory postural adjustments, but how this coordinated control is organized by the central nervous system remains unclear: either as combined or separate streams of postural-focal motor commands. For example, a focal arm task that dictates extremely tight temporal constraints may induce a focal response in absence of an anticipatory postural adjustment, providing evidence for separate focal-postural control streams. This study sought to probe the organization of focal-postural control via an interceptive task with very little available response time, and to determine whether focal-postural coordination depends on temporal and/or spatial foreknowledge of the task. Ten healthy young adults (5 males and 5 females; 20-29 years) reacted to catch a ball when standing under four conditions of temporal and spatial foreknowledge. Response onset was characterized by muscle activity from both postural and focal arm muscles. The catching task resulted in rapid muscle responses, but there was no difference between the fastest focal and postural muscle onsets. As expected, temporal cuing resulted in faster focal and postural onsets compared to spatial and control cuing trials. The accompaniment and time-locking of focal and postural muscle onsets, suggests that postural-focal coupling remains intact even under external time constraints and provides evidence for a single combined command stream of postural and focal control under such circumstances.

  10. 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…

  11. Postural dependence of human locomotion during gait initiation

    PubMed Central

    Mille, Marie-Laure; Simoneau, Martin

    2014-01-01

    The initiation of human walking involves postural motor actions for body orientation and balance stabilization that must be effectively integrated with locomotion to allow safe and efficient transport. Our ability to coordinately adapt these functions to environmental or bodily changes through error-based motor learning is essential to effective performance. Predictive compensations for postural perturbations through anticipatory postural adjustments (APAs) that stabilize mediolateral (ML) standing balance normally precede and accompany stepping. The temporal sequencing between these events may involve neural processes that suppress stepping until the expected stability conditions are achieved. If so, then an unexpected perturbation that disrupts the ML APAs should delay locomotion. This study investigated how the central nervous system (CNS) adapts posture and locomotion to perturbations of ML standing balance. Healthy human adults initiated locomotion while a resistance force was applied at the pelvis to perturb posture. In experiment 1, using random perturbations, step onset timing was delayed relative to the APA onset indicating that locomotion was withheld until expected stability conditions occurred. Furthermore, stepping parameters were adapted with the APAs indicating that motor prediction of the consequences of the postural changes likely modified the step motor command. In experiment 2, repetitive postural perturbations induced sustained locomotor aftereffects in some parameters (i.e., step height), immediate but rapidly readapted aftereffects in others, or had no aftereffects. These results indicated both rapid but transient reactive adaptations in the posture and gait assembly and more durable practice-dependent changes suggesting feedforward adaptation of locomotion in response to the prevailing postural conditions. PMID:25231611

  12. Reversible postural orthostatic tachycardia syndrome.

    PubMed

    Abdulla, Aza; Rajeevan, Thirumagal

    2015-07-16

    Postural orthostatic tachycardia syndrome (POTS) is a relatively rare syndrome recognised since 1940. It is a heterogenous condition with orthostatic intolerance due to dysautonomia and is characterised by rise in heart rate above 30 bpm from base line or to more than 120 bpm within 5-10 min of standing with or without change in blood pressure which returns to base line on resuming supine position. This condition present with various disabling symptoms such as light headedness, near syncope, fatigue, nausea, vomiting, tremor, palpitations and mental clouding, etc. However there are no identifiable signs on clinical examination and patients are often diagnosed to have anxiety disorder. The condition predominantly affects young female between the ages of 15-50 but is rarely described in older people. We describe an older patient who developed POTS which recovered over 12 mo. Recognising this condition is important as there are treatment options available to alleviate the disabling symptoms.

  13. Quantifying and Reducing Posture-Dependent Distortion in Ballistocardiogram Measurements.

    PubMed

    Javaid, Abdul Qadir; Wiens, Andrew D; Fesmire, Nathaniel Forrest; Weitnauer, Mary Ann; Inan, Omer T

    2015-09-01

    Ballistocardiography is a noninvasive 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 preejection 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 nonideal posture, as well as enabling high-quality seated BCG measurements.

  14. Integrated postural analysis in children with haemophilia.

    PubMed

    Boccalandro, E; Pasta, G; Mannucci, P M; Santagostino, E; Peyvandi, F; Seuser, A; Mancuso, M E; Solimeno, L P

    2014-03-01

    The maintenance of a correct posture in haemophilic boys might contribute to prevent joint bleeds, chronic pain and dysfunction. This single-centre study was aimed at evaluating whether or not postural alterations are more common in haemophilic than in non-haemophilic boys and whether they are related to the orthopaedic status. Posture and balance were investigated in boys with severe/moderate haemophilia (cases) and in age-matched non-haemophilic peers (controls). Thirty-five cases (89% with haemophilia A: 74% with severe disease) were included in the study and compared with 57 controls. Posture was evaluated on digital pictures of anterior, lateral and posterior views of the habitual standing position. Balance was examined with a portable force platform with eyes open and closed. The trajectory of the total body centre of force (CoF) displacement over the platform was computed by multiple planes obtaining different measures: sway area, velocity, acceleration and body loads. The joint status of cases was assessed with the Haemophilia Joint Health Score. Cases were more disharmonic than controls (52% vs. 26% in controls; P = 0.04), swayed significantly less and more slowly than controls (P < 0.05 for several parameters of CoF displacement) revealing stiffness of the musculoskeletal system. However, they were able to maintain their stance within a similar sway area. Haemophilic boys have more postural disharmonies than non-haemophilic peers, hence a global evaluation of the orthopaedic status should include also balance and posture examination to identify early dysfunction and establish a tailored physical or rehabilitation programme.

  15. Delayed stochastic differential model for quiet standing

    NASA Astrophysics Data System (ADS)

    Yao, W.; Yu, P.; Essex, C.

    2001-02-01

    A physiological quiet standing model, described by a delayed differential equation, subject to a white noise perturbation, is proposed to study the postural control system of human beings. It has been found that the white noise destabilizes the equilibrium state, and inertia accelerates the destabilizing process, and that the position of a person is detected and processed by the person's nervous system with a delay. This paper focuses on the analysis of Hopf bifurcation and its stability in this context. Based on the analytical predictions confirmed by numerical simulations, it has been shown that the posture of a person is controlled in such a way that possible amplitude oscillations are minimized.

  16. Postural orthostatic tachycardia syndrome: a clinical review.

    PubMed

    Johnson, Jonathan N; Mack, Kenneth J; Kuntz, Nancy L; Brands, Chad K; Porter, Coburn J; Fischer, Philip R

    2010-02-01

    Postural orthostatic tachycardia syndrome was defined in adult patients as an increase >30 beats per minute in heart rate of a symptomatic patient when moving from supine to upright position. Clinical signs may include postural tachycardia, headache, abdominal discomfort, dizziness/presyncope, nausea, and fatigue. The most common adolescent presentation involves teenagers within 1-3 years of their growth spurt who, after a period of inactivity from illness or injury, cannot return to normal activity levels because of symptoms induced by upright posture. Postural orthostatic tachycardia syndrome is complex and likely has numerous, concurrent pathophysiologic etiologies, presenting along a wide spectrum of potential symptoms. Nonpharmacologic treatment includes (1) increasing aerobic exercise, (2) lower-extremity strengthening, (3) increasing fluid/salt intake, (4) psychophysiologic training for management of pain/anxiety, and (5) family education. Pharmacologic treatment is recommended on a case-by-case basis, and can include beta-blocking agents to blunt orthostatic increases in heart rate, alpha-adrenergic agents to increase peripheral vascular resistance, mineralocorticoid agents to increase blood volume, and serotonin reuptake inhibitors. An interdisciplinary research approach may determine mechanistic root causes of symptoms, and is investigating novel management plans for affected patients.

  17. Human Balance out of Equilibrium: Nonequilibrium Statistical Mechanics in Posture Control

    NASA Astrophysics Data System (ADS)

    Lauk, Michael; Chow, Carson C.; Pavlik, Ann E.; Collins, James J.

    1998-01-01

    During quiet standing, the human body sways in a stochastic manner. Here we show that the fluctuation-dissipation theorem can be applied to the human postural control system. That is, the dynamic response of the postural system to a weak mechanical perturbation can be predicted from the fluctuations exhibited by the system under quasistatic conditions. We also show that the estimated correlation and response functions can be described by a simple stochastic model consisting of a pinned polymer. These findings suggest that the postural control system utilizes the same control mechanisms under quiet-standing and dynamic conditions.

  18. 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…

  19. 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.

  20. 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

    2009-12-01

    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.

  1. 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.

  2. Postural disturbances resulting from unilateral and bilateral diaphragm contractions: a phrenic nerve stimulation study.

    PubMed

    Hamaoui, Alain; Hudson, Anna L; Laviolette, Louis; Nierat, Marie-Cécile; Do, Manh-Cuong; Similowski, Thomas

    2014-10-15

    Thoracoabdominal breathing movements are a complex source of postural disturbance, but there are contradictory reports in the literature with inspiration described as having either a backward or a forward disturbing effect. To elucidate the mechanisms underlying this phenomenon, the present study studied the postural disturbance caused by isolated contractions of the diaphragm. Eight male and four female healthy subjects followed an original paradigm of phrenic nerve stimulation (bilateral and unilateral) and "diaphragmatic" voluntary sniff maneuvers in the seated and standing postures. Center of gravity (CG) acceleration was calculated from force plate recordings, and respiratory kinematics were assessed with thoracic and abdominal sensor belts. CG and respiratory signals revealed that, while seated, bilateral phrenic stimulation and sniff maneuvers consistently produced expansion of the abdomen associated with a forward peak of CG acceleration. In the standing posture, the direction of the CG peak was reversed and always directed backward. Unilateral phrenic stimulation induced an additional medial-lateral acceleration of the CG, directed toward the nonactive side while seated, but in the opposite direction while standing. These results suggest that isolated diaphragmatic contractions produce a constant disturbing pattern for a given posture, but with opposite effects between standing and seated postures. This could be related to the different biomechanical configuration of the body in each posture, corresponding to distinct kinematic patterns of the osteoarticular chain. In addition, the lateral component of the CG acceleration induced by unilateral diaphragm contractions could be clinically relevant in patients with hemidiaphragm paralysis.

  3. Effects of zopiclone, triazolam, and nitrazepam on standing steadiness.

    PubMed

    Tada, K; Sato, Y; Sakai, T; Ueda, N; Kasamo, K; Kojima, T

    1994-01-01

    We examined the effects of the nonbenzodiazepine hypnotic zopiclone and the benzodiazepine hypnotics triazolam and nitrazepam on standing steadiness. Eight healthy volunteers received placebo, zopiclone (7.5 mg), triazolam (0.25 mg), and nitrazepam (5 mg) in a random-order, double-blind crossover design. Postural sway was assessed before and 1 and 2 h after drug administration using a stabilometer connected to a microcomputer. Triazolam significantly impaired standing steadiness. Zopiclone also impaired standing steadiness but the degree of impairment seemed to be less marked. Nitrazepam 5 mg had no significant effects on postural sway. Triazolam 0.25 mg, zopiclone 7.5 mg, and nitrazepam 5 mg, which are reported to be equipotent to each other as hypnotics, are not equipotent with respect to their effects on postural sway.

  4. 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

  5. Effect of posture positions on the evaporative resistance and thermal insulation of clothing.

    PubMed

    Wu, Y S; Fan, J T; Yu, W

    2011-03-01

    Evaporative resistance and thermal insulation of clothing are important parameters in the design and engineering of thermal environments and functional clothing. Past work on the measurement of evaporative resistance of clothing was, however, limited to the standing posture with or without body motion. Information on the evaporative resistance of clothing when the wearer is in a sedentary or supine posture and how it is related to that when the wearer is in a standing posture is lacking. This paper presents original data on the effect of postures on the evaporative resistance of clothing, thermal insulation and permeability index, based on the measurements under three postures, viz. standing, sedentary and supine, using the sweating fabric manikin-Walter. Regression models are also established to relate the evaporative resistance and thermal insulation of clothing under sedentary and supine postures to those under the standing posture. The study further shows that the apparent evaporated resistances of standing and sedentary postures measured in the non-isothermal condition are much lower than those in the isothermal condition. The apparent evaporative resistances measured using the mass loss method are generally lower than those measured using the heat loss method due to moisture absorption or condensation within clothing. STATEMENT OF RELEVANCE: The thermal insulation and evaporative resistance values of clothing ensembles under different postures are essential data for the ergonomics design of thermal environments (e.g. indoors or a vehicle's interior environment) and functional clothing. They are also necessary for the prediction of thermal comfort or duration of exposure in different environmental conditions.

  6. Normative values for the Foot Posture Index

    PubMed Central

    Redmond, Anthony C; Crane, Yvonne Z; Menz, Hylton B

    2008-01-01

    Background The Foot Posture Index (FPI) is a validated method for quantifying standing foot posture, and is being used in a variety of clinical settings. There have however, been no normative data available to date for comparison and reference. This study aimed to establish normative FPI reference values. Methods Studies reporting FPI data were identified by searching online databases. Nine authors contributed anonymised versions of their original datasets comprising 1648 individual observations. The datasets included information relating to centre, age, gender, pathology (if relevant), FPI scores and body mass index (BMI) where available. FPI total scores were transformed to interval logit scores as per the Rasch model and normal ranges were defined. Comparisons between groups employed t-tests or ANOVA models as appropriate and data were explored descriptively and graphically. Results The main analysis based on a normal healthy population (n = 619) confirmed that a slightly pronated foot posture is the normal position at rest (mean back transformed FPI raw score = +4). A 'U' shaped relationship existed for age, with minors and older adults exhibiting significantly higher FPI scores than the general adult population (F = 51.07, p < 0.001). There was no difference between the FPI scores of males and females (2.3 versus 2.5; t = -1.44, p = 0.149). No relationship was found between the FPI and BMI. Systematic differences from the adult normals were confirmed in patients with neurogenic and idiopathic cavus (F = 216.981, p < 0.001), indicating some sensitivity of the instrument to detect a posturally pathological population. Conclusion A set of population norms for children, adults and older people have been derived from a large sample. Foot posture is related to age and the presence of pathology, but not influenced by gender or BMI. The normative values identified may assist in classifying foot type for the purpose of research and clinical decision making. PMID

  7. The relationship between a child's postural stability and manual dexterity.

    PubMed

    Flatters, Ian; Mushtaq, Faisal; Hill, Liam J B; Holt, Raymond J; Wilkie, Richard M; Mon-Williams, Mark

    2014-09-01

    The neural systems responsible for postural control are separate from the neural substrates that underpin control of the hand. Nonetheless, postural control and eye-hand coordination are linked functionally. For example, a stable platform is required for precise manual control tasks (e.g. handwriting) and thus such skills often cannot develop until the child is able to sit or stand upright. This raises the question of the strength of the empirical relationship between measures of postural stability and manual motor control. We recorded objective computerised measures of postural stability in stance and manual control in sitting in a sample of school children (n = 278) aged 3-11 years in order to explore the extent to which measures of manual skill could be predicted by measures of postural stability. A strong correlation was found across the whole sample between separate measures of postural stability and manual control taken on different days. Following correction for age, a significant but modest correlation was found. Regression analysis with age correction revealed that postural stability accounted for between 1 and 10% of the variance in manual performance, dependent on the specific manual task. These data reflect an interdependent functional relationship between manual control and postural stability development. Nevertheless, the relatively small proportion of the explained variance is consistent with the anatomically distinct neural architecture that exists for 'gross' and 'fine' motor control. These data justify the approach of motor batteries that provide separate assessments of postural stability and manual dexterity and have implications for therapeutic intervention in developmental disorders.

  8. Functional muscle synergies constrain force production during postural tasks.

    PubMed

    McKay, J Lucas; Ting, Lena H

    2008-01-01

    We recently demonstrated that a set of five functional muscle synergies were sufficient to characterize both hindlimb muscle activity and active forces during automatic postural responses in cats standing at multiple postural configurations. This characterization depended critically upon the assumption that the endpoint force vector (synergy force vector) produced by the activation of each muscle synergy rotated with the limb axis as the hindlimb posture varied in the sagittal plane. Here, we used a detailed, 3D static model of the hindlimb to confirm that this assumption is biomechanically plausible: as we varied the model posture, simulated synergy force vectors rotated monotonically with the limb axis in the parasagittal plane (r2=0.94+/-0.08). We then tested whether a neural strategy of using these five functional muscle synergies provides the same force-generating capability as controlling each of the 31 muscles individually. We compared feasible force sets (FFSs) from the model with and without a muscle synergy organization. FFS volumes were significantly reduced with the muscle synergy organization (F=1556.01, p<0.01), and as posture varied, the synergy-limited FFSs changed in shape, consistent with changes in experimentally measured active forces. In contrast, nominal FFS shapes were invariant with posture, reinforcing prior findings that postural forces cannot be predicted by hindlimb biomechanics alone. We propose that an internal model for postural force generation may coordinate functional muscle synergies that are invariant in intrinsic limb coordinates, and this reduced-dimension control scheme reduces the set of forces available for postural control.

  9. 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…

  10. 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

  11. Effects of lumbar extensor fatigue and surface inclination on postural control during quiet stance.

    PubMed

    Lin, Dingding; Nussbaum, Maury A

    2012-11-01

    A number of work environments require workers to perform tasks on inclined surfaces. Such tasks, along with muscle fatigue, can impair postural control and increase falling risks. The objective of this study was to determine the effects of surface inclination angle, standing direction, and lumbar extensor fatigue on postural control during quiet standing. A group of 16 young, healthy participants were tested while standing on inclined surfaces before and after lumbar extensor fatigue (induced by repetitive isotonic exercise). Three inclination angles (0°, 18° and 26°) and three standing directions (uphill, downhill, and lateral facing) were examined. Postural control was assessed using several measures derived from center-of-pressure time series and subjectively perceived stability. Significant main and interactive effects of inclination angle and standing direction were found for all dependent measures. The adverse effects of standing on inclined surfaces were found to differ between the three standing directions. In general, dose-response relationships with inclination angle were evident, particularly in the lateral-facing direction. Fatigue-related effects differed between conditions, suggesting that the adverse effect of lumbar extensor fatigue on postural control depend on inclination angle and standing direction. These findings may facilitate the development of fall prevention interventions for work involving inclined surfaces.

  12. Autoimmune Basis for Postural Tachycardia Syndrome

    ClinicalTrials.gov

    2016-10-14

    Postural Orthostatic Tachycardia Syndrome; Postural Tachycardia Syndrome; Tachycardia; Arrhythmias, Cardiac; Autonomic Nervous System Diseases; Orthostatic Intolerance; Cardiovascular Diseases; Primary Dysautonomias

  13. Lumbar spine postures in marines during simulated operational positions.

    PubMed

    Berry, David B; Rodríguez-Soto, Ana E; Su, Jeannie; Gombatto, Sara P; Shahidi, Bahar; Palombo, Laura; Chung, Christine; Jensen, Andrew; Kelly, Karen R; Ward, Samuel R

    2017-01-04

    Low back pain has a 70% higher prevalence in members of the armed forces than in the general population, possibly due to the loads and positions soldiers experience during training and combat. Although the influence of heavy load carriage on standing lumbar spine posture in this population is known, postures in other operationally relevant positions are unknown. Therefore, the purpose of this study was to characterize the effect of simulated military operational positions under relevant loading conditions on global and local lumbar spine postures in active duty male US Marines. Secondary objectives were to evaluate if intervertebral disc degeneration and low back pain affect lumbar spine postures. Magnetic resonance images were acquired on an upright scanner in the following operational positions: Natural standing with no external load, standing with body armor (11.3 kg), sitting with body armor, and prone on elbows with body armor. Custom software was used to measure global lumbar spine posture: Lumbosacral flexion, sacral slope, lordosis, local measures of intervertebral angles, and intervertebral distances. Sitting resulted in decreased lumbar lordosis at all levels of the spine except L1-L2. When subjects were prone on elbows, a significant increase in local lordosis was observed only at L5-S1 compared with all other positions. Marines with disc degeneration (77%) or history of low back pain (72%) had decreased lumbar range of motion and less lumbar extension than healthy Marines. These results indicate that a male Marine's pathology undergoes a stereotypic set of postural changes during functional tasks, which may impair performance. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:XX-XX, 2017.

  14. The role of lumbopelvic posture in pelvic floor muscle activation in continent women.

    PubMed

    Capson, Angela Christine; Nashed, Joseph; Mclean, Linda

    2011-02-01

    This study was undertaken to determine the effect of changing standing lumbopelvic posture on pelvic floor muscle (PFM) activation amplitude and timing and the resultant vaginal manometry values recorded during static and dynamic tasks. Sixteen nulliparous, continent women between the ages of 22 and 41 years performed five tasks (quiet standing, maximal effort cough, Valsalva manoeuvre, maximum voluntary contraction (MVC) of the PFMs, and a load-catching task) in three different standing postures (normal lumbopelvic posture, hyperlordosis and hypolordosis). Electromyographic (EMG) data were recorded from the PFMs bilaterally using a Periform™ vaginal probe coupled to Delsys™ Bagnoli-8 EMG amplifiers. In separate trials, vaginal manometry was obtained using a Peritron™ perineometer. Lumbopelvic angle was recorded simultaneously with EMG and vaginal manometry using an Optotrak™ 3D motion analysis system to ensure that subjects maintained the required posture throughout the three trials of each task. All data were filtered using a moving 100 ms RMS window and peak values were determined for each trial and task. Repeated-measures analyses of variance were performed on the peak PFM EMG, intra-vaginal pressure amplitudes, and lumbopelvic angles as well as activation onset data for the cough and load-catching tasks. There was significantly higher resting PFM activity in all postures in standing as compared to supine, and in the standing position, there was higher resting PFM activity in the hypo-lordotic posture as compared to the normal and hyperlordotic postures. During the MVC, cough, Valsalva, and load-catching tasks, subjects generated significantly more PFM EMG activity when in their habitual posture than when in hyper- or hypo-lordotic postures. Conversely, higher peak vaginal manometry values were generated in the hypo-lordotic posture for all tasks in all cases. These results clearly indicate that changes in lumbopelvic posture influence both the

  15. Anticipatory postural adjustments modify the movement-related potentials of upper extremity voluntary movement.

    PubMed

    Yoshida, S; Nakazawa, K; Shimizu, E; Shimoyama, I

    2008-01-01

    To elucidate the effect on movement-related potentials (MRPs) of anticipatory postural adjustments (APAs) accompanied by voluntary focal movement, we examined the MRPs of shoulder flexion movement under standing and sitting postural conditions in 12 normal subjects. MRPs were evaluated based on three components: readiness potential (RP), motor potential (MP), and movement-monitoring potential. APAs were observed in the activities of postural muscles including the biceps femoris and erector spinae muscles only under standing conditions. The amplitudes of the three MRP components were larger under standing conditions than under sitting conditions for all recorded electrode positions, and the RP and MP amplitudes at the vertex position, which lies over the supplementary motor area (SMA), showed a prominent increase under standing conditions with the highest statistical significance. These results suggest that a recruited neural process of the cortical area including the SMA may be necessary to generate voluntary movement accompanied by APA.

  16. Postural Orthostatic Tachycardia Syndrome

    PubMed Central

    2014-01-01

    The postural orthostatic tachycardia syndrome is a disease characterized by excessively increased heart rate during orthostatic challenge associated with symptoms of orthostatic intolerance including dizziness, exercise intolerance, headache, fatigue, memory problems, nausea, blurred vision, pallor, and sweating, which improve with recumbence. Postural orthostatic tachycardia syndrome patients may present with a multitude of additional symptoms that are attributable to vascular vasoconstriction. Observed signs and symptoms in a patient with postural orthostatic tachycardia syndrome include tachycardia at rest, exaggerated heart rate increase with upright position and exercise, crushing chest pain, tremor, syncope, loss of vision, confusion, migraines, fatigue, heat intolerance, parasthesia, dysesthesia, allodynia, altered traditional senses, and thermoregulatory abnormalities. There are a number of possible dermatological manifestations of postural orthostatic tachycardia syndrome easily explained by its recently discovered pathophysiology. The author reports the case of a 22-year-old woman with moderate-to-severe postural orthostatic tachycardia syndrome with numerous dermatological manifestations attributable to the disease process. The cutaneous manifestations observed in this patient are diverse and most noticeable during postural orthostatic tachycardia syndrome flares. The most distinct are evanescent, hyperemic, sharply demarcated, irregular patches on the chest and neck area that resolve upon diascopy. This distinct “evanescent hyperemia” disappears spontaneously after seconds to minutes and reappears unexpectedly. Other observed dermatological manifestations of this systemic disease include Raynaud’s phenomenon, koilonychia, onychodystrophy, madarosis, dysesthesia, allodynia, telogen effluvium, increased capillary refill time, and livedo reticularis. The treatment of this disease poses a great challenge. The author reports the unprecedented use of an

  17. 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.

  18. Postural reactions to neck vibration in Parkinson's disease.

    PubMed

    Valkovic, Peter; Krafczyk, Siegbert; Saling, Marian; Benetin, Ján; Bötzel, Kai

    2006-01-01

    To test the hypothesis that reduced reactions to proprioceptive input signals contribute to postural instability in Parkinson's disease (PD), pulses of mechanical vibration were applied to the neck muscles of PD patients and healthy controls. This stimulus elicits postural reactions in standing subjects. Participating were 13 moderately affected PD patients, 13 severely affected PD patients, and 13 age-matched healthy subjects. Patients were tested on and off medication. Three-second-long pulses of vibration were regularly (10 times) applied to the posterior neck muscles while subjects kept their eyes open or closed. Postural responses to the stimuli were measured by static posturography. No intergroup difference in the pattern and latencies of responses was found. However, the amplitudes of the postural reactions (shift of center of foot pressure) were significantly larger in advanced PD patients; those of moderately affected PD patients did not differ from those of control subjects. Moreover, the size of postural responses in both latter groups decreased across the trial contrary to that of advanced PD patients. Comparison of the measures during on and off testing revealed no significant differences. These results indicate that neither afferent proprioceptive deficits nor central integrative functions but rather scaling and habituation of erroneous proprioceptive information are disturbed in the postural control of advanced PD. Nondopaminergic structures seem to be responsible for this impairment.

  19. Lighten up: Specific postural instructions affect axial rigidity and step initiation in patients with Parkinson’s disease

    PubMed Central

    Cohen, Rajal G.; Gurfinkel, Victor S.; Kwak, Elizabeth; Warden, Amelia C.; Horak, Fay B.

    2015-01-01

    Background Parkinson’s disease (PD) is associated with stooped postural alignment, increased postural sway, and reduced mobility. The Alexander Technique (AT) is a mindfulness-based approach to improving posture and mobility by reducing muscular interference while maintaining upward intentions. Evidence suggests that AT can reduce disability associated with PD, but a mechanism for this effect has not yet been established. Objective We investigated whether AT-based instructions reduce axial rigidity and increase upright postural alignment, and whether these instructions have different effects on postural alignment, axial rigidity, postural sway, and mobility than effort-based instructions regarding posture. Method Twenty subjects with PD practiced two sets of instructions and then attempted to implement both approaches (as well as a relaxed control condition) during quiet standing and step initiation. The ‘Lighten Up’ instructions relied on AT principles of reducing excess tension while encouraging length. The ‘Pull Up’ instructions relied on popular concepts of effortful posture correction. We measured kinematics, resistance to axial rotation, and ground reaction forces. Results Both sets of experimental instructions led to increases in upright postural alignment relative to the control condition. Only the Lighten Up instructions led to reduced postural sway, reduced axial postural tone, greater modifiability of tone, and a smoother center of pressure trajectory during step initiation, possibly indicating greater movement efficiency. Conclusion Mindful movement approaches such as AT may benefit balance and mobility in subjects with PD by acutely facilitating increased upright postural alignment while decreasing rigidity. PMID:25665828

  20. 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.

  1. Sympathovagal balance analysis in idiopathic postural orthostatic tachycardia syndrome.

    PubMed

    Russo, Vincenzo; De Crescenzo, Ilaria; Ammendola, Ernesto; Santangelo, Lucio; Calabrò, Raffaele

    2007-08-01

    The idiopathic postural tachycardia syndrome (POTS) is a complex disorder characterized by chronic orthostatic symptoms and an increase in heart rate within 10 minutes of standing on upright posture, without significant orthostatic hypotension. We describe a case of a 36 year-old patient with POTS, diagnosed by head-up tilt testing. Power spectral analysis of heart rate variability (HRV), performed during the tilt test, revealed the ratio of low and high frequency powers (LF/HF) that increased with the onset of orthostatic intolerance. The increase in LF/HF power ratio may represent sympathetic beta-receptors hyperactivity. Atenolol alleviated his clinical symptoms.

  2. 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.

  3. 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

  4. [The influence of posture on transmission and absorption of vibration energy in whole body vibration exercise].

    PubMed

    Berschin, G; Sommer, H-M

    2010-03-01

    Muscle exercise using whole body vibration platforms is well known as an alternative physical exercise in therapy as well as in high performance sports. Various studies could show an effectiveness in particular to improve maximal strength and springiness. Using these platforms there is no consideration to posture although the damage potential of vibration stress i. e. on intervertebral discs is well-known. Therefore the effect of posture on the transmission and absorption of vibration loads in bipedal standing was examined in a study with 20 sport students. They were exposed to a whole body vibration load in bipedal standing at a vibration frequency of 25 Hz. The transmission of energy was measured at the head in different postural positions. An average transmission of 9 % was measured in spontaneous bipedal standing. It significantly decreased with gradual changes of posture. After 6 weeks posture conditioning exercise this effect was significantly improved. In conclusion different posture in bipedal standing implies not only different energy absorption but also different effects on muscle performance which can explain the partly inconsistent results after vibration exercise. In addition whole body vibration exercise in a prone or sitting position may increase the risk of overload and should be avoided because of reduced energy absorption capacity.

  5. 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.

  6. Effect of Posture during Trumpet and Marching Euphonium Performance on the Trunk and Lower Limb Musculoskeletal System

    PubMed Central

    Mitani, Yasuhiro; Kitagawa, Tomomi; Matsugi, Akiyoshi; Mukai, Kouichi

    2013-01-01

    [Purpose] The purpose of the present study was to investigate the effect of trumpet and marching euphonium performance posture on the trunk and lower limb musculoskeletal system. [Subjects] The subjects were 10 female university students. [Methods] Subjects maintained a resting position, a trumpet performance posture, and a marching euphonium performance posture. The angles and muscle activities of the trunk and lower limbs were then measured. [Results] The anterior tilt angle of the trunk decreased significantly in the trumpet and marching euphonium performance postures compared with the resting standing position, as well as in the marching euphonium performance posture compared with the trumpet performance posture. The muscle activity of the cervical paraspinal muscles, upper fibers of the trapezius, and lumbar paraspinal muscles increased significantly in the marching euphonium performance posture compared with the resting standing position, as well as in the marching euphonium performance posture compared with the trumpet performance posture. [Conclusion] The results suggest that the performance position for trumpet and the marching euphonium performance increases the load on the cervical and thoracic musculoskeletal system, which increases with greater instrument weight. However, the same instrument performance postures had no affect on the musculoskeletal system of the lower limbs. PMID:24259926

  7. Posture and Movement

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Session TP3 includes short reports on: (1) Modification of Goal-Directed Arm Movements During Inflight Adaptation to Microgravity; (2) Quantitative Analysis of Motion control in Long Term Microgravity; (3) Does the Centre of Gravity Remain the Stabilised Reference during Complex Human Postural Equilibrium Tasks in Weightlessness?; and (4) Arm End-Point Trajectories Under Normal and Microgravity Environments.

  8. Postural orthostatic tachycardia syndrome.

    PubMed

    Agarwal, A K; Garg, R; Ritch, A; Sarkar, P

    2007-07-01

    Postural orthostatic tachycardia syndrome (POTS) is an autonomic disturbance which has become better understood in recent years. It is now thought to encompass a group of disorders that have similar clinical features, such as orthostatic intolerance, but individual distinguishing parameters--for example, blood pressure and pulse rate. The clinical picture, diagnosis, and management of POTS are discussed.

  9. Artificial balancer - supporting device for postural reflex.

    PubMed

    Wojtara, Tytus; Sasaki, Makoto; Konosu, Hitoshi; Yamashita, Masashi; Shimoda, Shingo; Alnajjar, Fady; Kimura, Hidenori

    2012-02-01

    The evolutionarily novel ability to keep ones body upright while standing or walking, the human balance, deteriorates in old age or can be compromised after accidents or brain surgeries. With the aged society, age related balance problems are on the rise. Persons with balance problems are more likely to fall during their everyday life routines. Especially in elderly, falls can lead to bone fractures making the patient bedridden, weakening the body and making it more prone to other diseases. Health care expenses for a fall patient are often very high. There is a great deal of research being done on exoskeletons and power assists. However, these technologies concentrate mainly on the amplifications of human muscle power while balance has to be provided by the human themself. Our research has been focused on supporting human balance in harmony with the human's own posture control mechanisms such as postural reflexes. This paper proposes an artificial balancer that supports human balance through acceleration of a flywheel attached to the body. Appropriate correcting torques are generated through our device based on the measurements of body deflections. We have carried out experiments with test persons standing on a platform subject to lateral perturbations and ambulatory experiments while walking on a balance beam. These experiments have demonstrated the effectiveness of our device in supporting balance and the possibility of enhancing balance-keeping capability in human beings through the application of external torque.

  10. Individuals with chronic low back pain do not modulate the level of transversus abdominis muscle contraction across different postures.

    PubMed

    Miura, Takuya; Yamanaka, Masanori; Ukishiro, Kengo; Tohyama, Harukazu; Saito, Hiroshi; Samukawa, Mina; Kobayashi, Takumi; Ino, Takumi; Takeda, Naoki

    2014-12-01

    The aim of this study was to evaluate the thickness of the transversus abdominis (TrA) muscle in three basic postures in subjects with and without chronic low back pain. Subjects were classified into a chronic low back pain group (n = 27) and a healthy control group (n = 23). The thickness of the TrA muscle was measured at rest and during the abdominal drawing-in manoeuvre (ADIM) in supine, sitting and standing postures using B-mode ultrasound imaging. Contraction ratio (TrA thickness during the ADIM/TrA thickness at rest) was calculated for each posture. At rest, the TrA thickness in the sitting and standing postures was significantly greater than in the supine posture (p < 0.017) in the control group, but similar in all three postures in the low back pain group. TrA thickness was similar in the low back pain and control group in all three postures. During the ADIM, TrA thickness was significantly greater in the control group than in the chronic low back pain group in all three postures. The contraction ratio was also significantly higher in the control group than in the chronic low back pain group in all three postures. These results indicate that the automatic postural contraction of the TrA observed in the control subjects in the sitting and standing postures was not demonstrated in subjects with chronic low back pain. The present study revealed the one aspect of different response of the TrA muscle to changing posture between two groups.

  11. The role of anticipatory postural adjustments in compensatory control of posture: 2. Biomechanical analysis.

    PubMed

    Santos, Marcio J; Kanekar, Neeta; Aruin, Alexander S

    2010-06-01

    The central nervous system (CNS) utilizes anticipatory (APAs) and compensatory (CPAs) postural adjustments to maintain equilibrium while standing. It is known that these postural adjustments involve displacements of the center of mass (COM) and center of pressure (COP). The purpose of the study was to investigate the relationship between APAs and CPAs from a kinetic and kinematic perspective. Eight subjects were exposed to external predictable and unpredictable perturbations induced at the shoulder level while standing. Kinematic and kinetic data were recorded and analyzed during the time duration typical for anticipatory and compensatory postural adjustments. When the perturbations were unpredictable, the COM and COP displacements were larger compared to predictable conditions with APAs. Thus, the peak of COM displacement, after the pendulum impact, in the posterior direction reached 28+/-9.6mm in the unpredictable conditions with no APAs whereas it was 1.6 times smaller, reaching 17+/-5.5mm during predictable perturbations. Similarly, after the impact, the peak of COP displacement in the posterior direction was 60+/-14 mm for unpredictable conditions and 28+/-3.6mm for predictable conditions. Finally, the times of the peak COM and COP displacements were similar in the predictable and unpredictable conditions. This outcome provides additional knowledge about how body balance is controlled in presence and in absence of information about the forthcoming perturbation. Moreover, it suggests that control of posture could be enhanced by better utilization of APAs and such an approach could be considered as a valuable modality in the rehabilitation of individuals with balance impairment.

  12. 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.

  13. Orthostatic tremor during modification of standing.

    PubMed

    Spiegel, Jörg; Krick, Christoph; Fuss, Gerhard; Sood, Dania; Becker, Georg; Dillmann, Ulrich

    2006-02-01

    Primary orthostatic tremor (OT) occurs only during standing. We studied whether modification of the condition standing influences OT. In seven patients with OT, surface EMG was recorded from both tibialis anterior and gastrocnemius muscles during two maneuvers: relief, whereby the patient was gradually lifted by a crane, and tilting, whereby the patient was tilted by a tilting table to positions of 90 degrees (upright standing), 45 degrees (diagonal position), and 0 degrees (lying position). We determined the parameters tremor frequency, tremor intensity, coherence, and phase shift between the different muscles. Relief did not influence OT. In contrast, tilting modified significantly tremor intensity and phase shifts; tremor frequencies and coherences were not influenced. We chose both these maneuvers because of their different impact on the standing condition: relief modifies the factors afferent input and muscle forcing but not the factor postural set, whereas tilting modifies all three factors. The fact that tilting modifies OT, whereas relief does not, suggests an important role of postural set in OT generation. Afferent input and muscle forcing seem to play less important role.

  14. Anticipatory postural adjustments associated with a loading perturbation in children with hemiplegic and diplegic cerebral palsy.

    PubMed

    Shiratori, T; Girolami, G L; Aruin, A S

    2016-10-01

    Anticipatory postural adjustments (APAs) in preparation for predictable externally induced loading perturbation were studied in children with typically development (TD), hemiplegic (HEMI), and diplegic (DIPL) cerebral palsy. Twenty-seven children (n = 9 in each group) were asked to stand and catch a load dropped from a pre-specified height. Electrical activity of the leg and trunk muscles and center of pressure (COP) displacements were recorded to quantify the APAs. All groups were able to generate APAs prior to the perturbation, but the magnitude was smaller and the onset was delayed in the dorsal (agonist) postural muscles in both HEMI and DIPL as compared to TD. HEMI and DIPL also generated APAs in the antagonist postural muscles. Anticipatory backward COP displacement was significantly different from the baseline value only in the TD and HEMI. HEMI and DIPL displayed a different postural control strategy; HEMI showed no difference in background postural activity from TD, but with diminished APAs in the agonist postural muscles compared to TD, while DIPL showed a higher background postural activity and diminished APAs in the agonist postural muscles compared to TD. These differences are important to consider when designing rehabilitation programs to improve posture and movement control in children with hemiplegic and diplegic cerebral palsy.

  15. Can Postural Instability Respond to Galvanic Vestibular Stimulation in Patients with Parkinson’s Disease?

    PubMed Central

    Kataoka, Hiroshi; Okada, Yohei; Kiriyama, Takao; Kita, Yorihiro; Nakamura, Junji; Morioka, Shu; Shomoto, Koji; Ueno, Satoshi

    2016-01-01

    Objective Galvanic vestibular stimulation (GVS) activates the vestibular afferents, and these changes in vestibular input exert a strong influence on the subject’s posture or standing balance. In patients with Parkinson’s disease (PD), vestibular dysfunction might contribute to postural instability and gait disorders. Methods Current intensity was increased to 0.7 mA, and the current was applied to the patients for 20 minutes. To perform a sham stimulation, the current intensity was increased as described and then decreased to 0 mA over the course of 10 seconds. The patient’s status was recorded continuously for 20 minutes with the patient in the supine position. Results Three out of 5 patients diagnosed with PD with postural instability and/or abnormal axial posture showed a reduction in postural instability after GVS. The score for item 12 of the revised Unified Parkinson’s Disease Rating Scale part 3 was decreased in these patients. Conclusions The mechanism of postural instability is complex and not completely understood. In 2 out of the 5 patients, postural instability was not changed in response to GVS. Nonetheless, the GVS-induced change in postural instability for 3 patients in our study suggests that GVS might be a therapeutic option for postural instability. PMID:26648182

  16. Postural stability in altered and unaltered sensory environments following fatiguing exercise of lower extremity joints.

    PubMed

    Dickin, D C; Doan, J B

    2008-12-01

    Investigations of postural recovery following controlled external perturbations have provided models for healthy and pathological balance behavior. Less work, however, has investigated postural responses related to internal perturbations of the balance system. In this study, lower extremity joint (knee, or ankle) and overall fatigue of the dominant leg provided the internal perturbations to the balance system. Postural sway was examined during unilateral dominant leg standing before and immediately following fatiguing exercise, as well as at 10, 20, and 30 min post-fatigue activity. Sway was measured in both firm and sway-referenced support surface (external perturbation) conditions. Both joint-localized fatigue and overall fatigue were found to induce impairments in postural control, which were further exacerbated by external postural perturbations. Follow-up pairwise comparisons indicated that these impairments persisted at 10 and 30 min post-fatigue. No differences in postural sway were found between fatigue locations or across any interactions between sway and fatigue location. The results indicated that muscular fatigue imposed a prolonged internal perturbation to postural control, regardless of any individual or combined joint fatigue localization. This global effect, combined with the prolonged impairment in postural response, provides support for critical contributions from a central mechanism to postural deficits due to fatigue.

  17. 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

  18. The influence of horizontally rotating sound on standing balance.

    PubMed

    Gandemer, Lennie; Parseihian, Gaëtan; Kronland-Martinet, Richard; Bourdin, Christophe

    2014-12-01

    Postural control is known to be the result of the integration and processing of various sensory inputs by the central nervous system. Among the various afferent inputs, the role of auditory information in postural regulation has been addressed in relatively few studies, which led to conflicting results. The purpose of the present study was to investigate the influence of a rotating auditory stimulus, delivered by an immersive 3D sound spatialization system, on the standing posture of young subjects. The postural sway of 20 upright, blindfolded subjects was recorded using a force platform. Use of various sound source rotation velocities followed by sudden immobilization of the sound was compared with two control conditions: no sound and a stationary sound source. The experiment showed that subjects reduced their body sway amplitude and velocity in the presence of rotating sound compared with the control conditions. The faster the sound source was rotating, the greater the reduction in subject body sway. Moreover, disruption of subject postural regulation was observed as soon as the sound source was immobilized. These results suggest that auditory information cannot be neglected in postural control and that it acts as additional information influencing postural regulation.

  19. 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.

  20. 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.

  1. Postural adjustments associated with rapid voluntary arm movements 1. Electromyographic data.

    PubMed Central

    Friedli, W G; Hallett, M; Simon, S R

    1984-01-01

    Normal subjects made bilaterally symmetric rapid elbow flexions or extensions ("focal movement") while free standing or when supported by being strapped to a firm wall behind them (different "postural set"). In some trials a load opposed the movement two thirds of the way into its course. Electromyographic activity in leg and trunk muscles ("associated postural adjustments") demonstrated specific patterns for each type of movement. Activity in these muscles began prior to activity in the arm muscles and demonstrated a distal-to-proximal order of activation. The EMG patterns were characterised by alternating activity in the antagonist pairs similar to the triphasic pattern seen in the arm muscles. When the movement type was changed change of the pattern of the postural muscles occurred over several trials. It is concluded that the associated postural adjustments are pre-programmed motor activity linked to the focal movement, specific for the focal movement including anticipated events and the postural set. PMID:6736995

  2. Evaluation of postural stability in children with hemiplegic cerebral palsy

    PubMed Central

    Kenis-Coskun, Ozge; Giray, Esra; Eren, Beyhan; Ozkok, Ozlem; Karadag-Saygi, Evrim

    2016-01-01

    [Purpose] Postural stability is the ability of to maintain the position of the body within the support area. This function is affected in cerebral palsy. The aim of the present study was to compare static and dynamic postural stability between children with hemiplegic cerebral palsy and healthy controls. [Subjects and Methods] Thirty-seven children between the ages of 5 and 14 diagnosed with hemiplegic cerebral palsy (19 right, 18 left) and 23 healthy gender- and age-matched controls were included in the study. Postural stability was evaluated in both of the groups using a Neurocom Balance. Sway velocity was measured both with the eyes open and closed. Sit to stand and turning abilities were also assessed. [Results] The sway velocities with the eyes open and closed were significantly different between the groups. The weight transfer time in the Sit to Stand test was also significantly slower in children with cerebral palsy. Children with cerebral palsy also showed slower turning times and greater sway velocities during the Step and Quick Turn test on a force plate compared with their healthy counterparts. [Conclusion] Both static and dynamic postural stability parameters are affected in hemiplegic cerebral palsy. Further research is needed to define rehabilitation interventions to improve these parameters in patients. PMID:27313338

  3. Anticipatory postural adjustments in children with hemiplegia and diplegia.

    PubMed

    Girolami, Gay L; Shiratori, Takako; Aruin, Alexander S

    2011-12-01

    Anticipatory postural adjustments (APAs) play an important role in the performance of many activities requiring the maintenance of standing posture. However, little is known about if and how children with cerebral palsy (CP) generate APAs. Two groups of children with CP (hemiplegia and diplegia) and a group of children with typical motor development performed arm flexion and extension movements while standing on a force platform. Electromyographic activity of six trunk and leg muscles and displacement of center of pressure (COP) were recorded. Children with CP were able to generate anticipatory postural adjustments and produce directionally specific APAs and COP displacements similar to those described in adults and typically developing children. However, children with diplegia were unable to generate APAs of the same magnitude as children with typical development and hemiplegia and had higher baseline muscle activity prior to movement. In children with diplegia, COP was posteriorly displaced and peak acceleration was smaller during bilateral extension compared to children with hemiplegia. The outcomes of the study highlight the role of APAs in the control of posture of children with CP and point out the similarities and differences in anticipatory control in children with diplegia and hemiplegia. These differences may foster ideas for treatment strategies to enhance APAs in children with CP.

  4. 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.

  5. Posture Statement 2006

    DTIC Science & Technology

    2006-02-01

    dispersed, comprising formal, informal, family, and cultural associations tied by varied and sometimes near- invisible links. Th ey ex- ploit the...coordination, and communication between all levels of government. USSOCOM’s leadership, vision, and initiative in prosecuting the GWOT was validated most...Rather, the new vision expresses a need for low density, high demand SOF assets to be postured with a “presence for purpose”, to be at the “right place

  6. 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

  7. Modulation of Ankle Muscle Postural Reflexes in Stroke: Influence of Weight-bearing Load

    PubMed Central

    Marigold, Daniel S.; Eng, Janice J.; Inglis, J. Timothy

    2011-01-01

    Objective Given the known sensorimotor deficits and asymmetric weight-bearing posture in stroke, the aim of this study was to determine whether stroke affects the modulation of standing postural reflexes with varying weight-bearing load. Methods Ten individuals with chronic stroke and 10 healthy older adult controls were exposed to unexpected forward and backward platform translations while standing. Three different stance conditions were imposed: increased weight-bearing load, decreased weight-bearing load, and self-selected stance. Surface EMG from bilateral ankle dorsiflexors (tibialis anterior) and extensors (gastrocnemius) were recorded and the magnitude of background muscle activity (prior to the platform translation) and postural reflex onset latency and magnitude (75 ms following reflex onset) were determined. Results Load modulation of ankle extensors was found in controls and individuals with stroke. Although controls demonstrated modulation of ankle dorsiflexors to different loads, individuals with stroke did not show this modulation. Further, load did not change the onset latency of postural reflexes of the individuals with stroke. Conclusion The delayed paretic muscle onset latencies in conjunction with impaired modulation of ankle dorsiflexor postural reflexes may contribute to the instability and frequent falls observed among individuals with stroke. Significance The results provide some insight into standing postural reflexes following stroke. PMID:15546787

  8. 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.

  9. Postural development in rats.

    PubMed

    Lelard, T; Jamon, M; Gasc, J-P; Vidal, P-P

    2006-11-01

    Mammals adopt a limited number of postures during their day-to-day activities. These stereotyped skeletal configurations are functionally adequate and limit the number of degrees of freedom to be controlled by the central nervous system. The temporal pattern of emergence of these configurations in altricial mammals is unknown. We therefore carried out an X-ray study in unrestrained rats from birth (P0) until postnatal day 23 (P23). The X-rays showed that many of the skeletal configurations described in adult rodents were already present at birth. By contrast, limb placement changed abruptly at around P10. These skeletal configurations, observed in anesthetized pups, required the maintenance of precise motor control. On the other hand, motor control continued to mature, as shown by progressive changes in resting posture and head movements from P0 to P23. We suggest that a few innate skeletal configurations provide the necessary frames of reference for the gradual construction of an adult motor repertoire in altricial mammals, such as the rat. The apparent absence of a requirement for external sensorial cues in the maturation of this repertoire may account for the maturation of postural and motor control in utero in precocial mammals (Muir et al., 2000 for a review on the locomotor behavior of altricial and precocial animals).

  10. Inter- and intra-rater agreement of static posture analysis using a mobile application

    PubMed Central

    Boland, David M.; Neufeld, Eric V.; Ruddell, Jack; Dolezal, Brett A.; Cooper, Christopher B.

    2016-01-01

    [Purpose] To determine the intra- and inter-rater agreement of a mobile application, PostureScreen Mobile® (PSM), that assesses static standing posture. [Subjects and Methods] Three examiners with different levels of experience of assessing posture, one licensed physical therapist and two untrained undergraduate students, performed repeated postural assessments of 10 subjects, fully clothed or minimally clothed, using PSM on two nonconsecutive days. Anterior and right lateral images were captured and seventeen landmarks were identified on them. Intraclass correlation coefficients (ICCs) were calculated for each of 13 postural measures to evaluate inter-rater agreement on the first visit (fully or minimally clothed), as well as intra-rater agreement between the first and second visits (minimally clothed). [Results] Eleven postural measures were ultimately analyzed for inter- and intra-rater agreement. Inter-rater agreement was almost perfect (ICC≥0.81) for four measures and substantial (0.60postural screening tool that requires little formal training. To maximize inter- and intra-rater agreement, postural screening using this mobile application should be conducted with subjects wearing minimal clothing. Assessing static standing posture via PSM gives repeatable measures for anatomical landmarks that were found to have substantial or almost perfect agreement. Our data also suggest that this technology may also be useful for diagnosing forward head posture. PMID:28174460

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

    PubMed

    Barczyk-Pawelec, Katarzyna; Sipko, Tomasz

    2016-10-04

    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.

  12. 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

  13. 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.

  14. Posture sway and the transition rate for a fall

    NASA Astrophysics Data System (ADS)

    Koleva, Radostina; Widom, A.; Garelick, D.; Harris, Meredith

    2001-04-01

    Postural body sway displacements for quiet standing subjects (measured with a new ultrasonic device) are reported. Two of the well-known strategies for balancing, namely ankle and hip movements, were probed. The data are modeled using a Fokker-Planck-Langevin stochastic theory. Both analytic and computer simulation techniques are employed. The Kramers transition rate for a fall is expressed as a function of experimental parameters. The root mean square velocity is especially important for determining the fall probability.

  15. 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

  16. Skeletal Muscle Pump Drives Control of Cardiovascular and Postural Systems

    PubMed Central

    Verma, Ajay K.; Garg, Amanmeet; Xu, Da; Bruner, Michelle; Fazel-Rezai, Reza; Blaber, Andrew P.; Tavakolian, Kouhyar

    2017-01-01

    The causal interaction between cardio-postural-musculoskeletal systems is critical in maintaining postural stability under orthostatic challenge. The absence or reduction of such interactions could lead to fainting and falls often experienced by elderly individuals. The causal relationship between systolic blood pressure (SBP), calf electromyography (EMG), and resultant center of pressure (COPr) can quantify the behavior of cardio-postural control loop. Convergent cross mapping (CCM) is a non-linear approach to establish causality, thus, expected to decipher nonlinear causal cardio-postural-musculoskeletal interactions. Data were acquired simultaneously from young participants (25 ± 2 years, n = 18) during a 10-minute sit-to-stand test. In the young population, skeletal muscle pump was found to drive blood pressure control (EMG → SBP) as well as control the postural sway (EMG → COPr) through the significantly higher causal drive in the direction towards SBP and COPr. Furthermore, the effect of aging on muscle pump activation associated with blood pressure regulation was explored. Simultaneous EMG and SBP were acquired from elderly group (69 ± 4 years, n = 14). A significant (p = 0.002) decline in EMG → SBP causality was observed in the elderly group, compared to the young group. The results highlight the potential of causality to detect alteration in blood pressure regulation with age, thus, a potential clinical utility towards detection of fall proneness. PMID:28345674

  17. 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.

  18. Anticipatory postural adjustments in individuals with multiple sclerosis.

    PubMed

    Krishnan, Vennila; Kanekar, Neeta; Aruin, Alexander S

    2012-01-11

    Individuals with multiple sclerosis (MS) frequently exhibit difficulties in balance maintenance. It is known that anticipatory postural adjustments (APAs) play an important role in postural control. However, no information exists on how people living with MS utilize APAs for control of posture. A group of individuals with MS and a group of healthy control subjects performed rapid arm flexion and extension movements while standing on a force platform. Electromyographic (EMG) activity of six trunk and leg muscles and displacement of center of pressure (COP) were recorded and quantified within the time intervals typical of APAs. Individuals with MS demonstrated diminished ability to produce directional specific patterns of anticipatory EMGs as compared to control subjects. In addition, individuals with MS demonstrated smaller magnitudes of anticipatory muscle activation. This was associated with larger displacements of the COP during the balance restoration phase. These results suggest the importance of anticipatory postural control in maintenance of vertical posture in individuals with MS. The outcome of the study could be used while developing rehabilitation strategies focused on balance restoration in individuals with MS.

  19. 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

  20. Posture modulates implicit hand maps.

    PubMed

    Longo, Matthew R

    2015-11-01

    Several forms of somatosensation require that afferent signals be informed by stored representations of body size and shape. Recent results have revealed that position sense relies on a highly distorted body representation. Changes of internal hand posture produce plastic alterations of processing in somatosensory cortex. This study therefore investigated how such postural changes affect implicit body representations underlying position sense. Participants localised the knuckles and tips of each finger in external space in two postures: the fingers splayed (Apart posture) or pressed together (Together posture). Comparison of the relative locations of the judgments of each landmark were used to construct implicit maps of represented hand structure. Spreading the fingers apart produced increases in the implicit representation of hand size, with no apparent effect on hand shape. Thus, changes of internal hand posture produce rapid modulation of how the hand itself is represented, paralleling the known effects on somatosensory cortical processing.

  1. 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.

  2. 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

  3. 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

  4. Forced Changes of Combat Posture

    DTIC Science & Technology

    1988-09-30

    effectiveness. Adkins’s thesi-s on modeling battlefield decision-making provided additional factors. M& Quic addressed the questien of posture change directly in...the study was to gain increased knowledge of the fac- - tors associated with forced changes in combat posture, in order to develop a model of forced...posture change model for use, with appro- priate parameter values, at the divisional and regimental levels. Principles guiding the model development may

  5. Sagittal Spinal and Pelvic Postures of Highly-Trained Young Canoeists

    PubMed Central

    López-Miñarro, Pedro A.; Muyor, José M.; Alacid, Fernando

    2011-01-01

    The objective of this study was to determine the sagittal spinal curvatures and pelvic position in standing and kneeling in the canoe in young canoeists. Forty-four young highly-trained canoeists (mean age: 15.11 ± 0.61 years) were recruited. Thoracic and lumbar curvatures and pelvic inclination were evaluated with a Spinal Mouse system in standing position and in the base position (kneeling on one knee in the canoe) and catch phase of the stroke. The mean thoracic kyphosis, lumbar lordosis and pelvic inclination in standing were 44.66 ± 8.80º, −30.34 ± 8.31º, and 14.20 ± 7.32º, respectively. In the canoe, the thoracic, lumbar and pelvic angles were 39.66 ± 9.52º, −24.32 ± 6.79º, and 15.18 ± 4.34º, respectively, for the base position (p<0.001 with respect to standing, except for pelvic inclination), and 28.93 ± 10.45º, −13.45 ± 10.60º, and 37.61 ± 6.27º, respectively, for the catch phase of the stroke (p<0.001 with respect to standing and base position). A higher percentage of hyperkyphotic postures in standing than in the canoe was found, while thoracic hypokyphosis increased in the catch phase of the stroke. In regards to the lumbar curve, the percentage of hypolordosis postures in the base position was higher than when standing. Lumbar kyphotic postures were detected in the catch phase of the stroke. In conclusion, the standing thoracic hyperkyphosis in young canoeists may be related to factors other than the posture and movement in the canoe. The canoeists adopted a lumbar flexed posture at the catch phase of the stroke, although this position may not affect the sagittal configuration of lumbar spine in standing. Postural training should be included in the training program of canoeists to improve the thoracic posture in the standing position. PMID:23487014

  6. Orthostatic Hypotension (Postural Hypotension)

    MedlinePlus

    ... while you're standing and will compare the measurements. Your doctor will diagnose orthostatic hypotension if you ... breathing: You breathe in deeply and push the air out through your lips, as if you were ...

  7. Vertical heterophoria and postural control in nonspecific chronic low back pain.

    PubMed

    Matheron, Eric; Kapoula, Zoï

    2011-03-30

    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.

  8. Development of action representation during adolescence as assessed from anticipatory control in a bimanual load-lifting task.

    PubMed

    Barlaam, F; Fortin, C; Vaugoyeau, M; Schmitz, C; Assaiante, C

    2012-09-27

    The aim of this study was to explore, during adolescence, alterations in the use of a sensori-motor representation as unveiled by the measurement of anticipatory postural control in a bimanual load-lifting task. We hypothesised that adolescence constitutes a period of refinement of anticipatory postural control due to on-going updates of the body schema and sensori-motor representations. The anticipatory postural control was assessed using a bimanual load-lifting paradigm in which subjects stabilise their left postural forearm, which is supporting an object, while they use their right hand to lift up the object. Kinematics and electromyographic data were recorded in two groups of adolescents (11-13 and 14-16 years of age) and a group of adults. Age and gender effects were tested. During voluntary unloading, the postural forearm stabilisation in adolescents was still different from the adult one, suggesting that further improvement of the postural forearm stabilisation must take place after the age of 16. No differences occur in the two adolescent groups. Moreover, girls presented a better stabilisation of the postural forearm than boys, indicating an earlier refinement of anticipatory postural control. The decrease of activity over postural flexors, which ensure postural stabilisation, appeared later in adolescents with respect to adults. Delayed timing adjustments and increased variability could reflect intense developmental processes underlain by an intense period of CNS maturation during adolescence. We discuss the role of brain maturation in the refinement of sensori-motor representations and the update of body schema.

  9. Posture analysis among Flemish secondary school teachers: difference between the use of chalkboards and electronic school boards during classroom teaching.

    PubMed

    Bogaert, Inge; De Martelaer, Kristine; Beutels, Michèle; De Ridder, Karolien; Zinzen, Evert

    2016-11-01

    The aim of this study was to (i) make a posture analysis of teachers during theoretical classroom teaching; (ii) to estimate the risk for the development of musculoskeletal problems (MSP); (iii) test the hypotheses that an electronic school board (EB) has more ergonomic advantages for teachers. Thirty-five secondary school teachers, of which 15 used an EB and 20 used chalkboards, were selected by convenience sampling and filmed during 30 min of a theoretical course. Posture analysis of back, arms, legs and risk assessment was performed using the Ovako Working Posture Analysis System. Most of the teachers' postures did not indicate a higher risk for MSP. However, some postures may be harmful when accumulated for several hours of teaching a day; especially, long periods of standing and standing with a bended back. Results also indicated that currently the use of an EB does not improve teachers' posture. Practitioner Summary: The relationship between objectively measured physical work load and risk for injuries among teachers was not analysed so far. In this study teachers' posture was analysed using the OWAS method. Prolonged standing and forward bending were identified as risk postures. Also, using an electronic school board currently does not improve posture.

  10. Development of a cost effective three-dimensional posture analysis tool: validity and reliability

    PubMed Central

    2013-01-01

    Background The lack of clear understanding of the association between sitting posture and adolescent musculoskeletal pain, might reflect invalid and/or unreliable posture measurement instruments. The psychometric properties of any new measurement instrument should be demonstrated prior to use for research or clinical purposes. This paper describes psychometric testing of a new three-dimensional (3D), portable, non-invasive posture analysis tool (3D-PAT), from sequential studies using a mannequin and high school students. Methods The first study compared the 3D-(X-, Y- and Z-) coordinates of reflective markers placed on a mannequin using the 3D-PAT, and the Vicon motion analysis system. This study also tested the reliability of taking repeated measures of the 3D-coordinates of the reflective markers. The second study determined the concurrent validity and test-retest reliability of the 3D-PAT measurements of nine sitting postural angles of high school students undertaking a standard computing task. In both studies, concordance correlation coefficients and Intraclass correlation coefficients described test-retest reliability, whilst Pearson product moment correlation coefficients and Bland-Altman plots demonstrated concurrent validity. Results The 3D-PAT provides reliable and valid 3D measurements of five of the nine postural angles i.e. head flexion, neck flexion, cranio-cervical angle, trunk flexion and head lateral bending in adolescents undertaking a standard task. Conclusions The 3D-PAT is appropriate for research and clinical settings to measure five upper quadrant postural angles in three dimensions. As a measurement instrument it can provide further understanding of the relationship between sitting posture, changes to sitting posture and adolescent musculoskeletal pain. PMID:24289665

  11. Determining posture from physiological tremor.

    PubMed

    Albert, Mark V; Kording, Konrad P

    2011-12-01

    The measurement of body and limb posture is important to many clinical and research studies. Current approaches either directly measure posture (e.g., using optical or magnetic methods) or more indirectly measure it by integrating changes over time (e.g., using gyroscopes and/or accelerometers). Here, we introduce a way of estimating posture from movements without requiring integration over time and the resulting complications. We show how the almost imperceptible tremor of the hand is affected by posture in an intuitive way and therefore can be used to estimate the posture of the arm. We recorded postures and tremor of the arms of volunteers. By using only the minor axis in the covariance of hand tremor, we could estimate the angle of the forearm with a standard deviation of about 4° when the subject's elbow is resting on a table and about 10° when it is off the table. This technique can also be applied as a post hoc analysis on other hand-position data sets to extract posture. This new method allows the estimation of body posture from tremor, is complementary to other techniques, and so can become a useful tool for future research and clinical applications.

  12. 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

    2017-03-16

    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.Hypertension Research advance online publication, 16 March 2017; doi:10.1038/hr.2017.39.

  13. Dynamic posture analysis of Spacelab-1 crew members.

    PubMed

    Anderson, D J; Reschke, M F; Homick, J E; Werness, S A

    1986-01-01

    Dynamic posture testing was conducted on the science crew of the Spacelab-1 mission on a single axis linear motion platform. Tests took place in pre- and post-flight sessions lasting approximately 20 min each. The pre-flight tests were widely spaced over the several months prior to the mission while the post-flight tests were conducted over the first, second, fourth, and sixth days after landing. Two of the crew members were also tested on the day of landing. Consistent with previous postural testing conducted on flight crews, these crew members were able to complete simple postural tasks to an acceptable level even in the first few hours after landing. Our tests were designed to induce dynamic postural responses using a variety of stimuli and from these responses, evaluate subtle changes in the postural control system which had occurred over the duration of the flight. Periodic sampling post-flight allowed us to observe the time course of readaptation to terrestrial life. Our observations of hip and shoulder position, when subjected to careful analysis, indicated modification of the postural response from pre- to post-flight and that demonstrable adjustments in the dynamic control of their postural systems were taking place in the first few days after flight. For transient stimuli where the platform on which they were asked to stand quickly moved a few centimeters fore or aft then stopped, ballistic or open loop 'programs' would closely characterize the response. During these responses the desired target position was not always achieved and of equal importance not always properly corrected some 15 seconds after the platform ceased to move. The persistent observation was that the subjects had a much stronger dependence on visual stabilization post-flight than pre-flight. This was best illustrated by a slow or only partial recovery to an upward posture after a transient base-of-support movement with eyes open. Postural responses to persistent wideband pseudorandom

  14. Effects of Four Days Hiking on Postural Control

    PubMed Central

    Vieira, Marcus Fraga; de Avelar, Ivan Silveira; Silva, Maria Sebastiana; Soares, Viviane; Lobo da Costa, Paula Hentschel

    2015-01-01

    Hiking is a demanding form of exercise that may cause delayed responses of the postural muscles and a loss of somatosensory information, particularly when repeatedly performed for several days. These effects may negatively influence the postural control of hikers. Therefore, the aim of this study was to investigate the effects of a four-day hike on postural control. Twenty-six adults of both sexes travelled 262 kilometers, stopping for lunch and resting in the early evening each day. Force platforms were used to collect center of pressure (COP) data at 100 Hz for 70 seconds before hiking started and immediately after arriving at the rest station each day. The COP time course data were analyzed according to global stabilometric descriptors, spectral analysis and structural descriptors using sway density curve (SDC) and stabilometric diffusion analysis (SDA). Significant increases were found for global variables in both the anterior-posterior and medial-lateral directions (COP sway area, COP total sway path, COP mean velocity, COP root mean square value and COP range). In the spectral analysis, only the 80% power frequency (F80) in the anterior-posterior direction showed a significant increase, reflecting the increase of the sway frequencies. The SDC revealed a significant increase in the mean distance between peaks (MD) and a significant decrease in the mean peak amplitudes (MP), suggesting that a larger torque amplitude is required for stabilization and that the postural stability is reduced. The SDA revealed a decrease in the long-term slope (Hl) and increases in the short-term (Ks) and the long-term (Kl) intercepts. We considered the likelihood that the presence of local and general fatigue, pain and related neuromuscular adaptations and somatosensory deficits may have contributed to these postural responses. Together, these results demonstrated that four days of hiking increased sway frequencies and deteriorated postural control in the standing position. PMID

  15. Effects of four days hiking on postural control.

    PubMed

    Vieira, Marcus Fraga; de Avelar, Ivan Silveira; Silva, Maria Sebastiana; Soares, Viviane; Lobo da Costa, Paula Hentschel

    2015-01-01

    Hiking is a demanding form of exercise that may cause delayed responses of the postural muscles and a loss of somatosensory information, particularly when repeatedly performed for several days. These effects may negatively influence the postural control of hikers. Therefore, the aim of this study was to investigate the effects of a four-day hike on postural control. Twenty-six adults of both sexes travelled 262 kilometers, stopping for lunch and resting in the early evening each day. Force platforms were used to collect center of pressure (COP) data at 100 Hz for 70 seconds before hiking started and immediately after arriving at the rest station each day. The COP time course data were analyzed according to global stabilometric descriptors, spectral analysis and structural descriptors using sway density curve (SDC) and stabilometric diffusion analysis (SDA). Significant increases were found for global variables in both the anterior-posterior and medial-lateral directions (COP sway area, COP total sway path, COP mean velocity, COP root mean square value and COP range). In the spectral analysis, only the 80% power frequency (F80) in the anterior-posterior direction showed a significant increase, reflecting the increase of the sway frequencies. The SDC revealed a significant increase in the mean distance between peaks (MD) and a significant decrease in the mean peak amplitudes (MP), suggesting that a larger torque amplitude is required for stabilization and that the postural stability is reduced. The SDA revealed a decrease in the long-term slope (Hl) and increases in the short-term (Ks) and the long-term (Kl) intercepts. We considered the likelihood that the presence of local and general fatigue, pain and related neuromuscular adaptations and somatosensory deficits may have contributed to these postural responses. Together, these results demonstrated that four days of hiking increased sway frequencies and deteriorated postural control in the standing position.

  16. 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.

  17. The effect of actual and imaginary handgrip on postural stability during different balance conditions.

    PubMed

    VanderHill, M S; Wolf, E E; Langenderfer, J E; Ustinova, K I

    2014-09-01

    The stabilizing effect of holding an object on upright posture has been demonstrated in a variety of settings. The mechanism of this effect is unknown but could be attributed to either additional sensorimotor activity triggered by a hand contact or cognitive efforts related to performance of a supra-postural task. A potential mechanism was investigated by comparing postural stability in young healthy individuals while gripping a custom instrumented wooden stick with a 5N force and while imagining holding the same stick in the hand. Twenty subjects were tested during three standing balance conditions: on a stationary surface, on a freely moving rockerboard, and with an unexpected perturbation of 10° forward rockerboard tipping. Postural stability was evaluated as velocity of the center of mass (COM) and center of pressure (COP) compared across all experimental conditions. COM and COP velocities were equally reduced when subjects gripped the stick and imagined gripping while standing stationary and on the rockerboard. When perturbed, subjects failed to show any postural stability improvements regardless of handgrip task. Results indicate a stabilizing effect of focusing attention on motor task performance. This cognitive strategy does not appear to contribute any additional stabilization when subjects are perturbed. This study adds to the current understanding of postural stabilization strategies.

  18. Dual-tasking postural control in patients with right brain damage.

    PubMed

    Bourlon, Clémence; Lehenaff, Laurent; Batifoulier, Cécile; Bordier, Aurélie; Chatenet, Aurélia; Desailly, Eric; Fouchard, Christian; Marsal, Muriel; Martinez, Marianne; Rastelli, Federica; Thierry, Anaïs; Bartolomeo, Paolo; Duret, Christophe

    2014-01-01

    The control of dual-tasking effects is a daily challenge in stroke neurorehabilitation. It maybe one of the reasons why there is poor functional prognosis after a stroke in the right hemisphere, which plays a dominant role in posture control. The purpose of this study was to explore cognitive motor interference in right brain-lesioned and healthy subjects maintaining a standing position while performing three different tasks: a control task, a simple attentional task and a complex attentional task. We measured the sway area of the subjects on a force platform, including the center of pressure and its displacements. Results showed that stroke patients presented a reduced postural sway compared to healthy subjects, who were able to maintain their posture while performing a concomitant attentional task in the same dual-tasking conditions. Moreover, in both groups, the postural sway decreased with the increase in attentional load from cognitive tasks. We also noticed that the stability of stroke patients in dual-tasking conditions increased together with the weight-bearing rightward deviation, especially when the attentional load of the cognitive tasks and lower limb motor impairments were high. These results suggest that stroke patients and healthy subjects adopt a similar postural regulation pattern aimed at maintaining stability in dual-tasking conditions involving a static standing position and different attention-related cognitive tasks. Our results indicate that attention processes might facilitate static postural control.

  19. The Stochastic Component of the Postural Sway Variability is Higher in Children with Balance Impairments.

    PubMed

    Kurz, Max J; Arpin, David J; Davies, Brenda L; Harbourne, Regina

    2013-08-01

    Children with balance impairments have an increased amount of variability in the sway of the center of pressure (COP) during standing. Limited efforts have been made to quantify the nature of the variability. This exploratory investigation examined the deterministic and stochastic features that comprise the time-dependent postural sway variability during standing. We measured the COP in standing of a heterogeneous group of children with balance impairments and an age-matched cohort of typically developing children, both with and without vision. The standard deviation of the COP was used to quantify the amount of variability present in the postural sway. A Langevin equation methodology was additionally employed to reconstruct the deterministic and stochastic features that comprised the postural sway variability. Our experiment resulted in three key findings: (1) removal of visual information increased the stochastic features of the postural sway variability, (2) the stochastic features were greater for the children with balance impairments, (3) the change in the amount of variability was strongly correlated with change the stochastic features. These results imply that the inability to suppress the stochastic features present in the nervous system may play a prominent role in the balance problems of children. Moreover, our results imply that alterations in the stochastic features drive the postural system away from successful balance strategies.

  20. 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.

  1. Posture interacts with arm weight support to modulate corticomotor excitability to the upper limb.

    PubMed

    Runnalls, Keith D; Anson, Greg; Byblow, Winston D

    2017-01-01

    The use of arm weight support (WS) to optimize movement quality may be an avenue for improved upper limb stroke rehabilitation; however, the underlying neurophysiological effects of WS are not well understood. Rehabilitation exercises may be performed when sitting or standing, but the interaction of posture with WS has not been examined until now. We explored the effect of posture with WS on corticomotor excitability (CME) in healthy adults. Thirteen participants performed static shoulder abduction in two postures (sitting and standing) at three levels of WS (0, 45, and 90 % of full support). Transcranial magnetic stimulation of primary motor cortex was used to elicit motor-evoked potentials (MEPs) in eight upper limb muscles. Stimulus-response (SR) curves were fitted to the MEP data using nonlinear regression. Whole-body posture interacted with WS to influence tonic activity and CME in all muscles examined. SR curve parameters revealed greater CME when standing compared to sitting for upper arm muscles, but lower CME to the shoulder, forearm, and hand. Distal to the shoulder, tonic activity and CME were modulated independent of any explicit differences in task requirements. Overall, these results support a model of integrated upper limb control influenced by whole-body posture and WS. These findings have implications for the application of WS in settings such as upper limb rehabilitation after stroke.

  2. Contribution of Muscle Strength and Integration of Afferent Input to Postural Instability in Persons with Stroke

    PubMed Central

    Marigold, Daniel S.; Eng, Janice J.; Tokuno, Craig D.; Donnelly, Catherine A.

    2011-01-01

    Objectives To determine the relationship of muscle strength to postural sway in persons with stroke under standing conditions in which vision and ankle proprioception were manipulated. Methods Forty persons with stroke and 40 healthy older adult controls were recruited from the community and underwent balance testing consisting of six conditions that manipulate vision and somatosensory information while standing. Postural sway was measured during each condition. In addition, lower extremity joint torques and cutaneous sensation from the plantar surface of the foot were assessed. Results Postural sway was increased with more challenging standing conditions (i.e. when multiple sensory systems were manipulated) to a greater extent with the group with stroke compared to controls. Muscle strength was only correlated to sway during the most challenging conditions. Furthermore, a greater number of persons with stroke fell during the balance testing compared to controls. Conclusions Impairments in re-weighting/integrating afferent information, in addition to muscle weakness appear to contribute to postural instability and falls in persons with stroke. These findings can be used by clinicians to design effective interventions for improving postural control following stroke. PMID:15537993

  3. 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

  4. 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.

  5. Threat-induced changes in attention during tests of static and anticipatory postural control.

    PubMed

    Zaback, Martin; Carpenter, Mark G; Adkin, Allan L

    2016-03-01

    Postural threat, manipulated through changes in surface height, influences postural control. Evidence suggests changes in attention may contribute to this relationship. However, limited research has explored where and how attention is reallocated when threatened. The primary aim of this study was to describe changes in attention when presented with a postural threat, while a secondary aim was to explore associations between changes in attention and postural control. Eighty-two healthy young adults completed tests of static (quiet standing) and anticipatory (rise to toes) postural control under threatening and non-threatening conditions. Participants completed an open-ended questionnaire after each postural task which asked them to list what they thought about or directed their attention toward. Each item listed was assigned a percentage value reflecting how much attention it occupied. Exit interviews were completed to help confirm where attention was directed. Five attention categories were identified: movement processes, threat-relevant stimuli, self-regulatory strategies, task objectives, and task-irrelevant information. For both postural tasks, the percentage values and number of items listed for movement processes, threat-relevant stimuli, and self-regulatory strategies increased under threatening compared to non-threatening conditions, while the percentage values and number of items listed for task objectives and task-irrelevant information decreased. Changes in attention related to movement processes and self-regulatory strategies were associated with changes in static postural control, while changes in attention related to threat-relevant stimuli were associated with changes in anticipatory postural control. These results suggest that threat-induced changes in attention are multidimensional and contribute to changes in postural control.

  6. [Menisci and posture].

    PubMed

    Sérgio, J S

    2000-01-01

    The first aim of this work is not only to review the localised perspective of meniscopathy, concerned with the consequences of meniscectomy, but to also view it in a broader dimension, in the behavioural aspect--related to postural activity. The second aim is to establish the relationship between these two dimensions. Meniscopathies invariably lead to degenerative alterations of the knee joint--not sufficiently explained by the local factors--that result in a situation of osteoarthritis. Some investigators established that the osteoarthritis process should not be confined only to the mechanical responsibility, due to some studies that also confirm the existence of biochemical alterations. However, others have also shown that the nervous system (NS) is likely to influence the inflammatory manifestations through the unmyelinated afferent fibers and sympathetic efferent fibers of the joints. These fibers can interact with non-neural elements, releasing some mediators, such as P substance (PS) and norepinephrine (NE), which, by themselves, or through other substances, contribute to the exacerbation of the inflammatory process. In order to relate the facts above, this longitudinal study comprised the following approaches clinical: anthropometric; biotechnical; and posturographic. It was characterised by five moments of data collection, the periodicity of which is related to the time of the surgery: the first moment is before surgery, followed by the remaining four, at six-week intervals, the sample being composed of--15 male caucasians, aged between 20 and 30 years, working for the Air Force. These Subjects were divided into two groups, according to the amount of meniscus removed in the longitudinal direction. Group A--meniscectomy < 1/2 the longitudinal body, composed of 7 subjects, with an average age of 21.4 years; and Group B, meniscectomy > 1/2 the longitudinal body, composed of: 8 subjects, with an average age of 24.1 years. The statistical analysis contained a

  7. [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.

  8. Effects of random whole-body vibration on postural control in Parkinson's disease.

    PubMed

    Turbanski, Stephan; Haas, Christian T; Schmidtbleicher, Dietmar; Friedrich, Antje; Duisberg, Petra

    2005-01-01

    We investigated spontaneous effects of random whole-body vibration (rWBV) on postural control in Parkinsonian subjects. Effects were examined in biomechanical tests from a total of 52 patients divided equally into one experimental and one control group. Postural control was tested pre- and post-treatment in two standardized conditions (narrow standing and tandem standing). The intervention was based on rWBV (ŷ: 3 mm, f: 6 Hz 1 Hz/sec) consisting of 5 series lasting 60 seconds each. The main findings from this study were that (1) rWBV can improve postural stability in Parkinson's disease (PD) spontaneously (2) these effects depend on the test condition. Based on the results of this study, rWBV can be regarded as an additional device in physical therapy in PD.

  9. 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

  10. Test Stand Construction

    NASA Technical Reports Server (NTRS)

    1964-01-01

    Construction crews install steel reinforcing rods at the base of what became the A-2 test stand. The excavation for the stand went down 50 feet with steel H-beams driven 100 feet deeper to form a foundation for the huge piers of the test stand.

  11. Spinal Posture of Thoracic and Lumbar Spine and Pelvic Tilt in Highly Trained Cyclists

    PubMed Central

    Muyor, José M.; López-Miñarro, Pedro A.; Alacid, Fernando

    2011-01-01

    The aim of this study was to evaluate sagittal thoracic and lumbar spinal curvatures and pelvic tilt in elite and master cyclists when standing on the floor, and sitting on a bicycle at three different handlebar-hand positions. A total of 60 elite male cyclists (mean age: 22.95 ± 3.38 years) and 60 master male cyclists (mean age: 34.27 ± 3.05 years) were evaluated. The Spinal Mouse system was used to measure sagittal thoracic and lumbar curvature in standing on the floor and sitting positions on the bicycle at three different handlebar-hand positions (high, medium, and low). The mean values for thoracic and lumbar curvatures and pelvic tilt in the standing position on the floor were 48.17 ± 8.05°, -27.32 ± 7.23°, and 13.65 ± 5.54°, respectively, for elite cyclists and 47.02 ± 9.24°, -25.30 ± 6.29°, and 11.25 ± 5.17° for master cyclists. A high frequency of thoracic hyperkyphosis in the standing position was observed (58.3% in elite cyclists and 53.3% in master cyclists), whereas predominately neutral values were found in the lumbar spine (88.3% and 76.7% in elite and master cyclists, respectively). When sitting on the bicycle, the thoracic curve was at a lower angle in the three handlebar-hand positions with respect to the standing position on the floor in both groups (p < 0.01). The lumbar curve adopted a kyphotic posture. In conclusion, cyclists present a high percentage of thoracic hyperkyphotic postures in standing positions on the floor. However, thoracic hyperkyphosis is not directly related to positions adopted on the bicycle. Key points This study evaluated thoracic and lumbar spinal curvatures and pelvic tilt in elite and master cyclists while standing and sitting on the bicycle. Elite and master cyclists showed a high frequency of thoracic hyperkyphosis and neutral lumbar lordosis in standing. Cyclists adopted a significantly lower thoracic kyphosis on the bicycle at the three handlebar positions analysed (upper, middle and lower handlebars

  12. Idiopathic orthostatic intolerance and postural tachycardia syndromes

    NASA Technical Reports Server (NTRS)

    Jacob, G.; Biaggioni, I.; Robertson, D. (Principal Investigator)

    1999-01-01

    Upright posture imposes a substantial gravitational stress on the body, for which we are able to compensate, in large part because of the autonomic nervous system. Alteration in autonomic function, therefore, may lead to orthostatic intolerance. On one extreme, patients with autonomic failure caused by degenerative loss of autonomic function are severely disabled by orthostatic hypotension and may faint whenever they stand up. Fortunately, such patients are relatively rare. On the other hand, disabling orthostatic intolerance can develop in otherwise normal young people. These patients can be severely impaired by symptoms of fatigue, tachycardia, and shortness of breath when they stand up. The actual incidence of this disorder is unknown, but these patients make up the largest group of patients referred to centers that specialize in autonomic disorders. We will review recent advances made in the understanding of this condition, potential pathophysiological mechanisms that contribute to orthostatic intolerance, therapeutic alternatives currently available for the management of these patients, and areas in which more research is needed.

  13. The effect of acute back muscle fatigue on postural control strategy in people with and without recurrent low back pain.

    PubMed

    Johanson, Ege; Brumagne, Simon; Janssens, Lotte; Pijnenburg, Madelon; Claeys, Kurt; Pääsuke, Mati

    2011-12-01

    Back muscle fatigue decreases the postural stability during quiet standing, but it is not known whether this fatigue-induced postural instability is due to an altered proprioceptive postural control strategy. Therefore, the aim of the study was to evaluate if acute back muscle fatigue may be a mechanism to induce or sustain a suboptimal proprioceptive postural control strategy in people with and without recurrent low back pain (LBP). Postural sway was evaluated on a force platform in 16 healthy subjects and 16 individuals with recurrent LBP during a control (Condition 1) and a back muscle fatigue condition (Condition 2). Back muscle fatigue was induced by performing a modified Biering-Sørensen test. Ankle and back muscle vibration, a potent stimulus for muscle spindles, was used to differentiate proprioceptive postural control strategies during standing on a stable and unstable support surface, where the latter was achieved by placing a foam pad under the feet. Ankle signals were predominantly used for postural control in all subjects although, in each condition, their influence was greater in people with LBP compared to healthy subjects (p < 0.001). The latter group adapted their postural control strategy when standing on an unstable surface so that input from back muscles increased (p < 0.001). However, such adaptation was not observed when the back muscles were fatigued. Furthermore, people with LBP continued to rely strongly on ankle proprioception regardless of the testing conditions. In conclusion, these findings suggest that impaired back muscle function, as a result of acute muscle fatigue or pain, may lead to an inability to adapt postural control strategies to the prevailing conditions.

  14. Postural sway and brain potentials evoked by visual depth stimuli.

    PubMed

    Kiyota, Takeo; Fujiwara, Katsuo

    2008-07-01

    This study measured the postural sway and brain potentials evoked by a visual depth stimulus. Thirteen subjects maintained standing posture on a force platform, and were administered two types of depth stimuli, strong and weak. The latency and amplitude of evoked potentials as well as changes in center of foot pressure (CFP) and the electromyogram (EMG) were examined. CFP displacement was found to change according to stimulus intensity. In the occipital lobe, evoked potentials exhibited a triphasic peak, with the first positive peak at approximately 120 ms (P120), the first negative peak at approximately 160 ms (N200), and the second positive peak at approximately 260 ms (P250). Brain evoked potentials correlated with CFP displacement as well as the latency of onset of EMG response. Onset of EMG response was probably related to the P120 component, whereas CFP displacement was related to the P250 component.

  15. Characterizing the human postural control system using detrended fluctuation analysis

    NASA Astrophysics Data System (ADS)

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

    2010-01-01

    Detrended fluctuation analysis is used to study the behaviour of the time series of the position of the center of pressure, output from the activity of a human postural control system. The results suggest that these trajectories present a crossover in their scaling properties from persistent (for high frequencies, short-range time scale) to anti-persistent (for low frequencies, long-range time scale) behaviours. The values of the scaling exponent found for the persistent parts of the trajectories are very similar for all the cases analysed. The similarity of the results obtained for the measurements done with both eyes open and both eyes closed indicate either that the visual system may be disregarded by the postural control system, while maintaining quiet standing, or that the control mechanisms associated with each type of information (visual, vestibular and somatosensory) cannot be disentangled with this technique.

  16. Numerical simulation of the influence of gravity and posture on cardiac performance

    NASA Technical Reports Server (NTRS)

    Peterson, Kristy; Ozawa, Edwin T.; Pantalos, George M.; Sharp, M. Keith

    2002-01-01

    A numerical model of the cardiovascular system was used to quantify the influences on cardiac function of intrathoracic pressure and intravascular and intraventricular hydrostatic pressure, which are fundamental biomechanical stimuli for orthostatic response. The model included a detailed arterial circulation with lumped parameter models of the atria, ventricles, pulmonary circulation, and venous circulation. The venous circulation was divided into cranial, central, and caudal regions with nonlinear compliance. Changes in intrathoracic pressure and the effects of hydrostatic pressure were simulated in supine, launch, sitting, and standing postures for 0, 1, and 1.8 G. Increasing intrathoracic pressure experienced with increasing gravity caused 12% and 14% decreases in cardiac output for 1 and 1.8 G supine, respectively, compared to 0 G. Similar results were obtained for launch posture, in which the effects of changing intrathoracic pressure dominated those of hydrostatic pressure. Compared to 0 G, cardiac output decreased 0.9% for 1 G launch and 15% for 1.8 G launch. In sitting and standing, the position of the heart above the hydrostatic indifference level caused the effects of changing hydrostatic pressure to dominate those of intrathoracic pressure. Compared to 0 G, cardiac output decreased 13% for 1 G sitting and 23% for 1.8 G sitting, and decreased 17% for 1 G standing and 31% for 1.8 G standing. For a posture change from supine to standing in 1 G, cardiac output decreased, consistent with the trend necessary to explain orthostatic intolerance in some astronauts during postflight stand tests. Simulated lower body negative pressure (LBNP) in 0 G reduced cardiac output and mean aortic pressure similar to I G standing, suggesting that LBNP provides at least some cardiovascular stimuli that may be useful in preventing postflight orthostatic intolerance. A unifying concept, consistent with the Frank-Starling mechanism of the heart, was that cardiac output was

  17. Numerical simulation of the influence of gravity and posture on cardiac performance.

    PubMed

    Peterson, Kristy; Ozawa, Edwin T; Pantalos, George M; Sharp, M Keith

    2002-02-01

    A numerical model of the cardiovascular system was used to quantify the influences on cardiac function of intrathoracic pressure and intravascular and intraventricular hydrostatic pressure, which are fundamental biomechanical stimuli for orthostatic response. The model included a detailed arterial circulation with lumped parameter models of the atria, ventricles, pulmonary circulation, and venous circulation. The venous circulation was divided into cranial, central, and caudal regions with nonlinear compliance. Changes in intrathoracic pressure and the effects of hydrostatic pressure were simulated in supine, launch, sitting, and standing postures for 0, 1, and 1.8 G. Increasing intrathoracic pressure experienced with increasing gravity caused 12% and 14% decreases in cardiac output for 1 and 1.8 G supine, respectively, compared to 0 G. Similar results were obtained for launch posture, in which the effects of changing intrathoracic pressure dominated those of hydrostatic pressure. Compared to 0 G, cardiac output decreased 0.9% for 1 G launch and 15% for 1.8 G launch. In sitting and standing, the position of the heart above the hydrostatic indifference level caused the effects of changing hydrostatic pressure to dominate those of intrathoracic pressure. Compared to 0 G, cardiac output decreased 13% for 1 G sitting and 23% for 1.8 G sitting, and decreased 17% for 1 G standing and 31% for 1.8 G standing. For a posture change from supine to standing in 1 G, cardiac output decreased, consistent with the trend necessary to explain orthostatic intolerance in some astronauts during postflight stand tests. Simulated lower body negative pressure (LBNP) in 0 G reduced cardiac output and mean aortic pressure similar to I G standing, suggesting that LBNP provides at least some cardiovascular stimuli that may be useful in preventing postflight orthostatic intolerance. A unifying concept, consistent with the Frank-Starling mechanism of the heart, was that cardiac output was

  18. Imaging Posture Veils Neural Signals

    PubMed Central

    Thibault, Robert T.; Raz, Amir

    2016-01-01

    Whereas modern brain imaging often demands holding body positions incongruent with everyday life, posture governs both neural activity and cognitive performance. Humans commonly perform while upright; yet, many neuroimaging methodologies require participants to remain motionless and adhere to non-ecological comportments within a confined space. This inconsistency between ecological postures and imaging constraints undermines the transferability and generalizability of many a neuroimaging assay. Here we highlight the influence of posture on brain function and behavior. Specifically, we challenge the tacit assumption that brain processes and cognitive performance are comparable across a spectrum of positions. We provide an integrative synthesis regarding the increasingly prominent influence of imaging postures on autonomic function, mental capacity, sensory thresholds, and neural activity. Arguing that neuroimagers and cognitive scientists could benefit from considering the influence posture wields on both general functioning and brain activity, we examine existing imaging technologies and the potential of portable and versatile imaging devices (e.g., functional near infrared spectroscopy). Finally, we discuss ways that accounting for posture may help unveil the complex brain processes of everyday cognition. PMID:27818629

  19. Posture, flexibility and grip strength in horse riders.

    PubMed

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

    2014-09-29

    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.

  20. 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

  1. The effects of safety handrails and the heights of scaffolds on the subjective and objective evaluation of postural stability and cardiovascular stress in novice and expert construction workers.

    PubMed

    Min, Seung-Nam; Kim, Jung-Yong; Parnianpour, Mohamad

    2012-05-01

    Work performed on scaffolds carries the risk of falling that disproportionately threatens the safety and health of novice construction workers. Hence, objective measures of the postural stability, cardiovascular stress, and subjective difficulty in maintaining postural balance were evaluated for four expert and four novice construction workers performing a manual task in a standing posture on a scaffold with and without safety handrails at two different elevation heights. Based on a multivariate analysis of variance, the experience, scaffold height, and presence of a handrail were found to significantly affect measures of the postural stability and cardiovascular stress. At a lower level of worker experience, a higher scaffold height, and in the absence of a handrail (which may correspond to higher risk of a fall), postural stability was significantly reduced, while cardiovascular stress and subjective difficulties in maintaining postural balance increased. We emphasize the importance of training and handrails for fall prevention at construction sites.

  2. Relationship between Spectral Characteristics of Spontaneous Postural Sway and Motion Sickness Susceptibility

    PubMed Central

    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. PMID:26657203

  3. The effects of fall-risk-increasing drugs on postural control: a literature review.

    PubMed

    de Groot, Maartje H; van Campen, Jos P C M; Moek, Marije A; Tulner, Linda R; Beijnen, Jos H; Lamoth, Claudine J C

    2013-11-01

    Meta-analyses showed that psychotropic drugs (antidepressants, neuroleptics, benzodiazepines, antiepileptic drugs) and some cardiac drugs (digoxin, type IA anti-arrhythmics, diuretics) are associated with increased fall risk. Because balance and gait disorders are the most consistent predictors of future falls, falls due to use of these so-called fall-risk-increasing drugs (FRIDs) might be partly caused by impairments of postural control that these drugs can induce. Therefore, the effects of FRIDs on postural control were examined by reviewing literature. Electronic databases and reference lists of identified papers were searched until June 2013. Only controlled research papers examining the effects of FRIDs on postural control were included. FRIDs were defined according to meta-analyses as antidepressants, neuroleptics, benzodiazepines, antiepileptic drugs, digoxin, type IA anti-arrhythmics, and diuretics. Ninety-four papers were included, of which study methods for quantifying postural control, and the effects of FRIDs on postural control were abstracted. Postural control was assessed with a variety of instruments, mainly evaluating aspects of body sway during quiet standing. In general, postural control was impaired, indicated by an increase in parameters quantifying body sway, when using psychotropic FRIDs. The effects were more pronounced when people were of a higher age, used psychotropics at higher daily doses, with longer half-lives, and administered for a longer period. From the present literature review, it can be concluded that psychotropic drugs cause impairments in postural control, which is probably one of the mediating factors for the increased fall risk these FRIDs are associated with. The sedative effects of these drugs on postural control are reversible, as was proven in intervention studies where FRIDs were withdrawn. The findings of the present literature review highlight the importance of using psychotropic drugs in the older population only at

  4. Common postural defects among music students.

    PubMed

    Blanco-Piñeiro, Patricia; Díaz-Pereira, M Pino; Martínez, Aurora

    2015-07-01

    Postural quality during musical performance affects both musculoskeletal health and the quality of the performance. In this study we examined the posture of 100 students at a Higher Conservatory of Music in Spain. By analysing video tapes and photographs of the students while performing, a panel of experts extracted values of 11 variables reflecting aspects of overall postural quality or the postural quality of various parts of the body. The most common postural defects were identified, together with the situations in which they occur. It is concluded that most students incur in unphysiological postures during performance. It is hoped that use of the results of this study will help correct these errors.

  5. Impaired plantar sensitivity among the obese is associated with increased postural sway.

    PubMed

    Wu, Xuefang; Madigan, Michael L

    2014-11-07

    Impaired foot plantar sensitivity has been hypothesized among individuals who are obese, and may contribute to their impaired balanced during quiet standing. The objective of this study was to investigate the effects of obesity on plantar sensitivity, and explore the relationship between plantar sensitivity and balance during quiet standing. Thirty-nine young adults from the university population participated in the study including 19 obese and 20 non-obese adults. Plantar sensitivity was measured as the force threshold at which an increasing force applied to the plantar surface of the foot was first perceived, and the force threshold at which a decreasing force was last perceived. Measurements were obtained while standing, and at two locations on the plantar surface of the dominant foot. Postural sway during quiet standing was then measured under three different sensory conditions. Results indicated less sensitive plantar sensitivity and increased postural sway among the obese, and statistically significant correlations between plantar sensitivity and postural sway that were characterized as weak to moderate in strength. As such, impaired plantar sensitivity among individuals who are obese may be a mechanism by which obesity degrades standing balance among these individuals.

  6. 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.

  7. 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.

  8. Improving postural control by applying mechanical noise to ankle muscle tendons.

    PubMed

    Borel, Liliane; Ribot-Ciscar, Edith

    2016-08-01

    The application of subthreshold mechanical vibrations with random frequencies (white mechanical noise) to ankle muscle tendons is known to increase muscle proprioceptive information and to improve the detection of ankle movements. The aim of the present study was to analyze the effect of this mechanical noise on postural control, its possible modulation according to the sensory strategies used for postural control, and the consequences of increasing postural difficulty. The upright stance of 20 healthy young participants tested with their eyes closed was analyzed during the application of four different levels of noise and compared to that in the absence of noise (control) in three conditions: static, static on foam, and dynamic (sinusoidal translation). The quiet standing condition was conducted with the eyes open and closed to determine the subjects' visual dependency to maintain postural stability. Postural performance was assessed using posturographic and motion analysis evaluations. The results in the static condition showed that the spectral power density of body sway significantly decreased with an optimal level of noise and that the higher the spectral power density without noise, the greater the noise effect, irrespective of visual dependency. Finally, noise application was ineffective in the foam and dynamic conditions. We conclude that the application of mechanical noise to ankle muscle tendons is a means to improve quiet standing only. These results suggest that mechanical noise stimulation may be more effective in more impaired populations.

  9. Motor systems and postural instability.

    PubMed

    Vassar, Rachel L; Rose, Jessica

    2014-01-01

    Acute alcohol intoxication and chronic alcohol dependence alter the neurologic control of posture and motor function. Ethanol delays the conduction of electric signals from the central nervous system to the muscles controlling posture and impairs the integration of sensory inputs required for maintaining vertical stance. Consequently, alcohol intoxication delays the ability to detect postural changes and enact the appropriate response. Common signs of acute alcohol intoxication include spinocerebellar and vestibulocerebellar ataxia, oculomotor changes, and increased reliance on visuospatial clues. Chronic alcoholism results in postural tremors and excessive sway during quiet stance that can persist even after sobriety is achieved. Underlying neurologic changes due to chronic alcoholism have been found to be associated with these characteristic postural changes and include decreased volume of the anterior superior vermis of the cerebellum, decreased connectivity within the corpus callosum, and overall cortical atrophy. Severity of motor impairments and other symptoms from alcoholism relate to a variety of factors, including duration of alcoholism, age, sex, and other health determinants and comorbidities. Imaging studies highlight the potential for partial recovery from neurologic and motor deficits caused by alcoholism. Emerging evidence on the motor and neurologic changes caused by alcohol dependence may allow for improved treatment and prevention of the morbidities associated with alcoholism.

  10. Sensorimotor integration in human postural control

    NASA Technical Reports Server (NTRS)

    Peterka, R. J.

    2002-01-01

    It is generally accepted that human bipedal upright stance is achieved by feedback mechanisms that generate an appropriate corrective torque based on body-sway motion detected primarily by visual, vestibular, and proprioceptive sensory systems. Because orientation information from the various senses is not always available (eyes closed) or accurate (compliant support surface), the postural control system must somehow adjust to maintain stance in a wide variety of environmental conditions. This is the sensorimotor integration problem that we investigated by evoking anterior-posterior (AP) body sway using pseudorandom rotation of the visual surround and/or support surface (amplitudes 0.5-8 degrees ) in both normal subjects and subjects with severe bilateral vestibular loss (VL). AP rotation of body center-of-mass (COM) was measured in response to six conditions offering different combinations of available sensory information. Stimulus-response data were analyzed using spectral analysis to compute transfer functions and coherence functions over a frequency range from 0.017 to 2.23 Hz. Stimulus-response data were quite linear for any given condition and amplitude. However, overall behavior in normal subjects was nonlinear because gain decreased and phase functions sometimes changed with increasing stimulus amplitude. "Sensory channel reweighting" could account for this nonlinear behavior with subjects showing increasing reliance on vestibular cues as stimulus amplitudes increased. VL subjects could not perform this reweighting, and their stimulus-response behavior remained quite linear. Transfer function curve fits based on a simple feedback control model provided estimates of postural stiffness, damping, and feedback time delay. There were only small changes in these parameters with increasing visual stimulus amplitude. However, stiffness increased as much as 60% with increasing support surface amplitude. To maintain postural stability and avoid resonant behavior, an

  11. Sensorimotor integration in human postural control.

    PubMed

    Peterka, R J

    2002-09-01

    It is generally accepted that human bipedal upright stance is achieved by feedback mechanisms that generate an appropriate corrective torque based on body-sway motion detected primarily by visual, vestibular, and proprioceptive sensory systems. Because orientation information from the various senses is not always available (eyes closed) or accurate (compliant support surface), the postural control system must somehow adjust to maintain stance in a wide variety of environmental conditions. This is the sensorimotor integration problem that we investigated by evoking anterior-posterior (AP) body sway using pseudorandom rotation of the visual surround and/or support surface (amplitudes 0.5-8 degrees ) in both normal subjects and subjects with severe bilateral vestibular loss (VL). AP rotation of body center-of-mass (COM) was measured in response to six conditions offering different combinations of available sensory information. Stimulus-response data were analyzed using spectral analysis to compute transfer functions and coherence functions over a frequency range from 0.017 to 2.23 Hz. Stimulus-response data were quite linear for any given condition and amplitude. However, overall behavior in normal subjects was nonlinear because gain decreased and phase functions sometimes changed with increasing stimulus amplitude. "Sensory channel reweighting" could account for this nonlinear behavior with subjects showing increasing reliance on vestibular cues as stimulus amplitudes increased. VL subjects could not perform this reweighting, and their stimulus-response behavior remained quite linear. Transfer function curve fits based on a simple feedback control model provided estimates of postural stiffness, damping, and feedback time delay. There were only small changes in these parameters with increasing visual stimulus amplitude. However, stiffness increased as much as 60% with increasing support surface amplitude. To maintain postural stability and avoid resonant behavior, an

  12. Anticipatory and compensatory postural adjustments in conditions of body asymmetry induced by holding an object.

    PubMed

    Chen, Bing; Lee, Yun-Ju; Aruin, Alexander S

    2015-11-01

    The effect of body asymmetry on anticipatory and compensatory postural adjustments was studied. Ten healthy subjects stood on the force platform and held an object in one hand which induced body asymmetry. Subjects were exposed to external perturbations applied to their shoulders while standing with either normal or narrow base of support. Bilateral electromyographic activity (EMG) of dorsal and ventral trunk and leg muscles and center-of-pressure displacements were recorded. Data was analyzed within the intervals typical for anticipatory (APA) and compensatory postural adjustments. Integrals of EMG activity and co-contraction and reciprocal activation of muscles were calculated and analyzed. Reciprocal activation of muscles on the target side and co-contraction of muscles on the contralateral side were seen when standing in asymmetrical stance and being subjected to external perturbations. Decreased magnitudes of co-contraction and reciprocal activation of muscles were seen in the APA phase while standing asymmetrically with narrow base of support. The findings highlight the importance of investigating the role of body asymmetry in maintaining control of vertical posture. The outcome of the study provides a foundation for future studies focusing on improvement in postural control in individuals with body asymmetry due to unilateral weakness.

  13. Orthodeoxia and postural orthostatic tachycardia in patients with pulmonary arteriovenous malformations: a prospective 8-year series.

    PubMed

    Santhirapala, V; Chamali, B; McKernan, H; Tighe, H C; Williams, L C; Springett, J T; Bellenberg, H R; Whitaker, A J; Shovlin, C L

    2014-11-01

    Postural changes in 258 patients with pulmonary arteriovenous malformations (PAVMs) reviewed between 2005 and 2013 were evaluated prospectively using validated pulse oximetry methods. Of the 257 completing the test, 75 (29%) demonstrated orthodeoxia with an oxygen saturation fall of at least 2% on standing. None described platypnoea (dyspnoea on standing). The heart rate was consistently higher in the erect posture: 74 (29%) had a postural orthostatic tachycardia of ≥20 min(-1), and in 25 (10%) this exceeded 30 min(-1). Orthostatic tachycardia was more pronounced in PAVM patients than controls without orthodeoxia (age-adjusted coefficient 5.5 (95% CIs 2.6, 8.4) min(-1), p<0.001). For PAVM patients, the age-adjusted pulse rise was 0.79 min(-1) greater for every 1% greater drop in oxygen saturation on standing (p<0.001). In contrast to the postural orthostatic tachycardia syndrome, in this population, there was a trend for more pronounced orthostatic tachycardia to be associated with better exercise tolerance.

  14. Biomechanical evaluation of the relationship between postural control and body mass index.

    PubMed

    Ku, P X; Abu Osman, N A; Yusof, A; Wan Abas, W A B

    2012-06-01

    Postural stability is crucial in maintaining body balance during quiet standing, locomotion, and any activities that require a high degree of balance performance, such as participating in sports and dancing. Research has shown that there is a relationship between stability and body mass. The aims of this study were to examine the impact that two variables had on static postural control: body mass index (BMI) and gender. Eighty healthy young adults (age=21.7±1.8 yr; height=1.65±0.09 m; mass=67.5±19.0 kg) participated in the study and the static postural control was assessed using the Biodex Balance System, with a 20 Hz sampling rate in the bipedic stance (BLS) and unipedic stance (ULS) for 30s. Five test evaluations were performed for each balance test. Postural control was found to be negatively correlated with increased adiposity, as the obese BMI group performed significantly poorer than the underweight, normal weight and overweight groups during BLS and ULS tests. The underweight, normal weight and overweight groups exhibited greater anterior-posterior stability in postural control during quiet stance. In addition, female displayed a trend of having a greater postural sway than male young adults, although it was evidenced in only some BMI groups. This study revealed that BMI do have an impact on postural control during both BLS and ULS. As such, BMI and gender-specific effects should be taken into consideration when selecting individuals for different types of sporting activities, especially those that require quiet standing.

  15. Design and Validation of a Low-Cost Portable Device to Quantify Postural Stability †

    PubMed Central

    Zhu, Yong

    2017-01-01

    Measurement of the displacement of the center-of-pressure (COP) is an important tool used in biomechanics to assess postural stability and human balance. The goal of this research was to design and validate a low-cost portable device that can offer a quick indication of the state of postural stability and human balance related conditions. Approximate entropy (ApEn) values reflecting the amount of irregularity hiding in COP oscillations were used to calculate the index. The prototype adopted a portable design using the measurements of the load cells located at the four corners of a low-cost force platform. The test subject was asked to stand on the device in a quiet, normal, upright stance for 30 s with eyes open and subsequently for 30 s with eyes closed. Based on the COP displacement signals, the ApEn values were calculated. The results indicated that the prototype device was capable of capturing the increase in regularity of postural control in the visual-deprivation conditions. It was also able to decipher the subtle postural control differences along anterior–posterior and medial–lateral directions. The data analysis demonstrated that the prototype would enable the quantification of postural stability and thus provide a low-cost portable device to assess many conditions related to postural stability and human balance such as aging and pathologies. PMID:28335461

  16. Aging causes a reorganization of cortical and spinal control of posture

    PubMed Central

    Papegaaij, Selma; Taube, Wolfgang; Baudry, Stéphane; Otten, Egbert; Hortobágyi, Tibor

    2013-01-01

    Classical studies in animal preparations suggest a strong role for spinal control of posture. In humans it is now established that the cerebral cortex contributes to postural control of unperturbed and perturbed standing. The age-related degeneration and accompanying functional changes in the brain, reported so far mainly in conjunction with simple manual motor tasks, may also affect the mechanisms that control complex motor tasks involving posture. This review outlines the age-related structural and functional changes at spinal and cortical levels and provides a mechanistic analysis of how such changes may be linked to the behaviorally manifest postural deficits in old adults. The emerging picture is that the age-related reorganization in motor control during voluntary tasks, characterized by differential modulation of spinal reflexes, greater cortical activation and cortical disinhibition, is also present during postural tasks. We discuss the possibility that this reorganization underlies the increased coactivation and dual task interference reported in elderly. Finally, we propose a model for future studies to unravel the structure-function-behavior relations in postural control and aging. PMID:24624082

  17. Design and Validation of a Low-Cost Portable Device to Quantify Postural Stability.

    PubMed

    Zhu, Yong

    2017-03-18

    Measurement of the displacement of the center-of-pressure (COP) is an important tool used in biomechanics to assess postural stability and human balance. The goal of this research was to design and validate a low-cost portable device that can offer a quick indication of the state of postural stability and human balance related conditions. Approximate entropy (ApEn) values reflecting the amount of irregularity hiding in COP oscillations were used to calculate the index. The prototype adopted a portable design using the measurements of the load cells located at the four corners of a low-cost force platform. The test subject was asked to stand on the device in a quiet, normal, upright stance for 30 s with eyes open and subsequently for 30 s with eyes closed. Based on the COP displacement signals, the ApEn values were calculated. The results indicated that the prototype device was capable of capturing the increase in regularity of postural control in the visual-deprivation conditions. It was also able to decipher the subtle postural control differences along anterior-posterior and medial-lateral directions. The data analysis demonstrated that the prototype would enable the quantification of postural stability and thus provide a low-cost portable device to assess many conditions related to postural stability and human balance such as aging and pathologies.

  18. Postural challenge affects motor cortical activity in young and old adults.

    PubMed

    Papegaaij, Selma; Taube, Wolfgang; van Keeken, Helco G; Otten, Egbert; Baudry, Stéphane; Hortobágyi, Tibor

    2016-01-01

    When humans voluntarily activate a muscle, intracortical inhibition decreases. Such a decrease also occurs in the presence of a postural challenge and more so with increasing age. Here, we examined age-related changes in motor cortical activity during postural and non-postural contractions with varying levels of postural challenge. Fourteen young (age 22) and twelve old adults (age 70) performed three conditions: (1) voluntary contraction of the soleus muscle in sitting and (2) leaning forward while standing with and (3) without being supported. Subthreshold transcranial magnetic stimulation was applied to the soleus motor area suppressing ongoing EMG, as an index of motor cortical activity. The area of EMG suppression was ~60% smaller (p<0.05) in unsupported vs. supported leaning and sitting, with no difference between these latter two conditions (p>0.05). Even though in absolute terms young compared with old adults leaned farther (p=0.018), there was no age effect or an age by condition interaction in EMG suppression. Leaning closer to the maximum without support correlated with less EMG suppression (rho=-0.44, p=0.034). We conclude that the critical factor in modulating motor cortical activity was postural challenge and not contraction aim or posture. Age did not affect the motor control strategy as quantified by the modulation of motor cortical activity, but the modulation appeared at a lower task difficulty with increasing age.

  19. 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

  20. Degraded postural performance after muscle fatigue can be compensated by skin stimulation.

    PubMed

    Thedon, Thibaud; Mandrick, Kevin; Foissac, Matthieu; Mottet, Denis; Perrey, Stéphane

    2011-04-01

    It has been shown that the ability of humans to maintain a quiet standing posture is degraded after fatigue of the muscles at the ankle. Yet, it has also been shown that skin stimulation at the ankle could improve postural performance. In the present study, we addressed the issue of the interaction of these two effects. Subjects were tested with the eyes closed in four conditions of quiet stance: with or without skin stimulation and before and after a fatigue protocol. The skin was stimulated with a piece of medical adhesive tape on the Achilles' tendon. The fatigue protocol consisted of multiple sets of ankle plantar flexion of both legs on stool. Without fatigue, we did not observe a significant effect of the tape. With fatigue, subjects decreased their postural performance significantly, but this effect was cancelled out when a piece of tape was glued on the Achilles' tendon. This indicated that the beneficial effect of the tape was unveiled by the degraded postural performance after fatigue. We conclude that, when the muscular sensory input flow normally relevant for the postural system is impaired due to fatigue, the weight of cutaneous information increases for the successful representation of movements in space to adjust postural control.

  1. 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

  2. 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.

  3. Postural discomfort and perceived exertion in standardized box-holding postures.

    PubMed

    Olendorf, M R; Drury, C G

    2001-12-15

    To help in the design or redesign of workplaces it would be helpful to know in advance the postural stress consequences of a wide range of body postures. This experiment evaluated 168 postures chosen to represent those in the Ovako Working-posture Analysing System (OWAS) using Rated Perceived Exertion (RPE) and Body Part Discomfort (BPD) measures. The postures comprised all combinations of three arm postures, four back postures, seven leg postures and two forces (weights of held boxes). Twelve male subjects held each posture for a fixed duration (20 s) before providing RPE and BPD ratings. Analysis of the ratings gave highly significant main effects, with the major driver being the object weight. As each factor was varied, the largest effect was on the body region corresponding to that factor. A simple main-effects-only additive model explained 91% of the variance of RPE means for the postures.

  4. Saw gin stands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The saw gin stand is the heart of the saw ginning system. Almost from the initial filing of patents for the spiked tooth gin and the saw gin in 1794 and 1796 by Whitney and then Holmes respectively (Hughs and Holt, 2015), the saw gin stand has predominated over early roller-type gins in the U.S. co...

  5. Planter unit test stand

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A planter test stand was developed to evaluate individual row-crop metering units in early 2013. This test stand provided the ability to quantify actual seed metering in terms of population, seed spacing, skips, and multiples over a range of meter RPMs and vacuum pressures. Preliminary data has been...

  6. Age Related Decline in Postural Control Mechanisms.

    ERIC Educational Resources Information Center

    Stelmach, George E.; And Others

    1989-01-01

    Studied voluntary and reflexive mechanisms of postural control of young (N=8) and elderly (N=8) adults through measurement of reflexive reactions to large-fast and small-slow ankle rotation postural disturbances. Found reflexive mechanisms relatively intact for both groups although elderly appeared more disadvantaged when posture was under the…

  7. Postural Control in Children with Autism.

    ERIC Educational Resources Information Center

    Kohen-Raz, Reuven; And Others

    1992-01-01

    Postural control was evaluated in 91 autistic, 166 normal, and 18 mentally retarded children using a computerized posturographic procedure. In comparison to normal children, the autistic subjects were less likely to exhibit age-related changes in postural performance, and postures were more variable and less stable. (Author/JDD)

  8. Learning Upright Standing on a Multiaxial Balance Board

    PubMed Central

    Valle, Maria Stella; Casabona, Antonino; Cavallaro, Carlo; Castorina, Gabriele; Cioni, Matteo

    2015-01-01

    Upright stance on a balance board is a skill requiring complex rearrangement of the postural control. Despite the large use of these boards in training the standing posture, a comprehensive analysis of the learning process underlying the control of these devices is lacking. In this paper learning to maintain a stable stance on a multiaxial oscillating board was studied by analyzing performance changes over short and long periods. Healthy participants were asked to keep the board orientation as horizontal as possible for 20 sec, performing two sessions of 8 trials separated by 15-min pause. Memory consolidation was tested one week later. Amplitude and variability of the oscillations around horizontal plane and area and sway path of the board displacement decreased rapidly over the first session. The performance was stable during the second session, and retained after 1 week. A similar behavior was observed in the anterior-posterior and medial-lateral directions for amplitude and variability parameters, with less stable balance in the anterior-posterior direction. Approximate entropy and mean power frequency, assessing temporal dynamics and frequency content of oscillations, changed only in the anterior-posterior direction during the retention test. Overall, the ability to stand on a balance board is rapidly acquired, and retained for long time. The asymmetric stability between anterior-posterior and medial-lateral directions replicates a structure observed in other standing stances, suggesting a possible transfer from previous postural experiences. Conversely, changes in the temporal dynamics and the frequency content could be associated with new postural strategies developed later during memory consolidation. PMID:26544694

  9. Role of brain hemispheric dominance in anticipatory postural control strategies.

    PubMed

    Cioncoloni, David; Rosignoli, Deborah; Feurra, Matteo; Rossi, Simone; Bonifazi, Marco; Rossi, Alessandro; Mazzocchio, Riccardo

    2016-07-01

    Most of the cerebral functions are asymmetrically represented in the two hemispheres. Moreover, dexterity and coordination of the distal segment of the dominant limbs depend on cortico-motor lateralization. In this study, we investigated whether postural control may be also considered a lateralized hemispheric brain function. To this aim, 15 young subjects were tested in standing position by measuring center of pressure (COP) shifts along the anteroposterior axis (COP-Y) during dynamic posturography before and after continuous Theta Burst Stimulation (cTBS) intervention applied to the dominant or non-dominant M1 hand area as well as to the vertex. We show that when subjects were expecting a forward platform translation, the COP-Y was positioned significantly backward or forward after dominant or non-dominant M1 stimulation, respectively. We postulate that cTBS applied on M1 may have disrupted the functional connectivity between intra- and interhemispheric areas implicated in the anticipatory control of postural stability. This study suggests a functional asymmetry between the two homologous primary motor areas, with the dominant hemisphere playing a critical role in the selection of the appropriate postural control strategy.

  10. Identification of the Unstable Human Postural Control System.

    PubMed

    Hwang, Sungjae; Agada, Peter; Kiemel, Tim; Jeka, John J

    2016-01-01

    Maintaining upright bipedal posture requires a control system that continually adapts to changing environmental conditions, such as different support surfaces. Behavioral changes associated with different support surfaces, such as the predominance of an ankle or hip strategy, is considered to reflect a change in the control strategy. However, tracing such behavioral changes to a specific component in a closed loop control system is challenging. Here we used the joint input-output (JIO) method of closed-loop system identification to identify the musculoskeletal and neural feedback components of the human postural control loop. The goal was to establish changes in the control loop corresponding to behavioral changes observed on different support surfaces. Subjects were simultaneously perturbed by two independent mechanical and two independent sensory perturbations while standing on a normal or short support surface. The results show a dramatic phase reversal between visual input and body kinematics due to the change in surface condition from trunk leads legs to legs lead trunk with increasing frequency of the visual perturbation. Through decomposition of the control loop, we found that behavioral change is not necessarily due to a change in control strategy, but in the case of different support surfaces, is linked to changes in properties of the plant. The JIO method is an important tool to identify the contribution of specific components within a closed loop control system to overall postural behavior and may be useful to devise better treatment of balance disorders.

  11. 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

  12. 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.

  13. What is the most effective posture to conduct vibration from the lower to the upper extremities during whole-body vibration exercise?

    PubMed Central

    Tsukahara, Yuka; Iwamoto, Jun; Iwashita, Kosui; Shinjo, Takuma; Azuma, Koichiro; Matsumoto, Hideo

    2016-01-01

    Background Whole-body vibration (WBV) exercise is widely used for training and rehabilitation. However, the optimal posture for training both the upper and lower extremities simultaneously remains to be established. Objectives The objective of this study was to search for an effective posture to conduct vibration from the lower to the upper extremities while performing WBV exercises without any adverse effects. Methods Twelve healthy volunteers (age: 22–34 years) were enrolled in the study. To measure the magnitude of vibration, four accelerometers were attached to the upper arm, back, thigh, and calf of each subject. Vibrations were produced using a WBV platform (Galileo 900) with an amplitude of 4 mm at two frequencies, 15 and 30 Hz. The following three postures were examined: posture A, standing posture with the knees flexed at 30°; posture B, crouching position with no direct contact between the knees and elbows; and posture C, crouching position with direct contact between the knees and elbows. The ratio of the magnitude of vibration at the thigh, back, and upper arm relative to that at the calf was used as an index of vibration conduction. Results Posture B was associated with a greater magnitude of vibration to the calf than posture A at 15 Hz, and postures B and C were associated with greater magnitudes of vibration than posture A at 30 Hz. Posture C was associated with a vibration conduction to the upper arm that was 4.62 times and 8.26 times greater than that for posture A at 15 and 30 Hz, respectively. Conclusion This study revealed that a crouching position on a WBV platform with direct contact between the knees and elbows was effective for conducting vibration from the lower to the upper extremities. PMID:26793008

  14. An investigation of rugby scrimmaging posture and individual maximum pushing force.

    PubMed

    Wu, Wen-Lan; Chang, Jyh-Jong; Wu, Jia-Hroung; Guo, Lan-Yuen

    2007-02-01

    Although rugby is a popular contact sport and the isokinetic muscle torque assessment has recently found widespread application in the field of sports medicine, little research has examined the factors associated with the performance of game-specific skills directly by using the isokinetic-type rugby scrimmaging machine. This study is designed to (a) measure and observe the differences in the maximum individual pushing forward force produced by scrimmaging in different body postures (3 body heights x 2 foot positions) with a self-developed rugby scrimmaging machine and (b) observe the variations in hip, knee, and ankle angles at different body postures and explore the relationship between these angle values and the individual maximum pushing force. Ten national rugby players were invited to participate in the examination. The experimental equipment included a self-developed rugby scrimmaging machine and a 3-dimensional motion analysis system. Our results showed that the foot positions (parallel and nonparallel foot positions) do not affect the maximum pushing force; however, the maximum pushing force was significantly lower in posture I (36% body height) than in posture II (38%) and posture III (40%). The maximum forward force in posture III (40% body height) was also slightly greater than for the scrum in posture II (38% body height). In addition, it was determined that hip, knee, and ankle angles under parallel feet positioning are factors that are closely negatively related in terms of affecting maximum pushing force in scrimmaging. In cross-feet postures, there was a positive correlation between individual forward force and hip angle of the rear leg. From our results, we can conclude that if the player stands in an appropriate starting position at the early stage of scrimmaging, it will benefit the forward force production.

  15. Postural sway and perception of affordances in children at risk for developmental coordination disorder.

    PubMed

    Chen, F C; Tsai, C L; Wu, S K

    2014-07-01

    Gibson (The ecological approach to visual perception, Houghton Mifflin, Boston, 1979/1986) defined affordances as opportunities for motor behaviors, and highly emphasized the interaction between perception and action. Research on children with developmental coordination disorder commonly reports difficulties in judgments of affordances (perception) and in postural control (action). However, how perception and action are coupled has not been studied yet. The present study sought to evaluate the relationship between control of postural sway and perception of affordances in children at risk for developmental coordination disorder (RDCD) and typically developing children (TDC). We hypothesized that the relationship between perception and action would differ between groups. Participants made a series of judgments about their maximum sitting height (SHmax) while standing with and without wearing 10 cm blocks on feet. Postural sway and the judgment accuracy were recorded. Our findings showed that RDCD swayed more during judgment sessions and made less accurate judgments compared to TDC. In addition, TDC reduced postural sway from inter-judgment to judgment sessions, whereas the postural sway of RDCD remained identical between sessions. Last, while TDC reduced postural sway across judgment trials and revealed a learning effect of the judgments about SHmax in the block condition, RDCD never modulated postural sway and did not learn their SHmax in both non-block and block conditions. Overall, modulation of postural sway differed between groups during judgment sessions and between inter-judgment and judgment sessions, whereby their perceptual judgments about SHmax were differentially influenced. To summarize, this study demonstrated a difference in perception and action coupling between RDCD and TDC.

  16. Vibration-induced post-effects: a means to improve postural asymmetry in lower leg amputees?

    PubMed

    Duclos, C; Roll, R; Kavounoudias, A; Roll, J-P; Forget, R

    2007-10-01

    Muscle vibration has been shown to induce long-lasting and oriented alteration of standing posture in healthy individuals. The postural alterations can last several minutes following the end of vibration and are called post-effects. The goal of this study was to determine whether persons with lower leg amputation that show persistent postural asymmetry after usual rehabilitation experience these postural post-effects and if this could improve their weight bearing on the prosthesis. Centre of pressure (CP) position during stance was recorded prior to and up to 13 min after a 30s unilateral vibration applied during sitting to lateral neck (trapezius) or hip (gluteus medius) muscles in 14 individuals with unilateral lower leg amputation and 18 controls. The amputees' postural asymmetry was confirmed prior to the vibration intervention. A CP displacement, without an increase in CP velocity, was observed in both groups of participants over the 13 min post-vibration. For both the neck or hip vibration sites, the CP shifts were directed in the medio-lateral plane and were oriented either towards the vibrated side or the opposite side across subjects. This led to a decrease of postural asymmetry in half of the group of amputees. Within subject, the orientation of the post-effect was constant and changed to the opposite direction with vibration of the opposite body side. It is suggested that the post-effects are produced by a change of the postural reference consequent to the sustained proprioceptive message induced during the muscle vibration period. The orientation of the post-effects is discussed in relation to the notion of reference frame preference. All in all, because post-effect orientation is constant within subject and adaptive, future studies should investigate if individuals with lower leg amputation could benefit from postural post-effects induced by muscle vibration to improve function.

  17. Quantitative analysis of upright standing in adults with late-onset Pompe disease

    PubMed Central

    Valle, Maria Stella; Casabona, Antonino; Fiumara, Agata; Castiglione, Dora; Sorge, Giovanni; Cioni, Matteo

    2016-01-01

    Pompe disease is a rare disorder producing muscle weakness and progressive impairments in performing daily motor activities, such as walking and standing. Most studies have focused on dysfunctions at cellular level, restricting the examination of gross motor functions to qualitative or subjective rating scales evaluations. With the aim of providing an instrumented quantification of upright standing in Pompe disease, we used a force platform to measure the center of pressure over three foot positions and with eyes open and closed. Amplitude and variability of body sway were measured to determine the level of postural stability, while power spectrum analysis and nonlinear computations were performed to explore the structure of the postural control. In comparison with healthy participants, patients with Pompe disease showed a reduced level of postural stability, but irrelevant variations in frequency content and spatio-temporal structure of the sway motion were detected. Changes in foot position did not increase the postural instability associated with Pompe disease, but prominent worsening occurred in the patients when they stand with eyes closed, particularly along the anterior-posterior direction. These results provide objective elements to monitor deficiencies of upright standing in Pompe disease, emphasizing the specific contributions of sway direction and sensory deficits. PMID:27845393

  18. Sit-to-Stand Movement in Children with Cerebral Palsy: A Critical Review

    ERIC Educational Resources Information Center

    dos Santos, Adriana Neves; Pavao, Silvia Leticia; Rocha, Nelci Adriana Cicuto Ferreira

    2011-01-01

    Sit-to-stand (STS) movement is widely performed in daily life and an important pre requisite for acquisition of functional abilities. However, STS is a biomechanical demanding task which requires high levels of neuromuscular coordination, muscle strength and postural control. As children with cerebral palsy (CP) exhibit a series of impairments in…

  19. 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.

  20. Postural analysis of nursing work.

    PubMed

    Hignett, S

    1996-06-01

    Back pain in the nursing profession is an acknowledged wide spread occupational hazard. This study used OWAS (Ovako Working posture Analysis System) to measure the severity of the working postures adopted by nurses on Care of the Elderly wards when carrying out manual handling operations for animate and inanimate loads. Twenty-six nurses were observed on 31 occasions to obtain 4299 observations, these data were collected and processed using the OWASCO and OWASAN programs, and then analysed by grouping the results into defined patient (animate) handling and non-patient (inanimate) handling tasks. A statistical comparison was made between the two groups using the percentage of action categories two, three and four, to the total number of action categories. A significant difference (p < 0.05) was found, demonstrating that the percentage of harmful postures adopted during patient handling tasks was significantly higher than during non-patient handling tasks. This high level of postural stress and the poor track record of risk management within the Health Care Industry leads to the recommendation that an attitudinal change is needed to successfully address and reduce the manual handling burden which is currently being carried by the nursing staff.

  1. Recognizing postural orthostatic tachycardia syndrome.

    PubMed

    Pavlik, Daniel; Agnew, Donna; Stiles, Lauren; Ditoro, Rachel

    2016-04-01

    This article describes the pathophysiology, clinical presentation, differential diagnosis, diagnosis, and management of postural orthostatic tachycardia syndrome (POTS), a potentially debilitating autonomic disorder that can have many causes and presentations. POTS can be mistaken for panic disorder, inappropriate sinus tachycardia, and chronic fatigue syndrome. Clinician suspicion for the syndrome is key to prompt patient diagnosis and treatment.

  2. Analysis of the compensatory postures adopted by day caregivers through OWAS-Ovako Working Posture Analysing System.

    PubMed

    Moreira, Helenara Salvati Bertolossi; Moreira, Mauricio Bertolossi; Vilagra, José Mohamud; Galvão, Isabele Maia; de Oliveira Júnior, Abel Santos; de Lima, Andrea Cristina

    2012-01-01

    The Ergonomic Work Analysis reports that there are many activities performed by the professional caregivers and that they are exposed to physical and psychological overload. This situation favors the emergence of pain which influences the quality of life in the work place. In this way, the objective of this study was to verify the main postural constraints adopted by caregivers in public day cares. Visits were conducted in 28 day cares aiming at performing an interview to 126 caregivers who have been working for more than 4 years. From the questionnaire it was found that 80% of the participants refer some sort of pain, being 42% in the trunk, 33% in the shoulder and 25% in the lower limbs. The data from OWAS method showed that from the total of 30 postures performed during the work One could see that the main postures adopted by the caregivers were: flexion, lateral inclination and rotation of the trunk and most of the time they are standing. These movements, when bad performed, can lead to injuries in the lower limbs, upper limbs and trunk. It's necessary more attention to these workers.Thought preventive ergonomic actions to reduce pain symptoms and promote a work in health and safety.

  3. Postural sway reduction in aging men and women: Relation to brain structure, cognitive status, and stabilizing factors

    PubMed Central

    Sullivan, Edith V.; Rose, Jessica; Rohlfing, Torsten; Pfefferbaum, Adolf

    2009-01-01

    Postural stability becomes compromised with advancing age, but the neural mechanisms contributing to instability have not been fully explicated. Accordingly, this quantitative physiological and MRI study of sex differences across the adult age range examined the association between components of postural control and the integrity of brain structure and function under different conditions of sensory input and stance stabilization manipulation. The groups comprised 28 healthy men (age 30–73 years) and 38 healthy women (age 34–74 years), who completed balance platform testing, cognitive assessment, and structural MRI. The results supported the hypothesis that excessive postural sway would be greater in older than younger healthy individuals when standing without sensory or stance aids, and that introduction of such aids would reduce sway in both principal directions (anterior–posterior and medial–lateral) and in both the open-loop and closed-loop components of postural control even in older individuals. Sway reduction with stance stabilization, that is, standing with feet apart, was greater in men than women, probably because older men were less stable than women when standing with their feet together. Greater sway was related to evidence for greater brain structural involutional changes, indexed as ventricular and sulcal enlargement and white matter hyperintensity burden. In women, poorer cognitive test performance related to less sway reduction with the use of sensory aids. Thus, aging men and women were shown to have diminished postural control, associated with cognitive and brain structural involution, in unstable stance conditions and with diminished sensory input. PMID:17920729

  4. Acute postural modulation of the soleus H-reflex after Achilles tendon vibration.

    PubMed

    Lapole, Thomas; Canon, Francis; Pérot, Chantal

    2012-08-15

    Alteration of Soleus (SOL) H-reflex has been reported after prolonged vibratory exposure and it was hypothesized that presynaptic inhibition, known to depress the H-reflex during vibration, largely contributed to the H-reflex changes. To confirm this hypothesis, the purpose of the present study was to quantify the SOL H-reflex changes between sitting and standing positions (postural modulation) with or without the after-effects of 1h of Achilles tendon vibration. Indeed, postural modulation of the SOL H-reflex has been reported to inform on the level of presynaptic inhibition exerted on Ia afferents. SOL H-reflex and M waves were measured in healthy voluntary subjects in both sitting and standing positions before and after 1h of Achilles vibration (frequency: 50 Hz) applied in sitting position (vibration group, n=11) or before and after 1h of sitting position only (control group, n=6). SOL H(max)/M(max) ratios were calculated. Furthermore, in order to quantify presynaptic inhibition induced by prolonged vibration, an index of SOL H-reflex postural modulation was calculated as the standing H(max)/M(max) ratio relative to the sitting one. After 1h of Achilles tendon vibration, a significant decrease in the SOL H(max)/M(max) ratio was observed both in sitting and standing positions (p<0.05). However, the decrease was more pronounced in the standing position, leading to a significant decrease of the index of SOL H-reflex postural modulation. Those results suggest that presynaptic inhibition could have largely contributed to the H-reflex decrease observed after one bout of vibration.

  5. Short-term differential training decreases postural sway.

    PubMed

    James, Eric G

    2014-01-01

    Differential training has been shown to enhance motor learning in sports skills. In the present study differential training was applied to the minimization of postural sway. A differential training group performed 15 one minute practice trials, each with different postural movement instructions. A repetitive practice group performed 15 trials standing as still as possible for one minute. Pre- and post-tests were performed standing as still as possible in 1 and 2-leg stance. Accelerometry data were collected approximately at the level of the center of mass (COM) and at the head. The root mean square jerk (RMSJ) of movement at the COM and head was estimated for the anteroposterior and mediolateral axes of motion. A significant Group × Test interaction revealed that the differential training led to lower anteroposterior RMSJ on the post-test than on the Pre-test in both the 1 and 2-leg stance tasks. A significant Group × Effector × Test interaction revealed that the decrease in anteroposterior RMSJ with differential training occurred in the RMSJ of the head but not the COM. The repetitive practice did not lead to a significant change in anteroposterior RMSJ at either the COM or the head. Neither form of training led to a significant change in mediolateral RMSJ. The results indicated that differential training can enhance motor learning not only in complex sports skills but in relatively simple motor tasks such as maintaining quiet stance.

  6. Magnifying the Scale of Visual Biofeedback Improves Posture.

    PubMed

    Jehu, Deborah A; Thibault, Jérémie; Lajoie, Yves

    2016-06-01

    Biofeedback has been shown to minimize body sway during quiet standing. However, limited research has reported the optimal sensitivity parameters of visual biofeedback related to the center of pressure (COP) sway. Accordingly, 19 young adults (6 males; 13 females; aged 21.3 ± 2.5) stood with feet together and performed three visual biofeedback intensities [unmodified biofeedback (UMBF), BF magnified by 5 (BF5), BF magnified by 10 (BF10)], along with control trials with no biofeedback (NBF). The participants were instructed to stand as still as possible while minimizing the movements of the visual target. The findings revealed that UMBF produced significantly greater COP displacement in both the anterior-posterior (AP) and medial-lateral directions, as well as greater standard deviation of the COP in the AP direction (p < 0.05). Additionally, NBF showed significantly greater 95 % area ellipse than the UMBF, BF5, and BF10 intensities (p < 0.001). Therefore, the most sensitive COP scales generated the least amount of postural sway. However, there were no significant differences on any of the COP measures between BF5 and BF10. This research provides insight with respect to the proper scale on which biofeedback should be given in order to improve postural control (i.e., BF5 or BF10).

  7. Postural tachycardia syndrome: a heterogeneous and multifactorial disorder.

    PubMed

    Benarroch, Eduardo E

    2012-12-01

    Postural tachycardia syndrome (POTS) is defined by a heart rate increment of 30 beats/min or more within 10 minutes of standing or head-up tilt in the absence of orthostatic hypotension; the standing heart rate is often 120 beats/min or higher. POTS manifests with symptoms of cerebral hypoperfusion and excessive sympathoexcitation. The pathophysiology of POTS is heterogeneous and includes impaired sympathetically mediated vasoconstriction, excessive sympathetic drive, volume dysregulation, and deconditioning. POTS is frequently included in the differential diagnosis of chronic unexplained symptoms, such as inappropriate sinus tachycardia, chronic fatigue, chronic dizziness, or unexplained spells in otherwise healthy young individuals. Many patients with POTS also report symptoms not attributable to orthostatic intolerance, including those of functional gastrointestinal or bladder disorders, chronic headache, fibromyalgia, and sleep disturbances. In many of these cases, cognitive and behavioral factors, somatic hypervigilance associated with anxiety, depression, and behavioral amplification contribute to symptom chronicity. The aims of evaluation in patients with POTS are to exclude cardiac causes of inappropriate tachycardia; elucidate, if possible, the most likely pathophysiologic basis of postural intolerance; assess for the presence of treatable autonomic neuropathies; exclude endocrine causes of a hyperadrenergic state; evaluate for cardiovascular deconditioning; and determine the contribution of emotional and behavioral factors to the patient's symptoms. Management of POTS includes avoidance of precipitating factors, volume expansion, physical countermaneuvers, exercise training, pharmacotherapy (fludrocortisone, midodrine, β-blockers, and/or pyridostigmine), and behavioral-cognitive therapy. A literature search of PubMed for articles published from January 1, 1990, to June 15, 2012, was performed using the following terms (or combination of terms): POTS

  8. Foot anatomy specialization for postural sensation and control.

    PubMed

    Wright, W G; Ivanenko, Y P; Gurfinkel, V S

    2012-03-01

    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.

  9. NEO Test Stand Analysis

    NASA Technical Reports Server (NTRS)

    Pike, Cody J.

    2015-01-01

    A project within SwampWorks is building a test stand to hold regolith to study how dust is ejected when exposed to the hot exhaust plume of a rocket engine. The test stand needs to be analyzed, finalized, and fabrication drawings generated to move forward. Modifications of the test stand assembly were made with Creo 2 modeling software. Structural analysis calculations were developed by hand to confirm if the structure will hold the expected loads while optimizing support positions. These calculations when iterated through MatLab demonstrated the optimized position of the vertical support to be 98'' from the far end of the stand. All remaining deflections were shown to be under the 0.6'' requirement and internal stresses to meet NASA Ground Support Equipment (GSE) Safety Standards. Though at the time of writing, fabrication drawings have yet to be generated, but are expected shortly after.

  10. Effect of visual stimulus using central and peripheral visual field on postural control of normal subjects.

    PubMed

    Park, Du-Jin

    2016-06-01

    [Purpose] This study investigated the effects of visual stimulus using central and peripheral vision fields on postural control. [Subjects and Methods] The subjects consisted of 40 young adult volunteers (15 males, 25 females) who had been informed of the study purpose and procedure. The subjects were randomly divided into four groups of differing visual stimulus. Each group was given visual intervention in a standing position for 3 minutes. Postural control was evaluated before and after visual intervention. [Results] The results of the functional reach test and body sway test showed significant differences among the four groups. [Conclusion] The two-way peripheral vision-field group showed significantly more body sway after visual intervention than the other three groups. This finding may suggest two-way peripheral vision field is a more effective visual stimulus for training postural control and balance.

  11. 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.

  12. Management of specific and excessive posturing behavior in a hyacinth macaw (Anodorhynchus hyacinthinus) by using applied behavior analysis.

    PubMed

    Clayton, Leigh Ann; Friedman, Susan G; Evans, Liz A

    2012-06-01

    Applied behavior analysis was used in a female hyacinth macaw (Anodorhynchus hyacinthinus) to reduce specific, excessive mating-type posturing that had become disruptive due to increased frequency, duration, and intensity. A functional assessment and intervention design worksheet was used to evaluate behavior-environment relations and to develop an individualized behavior-change plan. The functional assessment indicated that human attention was maintaining the behavior. The intervention, differential reinforcement of incompatible behavior, was implemented to increase attention for standing upright and to remove attention for posturing. Within 1 month, posturing decreased to acceptable levels and was replaced with an upright posture. Problem behaviors that appear "reproductive" may be responsive to behavior management alone. Applied behavior analysis and a functional assessment and intervention design are ideal tools to address problem behavior in avian patients.

  13. Understanding and Managing Neurally Mediated Syncope in the Adolescent

    ERIC Educational Resources Information Center

    Rollinson, Nancy L.

    2005-01-01

    Syncope and near-syncopal symptoms are common events in the adolescent population. Syncope is defined as the transient loss of postural tone and consciousness with spontaneous recovery. Although most syncopal events are benign, they can generate extreme anxiety in the adolescent and his or her family. The reoccurrence of these events can have a…

  14. Effects of postural task requirements on the speed-accuracy trade-off.

    PubMed

    Duarte, Marcos; Latash, Mark L

    2007-07-01

    We investigated the speed-accuracy trade-off in a task of pointing with the big toe of the right foot by a standing person that was designed to accentuate the importance of postural adjustments. This was done to test two hypotheses: (1) movement time during foot pointing will scale linearly with ID during target width changes, but the scaling will differ across movement distances; and (2) variations in movement time will be reflected in postural preparations to foot motion. Ten healthy adults stood on the force plate and were instructed to point with the big toe of the right foot at a target (with widths varying from 2 to 10 cm) placed on the floor in front of the subject at a distance varying from 10 to 100 cm. The instruction given to the subjects was typical for Fitts' paradigm: "be as fast and as accurate as possible in your pointing movement". The results have shown that movement time during foot pointing movements scaled with both target distance (D) and target width (W), but the two dependences could not be reduced to a single function of W/D, confirming the first hypothesis. With respect to the second hypothesis, we found that changes in task parameters led to proportional variations in movement speed and indices of variability of the postural adjustments prior to leg movement initiation, confirming the second hypothesis. Both groups of observations were valid over the whole range of distances despite the switch of the movement strategy in the middle of this range. We conclude that the speed-accuracy trade-off in a task with postural adjustments originates at the level of movement planning. The different dependences of movement time on D and W may be related to spontaneous postural sway (migration of the point of application of the resultant force acting on the body of the standing person). The results may have practical implications for posture and gait rehabilitation techniques that use modifications of stepping accuracy.

  15. Angular and linear spinal parameters associated with relaxed and erect postures in healthy subjects.

    PubMed

    Prushansky, Tamara; Geller, Shira; Avraham, Amir; Furman, Chen; Sela, Lee

    2013-04-01

    Spinal posture assessment is an essential component in physical evaluation. Establishing reproducible value of spinal curves is necessary for detecting postural changes. Therefore, the main objectives of this study were to assess the reproducibility of spinal curves in relaxed standing of healthy subjects and to explore the extent and pattern of change upon transition from relaxed to a fully erect posture. Thirty young women and men were measured twice over a 1 week interval for recording the cervical, thoracic, and lumbar curves values using an ultrasound-based system. Thereafter, additional 28 men and women extracted from the same reference group were assigned for a single measurement session, in which the same angular values were obtained in relaxed and fully erect standing postures, as well as stature using stadiometer. Excellent, good, and poor reproducibility indices, standard error of measurement (SEM), and smallest real difference (SRD), were noted for the thoracic (interclass correlation coefficient, ICC(3,3) = 0.95, SEM = 1.2°, SRD = 3.3°), lumbar (ICC(3,3) = 0.85, SEM = 2.6°, SRD = 7.2°), and cervical (ICC(3,3) = 0.68, SEM = 3.8°, SRD = 10.5°) curves, respectively. Erecting from relaxed posture was associated with a significant (>SRD) thoracic angle difference of 7.2° in men and 4.8° in women which was expressed in a height increase of 1.3 cm in men and 0.8 cm in women. These changes were significantly larger in men in whom the angular and height differences were also significantly correlated (r = 0.7). Using this system, angular measurements are highly reproducible in the thoracic curvature in young healthy adults, leading to the use of the associated SRD as a criterion for thoracic postural flexibility.

  16. 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.

  17. 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.

  18. Postural risk assessment of mechanised firewood processing.

    PubMed

    Spinelli, Raffaele; Aminti, Giovanni; De Francesco, Fabio

    2017-03-01

    The study assessed the postural risk of mechanised firewood processing with eight machines, representing the main technology solutions available on the market. Assessment was conducted with the Ovako Working posture Analysis System (OWAS) on 1000 still frames randomly extracted from videotaped work samples. The postural risk associated with firewood processing was variable and associated with technology type. Simple, manually operated new machines incurred a higher postural risk compared with semi- or fully automatic machines. In contrast, new semi-automatic and automatic machines were generally free from postural risk. In all cases, attention should be paid to postural risk that may occur during blockage resolution. The study did not cover the postural risk of firewood processing sites as a whole. The study provided useful information for selecting firewood processing machinery and for improving firewood machinery design, as part of a more articulate strategy aimed at enhancing the safety of firewood processing work sites. Practitioner Summary: The postural risk associated with mechanised firewood processing (eg cutting and splitting) depends on the type of equipment. Postural risk is highest (OWAS Action Category 2) with new in-line machines, designed for operation by a single worker. Fully automatic machines present minimum postural risk, except during blockage resolution.

  19. Recovery of Posture Stability at Different Foot Placements in Patients Who Underwent Minimally Invasive Total Hip Arthroplasty: A One-Year Follow-Up Study

    PubMed Central

    Chang, Chun-Ju; Lin, Na-Ling; Lee, Mel S.; Chern, Jen-Suh

    2015-01-01

    To understand the progression of recovery in postural stability and physical functioning after patients received the minimally invasive total hip arthroplasty (MTHA), we monitor the pain level, functional capacity, and postural stability before and after operation within one year. In total of 23 subjects in our study, we found out that MTHA was effective in relieving pain in first 2 weeks and restoring the hip joint integrity, but the postural stability was influenced especially in tandem stand in both anterior-posterior and medial-lateral directions. The recovery of postural stability and functional capacity in one year duration fluctuated and no consistent improvement tendency was found. We suggested clinicians designing postsurgery rehabilitation program for consistent and progressive long-term recovery of postural stability and fall prevention to optimize surgical results and prevent undesired postoperative consequences. PMID:26583110

  20. The Advantage of Standing Up to Fight and the Evolution of Habitual Bipedalism in Hominins

    PubMed Central

    Carrier, David R.

    2011-01-01

    Background Many quadrupedal species stand bipedally on their hindlimbs to fight. This posture may provide a performance advantage by allowing the forelimbs to strike an opponent with the range of motion that is intrinsic to high-speed running, jumping, rapid braking and turning; the range of motion over which peak force and power can be produced. Methodology/Principal Findings To test the hypothesis that bipedal (i.e., orthograde) posture provides a performance advantage when striking with the forelimbs, I measured the force and energy produced when human subjects struck from “quadrupedal” (i.e., pronograde) and bipedal postures. Downward and upward directed striking energy was measured with a custom designed pendulum transducer. Side and forward strikes were measured with a punching bag instrumented with an accelerometer. When subjects struck downward from a bipedal posture the work was 43.70±12.59% (mean ± S.E.) greater than when they struck from a quadrupedal posture. Similarly, 47.49±17.95% more work was produced when subjects struck upward from a bipedal stance compared to a quadrupedal stance. Importantly, subjects did 229.69±44.19% more work in downward than upward directed strikes. During side and forward strikes the force impulses were 30.12±3.68 and 43.04±9.00% greater from a bipedal posture than a quadrupedal posture, respectively. Conclusions/Significance These results indicate that bipedal posture does provide a performance advantage for striking with the forelimbs. The mating systems of great apes are characterized by intense male-male competition in which conflict is resolved through force or the threat of force. Great apes often fight from bipedal posture, striking with both the fore- and hindlimbs. These observations, plus the findings of this study, suggest that sexual selection contributed to the evolution of habitual bipedalism in hominins. PMID:21611167

  1. Effect of light touch on postural sway in individuals with balance problems: a systematic review.

    PubMed

    Baldan, A M S; Alouche, S R; Araujo, I M G; Freitas, S M S F

    2014-01-01

    The aim of the present review was to examine the experimental, case-control studies that investigated the effect of light touch on postural sway in individuals with balance problems due to aging, brain lesion or other motor or sensory deficits. Articles published before the end of March of 2013 were searched in PubMed, Scielo and Lilacs databases using terms related to postural control and sensory information. Twelve studies that assessed the postural sway of individuals with balance problems during quiet standing with the light touch using a force plate were reviewed. Two reviewers rated all selected articles as having good quality. The effect of light touch on postural control was reported by all eligible studies regardless of the cause of the balance problem of the participants. Such effect was more evident when the applied vertical force was greater than 1N, but if individuals with poor balance took more advantage of the light touch than healthy ones it depended on the source of their balance problems and not the amount of the applied force. These findings suggested that the maintenance of the fingertip lightly touching an external surface could provide additional somatosensory information for individuals with poor balance and then it could be used as a strategy to improve the control of upright standing during intervention programs.

  2. Effects of anticipatory anxiety and visual input on postural sway in an aversive situation.

    PubMed

    Ishida, Mitsuo; Saitoh, Junko; Wada, Maki; Nagai, Masanori

    2010-04-19

    We have previously reported that state anxiety scores were positively correlated with postural sway while standing upright and gazing at a visual target (Ohno et al., 2004 [16]). The present study examines the effect of anticipatory anxiety and visual input on postural control in healthy individuals. An unpredictable aversive sound (100dB SPL) was delivered in order to induce anticipatory anxiety. Participants were asked to stand upright on a force plate with their eyes open and closed, and their center of pressure (COP) was measured. Analysis of the postural parameters revealed that the path lengths of the COP and the enveloped areas were greater in the anticipatory situation with the aversive sound than in the silent situation. Fast Fourier transform analysis showed that the frequency component related to vestibular inputs (0.1-1.0Hz) was increased during the anticipatory situation. The lower frequency (<0.1Hz) component was decreased in the medio-lateral axis during anticipation with the eyes closed due to shifting mean power frequencies to high frequency. The results suggest that anticipatory anxiety in healthy participants amplified the sway regardless of whether the eyes were open or closed, and that the vestibular inputs greatly influenced the amplification of postural sway.

  3. Analysis of postural sway in patients with normal pressure hydrocephalus: effects of shunt implantation.

    PubMed

    Czerwosz, L; Szczepek, E; Blaszczyk, J W; Sokolowska, B; Dmitruk, K; Dudzinski, K; Jurkiewicz, J; Czernicki, Z

    2009-12-07

    Poor postural balance is one of the major risk factors for falling in normal pressure hydrocephalus (NPH). Postural instability in the clinic is commonly assessed based upon force platform posturography. In this study we focused on the identification of changes in sway characteristics while standing quiet in patients with NPH before and after shunt implantation. Postural sway area and sway radius were analyzed in a group of 9 patients and 46 controls of both genders. Subject's spontaneous sway was recorded while standing quiet on a force platform for 30-60 s, with eyes open and then closed. Both analyzed sway descriptors identified between-group differences and also an effect of shunt implantation in the NPH group. Sway radius and sway area in patients exhibited very high values compared with those in the control group. Importantly, the effect of eyesight in patients was not observed before shunt implantation and reappeared after the surgical treatment. The study documents that static force platform posturography may be a reliable measure of postural control improvement due to shunt surgery.

  4. Altered timing of postural reflexes contributes to falling in persons with chronic stroke.

    PubMed

    Marigold, Daniel S; Eng, Janice J

    2006-06-01

    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.

  5. 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

  6. The role of haptic cues from rough and slippery surfaces in human postural control

    NASA Technical Reports Server (NTRS)

    Jeka, J. J.; Lackner, J. R.

    1995-01-01

    Haptic information is critically important in complex sensory-motor tasks such as manipulating objects. Its comparable importance in spatial orientation is only beginning to be recognized. We have shown that postural sway in humans is significantly reduced by lightly touching a stable surface with a fingertip at contact force levels far below those physically necessary to stabilize the body. To investigate further the functional relationship between contact forces at the hand and postural equilibrium, we had subjects stand in the tandem Romberg stance while being allowed physically supportive (force contact) and non-physically supportive (touch contact) amounts of index fingertip force on surfaces with different frictional characteristics. Mean sway amplitude (MSA) was reduced by over 50% with both touch and force contact of the fingertip, compared to standing without fingertip contact. No differences in MSA were observed when touching rough or slippery surfaces. The amplitude of EMG activity in the peroneal muscles and the timing relationships between fingertip forces, body sway and EMG activity suggested that with touch contact of the finger or with force contact on a slippery surface long-loop "reflexes" involving postural muscles were stabilizing sway. With force contact of the fingertip on a rough surface, MSA reduction was achieved primarily through physical support of the body. This pattern of results indicates that light touch contact cues from the fingertip in conjunction with proprioceptive signals about arm configuration are providing information about body sway that can be used to reduce MSA through postural muscle activation.

  7. Effect of selective fatiguing of the shank muscles on single-leg-standing sway.

    PubMed

    Suponitsky, Y; Verbitsky, O; Peled, E; Mizrahi, J

    2008-08-01

    Control of standing requires the continuous activity of the leg muscles. In single leg standing the system is less redundant and muscular activity is more intensive. The objective of this study was to examine the effect of force imbalance of the shank muscles, evoked by their selective fatiguing, on postural control in single-leg standing. Five healthy subjects performed two single-leg standing trials, lasting as long as the subject could maintain steady balance, and separated by a 240s quasi-isotonic sustained effort to induce fatigue of the Tibialis Anterior and Peroneus muscles. The following were on-line monitored: sway-related parameters, e.g., ground reaction force and center of pressure in the standing trials; and electromyogram of the Tibialis Anterior, Peroneus and Gastrocnemius muscles in all experiments. Simple and multiple linear regressions served to study the fatigue effects on the relationship between muscle activity and postural sway. The results indicate that the evoked muscle imbalance leads to (a) increased postural sway; (b) increased correlation between muscle activity, and sway-related parameters. Thus, with the reduction of the level of redundancy the system becomes more synchronized. These results have potential relevance for cases of muscle impairment, in which electrical stimulation is required to augment muscle activity.

  8. Assessment of postural stability in patients with cerebellar disease using gyroscope data.

    PubMed

    Kutílek, Patrik; Socha, Vladimír; Čakrt, Ondřej; Svoboda, Zdeněk

    2015-07-01

    This study examines a relatively new method of studying and quantifying human postural stability in patients with degenerative cerebellar disease. Trunk sway and feet sway were measured during quiet stance. To test the method, ten patients and eleven healthy subjects performed two different stance tasks: standing with eyes open on a firm surface and standing with eyes closed on a foam support surface. Data were recorded using three body-worn gyroscopes (Xsens Technologies B.V.) to measure roll and pitch angular movements of the lower trunk, and left and right foot. The pitch versus roll plots of the trunk and feet were created, and the areas of the convex hull shapes were calculated. It was found that the area of the convex hull of the pitch versus roll plots is suitable for the identification of postural instability disorders caused by degenerative cerebellar disease.

  9. Slow breathing influences cardiac autonomic responses to postural maneuver: Slow breathing and HRV.

    PubMed

    Vidigal, Giovanna Ana de Paula; Tavares, Bruna S; Garner, David M; Porto, Andrey A; Carlos de Abreu, Luiz; Ferreira, Celso; Valenti, Vitor E

    2016-05-01

    Chronic slow breathing has been reported to improve Heart Rate Variability (HRV) in patients with cardiovascular disorders. However, it is not clear regarding its acute effects on HRV responses on autonomic analysis. We evaluated the acute effects of slow breathing on cardiac autonomic responses to postural change manoeuvre (PCM). The study was conducted on 21 healthy male students aged between 18 and 35 years old. In the control protocol, the volunteer remained at rest seated for 15 min under spontaneous breathing and quickly stood up within 3 s and remained standing for 15 min. In the slow breathing protocol, the volunteer remained at rest seated for 10 min under spontaneous breath, then performed slow breathing for 5 min and rapidly stood up within 3 s and remained standing for 15 min. Slow breathing intensified cardiac autonomic responses to postural maneuver.

  10. 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.

  11. 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.

  12. Looking northeast from Test Stand 'A' superstructure towards Test Stand ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking northeast from Test Stand 'A' superstructure towards Test Stand 'D' tower (4223/E-24, left background), Test Stand 'C' tower (4217/E-18, center), and Test Stand 'B' (4215/E-16, right foreground). - Jet Propulsion Laboratory Edwards Facility, Edwards Air Force Base, Boron, Kern County, CA

  13. The Steps to Perfect Posture

    ERIC Educational Resources Information Center

    Chappell, Jon

    2007-01-01

    Many people have memories of being told to "stop slouching" while seated at the piano bench. But the reality is that good piano posture is not as simple as bolting upright on the bench when the teacher barks. According to Eric Sutz, a Chicago-area piano teacher and performer, one should see a natural curve in his/her lower lumbar area and should…

  14. Validation of a computer analysis to determine 3-D rotations and translations of the rib cage in upright posture from three 2-D digital images

    PubMed Central

    Harrison, Deed E.; Janik, Tadeusz J.; Cailliet, Rene; Normand, Martin C.; Perron, Denise L.; Ferrantelli, Joseph R

    2006-01-01

    Since thoracic cage posture affects lumbar spine coupling and loads on the spinal tissues and extremities, a scientific analysis of upright posture is needed. Common posture analyzers measure human posture as displacements from a plumb line, while the PosturePrint™ claims to measure head, rib cage, and pelvic postures as rotations and translations. In this study, it was decided to evaluate the validity of the PosturePrint™ Internet computer system’s analysis of thoracic cage postures. In a university biomechanics laboratory, photographs of a mannequin thoracic cage were obtained in different postures on a stand in front of a digital camera. For each mannequin posture, three photographs were obtained (left lateral, right lateral, and AP). The mannequin thoracic cage was placed in 68 different single and combined postures (requiring 204 photographs) in five degrees of freedom: lateral translation (Tx), lateral flexion (Rz), axial rotation (Ry), flexion–extension (Rx), and anterior–posterior translation (Tz). The PosturePrint™ system requires 13 reflective markers to be placed on the subject (mannequin) during photography and 16 additional “click-on” markers via computer mouse before a set of three photographs is analyzed by the PosturePrint™ computer system over the Internet. Errors were the differences between the positioned mannequin and the calculated positions from the computer system. Average absolute value errors were obtained by comparing the exact inputted posture to the PosturePrint™’s computed values. Mean and standard deviation of computational errors for sagittal displacements of the thoracic cage were Rx=0.3±0.1°, Tz=1.6±0.7 mm, and for frontal view displacements were Ry=1.2±1.0°, Rz=0.6±0.4°, and Tx=1.5±0.6 mm. The PosturePrint™ system is sufficiently accurate in measuring thoracic cage postures in five degrees of freedom on a mannequin indicating the need for a further study on human subjects. PMID:16547756

  15. PPT Thrust Stand

    NASA Technical Reports Server (NTRS)

    Haag, Thomas W.

    1995-01-01

    A torsional-type thrust stand has been designed and built to test Pulsed Plasma Thrusters (PPT's) in both single shot and repetitive operating modes. Using this stand, momentum per pulse was determined strictly as a function of thrust stand deflection, spring constant, and natural frequency. No empirical corrections were required. The accuracy of the method was verified using a swinging impact pendulum. Momentum transfer data between the thrust stand and the pendulum were consistent to within 1%. Following initial calibrations, the stand was used to test a Lincoln Experimental Satellite (LES-8/9) thruster. The LES-8/9 system had a mass of approximately 7.5 kg, with a nominal thrust to weight ratio of 1.3 x 10(exp -5). A total of 34 single shot thruster pulses were individually measured. The average impulse bit per pulse was 266 microN-s, which was slightly less than the value of 300 microN-s published in previous reports on this device. Repetitive pulse measurements were performed similar to ordinary steady-state thrust measurements. The thruster was operated for 30 minutes at a repetition rate of 132 pulses per minute and yielded an average thrust of 573 microN. Using average thrust, the average impulse bit per pulse was estimated to be 260 microN-s, which was in agreement with the single shot data. Zero drift during the repetitive pulse test was found to be approximately 1% of the measured thrust.

  16. The influence of somatosensory and muscular deficits on postural stabilization: Insights from an instrumented analysis of subjects affected by different types of Charcot-Marie-Tooth disease.

    PubMed

    Lencioni, Tiziana; Piscosquito, Giuseppe; Rabuffetti, Marco; Bovi, Gabriele; Calabrese, Daniela; Aiello, Alessia; Di Sipio, Enrica; Padua, Luca; Diverio, Manuela; Pareyson, Davide; Ferrarin, Maurizio

    2015-08-01

    Charcot-Marie-Tooth (CMT) disease is the most common hereditary neuromuscular disorder. CMT1 is primarily demyelinating, CMT2 is primarily axonal, and CMTX1 is characterized by both axonal and demyelinating abnormalities. We investigated the role of somatosensory and muscular deficits on quiet standing and postural stabilization in patients affected by different forms of CMT, comparing their performances with those of healthy subjects. Seventy-six CMT subjects (CMT1A, CMT2 and CMTX1) and 41 healthy controls were evaluated during a sit-to-stand transition and the subsequent quiet upright posture by means of a dynamometric platform. All CMT patients showed altered balance and postural stabilization compared to controls. Multivariate analysis showed that in CMT patients worsening of postural stabilization was related to vibration sense deficit and to dorsi-flexor's weakness, while quiet standing instability was related to the reduction of pinprick sensibility and to plantar-flexor's weakness. Our results show that specific sensory and muscular deficits play different roles in balance impairment of CMT patients, both during postural stabilization and in static posture. An accurate evaluation of residual sensory and muscular functions is therefore necessary to plan for the appropriate balance rehabilitation treatment for each patient, besides the CMT type.

  17. Postural consistency in skilled archers.

    PubMed

    Stuart, J; Atha, J

    1990-01-01

    The consistency of an archer's postural set at the moment of loose (arrow release) is commonly perceived to be an important determinant of success. The coach seeks, among other things, to provide the archer with information about postural consistency, details of which he acquires by eye or occasionally by video-recordings. The gains that might be achieved from more precise information are examined here. Nine skilled archers, classified into either skilled or elite groups according to their officially computed handicap, were continuously monitored and measured with a three-dimensional co-ordinate analyser (Charnwood Dynamics Coda-3 Scanner) while shooting two ends (series) of three arrows each. Considerable variability was observed in the precision with which the positions of head, elbow and bow at the moment of loose were replicated by archers of similar levels of skill. These results are interpreted to suggest that precise postural consistency may not be the primary feature distinguishing between the performance of archers at the higher skill levels.

  18. Acute effects of Dry Immersion on kinematic characteristics of postural corrective responses

    NASA Astrophysics Data System (ADS)

    Sayenko, D. G.; Miller, T. F.; Melnik, K. A.; Netreba, A. I.; Khusnutdinova, D. R.; Kitov, V. V.; Tomilovskaya, E. S.; Reschke, M. F.; Gerasimenko, Y. P.; Kozlovskaya, I. B.

    2016-04-01

    Impairments in balance control are inevitable following exposure to microgravity. However, the role of particular sensory system in postural disorders at different stages of the exposure to microgravity still remains unknown. We used a method called Dry Immersion (DI), as a ground-based model of microgravity, to elucidate the effects of 6-h of load-related afferent inputs on kinematic characteristics of postural corrective responses evoked by pushes to the chest of different intensities during upright standing. The structure of postural corrective responses was altered following exposure to DI, which was manifested by: (1) an increase of the ankle and knee flexion during perturbations of medium intensity, (2) the lack of the compensatory hip extension, as well as diminished knee and ankle flexion with a further increase of the perturbation intensity to submaximal level. We suggest that the lack of weight-bearing increases the reactivity of the balance control system, whereas the ability to scale the responses proportionally to the perturbation intensity decreases. Disrupted neuromuscular coordination of postural corrective responses following DI can be attributed to adaptive neural modifications on the spinal and cortical levels. The present study provides evidence that even a short-term lack of load-related afferent inputs alters kinematic patterns of postural corrective responses, and can result in decreased balance control. Because vestibular input is not primarily affected during the DI exposure, our results indicate that activity and the state of the load-related afferents play critical roles in balance control following real or simulated microgravity.

  19. Monitoring of posture allocations and activities by a shoe-based wearable sensor.

    PubMed

    Sazonov, Edward S; Fulk, George; Hill, James; Schutz, Yves; Browning, Raymond

    2011-04-01

    Monitoring of posture allocations and activities enables accurate estimation of energy expenditure and may aid in obesity prevention and treatment. At present, accurate devices rely on multiple sensors distributed on the body and thus may be too obtrusive for everyday use. This paper presents a novel wearable sensor, which is capable of very accurate recognition of common postures and activities. The patterns of heel acceleration and plantar pressure uniquely characterize postures and typical activities while requiring minimal preprocessing and no feature extraction. The shoe sensor was tested in nine adults performing sitting and standing postures and while walking, running, stair ascent/descent and cycling. Support vector machines (SVMs) were used for classification. A fourfold validation of a six-class subject-independent group model showed 95.2% average accuracy of posture/activity classification on full sensor set and over 98% on optimized sensor set. Using a combination of acceleration/pressure also enabled a pronounced reduction of the sampling frequency (25 to 1 Hz) without significant loss of accuracy (98% versus 93%). Subjects had shoe sizes (US) M9.5-11 and W7-9 and body mass index from 18.1 to 39.4 kg/m2 and thus suggesting that the device can be used by individuals with varying anthropometric characteristics.

  20. Gravity and observer's body orientation influence the visual perception of human body postures.

    PubMed

    Lopez, Christophe; Bachofner, Christelle; Mercier, Manuel; Blanke, Olaf

    2009-05-04

    Since human behavior and perception have evolved within the Earth's gravitational field, humans possess an internal model of gravity. Although gravity is known to influence the visual perception of moving objects, the evidence is less clear concerning the visual perception of static objects. We investigated whether a visual judgment of the stability of human body postures (static postures of a human standing on a platform and tilted in the roll plane) may also be influenced by gravity and by the participant's orientation. Pictures of human body postures were presented in different orientations with respect to gravity and the participant's body. The participant's body was aligned to gravity (upright) or not (lying on one side). Participants performed stability judgments with respect to the platform, imagining that gravity operates in the direction indicated by the platform (that was or was not concordant with physical gravity). Such visual judgments were influenced by the picture's orientation with respect to physical gravity. When pictures were tilted by 90 degrees with respect to physical gravity, the human postures that were tilted toward physical gravity (down) were perceived as more unstable than similar postures tilted away from physical gravity (up). Stability judgments were also influenced by the picture's orientation with respect to the participant's body. This indicates that gravity and the participant's body position may influence the visual perception of static objects.

  1. Continuous assessment of work activities and posture in long-term care nurses.

    PubMed

    Hodder, Joanne N; Holmes, Michael W R; Keir, Peter J

    2010-09-01

    The high prevalence of low back injuries in nursing has prompted the use of mechanical lift assists while overall assessment of activities and postures remains limited. The purpose of this study was to chronicle trunk posture and work tasks of long-term healthcare professionals. An inclinometer monitored trunk posture for 27 workers, 20 of whom were also observed continuously throughout their shift. Patient lifts and transfers accounted for less than 4% of the shift while patient care, unloaded standing and walking and miscellaneous tasks accounted for 85%. Manual lifts and transfers occurred twice as often as mechanically assisted lifts but took only half the time. The workers had a median trunk flexion angle of 9.2 degrees , spent 25% of their time flexed beyond 30 degrees and had peak flexion angles greater than 75 degrees in many tasks. Analysis of posture throughout the entire working shift indicates that, in addition to lifts and transfers, emphasis needs to be placed on patient care and miscellaneous activities when assessing injury risk for nurses. STATEMENT OF RELEVANCE: Patient handling has been the focus in the effort to reduce back pain and injury in nursing. In addition to the use of mechanical lifts, there is a need to examine other aspects of nursing, including patient care and other ancillary tasks, which comprise the majority of the work shift and, while often unloaded, exhibit extreme postures that may also lead to injury.

  2. Influence of foot posture on the functioning of the windlass mechanism.

    PubMed

    Lucas, Rachel; Cornwall, Mark

    2017-01-17

    The absence of a functioning windlass mechanism may delay re-supination of the foot during locomotion and put excess stress on the mid-tarsal joint and soft tissues of the foot. The purpose of this study was to describe the foot posture of individuals that have an impaired or absent windlass mechanism. Forty-seven individuals (34 females and 13 males) with a mean age of 26 years were recruited to participate in this study. The Foot Posture Index was used to visually assess the posture of both feet. In addition, a digital gauge was used to measure dorsal arch height and midfoot width in bilateral resting standing. Dorsal arch height and mid-foot width were also measured in non-weight bearing. Finally, for those individuals without a functioning windlass mechanism, the amount of medial wedging needed to restore its function was measured. Subjects with an "absent" or "impaired" windlass mechanism had a mean Foot Posture Index of +6.8 (sd=2.5) compared to +2.5 (sd=3.1) for those with a functioning windlass mechanism. A series of independent t-tests showed that individuals without a functioning windlass mechanism had a more pronated foot posture, a lower dorsal arch height and a wider mid-foot width compared to those that had a functioning windlass mechanism. Finally, an average medial wedge of 5.1mm (sd=2.1) was able to produce a functioning windlass mechanism in those individuals that previously lacked one.

  3. Study of postures in sugarcane cutters in the Pontal of Paranapanema-SP, Brazil.

    PubMed

    de Anchieta Messias, Iracimara; Okuno, Emico

    2012-01-01

    The expansion of sugarcane monoculture in Brazil in the last decades has pointed out to the necessity of considering the question of sugarcane cutters occupational health. In this work we present a cross-sectional study aiming to examine the occupational posture of a group of sugarcane cutters, which work in a cane field located in the region of Pontal do Paranapanema- SP, Brazil. The study was made using the Ergonomic Analysis of Work - EAW methodology and the postural analysis method by Win-OWAS. Through the obtained records of postures, it was observed that during a workday the sugarcane cutters remain standing erect on two legs or in one leg 66% of the time and that their trunk remain tilted and in rotation, according to 63% of the positions categorized. It was also observed that the sugarcane cutter trunk performs repetitive and boundless movements during his routine of work, which can expose this individual to additional wear of their musculoskeletal functions. The activities in which the individual engages have favorable or adverse influence on his posture. The repetitive movements involved in specialized occupations are equivalent to repeated exercises, thus may be responsible for the excessive development of certain muscle groups. The study suggests that the postures adopted by sugarcane cutters can overload their musculoskeletal system and predispose the cutters to work-related musculoskeletal diseases.

  4. The effects of repetitive haemarthrosis on postural balance in children with haemophilia.

    PubMed

    Souza, F M B; McLaughlin, P; Pereira, R P; Minuque, N P; Mello, M H M; Siqueira, C; Villaça, P; Tanaka, C

    2013-07-01

    Sensory information from visual, vestibular and proprioceptive systems is necessary to control posture and balance. Impairment in proprioception due to repetitive joints bleeding may lead to a deficit in postural balance which, in turn, leads to high joint stress and risk of bleeding recurrence. Despite the increase in attention in this field during the past few years, the data concerning to how bleeds can affect postural control in children with haemophilia (CWH) remain scarce. This study aimed to evaluate the postural balance in CWH. Twenty CWH Haemophilia Group (HG) and 20 age-matched children Control Group (CG) were recruited to this study. A force plate was used to record centre of pressure (COP) displacement under four different postural conditions during quiet standing: eyes open on firm surface, eyes open on foam surface, eyes closed on firm surface and eyes closed on a foam surface. Variables of COP as sway area and mean velocity and in anterior-posterior (y) medio-lateral (x) direction were processed and for each variable sensory, quotients were calculated and compared between groups. No differences were found in visual and vestibular quotients variables between groups. A higher value was found in sway area variable on proprioception quotient in the HG when compared with CG (P = 0.042). CWH with repetitive joint bleed on lower limbs showed differences in postural balance when compared with non-haemophiliac children. The identification of early balance impairments in CWH can help us understand better the effects of bleeds inside joints on postural control and plan a more effective preventive and rehabilitative treatment.

  5. Directional postural responses induced by vibrotactile stimulations applied to the torso.

    PubMed

    Lee, Beom-Chan; Martin, Bernard J; Sienko, Kathleen H

    2012-10-01

    It has been shown that torso-based vibrotactile feedback significantly reduces postural sway in balance-compromised adults during quiet standing and in response to perturbations. This study aimed to determine whether vibrotactile stimulations applied to different torso locations induced directional postural responses and whether torso cutaneous information contributes to body representation. Eleven healthy young adults equipped with an inertial measurement unit (IMU) placed on the torso were asked to maintain an upright posture with closed eyes. Six vibrators (tactors) were placed on the torso in contact with the skin over the left and right external oblique, internal oblique, and erector spinae muscles at the L4/L5 level. Each tactor was randomly activated four times per location at a frequency of 250 Hz for a period of 5 s. The IMU results indicated that vibration applied individually over the internal oblique and erector spinae muscles induced a postural shift of about one degree oriented in the direction of the stimulation, while simultaneous activation of all tactors and activation of tactors over external oblique muscles produced insignificant postural effects. The root mean square of the sway signal was significantly higher during vibration than before or after. However, the center of pressure displacement, measured by a force plate, was uninfluenced by any vibration. These results suggest a multi-joint postural response including a torso inclination associated with vibration-induced changes in cutaneous information. The directional aspect of vibration-induced postural shifts suggests that cutaneous information from the stimulated areas contributes to proprioception and upper body spatial representation.

  6. Beyond deficit or compensation: new insights on postural control after long-term total visual loss.

    PubMed

    Russo, Maitê M; Lemos, Thiago; Imbiriba, Luís A; Ribeiro, Nathalia L; Vargas, Claudia D

    2017-02-01

    Loss of vision is well known to affect postural control in blind subjects. This effect has classically been framed in terms of deficit or compensation depending on whether body sway increases or decreases in comparison with that of sighted subjects with the eyes open. However, studies have shown that postural responses can be modulated by the context and that changes in postural sway may not necessarily mean a worsened or improved postural control. The goal of our study was to test whether balance is affected by the context in blind subjects. Additional to the quantification of center of pressure (COP) displacement, measurements of body motion (COG) and the correspondent net neuromuscular response (COP-COG) were evaluated in anterior-posterior and medial-lateral directions. Thirty-eight completely blind and thirty-two sighted subjects participated of this study. The volunteers were asked to stand barefoot on a force platform for 60 s in two different conditions: feet apart and feet together. Sighted participants performed the tests with both the eyes open and eyes closed. Results showed that the COP-COG displacements in the blind group were greater than those of the sighted group with eyes open in almost all conditions tested, but not in eyes closed condition. However, the COP and COG results confirmed that the postural responses were context dependent. Together these results suggest that total visual loss does not just lead to a balance deficit or compensation, but to a specific postural signature that might imply in enhancing COP, COG and/or COP-COG in specific postural conditions.

  7. Postural control in bipolar disorder: increased sway area and decreased dynamical complexity.

    PubMed

    Bolbecker, Amanda R; Hong, S Lee; Kent, Jerillyn S; Klaunig, Mallory J; O'Donnell, Brian F; Hetrick, William P

    2011-01-01

    Structural, neurochemical, and functional abnormalities have been identified in the brains of individuals with bipolar disorder, including in key brain structures implicated in postural control, i.e. the cerebellum, brainstem, and basal ganglia. Given these findings, we tested the hypothesis that postural control deficits are present in individuals with bipolar disorder. Sixteen participants with bipolar disorder (BD) and 16 age-matched non-psychiatric healthy controls were asked to stand as still as possible on a force platform for 2 minutes under 4 conditions: (1) eyes open-open base; (2) eyes closed-open base; (3) eyes open-closed base; and (4) eyes closed-closed base. Postural sway data were submitted to conventional quantitative analyses of the magnitude of sway area using the center of pressure measurement. In addition, data were submitted to detrended fluctuation analysis, a nonlinear dynamical systems analytic technique that measures complexity of a time-series, on both the anterior-posterior and medio-lateral directions. The bipolar disorder group had increased sway area, indicative of reduced postural control. Decreased complexity in the medio-lateral direction was also observed for the bipolar disorder group, suggesting both a reduction in dynamic range available to them for postural control, and that their postural corrections were primarily dominated by longer time-scales. On both of these measures, significant interactions between diagnostic group and visual condition were also observed, suggesting that the BD participants were impaired in their ability to make corrections to their sway pattern when no visual information was available. Greater sway magnitude and reduced complexity suggest that individuals with bipolar disorder have deficits in sensorimotor integration and a reduced range of timescales available on which to make postural corrections.

  8. Changes in multi-segmented body movements and EMG activity while standing on firm and foam support surfaces.

    PubMed

    Fransson, P A; Gomez, S; Patel, M; Johansson, L

    2007-09-01

    Postural control ensures stability during both static posture and locomotion by initiating corrective adjustments in body movement. This is particularly important when the conditions of the support surface change. We investigated the effects of standing on a compliant foam surface using 12 normal subjects (mean age 26 years) in terms of: linear movements at the head, shoulder, hip and knee; EMG activity of the tibialis anterior and gastrocnemius muscles and torques towards the support surface. As subjects repeated the trials with eyes open or closed, we were also able to determine the effects of vision on multi-segmented body movements during standing upon different support surface conditions. As expected, EMG activity, torque variance values and body movements at all measured positions increased significantly when standing on foam compared with the firm surface. Linear knee and hip movements increased more, relative to shoulder and head movements while standing on foam. Vision stabilized the head and shoulder movements more than hip and knee movements while standing on foam support surface. Moreover, vision significantly reduced the tibialis anterior EMG activity and torque variance during the trials involving foam. In conclusion, the foam support surface increased corrective muscle and torque activity, and changed the firm-surface multi-segmented body movement pattern. Vision improved the ability of postural control to handle compliant surface conditions. Several essential features of postural control have been found from recording movements from multiple points on the body, synchronized with recording torque and EMG.

  9. Standing wave compressor

    DOEpatents

    Lucas, Timothy S.

    1991-01-01

    A compressor for compression-evaporation cooling systems, which requires no moving parts. A gaseous refrigerant inside a chamber is acoustically compressed and conveyed by means of a standing acoustic wave which is set up in the gaseous refrigerant. This standing acoustic wave can be driven either by a transducer, or by direct exposure of the gas to microwave and infrared sources, including solar energy. Input and output ports arranged along the chamber provide for the intake and discharge of the gaseous refrigerant. These ports can be provided with optional valve arrangements, so as to increase the compressor's pressure differential. The performance of the compressor in either of its transducer or electromagnetically driven configurations, can be optimized by a controlling circuit. This controlling circuit holds the wavelength of the standing acoustical wave constant, by changing the driving frequency in response to varying operating conditions.

  10. The difference between standing and sitting in 3 different seat inclinations on abdominal muscle activity and chest and abdominal expansion in woodwind and brass musicians

    PubMed Central

    Ackermann, Bronwen J.; O'Dwyer, Nicholas; Halaki, Mark

    2014-01-01

    Wind instrumentalists require a sophisticated functioning of their respiratory system to control their air stream, which provides the power for optimal musical performance. The air supply must be delivered into the instrument in a steady and controlled manner and with enough power by the action of the expiratory musculature to produce the desired level of sound at the correct pitch. It is suggested that playing posture may have an impact on the abdominal muscle activity controlling this expired air, but there is no research on musicians to support this theory. This study evaluated chest and abdominal expansion, via respiratory inductive plethysmography, as well as activation patterns of lower and upper abdominal musculature, using surface electromyography, during performance of a range of typical orchestral repertoire by 113 woodwind and brass players. Each of the five orchestral excerpts was played in one of four randomly allocated postures: standing; sitting flat; sitting inclined forwards; and sitting inclined backwards. Musicians showed a clear preference for playing in standing rather than sitting. In standing, the chest expansion range and maximum values were greater (p < 0.01), while the abdominal expansion was less than in all sitting postures (p < 0.01). Chest expansion patterns did not vary between the three sitting postures, while abdominal expansion was reduced in the forward inclined posture compared to the other sitting postures (p < 0.05). There was no significant variation in abdominal muscle activation between the sitting postures, but the level of activation in sitting was only 2/3 of the significantly higher level observed in standing (p < 0.01). This study has demonstrated significant differences in respiratory mechanics between sitting and standing postures in wind musicians during playing of typical orchestral repertoire. Further research is needed to clarify the complex respiratory mechanisms supporting musical performance. PMID:25202290

  11. The difference between standing and sitting in 3 different seat inclinations on abdominal muscle activity and chest and abdominal expansion in woodwind and brass musicians.

    PubMed

    Ackermann, Bronwen J; O'Dwyer, Nicholas; Halaki, Mark

    2014-01-01

    Wind instrumentalists require a sophisticated functioning of their respiratory system to control their air stream, which provides the power for optimal musical performance. The air supply must be delivered into the instrument in a steady and controlled manner and with enough power by the action of the expiratory musculature to produce the desired level of sound at the correct pitch. It is suggested that playing posture may have an impact on the abdominal muscle activity controlling this expired air, but there is no research on musicians to support this theory. This study evaluated chest and abdominal expansion, via respiratory inductive plethysmography, as well as activation patterns of lower and upper abdominal musculature, using surface electromyography, during performance of a range of typical orchestral repertoire by 113 woodwind and brass players. Each of the five orchestral excerpts was played in one of four randomly allocated postures: standing; sitting flat; sitting inclined forwards; and sitting inclined backwards. Musicians showed a clear preference for playing in standing rather than sitting. In standing, the chest expansion range and maximum values were greater (p < 0.01), while the abdominal expansion was less than in all sitting postures (p < 0.01). Chest expansion patterns did not vary between the three sitting postures, while abdominal expansion was reduced in the forward inclined posture compared to the other sitting postures (p < 0.05). There was no significant variation in abdominal muscle activation between the sitting postures, but the level of activation in sitting was only 2/3 of the significantly higher level observed in standing (p < 0.01). This study has demonstrated significant differences in respiratory mechanics between sitting and standing postures in wind musicians during playing of typical orchestral repertoire. Further research is needed to clarify the complex respiratory mechanisms supporting musical performance.

  12. 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.

  13. Standing equine sinus surgery.

    PubMed

    Barakzai, Safia Z; Dixon, Padraic M

    2014-04-01

    Trephination of the equine sinuses is a common surgical procedure in sedated standing horses. Standing sinus flap surgery has become increasingly popular in equine referral hospitals and offers several advantages over sinusotomy performed under general anesthesia, including reduced patient-associated risks and costs; less intraoperative hemorrhage, allowing better visualization of the operative site; and allows surgeons to take their time. Other minimally invasive surgical procedures include sinoscopic surgery, balloon sinuplasty, and transnasal laser sinonasal fenestration. Despite the procedure used, appropriate indications for surgery, good patient selection, and familiarity with regional anatomy and surgical techniques are imperative for good results.

  14. 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.

  15. Study II: mechanoreceptive sensation is of increased importance for human postural control under alcohol intoxication.

    PubMed

    Modig, F; Patel, M; Magnusson, M; Fransson, P A

    2012-03-01

    Standing postural stability relies on input from visual, vestibular, proprioceptive and mechanoreceptive sensors. When the information from any of these sensors is unavailable or disrupted, the central nervous system maintains postural stability by relying more on the contribution from the reliable sensors, termed sensory re-weighting. Alcohol intoxication is known to affect the integrity of the vestibular and visual systems. The aim was to assess how mechanoreceptive sensory information contributed to postural stability at 0.00% (i.e. sober), 0.06% and 0.10% blood alcohol concentration (BAC) in 25 healthy subjects (mean age 25.1 years). The subjects were assessed with eyes closed and eyes open under quiet standing and while standing was perturbed by repeated, random-length, vibratory stimulation of the calf muscles. Plantar cutaneous mechanoreceptive sensation was assessed for both receptor types: slowly adapting (tactile sensitivity) and rapidly adapting (vibration perception). The correlation between recorded torque variance and the sensation from both mechanoreceptor types was calculated. The recorded stability during alcohol intoxication was significantly influenced by both the tactile sensation and vibration perception of the subjects. Moreover, the study revealed a fluctuating association between the subjects' vibration perception and torque variance during balance perturbations, which was significantly influenced by the level of alcohol intoxication, vision and adaptation. Hence, one's ability to handle balance perturbations under the influence of alcohol is strongly dependent on accurate mechanoreceptive sensation and efficient sensory re-weighting.

  16. 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.

  17. Photographic measurement of upper-body sitting posture of high school students: A reliability and validity study

    PubMed Central

    van Niekerk, Sjan-Mari; Louw, Quinette; Vaughan, Christopher; Grimmer-Somers, Karen; Schreve, Kristiaan

    2008-01-01

    Background All the reported measures of sitting posture, as well as photographs, have one flaw, as these measures are external to the body. These measures use calculations from external bony landmarks to estimate spinal posture, on the understanding that what is being measured externally reflects the shape, health and performance of structures of the underlying spine. Without a comparative measure of the relative position of the structures of the spine, the validity of any external spinal posture measure cannot be established. This paper reports on a study which tests the validity of photographs to measure adolescent sitting posture. Methods The study was conducted in a laboratory at the Department of Human Biology, University of Cape Town. A random sample of 40 adolescents were recruited from the Cape metropolitan schools, to detect differences of three degrees or more between the repeated measures of upright, normal or slouched posture (photographs) and between the posture photographs and LODOX measures. Eligible participants were healthy male and female subjects aged 15 or 16 years old, in Grade 10, and who were undertaking Computer or Computype studies at their schools. Two posture measurement tools were used in the study, namely: Photographs were taken using the Photographic Posture Analysis Method (PPAM) and Radiographs were taken using the LODOX (LODOX (Pty) Ltd) system. Subjects' posture was assessed in simulated computer workstations. The following angles were measured: the sagittal head angle, cervical angle, protraction/retraction angle, arm angle and the thoracic angle. Results Data from 39 subjects (19 males, 20 females) was used for analysis (17 15-year-olds (7 boys and 10 girls), 22 16-year-olds (12 boys and 10 girls)). All but one photographic angle showed moderate to good correlation with the LODOX angles (Pearson r values 0.67–0.95) with the exception being the shoulder protraction/retraction angle Pearson r values. Bland Altman limits of

  18. Comparison of maximum voluntary isometric contraction of the biceps on various posture and respiration conditions for normalization of electromyography data

    PubMed Central

    Lee, Sang-Yeol; Jo, Marg-Eun

    2016-01-01

    [Purpose] Maximum voluntary isometric contraction can increase the reliability of electromyography data by controlling respiration; however, many studies that use normalization of electromyography data fail to account for this. This study aims to check changes in maximum voluntary isometric contraction based on changes in posture and respiration conditions. [Subjects and Methods] Twenty-two healthy volunteers were included in this study. Using 22 healthy subjects, MVIC of the biceps brachii muscle was measured in three respiration conditions: (1) Maximum voluntary isometric contraction during inspiration after maximal expiration, (2) Maximum voluntary isometric contraction during expiration after maximal inspiration and (3) Maximum voluntary isometric contraction during the Valsalva maneuver. The subjects were in tested in standing and supine postures under all three respiration conditions. [Results] A significant difference was observed in the standing and supine postures based on the respiration condition. A significant difference was observed in the maximum voluntary isometric contraction during inspiration after maximal expiration and maximum voluntary isometric contraction during the Valsalva maneuver conditions when the subjects were in the supine posture. [Conclusion] It is necessary to apply the same respiration condition and the same posture to each subject when measuring Maximum voluntary isometric contraction for the normalization of electromyography data. PMID:27942110

  19. Generation of postured voxel-based human models for the study of step voltage excited by lightning current

    NASA Astrophysics Data System (ADS)

    Gao, J.; Munteanu, I.; Müller, W. F. O.; Weiland, T.

    2011-07-01

    With the development of medical technique and computational electromagnetics, high resolution anatomic human models have already been widely developed and used in computation of electromagnetic fields induced in human body. Although these so called voxel-based human models are powerful tools for research on electromagnetic safety, their unchangeable standing posture makes it impossible to simulate a realistic scenario in which people have a lot of different postures. This paper describes a poser program package which was developed as an improved version of the free-from deformation technique to overcome this problem. It can set rotation angles of different human joints and then deform the original human model to make it have different postures. The original whole-body human model can be deformed smoothly, continuity of internal tissues and organs is maintained and the mass of different tissues and organs can be conserved in a reasonable level. As a typical application of the postured human models, this paper also studies the effect of the step voltage due to a lightning strike on the human body. Two voxel-based human body models with standing and walking posture were developed and integrated into simulation models to compute the current density distribution in the human body shocked by the step voltage. In order to speed up the transient simulation, the reduced c technique was used, leading to a speedup factor of around 20. The error introduced by the reduced c technique is discussed and simulation results are presented in detail.

  20. 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.

  1. Determining suitable dimensions for dairy goat feeding places by evaluating body posture and feeding reach.

    PubMed

    Keil, Nina M; Pommereau, Marc; Patt, Antonia; Wechsler, Beat; Gygax, Lorenz

    2017-02-01

    Confined goats spend a substantial part of the day feeding. A poorly designed feeding place increases the risk of feeding in nonphysiological body postures, and even injury. Scientifically validated information on suitable dimensions of feeding places for loose-housed goats is almost absent from the literature. The aim of the present study was, therefore, to determine feeding place dimensions that would allow goats to feed in a species-appropriate, relaxed body posture. A total of 27 goats with a height at the withers of 62 to 80 cm were included in the study. Goats were tested individually in an experimental feeding stall that allowed the height difference between the feed table, the standing area of the forelegs, and a feeding area step (difference in height between forelegs and hind legs) to be varied. The goats accessed the feed table via a palisade feeding barrier. The feed table was equipped with recesses at varying distances to the feeding barrier (5-55 cm in 5-cm steps) at angles of 30°, 60°, 90°, 120°, or 150° (feeding angle), which were filled with the goats' preferred food. In 18 trials, balanced for order across animals, each animal underwent all possible combinations of feeding area step (3 levels: 0, 10, and 20 cm) and of difference in height between feed table and standing area of forelegs (6 levels: 0, 5, 10, 15, 20, and 25 cm). The minimum and maximum reach at which the animals could reach feed on the table with a relaxed body posture was determined for each combination. Statistical analysis was performed using mixed-effects models. The animals were able to feed with a relaxed posture when the feed table was at least 10 cm higher than the standing height of the goats' forelegs. Larger goats achieved smaller minimum reaches and minimum reach increased if the goats' head and neck were angled. Maximum reach increased with increasing height at withers and height of the feed table. The presence of a feeding area step had no influence on minimum and

  2. Integrating multiple sensory systems to modulate neural networks controlling posture

    PubMed Central

    Gerasimenko, Y.; Burdick, J.; Zhong, H.; Roy, R. R.; Edgerton, V. R.

    2015-01-01

    In this study we investigated the ability of sensory input to produce tonic responses in hindlimb muscles to facilitate standing in adult spinal rats and tested two hypotheses: 1) whether the spinal neural networks below a complete spinal cord transection can produce tonic reactions by activating different sensory inputs and 2) whether facilitation of tonic and rhythmic responses via activation of afferents and with spinal cord stimulation could engage similar neuronal mechanisms. We used a dynamically controlled platform to generate vibration during weight bearing, epidural stimulation (at spinal cord level S1), and/or tail pinching to determine the postural control responses that can be generated by the lumbosacral spinal cord. We observed that a combination of platform displacement, epidural stimulation, and tail pinching produces a cumulative effect that progressively enhances tonic responses in the hindlimbs. Tonic responses produced by epidural stimulation alone during standing were represented mainly by monosynaptic responses, whereas the combination of epidural stimulation and tail pinching during standing or epidural stimulation during stepping on a treadmill facilitated bilaterally both monosynaptic and polysynaptic responses. The results demonstrate that tonic muscle activity after complete spinal cord injury can be facilitated by activation of specific combinations of afferent inputs associated with load-bearing proprioception and cutaneous input in the presence of epidural stimulation and indicate that whether activation of tonic or rhythmic responses is generated depends on the specific combinations of sources and types of afferents activated in the hindlimb muscles. PMID:26445868

  3. Integrating multiple sensory systems to modulate neural networks controlling posture.

    PubMed

    Lavrov, I; Gerasimenko, Y; Burdick, J; Zhong, H; Roy, R R; Edgerton, V R

    2015-12-01

    In this study we investigated the ability of sensory input to produce tonic responses in hindlimb muscles to facilitate standing in adult spinal rats and tested two hypotheses: 1) whether the spinal neural networks below a complete spinal cord transection can produce tonic reactions by activating different sensory inputs and 2) whether facilitation of tonic and rhythmic responses via activation of afferents and with spinal cord stimulation could engage similar neuronal mechanisms. We used a dynamically controlled platform to generate vibration during weight bearing, epidural stimulation (at spinal cord level S1), and/or tail pinching to determine the postural control responses that can be generated by the lumbosacral spinal cord. We observed that a combination of platform displacement, epidural stimulation, and tail pinching produces a cumulative effect that progressively enhances tonic responses in the hindlimbs. Tonic responses produced by epidural stimulation alone during standing were represented mainly by monosynaptic responses, whereas the combination of epidural stimulation and tail pinching during standing or epidural stimulation during stepping on a treadmill facilitated bilaterally both monosynaptic and polysynaptic responses. The results demonstrate that tonic muscle activity after complete spinal cord injury can be facilitated by activation of specific combinations of afferent inputs associated with load-bearing proprioception and cutaneous input in the presence of epidural stimulation and indicate that whether activation of tonic or rhythmic responses is generated depends on the specific combinations of sources and types of afferents activated in the hindlimb muscles.

  4. [Postural examination in daily occlusodontology].

    PubMed

    Serviere, F

    1989-03-01

    According to the osteopathic and chiropractic concepts, facing a TMJ problem, the practitioner has to determine if the trouble observed in the stomatognatic apparatus is the cause or the effect of the structural problems present anywhere else in the body. The postural examination allows to answer this question. Tow techniques can be used. First a static and dynamic posture test proposed by Bricot. The level of the cranium, the eyes, the shoulders, the wrists, the pelvis and the ankles is analysed, from a front view; from the side, the gravity line is inspected: vertex, auditory meatus, shoulder, hip joint, anterior side of the tibia, ankle joint. The vertical posture can be studied from the front: the arms are held straight and the antero-posterior length between the fingers is measured. From the back, one notes the recoil of the buttocks on one side. An ocular convergence test is performed. Then one uses a Romberg test (oscillation of the body when the eyes are closed), and a Fukuda stepping test. The patient is then asked to bite on a compress, and the same exams are redone. If no change occurs, we are dealing with an ascending problem: the origin of the problem is not the stomatognathic system. The second technique is the Meerssemann test that needs the practice of Applied Kinesiology muscle testing. The patient is lying supine and one tests: the dental occlusion, the two TMJs, the temporal muscles, masseters, pterygoids, sterno-cleido-mastoids, upper tapezius, left and right sacro-iliac joints, psoas muscles bilaterally.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. Deficits in task-specific modulation of anticipatory postural adjustments in individuals with spastic diplegic cerebral palsy.

    PubMed

    Tomita, Hidehito; Fukaya, Yoshiki; Ueda, Tomomi; Honma, Shota; Yamashita, Eriya; Yamamoto, Yoshiji; Mori, Etsuko; Shionoya, Katsuyoshi

    2011-05-01

    We examined whether individuals with spastic diplegic cerebral palsy (SDCP) have the ability to utilize lower leg muscles in anticipatory postural adjustments (APAs) associated with voluntary arm movement while standing, as well as the ability to modulate APAs with changes in the degree of postural perturbation caused by arm movement. Seven individuals with spastic diplegia (SDCP group, 12-22 yr of age) and seven age- and sex-matched individuals without disability (control group) participated in this study. Participants flexed both shoulders and lifted a load under two different load conditions, during which electromyographic activities of focal and postural muscles were recorded. Although the timing of anticipatory activation of the erector spinae and medial hamstring (MH) muscles was similar in the two participant groups, that of the gastrocnemius (GcM) muscle was significantly later in the SDCP group than in the control group. An increase in anticipatory postural muscle activity with an increase in load was observed in MH and GcM in the control group but not in GcM in the SDCP group. The degree of modulation in MH was significantly smaller in the SDCP group than in the control group. An additional experiment confirmed that these differences in APAs between the two participant groups were unlikely to be attributable to their differences in initial standing posture before load lift. The present findings suggest that lower leg muscles play a minor role in APAs in individuals with spastic diplegia. In addition, it is likely that these individuals have difficulty modulating anticipatory postural muscle activity with changes in the degree of postural perturbation.

  6. Correcting Poor Posture without Awareness or Willpower

    ERIC Educational Resources Information Center

    Wernik, Uri

    2012-01-01

    In this article, a new technique for correcting poor posture is presented. Rather than intentionally increasing awareness or mobilizing willpower to correct posture, this approach offers a game using randomly drawn cards with easy daily assignments. A case using the technique is presented to emphasize the subjective experience of living with poor…

  7. Postural Variables in Girls Practicing Volleyball

    ERIC Educational Resources Information Center

    Grabara, Malgorzata; Hadzik, Andrzej

    2009-01-01

    Study aim: To assess body posture of young female volleyball players in relation to their untrained mates. Material and methods: A group of 42 volleyball players and another of 43 untrained girls, all aged 13-16 years were studied with respect to their body posture indices by using computer posturography. Spinal angles and curvatures were…

  8. Functional Neuroanatomy for Posture and Gait Control.

    PubMed

    Takakusaki, Kaoru

    2017-01-01

    Here we argue functional neuroanatomy for posture-gait control. Multi-sensory information such as somatosensory, visual and vestibular sensation act on various areas of the brain so that adaptable posture-gait control can be achieved. Automatic process of gait, which is steady-state stepping movements associating with postural reflexes including headeye coordination accompanied by appropriate alignment of body segments and optimal level of postural muscle tone, is mediated by the descending pathways from the brainstem to the spinal cord. Particularly, reticulospinal pathways arising from the lateral part of the mesopontine tegmentum and spinal locomotor network contribute to this process. On the other hand, walking in unfamiliar circumstance requires cognitive process of postural control, which depends on knowledges of self-body, such as body schema and body motion in space. The cognitive information is produced at the temporoparietal association cortex, and is fundamental to sustention of vertical posture and construction of motor programs. The programs in the motor cortical areas run to execute anticipatory postural adjustment that is optimal for achievement of goal-directed movements. The basal ganglia and cerebellum may affect both the automatic and cognitive processes of posturegait control through reciprocal connections with the brainstem and cerebral cortex, respectively. Consequently, impairments in cognitive function by damages in the cerebral cortex, basal ganglia and cerebellum may disturb posture-gait control, resulting in falling.

  9. Variations in Writing Posture and Cerebral Organization

    ERIC Educational Resources Information Center

    Levy, Jerre; Reid, Marylou

    1976-01-01

    Investigated the relationship between hand writing posture and cerebral dominance of 48 left handed writers and 25 right handed writers. Determined that cerebral dominance is related to handedness and to whether or not the writing hand posture is normal or inverted. (SL)

  10. Neuromechanical tuning of nonlinear postural control dynamics

    NASA Astrophysics Data System (ADS)

    Ting, Lena H.; van Antwerp, Keith W.; Scrivens, Jevin E.; McKay, J. Lucas; Welch, Torrence D. J.; Bingham, Jeffrey T.; DeWeerth, Stephen P.

    2009-06-01

    Postural control may be an ideal physiological motor task for elucidating general questions about the organization, diversity, flexibility, and variability of biological motor behaviors using nonlinear dynamical analysis techniques. Rather than presenting "problems" to the nervous system, the redundancy of biological systems and variability in their behaviors may actually be exploited to allow for the flexible achievement of multiple and concurrent task-level goals associated with movement. Such variability may reflect the constant "tuning" of neuromechanical elements and their interactions for movement control. The problem faced by researchers is that there is no one-to-one mapping between the task goal and the coordination of the underlying elements. We review recent and ongoing research in postural control with the goal of identifying common mechanisms underlying variability in postural control, coordination of multiple postural strategies, and transitions between them. We present a delayed-feedback model used to characterize the variability observed in muscle coordination patterns during postural responses to perturbation. We emphasize the significance of delays in physiological postural systems, requiring the modulation and coordination of both the instantaneous, "passive" response to perturbations as well as the delayed, "active" responses to perturbations. The challenge for future research lies in understanding the mechanisms and principles underlying neuromechanical tuning of and transitions between the diversity of postural behaviors. Here we describe some of our recent and ongoing studies aimed at understanding variability in postural control using physical robotic systems, human experiments, dimensional analysis, and computational models that could be enhanced from a nonlinear dynamics approach.

  11. Functional Neuroanatomy for Posture and Gait Control

    PubMed Central

    Takakusaki, Kaoru

    2017-01-01

    Here we argue functional neuroanatomy for posture-gait control. Multi-sensory information such as somatosensory, visual and vestibular sensation act on various areas of the brain so that adaptable posture-gait control can be achieved. Automatic process of gait, which is steady-state stepping movements associating with postural reflexes including headeye coordination accompanied by appropriate alignment of body segments and optimal level of postural muscle tone, is mediated by the descending pathways from the brainstem to the spinal cord. Particularly, reticulospinal pathways arising from the lateral part of the mesopontine tegmentum and spinal locomotor network contribute to this process. On the other hand, walking in unfamiliar circumstance requires cognitive process of postural control, which depends on knowledges of self-body, such as body schema and body motion in space. The cognitive information is produced at the temporoparietal association cortex, and is fundamental to sustention of vertical posture and construction of motor programs. The programs in the motor cortical areas run to execute anticipatory postural adjustment that is optimal for achievement of goal-directed movements. The basal ganglia and cerebellum may affect both the automatic and cognitive processes of posturegait control through reciprocal connections with the brainstem and cerebral cortex, respectively. Consequently, impairments in cognitive function by damages in the cerebral cortex, basal ganglia and cerebellum may disturb posture-gait control, resulting in falling. PMID:28122432

  12. The effect of a hybrid assistive limb® on sit-to-stand and standing patterns of stroke patients

    PubMed Central

    Kasai, Rie; Takeda, Sunao

    2016-01-01

    [Purpose] The Hybrid Assistive Limb® (HAL®) robot suit is a powered exoskeleton that can assist a user’s lower limb movement. The purpose of this study was to assess the effectiveness of HAL® in stroke rehabilitation, focusing on the change of the sit-to-stand (STS) movement pattern and standing posture. [Subjects and Methods] Five stroke patients participated in this study. Single leg HAL® was attached to each subject’s paretic lower limb. The subjects performed STS three times both with and without HAL® use. A tri-axial accelerometer was used to assess the STS movement pattern. Forward-tilt angle (FTA) and the time required for STS were measured with and without HAL® use. Surface electromyography (EMG) of STS and standing were recorded to assess the vastus medialis muscle activities of the paretic limb. [Results] The average FTA without HAL® use was 35° and it improved to 43° with HAL® use. The time required for STS was longer for all subjects with HAL® use (without HAL® use: 3.42 s, with HAL® use: 5.11 s). The integrated EMGs of HAL® use compared to those without HAL®, were 83.6% and 66.3% for STS and standing, respectively. [Conclusion] HAL® may be effective in improving STS and standing patterns of stroke patients. PMID:27390416

  13. Evaluation of the temporal structure of postural sway fluctuations based on a comprehensive set of analysis tools

    NASA Astrophysics Data System (ADS)

    Kirchner, M.; Schubert, P.; Schmidtbleicher, D.; Haas, C. T.

    2012-10-01

    The analysis of postural control has a long history. Traditionally, the amount of body sway is solely used as an index of postural stability. Although this leads to some extent to an effective evaluation of balance performance, the control mechanisms involved have not yet been fully understood. The concept of nonlinear dynamics suggests that variability in the motor output is not randomness but structure, providing the stimulus to reveal the functionality of postural sway. The present work evaluates sway dynamics by means of COP excursions in a quiet standing task versus a dual-task condition in three different test times (30, 60, 300 s). Besides the application of traditional methods-which estimate the overall size of sway-the temporal pattern of body sway was quantified via wavelet transform, multiscale entropy and fractal analysis. We found higher sensitivity of the structural parameters to modulations of postural control strategies and partly an improved evaluation of sway dynamics in longer recordings. It could be shown that postural control modifications take place on different timescales corresponding to the interplay of the sensory systems. A continued application of nonlinear analysis can help to better understand postural control mechanisms.

  14. Influence of fear of falling on anticipatory postural control of medio-lateral stability during rapid leg flexion.

    PubMed

    Yiou, E; Deroche, T; Do, M C; Woodman, T

    2011-04-01

    During leg flexion from erect posture, postural stability is organized in advance during "anticipatory postural adjustments" (APA). During these APA, inertial forces are generated that propel the centre of gravity (CoG) laterally towards stance leg side. This study examined how fear of falling (FoF) may influence this anticipatory postural control of medio-lateral (ML) stability. Ten young healthy participants performed a series of leg flexions at maximal velocity from low and high surface heights (6 and 66 cm above ground, respectively). In this latter condition with increased FoF, stance foot was placed at the lateral edge of the support surface to induce maximal postural threat. Results showed that the amplitude of ML inertial forces generated during APA decreased with FoF; this decrease was compensated by an increase in APA duration so that the CoG position at time of swing foot-off was located further towards stance leg side. With these changes in ML APA, the CoG was propelled in the same final (unipodal) position above stance foot as in condition with low FoF. These results contrast with those obtained in the literature during quiet standing which showed that FoF did not have any influence on the ML component of postural control. It is proposed that ML APA are modified with increased FoF, in such a way that the risk of a sideway fall induced by the large CoG motion is attenuated.

  15. A comparison of low back kinetic estimates obtained through posture matching, rigid link modeling and an EMG-assisted model.

    PubMed

    Parkinson, R J; Bezaire, M; Callaghan, J P

    2011-07-01

    This study examined errors introduced by a posture matching approach (3DMatch) relative to dynamic three-dimensional rigid link and EMG-assisted models. Eighty-eight lifting trials of various combinations of heights (floor, 0.67, 1.2 m), asymmetry (left, right and center) and mass (7.6 and 9.7 kg) were videotaped while spine postures, ground reaction forces, segment orientations and muscle activations were documented and used to estimate joint moments and forces (L5/S1). Posture matching over predicted peak and cumulative extension moment (p < 0.0001 for all variables). There was no difference between peak compression estimates obtained with posture matching or EMG-assisted approaches (p = 0.7987). Posture matching over predicted cumulative (p < 0.0001) compressive loading due to a bias in standing, however, individualized bias correction eliminated the differences. Therefore, posture matching provides a method to analyze industrial lifting exposures that will predict kinetic values similar to those of more sophisticated models, provided necessary corrections are applied.

  16. a Review of the Biomechanics and Epidemiology of Working Postures (it Isn't always Vibration which is to BLAME!)

    NASA Astrophysics Data System (ADS)

    Magnusson, M. L.; Pope, M. H.

    1998-08-01

    Many vibrational environments also subject the worker to awkward, asymmetric and prolonged postures. This paper reviews the epidemiological, biomechanical and physiological factors involved in working postures which could lead to musculoskeletal problems. Too little or too much sitting leads to low back pain. Sedentary postures, including driving, also lead to a higher risk of a herniated disc. In sitting the pelvis rotates and higher pressures exist in the disk. A backrest inclined to 110° or more and with a lumbar support will reduce the disk pressure. Jobs involving excessive force application will be more apt to cause muscular and ligamentous damage. However, these excessive demands can occur in whole body vibration environments too. Neck, shoulder and arm problems are usually related to posture but can occur in WBV environments. Knee problems, in the standing worker, may be due to a flexed knee posture in an attempt to attenuate vibrations. Excessive postural demands on the neck, shoulder and arm will lead to higher muscle forces and higher joint forces. Recommendations are given to reduce risk of disability.

  17. Static and dynamic postural stability in veterans with combat-related mild traumatic brain injury.

    PubMed

    Pan, Tao; Liao, Ke; Roenigk, Kristen; Daly, Janis J; Walker, Mark F

    2015-10-01

    Persistent post-concussive symptoms are reported by 10-15% of individuals who suffer mild traumatic brain injury (mTBI), but their basis is often uncertain. One such symptom is disequilibrium, a sensation of impaired balance during standing and walking. The hypothesis for this study was that this subjective symptom is associated with objective and measurable deficits in static and dynamic postural stability. An infrared motion tracking system was used to record body motion during quiet standing and in response to waist perturbations in fourteen veterans (age 22-40 years, 13 male) of the Operations Enduring Freedom (OEF) and Iraqi Freedom (OIF), who had a history of mTBI that occurred 7 months to 7 years prior to testing. We compared body sway between veterans with mTBI reporting persistent disequilibrium (TD, n=8) and those with no vestibular symptoms (n=6), as well as to a group of non-veterans with no balance symptoms (n=10). Static postural stability was reduced in TD veterans in comparison to each of the other two groups (p<0.0002), most notably on a compliant surface with eyes closed. The TD group also had decreased dynamic stability of the upper trunk (p<0.05) and enhanced postural oscillations (p<0.02) following waist perturbations. Our findings support a physiological basis for persistent disequilibrium after mTBI and are consistent with impaired vestibular processing. Disruption of semicircular canal inputs is unlikely to be the cause, as head impulse responses were normal in all groups. The unexpected finding of dynamic postural oscillations requires further study but may indicate enhanced instability in sensorimotor networks responsible for postural control.

  18. Relationship between static postural control and the level of functional abilities in children with cerebral palsy

    PubMed Central

    Pavão, Sílvia L.; Nunes, Gabriela S.; Santos, Adriana N.; Rocha, Nelci A. C. F.

    2014-01-01

    Background: Postural control deficits can impair functional performance in children with cerebral palsy (CP) in daily living activities. Objective: To verify the relationship between standing static postural control and the functional ability level in children with CP. Method: The postural control of 10 children with CP (gross motor function levels I and II) was evaluated during static standing on a force platform for 30 seconds. The analyzed variables were the anteroposterior (AP) and mediolateral (ML) displacement of the center of pressure (CoP) and the area and velocity of the CoP oscillation. The functional abilities were evaluated using the mean Pediatric Evaluation of Disability Inventory (PEDI) scores, which evaluated self-care, mobility and social function in the domains of functional abilities and caregiver assistance. Results: Spearman's correlation test found a relationship between postural control and functional abilities. The results showed a strong negative correlation between the variables of ML displacement of CoP, the area and velocity of the CoP oscillation and the PEDI scores in the self-care and caregiver assistance domains. Additionally, a moderate negative correlation was found between the area of the CoP oscillation and the mobility scores in the caregiver assistance domain. We used a significance level of 5% (p <0.05). Conclusions: We observed that children with cerebral palsy with high CoP oscillation values had lower caregiver assistance scores for activities of daily living (ADL) and consequently higher levels of caregiver dependence. These results demonstrate the repercussions of impairments to the body structure and function in terms of the activity levels of children with CP such that postural control impairments in these children lead to higher requirements for caregiver assistance. PMID:25054383

  19. Multiscale entropy identifies differences in complexity in postural control in women with multiple sclerosis.

    PubMed

    Busa, Michael A; Jones, Stephanie L; Hamill, Joseph; van Emmerik, Richard E A

    2016-03-01

    Loss of postural center-of-pressure complexity (COP complexity) has been associated with reduced adaptability that accompanies disease and aging. The aim of this study was to identify if COP complexity is reduced: (1) in those with Multiple Sclerosis (MS) compared to controls; (2) when vision is limited compared to remaining intact; and (3) during more demanding postural conditions compared to quiet standing. Additionally, we explored the relationship between the COP complexity and disease severity, fatigue, cutaneous sensation and central motor drive. Twelve women with MS and 12 age-matched controls were tested under quiet standing and postural maximal lean conditions with normal and limited vision. The key dependent variable was the complexity index (CI) of the center of pressure. We observed a lower CI in the MS group compared to controls in both anterior-posterior (AP) and medio-lateral (ML) directions (p's<0.002), during the performance of maximal self-regulated leans (AP: p<0.001; ML: p=0.018), and under limited vision (AP: p=0.001; ML: p=0.006). No group-by-vision interaction (p>0.05) was observed, indicating that limiting vision did not impact COP complexity differently in the two groups. Decreased cutaneous sensitivity was associated with lower CI values in the AP direction among those with MS (r(2)=0.57); all other measures did not exhibit significant relationships. The findings reported here suggest that (1) MS is associated with diminished COP complexity under both normal and challenging postures, and (2) complexity is strongly correlated with cutaneous sensitivity, suggesting the unique contribution of impaired somatosensation on postural control deficits in persons with MS.

  20. The control of limb geometry in cat posture.

    PubMed Central

    Lacquaniti, F; Le Taillanter, M; Lopiano, L; Maioli, C

    1990-01-01

    1. The aim of this study is to address the problem of the controlled variable in quadrupedal stance. In particular, we considered whether the projection of the centre of mass of the body on the support surface or the joint torques or the geometrical configuration of the limbs are primarily controlled. 2. Cats were trained to stand freely on a platform which could be tilted in the sagittal plane by up to +/- 20 deg. The normal and tangential components of the contact forces at each paw were measured by means of load cells. The position of limb joints was recorded by means of the ELITE system. 3. The projection of the centre of body mass on the platform, as well as the orientation and length of limb axes, varied to only a limited extent with tilt angle. In particular, the limb axes were closely lined up with the vertical, as were the vectors of the contact forces at the paws. As a result, the torques at the proximal joints (scapula and hip) were close to zero and the torques at the other joints varied little with table tilt. 4. In order to test the different hypotheses on postural control, an external load (10-20% of the animal weight) was applied to the cat forequarters. The projected centre of mass consistently shifted forwards, contrary to the hypothesis that this parameter is controlled in stance. Instead, the geometry of limb posture remained unmodified after load application, even though the torques at forelimb joints were much greater than in the control. 5. This postural behaviour showed no sign of adaptation over a period of 24 h of continuous load application. 6. It is concluded that limb geometry is primarily controlled in stance. The results are discussed in the context of current notions on hierarchical control and body scheme. PMID:2231397

  1. Time course analysis of baroreflex sensitivity during postural stress.

    PubMed

    Westerhof, Berend E; Gisolf, Janneke; Karemaker, John M; Wesseling, Karel H; Secher, Niels H; van Lieshout, Johannes J

    2006-12-01

    Postural stress requires immediate autonomic nervous action to maintain blood pressure. We determined time-domain cardiac baroreflex sensitivity (BRS) and time delay (tau) between systolic blood pressure and interbeat interval variations during stepwise changes in the angle of vertical body axis (alpha). The assumption was that with increasing postural stress, BRS becomes attenuated, accompanied by a shift in tau toward higher values. In 10 healthy young volunteers, alpha included 20 degrees head-down tilt (-20 degrees), supine (0 degree), 30 and 70 degrees head-up tilt (30 degrees, 70 degrees), and free standing (90 degrees). Noninvasive blood pressures were analyzed over 6-min periods before and after each change in alpha. The BRS was determined by frequency-domain analysis and with xBRS, a cross-correlation time-domain method. On average, between 28 (-20 degrees) to 45 (90 degrees) xBRS estimates per minute became available. Following a change in alpha, xBRS reached a different mean level in the first minute in 78% of the cases and in 93% after 6 min. With increasing alpha, BRS decreased: BRS = -10.1.sin(alpha) + 18.7 (r(2) = 0.99) with tight correlation between xBRS and cross-spectral gain (r(2) approximately 0.97). Delay tau shifted toward higher values. In conclusion, in healthy subjects the sensitivity of the cardiac baroreflex obtained from time domain decreases linearly with sin(alpha), and the start of baroreflex adaptation to a physiological perturbation like postural stress occurs rapidly. The decreases of BRS and reduction of short tau may be the result of reduced vagal activity with increasing alpha.

  2. 20. Building 202, detail of stand A, rocket test stand ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. Building 202, detail of stand A, rocket test stand in test cell. View looking southeast. - Rocket Engine Testing Facility, GRC Building No. 202, NASA Glenn Research Center, Cleveland, Cuyahoga County, OH

  3. Perceived standing position after reduction of foot-pressure sensation by cooling the sole.

    PubMed

    Fujiwara, Katsuo; Asai, Hitoshi; Miyaguchi, Akiyoshi; Toyama, Hiroshi; Kunita, Kenji; Inoue, Katsumi

    2003-04-01

    We investigated the influence of the reduction of foot-pressure sensation by cooling the sole of the foot, at 1 degree C for 30 or 40 minutes, on the perception of standing position varied in the anteroposterior direction. The subjects were 16 healthy undergraduates. Firstly, for 4 of the subjects, cooling the sole of the foot decreased sensory information from the mechanoreceptors in the sole, by testing for an increase in the threshold for two-point discrepancy discrimination on the sole of the foot and for the disappearance of postural change with vibration to the sole. Next, the perception of standing position was measured by reproduction of a given standing reference position involving forward or backward leaning under both normal and cooled conditions of the feet. Standing position was varied in relation to the location of the center of foot pressure, defined as distance from the heel in percentage of the length of the foot. The reference positions, representing various locations of the center of foot pressure, were set at 10% increments from 20% to 80% of the length of the foot. With eyes closed, the subject first experienced the reference position and then attempted to reproduce it. The mean location of the center of foot pressure in the quiet standing posture was 45.7%. At the 40%, 50%, and 60% reference positions, those closest to quiet standing, absolute errors of reproduction were significantly larger than at other reference positions in both the normal and the cooled conditions. They were significantly larger in the cooled than in the normal condition. The 50% and 60% reference positions were reproduced significantly further forward in the cooled than in the normal condition. These results may be explained as due to an absence of marked changes in sensory information from both muscular activity and foot pressure when moving to reference positions close to the quiet standing posture.

  4. Static and dynamic posture control in postlingual cochlear implanted patients: effects of dual-tasking, visual and auditory inputs suppression

    PubMed Central

    Bernard-Demanze, Laurence; Léonard, Jacques; Dumitrescu, Michel; Meller, Renaud; Magnan, Jacques; Lacour, Michel

    2014-01-01

    Posture control is based on central integration of multisensory inputs, and on internal representation of body orientation in space. This multisensory feedback regulates posture control and continuously updates the internal model of body's position which in turn forwards motor commands adapted to the environmental context and constraints. The peripheral localization of the vestibular system, close to the cochlea, makes vestibular damage possible following cochlear implant (CI) surgery. Impaired vestibular function in CI patients, if any, may have a strong impact on posture stability. The simple postural task of quiet standing is generally paired with cognitive activity in most day life conditions, leading therefore to competition for attentional resources in dual-tasking, and increased risk of fall particularly in patients with impaired vestibular function. This study was aimed at evaluating the effects of postlingual cochlear implantation on posture control in adult deaf patients. Possible impairment of vestibular function was assessed by comparing the postural performance of patients to that of age-matched healthy subjects during a simple postural task performed in static (stable platform) and dynamic (platform in translation) conditions, and during dual-tasking with a visual or auditory memory task. Postural tests were done in eyes open (EO) and eyes closed (EC) conditions, with the CI activated (ON) or not (OFF). Results showed that the postural performance of the CI patients strongly differed from the controls, mainly in the EC condition. The CI patients showed significantly reduced limits of stability and increased postural instability in static conditions. In dynamic conditions, they spent considerably more energy to maintain equilibrium, and their head was stabilized neither in space nor on trunk: they behaved dynamically without vision like an inverted pendulum while the controls showed a whole body rigidification strategy. Hearing (prosthesis on) as well

  5. Get up, Stand up

    ERIC Educational Resources Information Center

    Melia, Ed

    2009-01-01

    Ignorance about dyslexia meant a miserable school experience for Barrie Hughes. He was in his 50s when he found the courage to stand up in front of a classroom of learners and admit he couldn't read. Barrie, who is now 59 and works for the parks department of Brighton and Hove Council, only began to learn how to read words in the last three years…

  6. Beam optics test stand

    NASA Astrophysics Data System (ADS)

    Humphries, S., Jr.; Hess, G.

    1988-04-01

    The design and construction of the Beam Optics Test Stand (BOTS) is presented. A variety of computer compatible diagnostics has been developed to facilitate experiments. Extensive theoretical work is presented leading to the identification of two potential methods to correct aberrations in magnetic optics: biased grid arrays and space charge corrected solenoidal lenses. A series of experiments is presented which demonstrates, for the first time, the feasibility of space charge corrected optics.

  7. Analysis of human postural responses to recoverable falls

    NASA Technical Reports Server (NTRS)

    Bortolami, S. B.; DiZio, P.; Rabin, E.; Lackner, J. R.

    2003-01-01

    We studied the kinematics and kinetics of human postural responses to "recoverable falls." To induce brief falling we used a Hold and Release (H&R) paradigm. Standing subjects actively resisted a force applied to their sternum. When this force was quickly released they were suddenly off balance. For a brief period, approximately 125 ms, until restoring forces were generated to shift the center of foot pressure in front of the center of mass, the body was in a forward fall acted on by gravity and ground support forces. We were able to describe the whole-body postural behavior following release using a multilink inverted pendulum model in a regime of "small oscillations." A three-segment model incorporating upper body, upper leg, and lower leg, with active stiffness and damping at the joints was fully adequate to fit the kinematic data from all conditions. The significance of our findings is that in situations involving recoverable falls or loss of balance the earliest responses are likely dependent on actively-tuned, reflexive mechanisms yielding stiffness and damping modulation of the joints. We demonstrate that haptic cues from index fingertip contact with a stationary surface lead to a significantly smaller angular displacement of the torso and a more rapid recovery of balance. Our H&R paradigm and associated model provide a quantifiable approach to studying recovery from potential falling in normal and clinical subjects.

  8. Analysis of human postural responses to recoverable falls.

    PubMed

    Bortolami, S B; DiZio, P; Rabin, E; Lackner, J R

    2003-08-01

    We studied the kinematics and kinetics of human postural responses to "recoverable falls." To induce brief falling we used a Hold and Release (H&R) paradigm. Standing subjects actively resisted a force applied to their sternum. When this force was quickly released they were suddenly off balance. For a brief period, approximately 125 ms, until restoring forces were generated to shift the center of foot pressure in front of the center of mass, the body was in a forward fall acted on by gravity and ground support forces. We were able to describe the whole-body postural behavior following release using a multilink inverted pendulum model in a regime of "small oscillations." A three-segment model incorporating upper body, upper leg, and lower leg, with active stiffness and damping at the joints was fully adequate to fit the kinematic data from all conditions. The significance of our findings is that in situations involving recoverable falls or loss of balance the earliest responses are likely dependent on actively-tuned, reflexive mechanisms yielding stiffness and damping modulation of the joints. We demonstrate that haptic cues from index fingertip contact with a stationary surface lead to a significantly smaller angular displacement of the torso and a more rapid recovery of balance. Our H&R paradigm and associated model provide a quantifiable approach to studying recovery from potential falling in normal and clinical subjects.

  9. Contraction of the human diaphragm during rapid postural adjustments.

    PubMed

    Hodges, P W; Butler, J E; McKenzie, D K; Gandevia, S C

    1997-12-01

    1. The response of the diaphragm to the postural perturbation produced by rapid flexion of the shoulder to a visual stimulus was evaluated in standing subjects. Gastric, oesophageal and transdiaphragmatic pressures were measured together with intramuscular and oesophageal recordings of electromyographic activity (EMG) in the diaphragm. To assess the mechanics of contraction of the diaphragm, dynamic changes in the length of the diaphragm were measured with ultrasonography. 2. With rapid flexion of the shoulder in response to a visual stimulus, EMG activity in the costal and crural diaphragm occurred about 20 ms prior to the onset of deltoid EMG. This anticipatory contraction occurred irrespective of the phase of respiration in which arm movement began. The onset of diaphragm EMG coincided with that of transversus abdominis. 3. Gastric and transdiaphragmatic pressures increased in association with the rapid arm flexion by 13.8 +/- 1.9 (mean +/- S.E.M.) and 13.5 +/- 1.8 cmH2O, respectively. The increases occurred 49 +/- 4 ms after the onset of diaphragm EMG, but preceded the onset of movement of the limb by 63 +/- 7 ms. 4. Ultrasonographic measurements revealed that the costal diaphragm shortened and then lengthened progressively during the increase in transdiaphragmatic pressure. 5. This study provides definitive evidence that the human diaphragm is involved in the control of postural stability during sudden voluntary movement of the limbs.

  10. Postural Control of Elderly Adults on Inclined Surfaces.

    PubMed

    da Costa Barbosa, Renata; Vieira, Marcus Fraga

    2017-03-01

    This study analyzed the postural control of older adults on inclined surfaces, and was conducted in 17 elderly adults and 18 young adults of both genders. Ground reaction forces and moments were collected using two AMTI force platforms, one of which was in a horizontal position (HOR), while the other was inclined 14° in relation to the horizontal plane. Each participant executed three 70 s-trials of bipedal standing with their eyes open and eyes closed in three inclination conditions: the HOR, the inclined position at ankle dorsi-flexion (UP), and the inclined position at ankle plantar-flexion (DOWN). Spectral analysis, global (mean velocity-Velm, ellipse area-Area and F80), and structural stabilometric descriptors (sway density curve-SDC, detrended fluctuation analysis-DFA, sample entropy-SEn) were employed to assess the center of pressure sway. Velm and F80 were greater for the elderly, whereas SDC, DFA, and SEn were smaller for this group. Global, SDC and DFA variables were sensitive to visual deprivation, however the relative difference from the EO to EC condition was higher in young than in elderly. The DOWN condition was more stable than the UP condition for both young and older adults. With regard to the UP condition, the challenge observed is essentially associated with the corresponding biomechanical constraints. In conclusion, the elderly showed significant differences compared to the young, but age per se may not necessarily result in compromised postural control.

  11. Evaluating the low back biomechanics of three different office workstations: Seated, standing, and perching.

    PubMed

    Le, Peter; Marras, William S

    2016-09-01

    The objective of this study was to evaluate how different workstations may influence physical behavior in office work through motion and how that may affect spinal loads and discomfort. Twenty subjects performed a typing task in three different workstations (seated, standing, and perching) for one hour each. Measures of postural transitions, spinal loads, discomfort, and task performance were assessed in order to understand the effects of workstation interaction over time. Results indicated that standing had the most amount of motion (6-8 shifts/min), followed by perching (3-7 shifts/min), and then seating (<1 shift/min). Standing had the highest reports of discomfort and seating the least. However, spinal loads were highest in A/P shear during standing (190N posterior shear, 407N anterior shear) compared to perching (65N posterior shear, 288N anterior shear) and seating (106N posterior shear, 287 anterior shear). These loads are below the risk threshold for shear, but may still elicit a cumulative response. Perching may induce motion through supported mobility in the perching stool, whereas standing motion may be due to postural discomfort. Office workstation designs incorporating supported movement may represent a reasonable trade-off in the costs-benefits between seating and standing.

  12. Classification of posture and activities by using decision trees.

    PubMed

    Zhang, Ting; Tang, Wenlong; Sazonov, Edward S

    2012-01-01

    Obesity prevention and treatment as well as healthy life style recommendation requires the estimation of everyday physical activity. Monitoring posture allocations and activities with sensor systems is an effective method to achieve the goal. However, at present, most devices available rely on multiple sensors distributed on the body, which might be too obtrusive for everyday use. In this study, data was collected from a wearable shoe sensor system (SmartShoe) and a decision tree algorithm was applied for classification with high computational accuracy. The dataset was collected from 9 individual subjects performing 6 different activities--sitting, standing, walking, cycling, and stairs ascent/descent. Statistical features were calculated and the classification with decision tree classifier was performed, after which, advanced boosting algorithm was applied. The computational accuracy is as high as 98.85% without boosting, and 98.90% after boosting. Additionally, the simple tree structure provides a direct approach to simplify the feature set.

  13. [Postural orthostatic tachycardia syndrome (POTS)--pathophysiology, diagnostics, and treatment].

    PubMed

    Rek, Marta; Kaczmarek, Krzysztof; Cygankiewicz, Iwona; Wranicz, Jerzy K; Ptaszyński, Paweł

    2014-01-01

    Postural orthostatic tachycardia syndrome (POTS) is one of the most common presentation of orthostatic intolerance. The syndrome is described as a multifactorial affliction. Main symptoms consist of persistent orthostatic tachycardia (heart rate increase at least 30 beats/min, lasting at least 10 min after assumic vertical position) with high noradrenalin serum concentration (measured in stand-up position). Additionally patients with POTS tend to have lover total blood volume. POTS is generally classified into dysatonomia disorders Symptoms in patients affected with POTS are chronic. The syndrome occurs predominantly in young women (approximately 80%). Due to complexity and variable intensity of symptoms POTS can severely impair daily activity and quality of life in otherwise healthy people. The correct diagnosis and identification of potential pathophysiological mechanisms of POTS is necessary before treatment administration. Adequate therapy can significantly reduce symptoms giving the patients a chance for a normal life.

  14. Osteopathic manipulative treatment for postural orthostatic tachycardia syndrome.

    PubMed

    Goodkin, Michael B; Bellew, Lawrence J

    2014-11-01

    Postural orthostatic tachycardia syndrome (POTS) is associated with many symptoms including orthostatic intolerance, fatigue, palpitations, and cognitive dysfunction. Treatment, which typically consists of exercise, increased dietary sodium and fluids, compression garments, and medications for orthostatic intolerance, frequently produces unsatisfactory results. The authors report the case of a 26-year-old woman who presented with a 6-year history of severe fatigue, orthostatic intolerance, heat intolerance, cognitive dysfunction, and diffuse pain. She had previously injured her jaw on an obstacle course. Results of a standing test were consistent with POTS. After standard medical therapy was unsuccessful, the patient was referred for osteopathic manipulative treatment. At her 18-month follow-up, the patient's symptoms had improved dramatically. Physicians should consider osteopathic evaluation and manipulative treatment when caring for patients with POTS.

  15. [Gait disorders in Parkinson disease. Clinical description, analysis of posture, initiation of stabilized gait].

    PubMed

    Kemoun, G; Defebvre, L

    2001-03-10

    A WELL INFORMED DESCRIPTION: The parkinsonian posture is generally described as a stooped one. At the beginning of the disease, the gait troubles remain moderate; gradually the gait is composed of small steps without a wide base; the patient tends to run after his centre of gravity by accelerating the step (festination phenomenon). Difficulties occurs for starting up (delay of gait initiation), for about-turn or for clearing obstacles. Kinetic jammings and standing around (freezing) can last several seconds and be responsible for falls. POSTURAL INSTABILITY, A MAJOR SYMPTOM IN PARKINSON'S DISEASE: This symptom is little improved by therapies and is responsible for serious disability. Postural instability induces a disequilibrium and is partially due to a simultaneous antagonist muscles contraction and to the impossibility of modifying postural responses to changing support conditions. The passive viscoelastic properties of muscles and tendons constitute a first line of defence against the disequilibrium and contribute to postural stability in the case of medium disturbances. Automatic and voluntary postural responses which come into play in the case of major disturbances can also be impaired (delay or defect of the responses). GAIT INITIATION FAILURE ARE FREQUENT: They result from an increase of the postural phase and a decrease of the propulsion forces, depending on a deficit of the postural anticipation mechanisms and also the sequential organization and the integration of two different motor programs, postural and locomotor. They can be controlled partially with sensory stimuli, notably visual inputs. DATA CONCERNING STABILIZED WALKING AND ITS PATHOPHYSIOLOGY REMAINS TO BE CLARIFIED: Spatial and temporal parameters are impaired: speed, step length and swing phase are reduced, while cadence increases to compensate these troubles. These modifications are the consequence of an incapacity to produce internal marks to generate regular steps. When the parkinsonian

  16. Postural Coordination during Socio-motor Improvisation

    PubMed Central

    Gueugnon, Mathieu; Salesse, Robin N.; Coste, Alexandre; Zhao, Zhong; Bardy, Benoît G.; Marin, Ludovic

    2016-01-01

    Human interaction often relies on socio-motor improvisation. Creating unprepared movements during social interaction is not a random process but relies on rules of synchronization. These situations do not only involve people to be coordinated, but also require the adjustment of their posture in order to maintain balance and support movements. The present study investigated posture in such a context. More precisely, we first evaluated the impact of amplitude and complexity of arm movements on posture in solo situation. Then, we assessed the impact of interpersonal coordination on posture using the mirror game in which dyads performed improvised and synchronized movements (i.e., duo situation). Posture was measured through ankle-hip coordination in medio-lateral and antero-posterior directions (ML and AP respectively). Our results revealed the spontaneous emergence of in-phase pattern in ML direction and antiphase pattern in AP direction for solo and duo situations. These two patterns respectively refer to the simultaneous flexion/extension of the ankles and the hips in the same or opposite direction. It suggests different functional roles of postural coordination patterns in each direction, with in-phase supporting task performance in ML (dynamical stability) and antiphase supporting postural control in AP (mechanical stability). Although amplitude of movement did not influence posture, movement complexity disturbed postural stability in both directions. Conversely, interpersonal coordination promoted postural stability in ML but not in AP direction. These results are discussed in terms of the difference in coupling strength between ankle-hip coordination and interpersonal coordination. PMID:27547193

  17. Carrying shopping bags does not alter static postural stability and gait parameters in healthy older females.

    PubMed

    Bampouras, Theodoros M; Dewhurst, Susan

    2016-05-01

    Food shopping is an important aspect of maintaining independence and social interaction in older age. Carriage of shopping bags alters the body's weight distribution which, depending on load distribution, could potentially increase instability during standing and walking. The study examined the effect of carrying UK style shopping bags on static postural stability and gait in healthy older and young females. Nine older (71.0±6.0 years) and 10 young (26.7±5.2 years) females were assessed in five conditions carrying no bags, one 1.5kg bag in each hand, one 3kg bag in each hand, one 1.5kg bag in preferred hand, one 3kg bag in preferred hand. Antero-posterior and medio-lateral displacement, and 95% ellipse area from a 30s quiet standing were used for postural stability assessment. Stride length and its coefficient of variation, total double support time, step asymmetry and gait stability ratio were calculated from 1min treadmill walking at self-selected speed for gait assessment. Carrying shopping bags did not negatively affect postural stability or gait variables, in either group. Further, in older individuals, a decrease in sway velocity was found when holding bags during the postural stability assessment (p<0.05), suggesting that carriage of bags, irrespective of the load distribution, may have a stabilising effect during quiet standing. These results should help to alleviate concerns regarding safety of carrying shopping bags and help encourage shopping, both as a social and as a physical activity.

  18. 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.

  19. Age-Related Changes in Dynamic Postural Control and Attentional Demands are Minimally Affected by Local Muscle Fatigue

    PubMed Central

    Remaud, Anthony; Thuong-Cong, Cécile; Bilodeau, Martin

    2016-01-01

    Normal aging results in alterations in the visual, vestibular and somtaosensory systems, which in turn modify the control of balance. Muscle fatigue may exacerbate these age-related changes in sensory and motor functions, and also increase the attentional demands associated with dynamic postural control. The purpose of this study was to investigate the effect of aging on dynamic postural control and posture-related attentional demands before and after a plantar flexor fatigue protocol. Participants (young adults: n = 15; healthy seniors: n = 13) performed a dynamic postural task along the antero-posterior (AP) and the medio-lateral (ML) axes, with and without the addition of a simple reaction time (RT) task. The dynamic postural task consisted in following a moving circle on a computer screen with the representation of the center of pressure (COP). This protocol was repeated before and after a fatigue task where ankle plantar flexor muscles were targeted. The mean COP-target distance and the mean COP velocity were calculated for each trial. Cross-correlation analyses between the COP and target displacements were also performed. RTs were recorded during dual-task trials. Results showed that while young adults adopted an anticipatory control mode to move their COP as close as possible to the target center, seniors adopted a reactive control mode, lagging behind the target center. This resulted in longer COP-target distance and higher COP velocity in the latter group. Concurrently, RT increased more in seniors when switching from static stance to dynamic postural conditions, suggesting potential alterations in the central nervous system (CNS) functions. Finally, plantar flexor muscle fatigue and dual-tasking had only minor effects on dynamic postural control of both young adults and seniors. Future studies should investigate why the fatigue-induced changes in quiet standing postural control do not seem to transfer to dynamic balance tasks. PMID:26834626

  20. Pain relief is associated with decreasing postural sway in patients with non-specific low back pain

    PubMed Central

    2012-01-01

    Background Increased postural sway is well documented in patients suffering from non-specific low back pain, whereby a linear relationship between higher pain intensities and increasing postural sway has been described. No investigation has been conducted to evaluate whether this relationship is maintained if pain levels change in adults with non-specific low back pain. Methods Thirty-eight patients with non-specific low back pain and a matching number of healthy controls were enrolled. Postural sway was measured by three identical static bipedal standing tasks of 90 sec duration with eyes closed in narrow stance on a firm surface. The perceived pain intensity was assessed by a numeric rating scale (NRS-11). The patients received three manual interventions (e.g. manipulation, mobilization or soft tissue techniques) at 3-4 day intervals, postural sway measures were obtained at each occasion. Results A clinically relevant decrease of four NRS scores in associated with manual interventions correlated with a significant decrease in postural sway. In contrast, if no clinically relevant change in intensity occurred (≤ 1 level), postural sway remained similar compared to baseline. The postural sway measures obtained at follow-up sessions 2 and 3 associated with specific NRS level showed no significant differences compared to reference values for the same pain score. Conclusions Alterations in self-reported pain intensities are closely related to changes in postural sway. The previously reported linear relationship between the two variables is maintained as pain levels change. Pain interference appears responsible for the altered sway in pain sufferers. This underlines the clinical use of sway measures as an objective monitoring tool during treatment or rehabilitation. PMID:22436337

  1. The role of prefrontal cortex during postural control in Parkinsonian syndromes a functional near-infrared spectroscopy study

    PubMed Central

    Mahoney, Jeannette R.; Holtzer, Roee; Izzetoglu, Meltem; Zemon, Vance; Verghese, Joe; Allali, Gilles

    2016-01-01

    Postural instability represents a main source of disability in Parkinsonian syndromes and its pathophysiology is poorly understood. Indirect probes (i.e., mental imagery) of brain involvement support the role of prefrontal cortex as a key cortical region for postural control in older adults with and without Parkinsonian syndromes. Using functional near infrared spectroscopy (fNIRs) as a direct online cortical probe, this study aimed to compare neural activation patterns in prefrontal cortex, postural stability, and their respective interactions, in (1) patients with Parkinsonian syndromes; (2) those with mild parkinsonian signs; (3) and healthy older adults. Among 269 non-demented older adults (76.41±6.70 years, 56% women), 26 individuals presented with Parkinsonian syndromes (Unified Parkinson’s disease rating scale (UPDRS): 11.08±3.60), 117 had mild parkinsonian signs (UPDRS: 3.21±2.49), and 126 individuals were included as a healthy control group. Participants were asked to stand upright and count silently for ten seconds while changes in oxygenated hemoglobin levels over prefrontal cortex were measured using fNIRs. We simultaneously evaluated postural stability with center of pressure velocity data recorded on an instrumented walkway. Compared to healthy controls and patients with mild parkinsonian signs, patients with Parkinsonian syndromes demonstrated significantly higher prefrontal oxygenation levels to maintain postural stability. The pattern of brain activation and postural control of participants with mild parkinsonian signs were similar to that of normal controls. These findings highlight the online role of the prefrontal cortex in postural control in patients with Parkinsonian syndromes and afford the opportunity to improve therapeutic options for postural instability. PMID:26551767

  2. Effects of dual tasking on the postural performance of people with and without multiple sclerosis: a pilot study.

    PubMed

    Jacobs, Jesse V; Kasser, Susan L

    2012-06-01

    People with multiple sclerosis (MS) exhibit both cognitive and postural impairments. This study examined the effects of MS and of dual tasking on postural performance, and explored associations among dual-task postural performance, cognitive capacity, fear of falling, and fatigue. Thirteen subjects with MS (Expanded Disability Status Scale: 0-4.5) and 13 matched subjects without MS performed three tasks of standing postural control, with and without dual tasking amid an auditory Stroop task: (1) step initiation, (2) forward leaning to the limits of stability, and (3) postural responses to rotations of the support surface. Two-factor general linear models were used to evaluate differences between the groups (with or without MS) and two conditions (single or dual tasking) for each postural task. During step initiation, dual tasking significantly delayed the onset of the anticipatory postural adjustment (APA) more for the subjects with MS than for those without MS, and step lengths increased for the subjects with MS but decreased for those without MS. No other significant group-by-condition interactions were evident on the recorded variables of stepping, leaning, postural responses, or Stroop-response accuracies and latencies. The scores for the subjects with MS on the Modified Fatigue Impact Scale significantly associated with the change between single-task to dual-task conditions in APA onset and foot-lift onset during step initiation as well as in lean position variability and lean onset times during forward leaning. The results suggest dual-task effects were more evident during step initiation and are associated with levels of fatigue for subjects with MS.

  3. Age-Related Changes in Dynamic Postural Control and Attentional Demands are Minimally Affected by Local Muscle Fatigue.

    PubMed

    Remaud, Anthony; Thuong-Cong, Cécile; Bilodeau, Martin

    2015-01-01

    Normal aging results in alterations in the visual, vestibular and somtaosensory systems, which in turn modify the control of balance. Muscle fatigue may exacerbate these age-related changes in sensory and motor functions, and also increase the attentional demands associated with dynamic postural control. The purpose of this study was to investigate the effect of aging on dynamic postural control and posture-related attentional demands before and after a plantar flexor fatigue protocol. Participants (young adults: n = 15; healthy seniors: n = 13) performed a dynamic postural task along the antero-posterior (AP) and the medio-lateral (ML) axes, with and without the addition of a simple reaction time (RT) task. The dynamic postural task consisted in following a moving circle on a computer screen with the representation of the center of pressure (COP). This protocol was repeated before and after a fatigue task where ankle plantar flexor muscles were targeted. The mean COP-target distance and the mean COP velocity were calculated for each trial. Cross-correlation analyses between the COP and target displacements were also performed. RTs were recorded during dual-task trials. Results showed that while young adults adopted an anticipatory control mode to move their COP as close as possible to the target center, seniors adopted a reactive control mode, lagging behind the target center. This resulted in longer COP-target distance and higher COP velocity in the latter group. Concurrently, RT increased more in seniors when switching from static stance to dynamic postural conditions, suggesting potential alterations in the central nervous system (CNS) functions. Finally, plantar flexor muscle fatigue and dual-tasking had only minor effects on dynamic postural control of both young adults and seniors. Future studies should investigate why the fatigue-induced changes in quiet standing postural control do not seem to transfer to dynamic balance tasks.

  4. The effect of face exploration on postural control in healthy children.

    PubMed

    Goulème, Nathalie; Seassau, Magali; Bucci, Maria Pia

    2015-07-01

    The objective was to explore how face exploration affects postural control in healthy children. The novelty here is that eye movements and posture were simultaneously recorded. Three groups of children participated in the study: 12 children of 7.8±0.5 years old, 13 children of 10.4±0.5 years old and 12 children of 15.7±0.9 years old. Eye movements were recorded by video-oculography and postural stability was recorded by a platform. Children were invited to explore five emotional faces (neutral, happy, sad fear and angry). Analysis of eye movements was done on saccadic latency, percentage of exploration time spent and number of saccades for each specific region of interest (ROI): eyes, nose and mouth. Analysis of posture was made on surface area, sway length and mean velocity of the center of pressures (CoP). Results showed that visual strategies, exploration and postural control develop during childhood and adolescence. Indeed, after nine years-old, children started to look the eyes ROI firstly, then the nose ROI and finally the mouth ROI. The number of saccades decreased with the age of children. The percentage of exploration time spent in eyes ROI was longer than the others ROIs and greater for unpleasant faces (sad, fear and angry) with respect to pleasant emotional face (happy). We found that in front of sad and happy faces the surface area of the CoP was significantly larger compared to other faces (neutral and angry). These results suggest that visual strategies and postural control change during children's development and can be influenced by the emotional face.

  5. 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

  6. Influence of posture on the relation between surface electromyogram amplitude and back muscle moment: consequences for the use of surface electromyogram to measure back load.

    PubMed

    Mouton, L J; Hof, A L; de Jongh, H J; Eisma, W H

    1991-11-01

    The aim of the study was to analyse the effect of posture on the relation between EMG amplitude and moment of the back muscles in different subjects, in order to gain a better insight into the possibilities of EMG as a means of measuring individual back load. Eight healthy subjects participated in the experiments. Isometric back extensions were performed in three postures: upright standing, standing with the spine flexed, and upright sitting. In each posture the lumbar moments of three maximal voluntary contractions were measured and then exertions of 10 to 90% of maximal voluntary contraction (increments of 10) were performed. EMG signals from the back muscles were recorded with four pairs of surface electrodes located 3 cm and 6 cm lateral to the midline of the spine at the L3 level. EMG signals were full-wave rectified and averaged over 2 s intervals of constant moment. The results show that posture has a considerable influence on the relationship between EMG and the lumbar moment. Besides this, large individual differences and an influence of electrode position on the relationship were found. Therefore it is concluded that whenever EMG is to be used as a means to measure individual back load, a calibration of the EMG amplitude to lumbar moment ratio is necessary for each subject, each electrode position, and each posture. Interpretation of EMG amplitudes has to be done on an individual basis and taking influences of posture and electrode location on the EMG-lumbar moment relationship into account.

  7. 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.

  8. 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.

  9. Suitability of commercial barometric pressure sensors to distinguish sitting and standing activities for wearable monitoring.

    PubMed

    Massé, F; Bourke, A K; Chardonnens, J; Paraschiv-Ionescu, A; Aminian, K

    2014-06-01

    Despite its medical relevance, accurate recognition of sedentary (sitting and lying) and dynamic activities (e.g. standing and walking) remains challenging using a single wearable device. Currently, trunk-worn wearable systems can differentiate sitting from standing with moderate success, as activity classifiers often rely on inertial signals at the transition period (e.g. from sitting to standing) which contains limited information. Discriminating sitting from standing thus requires additional sources of information such as elevation change. The aim of this study is to demonstrate the suitability of barometric pressure, providing an absolute estimate of elevation, for evaluating sitting and standing periods during daily activities. Three sensors were evaluated in both calm laboratory conditions and a pilot study involving seven healthy subjects performing 322 sitting and standing transitions, both indoor and outdoor, in real-world conditions. The MS5611-BA01 barometric pressure sensor (Measurement Specialties, USA) demonstrated superior performance to counterparts. It discriminates actual sitting and standing transitions from stationary postures with 99.5% accuracy and is also capable to completely dissociate Sit-to-Stand from Stand-to-Sit transitions.

  10. The Influence of Different Modes of Ventilation on Standing Balance of Athletes

    PubMed Central

    Malakhov, Maxim; Makarenkova, Elena; Melnikov, Andrey

    2014-01-01

    Background: The respiratory movements are one of the factors influencing standing balance. Although well-trained athletes have better postural performance compared to untrained men, it's not quite clear, if the formers' upright posture would be more stable during different ventilation modes, maximal voluntary hyperventilation and inspiratory breath-holding. There are no studies on this subject in the available literature. Objectives: The aim of this study was to investigate an influence of maximal inspiratory breath-holding and maximal voluntary hyperventilation on the standing balance of athletes. Patients and Methods: We assessed the amplitude and the velocity of postural sway in the athletes (n = 38) and untrained subjects (n = 28) by the force platform. The frequency characteristics of the center of pressure (CP) oscillations' were also analyzed. The amplitude and the frequency of respiratory movements were estimated by the strain gauge. Results: It was found that during quiet breath velocity and frequency of CP oscillations were lower in the athletes. Breath holding led to an increase of velocity and frequency of CP displacement in both groups, increase of these indices was more pronounced in the athletes. Maximal voluntary hyperventilation caused a significant increase of all stabilographic indices in both groups. Increase of frequency and amplitude of respiratory movements were mainly observed during hyperventilation in athletes and it caused an increase of the velocity of CP displacement. Changes of sway amplitude were the same in both groups. Conclusions: Breath holding led to activation of the postural control, which was more pronounced in the athletes. Hyperventilation caused an impairment of the postural stability. The athletes' postural system compensated the impact of hyperventilation more efficiently versus controls, but it was achieved at the expense of greater effort. PMID:25520763

  11. Recovery of postural equilibrium control following spaceflight

    NASA Technical Reports Server (NTRS)

    Paloski, W. H.; Reschke, M. F.; Black, F. O.; Doxey, D. D.; Harm, D. L.

    1992-01-01

    Decreased postural stability is observed in most astronauts immediately following spaceflight. Because ataxia may present postflight operational hazards, it is important to determine the incidence of postural instability immediately following landing and the dynamics of recovery of normal postural equilibrium control. It is postulated that postflight postural instability results from in-flight adaptive changes in central nervous system (CNS) processing of sensory information from the visual, vestibular, and proprioceptive systems. The purpose of the present investigation was to determine the magnitude and time course of postflight recovery of postural equilibrium control and, hence, readaptation of CNS processing of sensory information. Thirteen crew members from six spaceflight missions were studied pre- and postflight using a modified commercial posturography system. Postural equilibrium control was found to be seriously disrupted immediately following spaceflight in all subjects. Readaptation to the terrestrial environment began immediately upon landing, proceeded rapidly for the first 10-12 hours, and then proceeded much more slowly for the subsequent 2-4 days until preflight stability levels were reachieved. It is concluded that the overall postflight recovery of postural stability follows a predictable time course.

  12. Adolescent development

    MedlinePlus

    Development - adolescent; Growth and development - adolescent ... During adolescence, children develop the ability to: Understand abstract ideas. These include grasping higher math concepts, and developing moral ...

  13. Role of vestibular information in initiation of rapid postural responses

    NASA Technical Reports Server (NTRS)

    Runge, C. F.; Shupert, C. L.; Horak, F. B.; Zajac, F. E.; Peterson, B. W. (Principal Investigator)

    1998-01-01

    Patients with bilateral vestibular loss have difficulty maintaining balance without stepping when standing in tandem, on compliant surfaces, across narrow beams, or on one foot, especially with eyes closed. Normal individuals (with no sensory impairment) maintain balance in these tasks by employing quick, active hip rotation (a "hip strategy"). The absence of a hip strategy in vestibular patients responding to translations of a short support surface has previously been taken as evidence that the use of hip strategy requires an intact vestibular system. However, many tasks requiring hip strategy alter one or a combination of important system characteristics, such as initial state of the body (tandem stance), dynamics (compliant surfaces), or biomechanical limits of stability (narrow beams). Therefore, the balance deficit in these tasks may result from a failure to account for these support surface alterations when planning and executing sensorimotor responses. In this study, we tested the hypothesis that vestibular information is critical to trigger a hip strategy even on an unaltered support surface, which imposes no changes on the system characteristics. We recorded the postural responses of vestibular patients and control subjects with eyes closed to rearward support surface translations of varying velocity, in erect stance on a firm, flat surface. Subjects were instructed to maintain balance without stepping, if possible. Faster translation velocities (25 cm/s or more) produced a consistent pattern of early hip torque (first 400 ms) in control subjects (i.e., a hip strategy). Most of the patients with bilateral vestibular loss responded to the same translation velocities with similar torques. Contrary to our hypothesis, we conclude that vestibular function is not necessary to trigger a hip strategy. We postulate, therefore, that the balance deficit previously observed in vestibular patients during postural tasks that elicit a hip strategy may have been due to