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Sample records for force posture statement

  1. Crouched posture maximizes ground reaction forces generated by muscles.

    PubMed

    Hoang, Hoa X; Reinbolt, Jeffrey A

    2012-07-01

    Crouch gait decreases walking efficiency due to the increased knee and hip flexion during the stance phase of gait. Crouch gait is generally considered to be disadvantageous for children with cerebral palsy; however, a crouched posture may allow biomechanical advantages that lead some children to adopt a crouch gait. To investigate one possible advantage of crouch gait, a musculoskeletal model created in OpenSim was placed in 15 different postures from upright to severe crouch during initial, middle, and final stance of the gait cycle for a total of 45 different postures. A series of optimizations was performed for each posture to maximize transverse plane ground reaction forces in the eight compass directions by modifying muscle forces acting on the model. We compared the force profile areas across all postures. Larger force profile areas were allowed by postures from mild crouch (for initial stance) to crouch (for final stance). The overall ability to generate larger ground reaction force profiles represents a mechanical advantage of a crouched posture. This increase in muscle capacity while in a crouched posture may allow a patient to generate new movements to compensate for impairments associated with cerebral palsy, such as motor control deficits. PMID:22542242

  2. Human arm posture prediction in response to isometric endpoint forces.

    PubMed

    Davoudabadi Farahani, Saeed; Andersen, Michael Skipper; de Zee, Mark; Rasmussen, John

    2015-11-26

    The ability to predict the musculoskeletal response to external loads has multiple applications for the design of machines with a human interface and for the prediction of outcomes of musculoskeletal interventions. In this study, we applied an inverse-inverse dynamics technique to investigate its ability to predict arm posture in response to isometric hand forces. For each subject, we made a three-dimensional musculoskeletal model using the AnyBody Modelling System (AMS). Then, we had each subject-specific model hold a weight anteriorly to the right shoulder joint at a distance of half of the arm length. We selected the glenohumeral abduction angle (GHAA) as the only free parameter. Subsequently, we used inverse-inverse dynamics to find the optimal GHAA that minimised a performance criterion with physiological constraints. In this study, we investigated the performance of two different objective functions: summation of squared muscle activity (SSMA) and summation of squared normalised joint torques (SSNJT). To validate the simulation results, arm posture responses to different isometric downward hand forces were measured for six healthy male subjects. Five trials were performed for each loading condition. The results showed that, with an increase in hand load, there was a reduced GHAA in all subjects. Another interesting finding was that self-selected postures for lighter tasks varied more than postures for heavier tasks for all subjects. To understand this, we investigated the curvature of the objective function as a function of the load and observed an increased curvature with increased load. This may explain the reduced intra-subject variations observed for increasing loads. PMID:26482735

  3. The force output of handle and pedal in different bicycle-riding postures.

    PubMed

    Chen, Chia-Hsiang; Wu, Yu-Kuang; Chan, Ming-Sheng; Shih, Yo; Shiang, Tzyy-Yuang

    2016-01-01

    The purpose of this study was to analyse the force output of handle and pedal as well as the electromyography (EMG) of lower extremity in different cycling postures. Bilateral pedalling asymmetry indices of force and EMG were also determined in this study. Twelve healthy cyclists were recruited for this study and tested for force output and EMG during steady state cycling adopting different pedalling and handle bar postures. The standing posture increased the maximal stepping torque (posture 1: 204.2 ± 47.0 Nm; posture 2: 212.5 ± 46.1 Nm; posture 3: 561.5 ± 143.0 Nm; posture 4: 585.5 ± 139.1 Nm), stepping work (posture 1: 655.2 ± 134.6 Nm; posture 2: 673.2 ± 116.3 Nm; posture 3: 1852.3 ± 394.4 Nm; posture 4: 1911.3 ± 432.9 Nm), and handle force (posture 1: 16.6 ± 3.6 N; posture 2: 16.4 ± 3.6 N; posture 3: 26.5 ± 8.2 N; posture 4: 41.4 ± 11.1 N), as well as muscle activation (posture 1: 13.6-25.1%; posture 2: 13.0-23.9%; posture 3: 23.6-61.8%; posture 4: 22.5-65.8%) in the erector spine, rectus femoris, tibialis anterior, and soleus. However, neither a sitting nor a standing riding posture affected the hamstring. The riding asymmetry was detected between the right and left legs only in sitting conditions. When a cyclist changes posture from sitting to standing, the upper and lower extremities are forced to produce more force output because of the shift in body weight. These findings suggest that cyclists can switch between sitting and standing postures during competition to increase cycling efficiency in different situations. Furthermore, coaches and trainers can modify sitting and standing durations to moderate cycling intensity, without concerning unbalanced muscle development. PMID:26967311

  4. Effects of forward head posture on forced vital capacity and respiratory muscles activity.

    PubMed

    Han, Jintae; Park, Soojin; Kim, Youngju; Choi, Yeonsung; Lyu, Hyeonnam

    2016-01-01

    [Purpose] This study investigated the effects of forward head posture on forced vital capacity and deep breathing. [Subjects] Twenty-six subjects, divided into the two groups (normal and forward head posture groups), participated in this study. [Methods] Forced vital capacity and forced expiratory volume in 1 second were measured using respiratory function instrumentation that met the American Thoracic Society's recommendation for diagnostic spirometry. Accessory respiratory muscle activity during deep breathing was measured by electromyography. A Mann-Whitney test was used to compare the measure variables between the normal and forward head posture group. [Results] Forced vital capacity and forced expiratory volume in 1 second were significantly lower in the forward head posture group than in the normal group. Accessory respiratory muscle activity was also lower in the forward head posture group than in the normal group. In particular, the sternocleidomastoid and pectoralis major activity of the forward head posture group was significantly lower than that of normal group. Activities of the other muscles were generally decreased with forward head posture, but were not significantly different between the two groups. [Conclusion] These results indicate that forward head posture could reduce vital capacity, possibly because of weakness or disharmony of the accessory respiratory muscles. PMID:26957743

  5. 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. PMID:17313278

  6. Identification of hand postures by force myography using an optical fiber specklegram sensor

    NASA Astrophysics Data System (ADS)

    Fujiwara, Eric; Wu, Yu Tzu; Santos, Murilo F. M.; Schenkel, Egont A.; Suzuki, Carlos K.

    2015-09-01

    The identification of hand postures based on force myography (FMG) measurements using a fiber specklegram sensor is reported. The microbending transducers were attached to the user forearm in order to detect the radial forces due to hand movements, and the normalized intensity inner products of output specklegrams were computed with reference to calibration positions. The correlation between measured specklegrams and postures was carried out by artificial neural networks, resulting in an overall accuracy of 91.3% on the retrieval of hand configuration.

  7. Normative values for a video-force plate assessment of postural control in athletic children.

    PubMed

    Howell, David R; Meehan, William P

    2016-07-01

    The objective of this study was to provide normative data for young athletes during the three stances of the modified Balance Error Scoring System (mBESS) using an objective video-force plate system. Postural control was measured in 398 athletes between 8 and 18 years of age during the three stances of the mBESS using a video-force plate rating system. Girls exhibited better postural control than boys during each stance of the mBESS. Age was not significantly associated with postural control. We provide normative data for a video-force plate assessment of postural stability in pediatric athletes during the three stances of the mBESS. PMID:26863482

  8. Relationships between one-handed force exertions in all directions and their associated postures.

    PubMed

    Wilkinson, A T; Pinder, A D J; Grieve, D W

    1995-01-01

    Photographs were taken of subjects exerting in specified directions with one hand on the handle of a triaxial force measurement system. The applied forces were recorded and posture analysis was undertaken to investigate relationships between three-dimensional force exertion and posture. The postural stability diagram, which in previous studies has been applied to fore-and-aft exertions, was applied to the vertical plane containing the manual force vector and to the horizontal plane. The vertical plane analysis provided an insight into postures associated with weak and strong exertion. The horizontal plane analysis emphasized the importance of developing torque as well as thrust at the foot base in order to exert laterally directed forces. Exertions involving a right or left component were associated with a horizontal moment at the feet of the order of 50 Nm. This moment is an important factor in the demands made upon the body during asymmetrical exertion, and the mechanisms for achieving it deserve further investigation. RELEVANCE: Exertion is not normally restricted to the sagittal plane. The approach adopted in this paper gives an insight into how body deployment relates to the direction and magnitude of exertion. Biomechanical models of asymmetric exertion should reflect the principles that have emerged. PMID:11415527

  9. Secretary's annual report to Congress. Volume I. Posture statement, outlook and program review

    SciTech Connect

    1981-01-01

    Activities of all elements of the Department of Energy (DOE) except those of FERC are reported. Chapter I, the Posture Statement, gives an overview of the policies, programs, and strategies of DOE. It describes the national energy policy and its effects, sets out the current state of energy supply and demand in the US and around the world, describes the present assessment of future energy availability, and outlines the strategy for 1982. Additional chapters detail the major programs in the following Offices or Assistant Secretaryships: Conservation, Fossil Fuel, Nuclear Energy, Renewable Energy Resources, Electric Energy Systems and Energy Storage, Environment, Energy Supporting Research, Energy Production and Power Marketing, Energy Information, Economic Regulation, General Science, Defense, International Programs, Nuclear Non-Proliferation, Energy Contingency Planning, and Administration. Information is included in appendices on foreign direct investment in US energy sources and supplies for 1979, exports of energy resources by foreign companies, major recipients of DOE funding, DOE actions taken regarding disclosure of energy assets by DOE employees, and financial assistance programs. (MCW)

  10. Postural Stability Assessment of University Marching Musicians Using Force Platform Measures.

    PubMed

    Magnotti, Trevor D; McElhiney, Danielle; Russell, Jeffrey A

    2016-09-01

    Lower extremity injury is prevalent in marching musicians, and poor postural stability is a possible risk factor for this. The external load of an instrument may predispose these performers to injury by decreasing postural stability. The purpose of this study was to determine the relationship between instrument load and static and dynamic postural stability in this population. Fourteen university marching musicians were recruited and completed a balance assessment protocol on a force platform with and without their instrument. Mean center of pressure (CoP) displacement was then calculated for each exercise in the anterior/posterior and medial/lateral planes. Mean anterior/posterior CoP displacement significantly increased in the instrument condition for the static surface, eyes closed, 2 feet condition (p≤0.005; d=0.89). No significant differences were found in the medial/lateral plane between non-instrument and instrument conditions. Significant differences were not found between test stance conditions independent of group. Comparisons between the non-instrument-loaded and instrument-loaded conditions revealed possible significance of instrument load on postural stability in the anterior/posterior plane. Mean differences indicated that an unstable surface created a greater destabilizing effect on postural stability than instrument load. PMID:27575294

  11. Ability of Low-Cost Force-Feedback Device to Influence Postural Stability.

    PubMed

    Baud-Bovy, Gabriel; Tatti, Fabio; Borghese, Nunzio A

    2015-01-01

    Low-cost gaming technology offers promising devices for the rehabilitation of stroke patients at home. While several attempts have been made to use low-cost motion tracking devices (Kinect) or balance boards (Wii Board), the potential of low-cost haptic devices has yet to be explored in this context. The objective of this study was to investigate whether it is possible to influence postural stability with a low-cost device despite its technical limitations, and to explore the most promising modes of haptic interaction to increase and decrease postural stability. Two groups of younger subjects used a high-end (Omega.3) and a low-cost (Falcon) device respectively. A third group of older subjects used the Falcon. We show that light touch contact with the device improves stability, whereas the force tasks decrease it. The effects of the different tasks are consistent in the two age groups. Although there are differences in the participants' interaction with the two devices, the effect of the devices on postural stability is comparable. We conclude that a low-cost haptic device can be used to increase or decrease postural stability of healthy subjects with an age similar to that of typical stroke patients, in a safe and controllable way. PMID:25398181

  12. The effect of force-controlled biting on human posture control.

    PubMed

    Hellmann, D; Stein, T; Potthast, W; Rammelsberg, P; Schindler, H J; Ringhof, S

    2015-10-01

    Several studies have confirmed the neuromuscular effects of jaw motor activity on the postural stability of humans, but the mechanisms of functional coupling of the craniomandibular system (CMS) with human posture are not yet fully understood. The purpose of our study was, therefore, to investigate whether submaximum biting affects the kinematics of the ankle, knee, and hip joints and the electromyographic (EMG) activity of the leg muscles during bipedal narrow stance and single-leg stance. Twelve healthy young subjects performed force-controlled biting (FB) and non-biting (NB) during bipedal narrow stance and single-leg stance. To investigate the effects of FB on the angles of the hip, knee, and ankle joints, a 3D motion-capture system (Vicon MX) was used. EMG activity was recorded to enable analysis of the coefficient of variation of the muscle co-contraction ratios (CVR) of six pairs of postural muscles. Between FB and NB, no significant differences were found for the mean values of the angles of the ankle, knee, and hip joints, but the standard deviations were significantly reduced during FB. The values of the ranges of motion and the mean angular velocities for the three joints studied revealed significant reduction during FB also. CVR was also significantly reduced during FB for five of the six muscle pairs studied. Although submaximum biting does not change the basic strategy of posture control, it affects neuromuscular co-contraction patterns, resulting in increased kinematic precision. PMID:26282375

  13. The use of force-plate posturography in the assessment of postural instability.

    PubMed

    Błaszczyk, Janusz W

    2016-02-01

    Force-plate posturography is a simple method that is commonly used in the contemporary laboratory and clinic to assess postural control. Despite the obvious advantages and popularity of the method, universal standards for posturographic tests have not been developed thus far: most postural assessments are based on the standard spatiotemporal metrics of the center-of-foot pressure (COP) recorded during quiet stance. Unfortunately, the standard COP characteristics are strongly dependent on individual experimental design and are susceptible to distortions such as the noise of signal digitalization, which often makes the results from different laboratories incomparable and unreliable. The COP trajectories were recorded in subjects standing still, with eyes open (EO) and then, with eyes closed (EC). The 168 subjects were divided into 3 experimental groups: young adults, older adults, and patients with Parkinson's disease. Three novel output measures: the sway directional index (DI), the sway ratio (SR), and the sway vector (SV) were applied to assess the postural stability in the experimental groups. The controlled variables: age, pathology, and visual conditions, uniquely affected the output measures. The basic attributes of the SV: its reference position, magnitude, and azimuth, provided a unique set of descriptors for postural control that allowed me unambiguously to differentiate the decline in postural stability caused by natural ageing and Parkinson's disease. As shown in previous investigations, the SV attributes, when optimally filtered with a low-pass filter, were highly independent of the trial length and the sampling frequency, and were unaffected by the sampling noise. In conclusion, the SV may be recommended as the useful standard in static posturography. PMID:27004624

  14. Haptic perception of force magnitude and its relation to postural arm dynamics in 3D

    PubMed Central

    van Beek, Femke E.; Bergmann Tiest, Wouter M.; Mugge, Winfred; Kappers, Astrid M. L.

    2015-01-01

    In a previous study, we found the perception of force magnitude to be anisotropic in the horizontal plane. In the current study, we investigated this anisotropy in three dimensional space. In addition, we tested our previous hypothesis that the perceptual anisotropy was directly related to anisotropies in arm dynamics. In experiment 1, static force magnitude perception was studied using a free magnitude estimation paradigm. This experiment revealed a significant and consistent anisotropy in force magnitude perception, with forces exerted perpendicular to the line between hand and shoulder being perceived as 50% larger than forces exerted along this line. In experiment 2, postural arm dynamics were measured using stochastic position perturbations exerted by a haptic device and quantified through system identification. By fitting a mass-damper-spring model to the data, the stiffness, damping and inertia parameters could be characterized in all the directions in which perception was also measured. These results show that none of the arm dynamics parameters were oriented either exactly perpendicular or parallel to the perceptual anisotropy. This means that endpoint stiffness, damping or inertia alone cannot explain the consistent anisotropy in force magnitude perception. PMID:26643041

  15. Vibration transmissibility characteristics of the human hand-arm system under different postures, hand forces and excitation levels

    NASA Astrophysics Data System (ADS)

    Adewusi, S. A.; Rakheja, S.; Marcotte, P.; Boutin, J.

    2010-07-01

    Biodynamic responses of the hand-arm system have been mostly characterized in terms of driving-point force-motion relationships, which have also served as the primary basis for developing the mechanical-equivalent models. The knowledge of localized vibration responses of the hand-arm segments could help derive more effective biodynamic models. In this study, the transmission of z h-axis handle vibration to the wrist, elbow and the shoulder of the human hand and arm are characterized in the laboratory for the bent-arm and extended arm postures. The experiments involved six subjects grasping a handle subject to two different magnitudes of broad-band random vibration, and nine different combinations of hand grip and push forces. The vibration transmissibility data were acquired in the z h- and y h-axis at the wrist and shoulder, and along all the three axes around the elbow joint. The results show that the human hand-arm system in an extended arm posture amplifies the vibration transmitted to the upper-arm and the whole-body at frequencies below 25 Hz, but attenuates the vibration above 25 Hz more effectively than the bent-arm posture, except at the shoulder. The magnitudes of transmitted vibration under an extended arm posture along the y h-axis were observed to be nearly twice those for the bent-arm posture in the low frequency region. The results further showed that variations in the grip force mostly affect vibration transmissibility and characteristic frequencies of the forearm, while changes in the push force influenced the dynamic characteristics of the entire hand-arm system. The magnitudes of transmitted vibration in the vicinity of the characteristic frequencies were influenced by the handle vibration magnitude.

  16. Postural Responses to a Suddenly Released Pulling Force in Older Adults with Chronic Low Back Pain: An Experimental Study.

    PubMed

    Lee, Pei-Yun; Lin, Sang-I; Liao, Yu-Ting; Lin, Ruey-Mo; Hsu, Che-Chia; Huang, Kuo-Yuan; Chen, Yi-Ting; Tsai, Yi-Ju

    2016-01-01

    Chronic low back pain (CLBP), one of the most common musculoskeletal conditions in older adults, might affect balance and functional independence. The purpose of this study was to investigate the postural responses to a suddenly released pulling force in older adults with and without CLBP. Thirty community-dwelling older adults with CLBP and 26 voluntary controls without CLBP were enrolled. Participants were required to stand on a force platform while, with one hand, they pulled a string that was fastened at the other end to a 2-kg or to a 4-kg force in the opposite direction at a random order. The number of times the participants lost their balance and motions of center of pressure (COP) when the string was suddenly released were recorded. The results demonstrated that although the loss of balance rates for each pulling force condition did not differ between groups, older adults with CLBP had poorer postural responses: delayed reaction, larger displacement, higher velocity, longer path length, and greater COP sway area compared to the older controls. Furthermore, both groups showed larger postural responses in the 4-kg pulling force condition. Although aging is generally believed to be associated with declining balance and postural control, these findings highlight the effect of CLBP on reactive balance when responding to an externally generated force in an older population. This study also suggests that, for older adults with CLBP, in addition to treating them for pain and disability, reactive balance evaluation and training, such as reaction and movement strategy training should be included in their interventions. Clinicians and older patients with CLBP need to be made aware of the significance of impaired reactive balance and the increased risk of falls when encountering unexpected perturbations. PMID:27622646

  17. Effects of Vibration in Forced Posture on Biochemical Bone Metabolism Indices, and Morphometric and Mechanical Properties of the Lumbar Vertebra

    PubMed Central

    Zhang, Li; Ju, Xiaowei; Zhu, Lvgang; Huang, Changlin; Huang, Tao; Zuo, Xincheng; Gao, Chunfang

    2013-01-01

    Epidemiological studies have shown a relatively strong association between occupational lower back pain (LBP) and long-term exposure to vibration. However, there is limited knowledge of the impact of vibration and sedentariness on bone metabolism of the lumbar vertebra and the mechanism of bone-derived LBP. The aim of this study was to investigate the effects of vibration in forced posture (a seated posture) on biochemical bone metabolism indices, and morphometric and mechanical properties of the lumbar vertebra, and provide a scientific theoretical basis for the mechanism of bone-derived LBP, serum levels of Ca2+, (HPO4)2−, tartrate-resistant acid phosphatase (TRAP), bone-specific alkaline phosphatase (BALP), and bone gla protein (BGP),the pathological changes and biomechanics of lumbar vertebra of New Zealand white rabbits were studied. The results demonstrate that both forced posture and vibration can cause pathological changes to the lumbar vertebra, which can result in bone-derived LBP, and vibration combined with a seated posture could cause further damage to bone metabolism. Serological changes can be used as early markers for clinical diagnosis of bone-derived LBP. PMID:24265702

  18. Relationship between foot posture measurements and force platform parameters during two balance tasks in older and younger subjects

    PubMed Central

    Carvalho, Carlos E.; da Silva, Rubens A.; Gil, André W.; Oliveira, Márcio R.; Nascimento, Juliana A.; Pires-Oliveira, Deise A. A.

    2015-01-01

    [Purpose] The aim of this study was to compare age-related differences in balance and anthropometric posture measurements of the foot and to determine any relationship between them. [Subjects and Methods] Sixty-eight older and 42 younger adults participated in this study. Foot posture was tested for four domains: 1) hallux flexion and extension range of motion using a goniometer, 2) navicular height and 3) length of the foot using a pachymeter, and 4) footprint (width of forefoot, arch index and hallux valgus). Balance was tested under two conditions on a force platform: bipodal in 60-s trials and unipodal in 30-s trials. The sway area of the center of pressure and velocity in the anteroposterior and mediolateral directions were computed. [Results] Older individuals showed significantly poorer balance compared with younger adults under in the unipodal condition (center of pressure area 9.97 vs. 7.72 cm2). Older people presented a significantly lower hallux mobility and higher values for width of the forefoot and transverse arch index than younger adults. The correlations between all foot posture and center of pressure parameters varied across groups, from weak to moderate (r −0.01 to −0.46). Low hallux mobility was significantly related to higher center of pressure values in older people. [Conclusion] These results have clinical implications for balance and foot posture assessments. PMID:25931713

  19. TEST‐RETEST CONSISTENCY OF A POSTURAL SWAY ASSESSMENT PROTOCOL FOR ADOLESCENT ATHLETES MEASURED WITH A FORCE PLATE

    PubMed Central

    Lee, Aaron; Hugentobler, Jason A.; Kurowski, Brad G.; Myer, Gregory D.; Riley, Michael A.

    2013-01-01

    Purpose/Background: Postural control assessments can provide a powerful means of detecting concussion‐related neurophysiological abnormalities and are considered an important part of the concussion management processes. Studies with college athletes indicate that postural sway analyzed using complexity metrics may provide a sensitive and novel way to detect post‐concussion postural control impairments. The purpose of this study was to determine if a postural sway assessment protocol (PSAP) measured using a force plate system can serve as a reliable assessment tool for adolescent athletes. Methods: The short‐term and long‐term test‐retest reliability of the PSAP was examined in a group of adolescent female athletes under eyes open and eyes closed conditions. Detrended fluctuation analysis was used to evaluate the complexity of the times series data (i.e., degree of self‐similarity across time scales). Conventional measures of standard deviation and total path length (distance traveled by the center‐of‐pressure) were also assessed. Results: The complexity and conventional measures generally demonstrated good reliability coefficients for short‐term and long‐term test‐retest reliability with both eyes open and eyes closed conditions. Intra‐class Correlation Coefficient (ICC) values ranged from .38‐.90 The highest ICC values corresponded with the short‐term reliability for the eyes open condition, while the lower ICC values corresponded with the long‐term reliability for the eyes closed condition. Conclusions: The results of this study indicate that the PSAP demonstrated good short‐term and long‐term test‐retest reliability. In addition, no evidence of learning effects was elicited through this study. Future studies should further explore the validity and feasibility of the use of this protocol for different age groups, different types of athletes, and longitudinal evaluations of post‐concussion impairments. Clinical Relevance: This

  20. Canadian Athletic Therapists' Association Education Task Force Consensus Statements

    ERIC Educational Resources Information Center

    Lafave, Mark R.; Bergeron, Glen; Klassen, Connie; Parr, Kelly; Valdez, Dennis; Elliott, Jacqueline; Peeler, Jason; Orecchio, Elsa; McKenzie, Kirsty; Streed, Kristin; DeMont, Richard

    2016-01-01

    Context: A published commentary from 2 of the current authors acted as a catalyst for raising some key issues that have arisen in athletic therapy education in Canada over the years. Objective: The purpose of this article is to report on the process followed to establish a number of consensus statements related to postsecondary athletic therapy…

  1. Decorticate posture

    MedlinePlus

    Decorticate posture is an abnormal posturing in which a person is stiff with bent arms, clenched fists, and legs ... Decorticate posture is a sign of damage to the nerve pathway between the brain and spinal cord. Although it ...

  2. Decerebrate posture

    MedlinePlus

    ... Brain problem due to drugs, poisoning, or infection Head injury Brain problem due to liver failure Increased pressure ... of posture? Is there any history of a head injury or other condition? What other symptoms came before ...

  3. Dynamic fe Model of Sitting Man Adjustable to Body Height, Body Mass and Posture Used for Calculating Internal Forces in the Lumbar Vertebral Disks

    NASA Astrophysics Data System (ADS)

    Pankoke, S.; Buck, B.; Woelfel, H. P.

    1998-08-01

    Long-term whole-body vibrations can cause degeneration of the lumbar spine. Therefore existing degeneration has to be assessed as well as industrial working places to prevent further damage. Hence, the mechanical stress in the lumbar spine—especially in the three lower vertebrae—has to be known. This stress can be expressed as internal forces. These internal forces cannot be evaluated experimentally, because force transducers cannot be implementated in the force lines because of ethical reasons. Thus it is necessary to calculate the internal forces with a dynamic mathematical model of sitting man.A two dimensional dynamic Finite Element model of sitting man is presented which allows calculation of these unknown internal forces. The model is based on an anatomic representation of the lower lumbar spine (L3-L5). This lumber spine model is incorporated into a dynamic model of the upper torso with neck, head and arms as well as a model of the body caudal to the lumbar spine with pelvis and legs. Additionally a simple dynamic representation of the viscera is used. All these parts are modelled as rigid bodies connected by linear stiffnesses. Energy dissipation is modelled by assigning modal damping ratio to the calculated undamped eigenvalues. Geometry and inertial properties of the model are determined according to human anatomy. Stiffnesses of the spine model are derived from static in-vitro experiments in references [1] and [2]. Remaining stiffness parameters and parameters for energy dissipation are determined by using parameter identification to fit measurements in reference [3]. The model, which is available in 3 different postures, allows one to adjust its parameters for body height and body mass to the values of the person for which internal forces have to be calculated.

  4. A Review of the Purpose and Scope Statements of the Task Force on Excellence, Efficiency and Competitiveness of the Arizona Board of Regents.

    ERIC Educational Resources Information Center

    Coopers & Lybrand, New York, NY.

    One of the working papers in the final report of the Arizona Board of Regents' Task Force on Excellence, Efficiency and Competitiveness, this document presents a review, designed to raise questions, of the Task Force's purpose and scope statements. The primary portion of the study was a series of interviews with 105 Arizonans (holding key…

  5. 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.

  6. Exercise and Posture

    MedlinePlus

    ... Info For Teens Message Boards & Forums Donate Shop Exercise & Posture About Spondylitis / Exercise & Posture Overview For The ... Diet Blood Work and Spondylitis Spondylitis Awareness Month Exercise Exercise is an integral part of any spondylitis ...

  7. Draft environmental impact statement for the disposal of K. I. Sawyer Air Force Base, Michigan

    SciTech Connect

    1995-11-01

    Pursuant to the Defense Base Closure and Realignment Act, K. I. Sawyer AFB was closed in September 1995. This Environmental Impact Statement has been prepared in accordance with the National Environmental Policy Act to analyze the potential environmental consequences of the disposal and reasonable alternatives for reuse of the base. The document includes analyses of community setting, land use and aesthetics, transportation, utilities, hazardous materials and hazardous waste management, geology and soils, water resources, air quality, noise, biological resources, and cultural resources. Four reuse alternatives were examined: a Proposed Action that features air cargo, regional aircraft maintenance, regional passenger, and general aviation uses of the runway with an industrial component being developed in the military family housing area; an International Wayport Alternative that consists of international passenger, air cargo, and aircraft maintenance uses, as well as regional passenger and general aviation uses, and a large residential area; a Commercial Aviation Alternative that proposes a regional commercial airport with an Upper Peninsula vocational/educational training facility; and a Recreation Alternative that would retain more than 80 percent of the base for public facilities recreation land uses. All alternatives include industrial, institutional, commercial, and residential uses. A No-Action Alternative, which would entail no reuse of the base property, was also evaluated.

  8. ERS task force statement: diagnosis and treatment of primary spontaneous pneumothorax.

    PubMed

    Tschopp, Jean-Marie; Bintcliffe, Oliver; Astoul, Philippe; Canalis, Emilio; Driesen, Peter; Janssen, Julius; Krasnik, Marc; Maskell, Nicholas; Van Schil, Paul; Tonia, Thomy; Waller, David A; Marquette, Charles-Hugo; Cardillo, Giuseppe

    2015-08-01

    Primary spontaneous pneumothorax (PSP) affects young healthy people with a significant recurrence rate. Recent advances in treatment have been variably implemented in clinical practice. This statement reviews the latest developments and concepts to improve clinical management and stimulate further research.The European Respiratory Society's Scientific Committee established a multidisciplinary team of pulmonologists and surgeons to produce a comprehensive review of available scientific evidence.Smoking remains the main risk factor of PSP. Routine smoking cessation is advised. More prospective data are required to better define the PSP population and incidence of recurrence. In first episodes of PSP, treatment approach is driven by symptoms rather than PSP size. The role of bullae rupture as the cause of air leakage remains unclear, implying that any treatment of PSP recurrence includes pleurodesis. Talc poudrage pleurodesis by thoracoscopy is safe, provided calibrated talc is available. Video-assisted thoracic surgery is preferred to thoracotomy as a surgical approach.In first episodes of PSP, aspiration is required only in symptomatic patients. After a persistent or recurrent PSP, definitive treatment including pleurodesis is undertaken. Future randomised controlled trials comparing different strategies are required. PMID:26113675

  9. Postural sway and perceived comfort in pointing tasks.

    PubMed

    Solnik, Stanislaw; Pazin, Nemanja; Coelho, Chase J; Rosenbaum, David A; Zatsiorsky, Vladimir M; Latash, Mark L

    2014-05-21

    In this study, we explored relations between indices of postural sway and perceived comfort during pointing postures performed by standing participants. The participants stood on a force plate, grasped a pointer with the dominant (right) hand, and pointed to targets located at four positions and at two distances from the body. We quantified postural sway over 60-s intervals at each pointing posture, and found no effects of target location or distance on postural sway indices. In contrast, comfort ratings correlated significantly with indices of one of the sway components, trembling. Our observations support the hypothesis that rambling and trembling sway components involve different neurophysiological mechanisms. They also suggest that subjective perception of comfort may be more important than the actual posture for postural sway. PMID:24686189

  10. Nonstationary properties of postural sway.

    PubMed

    Carroll, J P; Freedman, W

    1993-01-01

    Postural sway during quite stance is usually assumed to be a stationary stochastic process. We tested this assumption by investigating the time invariance of the average value and variance of the postural sway of three subjects. The sway was measured with a force plate under three conditions: subject standing on two feet with eyes open; subject standing on two feet with eyes closed; and subject standing on one foot with eyes open. Data were collected in 1 min runs. More than 50 min of data were collected for each subject under each test condition. The data were averaged across all runs for each subject and condition. Trends were found to be present in the data. In addition, there were initial transient increases in the second-order moments about the trends. The transient changes in first- and second-order moments usually disappeared during the first 20 s. In light of these findings, we can reject the hypothesis that postural sway is a stationary process. The results imply that the usual methods to parameterize postural sway have to be either changed or reinterpreted. PMID:8478345

  11. Effect of Posture on Hip Angles and Moments during Gait

    PubMed Central

    Lewis, Cara L.; Sahrmann, Shirley A.

    2014-01-01

    Anterior hip pain is common in young, active adults. Clinically, we have noted that patients with anterior hip pain often walk in a swayback posture, and that their pain is reduced when the posture is corrected. The purpose of this study was to investigate a potential mechanism for the reduction in pain by testing the effect of posture on movement patterns and internal moments during gait in healthy subjects. Fifteen subjects were instructed to walk while maintaining three postures: 1) natural, 2) swayback, and 3) forward flexed. Kinematic and force data were collected using a motion capture system and a force plate. Walking in the swayback posture resulted in a higher peak hip extension angle, hip flexor moment and hip flexion angular impulse compared to natural posture. In contrast, walking in a forward flexed posture resulted in a decreased hip extension angle and decreased hip flexion angular impulse. Based on these results, walking in a swayback posture may result in increased forces required of the anterior hip structures, potentially contributing to anterior hip pain. This study provides a potential biomechanical mechanism for clinical observations that posture correction in patients with hip pain is beneficial. PMID:25262565

  12. Biomechanical capabilities influence postural control strategies in the cat hindlimb

    PubMed Central

    McKay, J. Lucas; Burkholder, Thomas J.; Ting, Lena H.

    2008-01-01

    During postural responses to perturbations, horizontal plane forces generated by the cat hindlimb are stereotypically directed either towards or away from the animal’s center of mass, independent of perturbation direction. We used a static, three-dimensional musculoskeletal model of the hindlimb to investigate possible biomechanical determinants of this “force constraint strategy” (Macpherson, 1988). We hypothesized that directions in which the hindlimb can produce large forces are preferentially used in postural control. We computed feasible force sets (FFS) based on hindlimb configurations of three cats during postural equilibrium tasks (Jacobs and Macpherson, 1996) and compared them to horizontal plane postural force directions. The grand mean FFS was bimodal, with maxima near the posterior-anterior axis (−86±8° and 71±4°), and minima near the medial-lateral axis (177±8° and 8±8°). Postural force directions clustered near both maxima; there were no medial postural forces near the absolute minimum. However, the medians of the anterior and posterior postural force direction histograms in the right hindlimb were rotated counter-clockwise from the FFS maxima (p<0.05; Wilcoxon signed-rank test). Because the posterior-anterior alignment of the FFS is consistent with a hindlimb structure optimized for locomotion, we conclude that the biomechanical capabilities of the hindlimb strongly influence, but do not uniquely determine the force directions observed in the force constraint strategy. Forces used in postural control may reflect a balance between a neural preference for using forces in the directions of large feasible forces and other criteria, such as the stabilization of the center of mass, and muscular coordination strategies. PMID:17156787

  13. Fingertip contact influences human postural control

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

    Touch and pressure stimulation of the body surface can strongly influence apparent body orientation, as well as the maintenance of upright posture during quiet stance. In the present study, we investigated the relationship between postural sway and contact forces at the fingertip while subjects touched a rigid metal bar. Subjects were tested in the tandem Romberg stance with eyes open or closed under three conditions of fingertip contact: no contact, touch contact (< 0.98 N of force), and force contact (as much force as desired). Touch contact was as effective as force contact or sight of the surroundings in reducing postural sway when compared to the no contact, eyes closed condition. Body sway and fingertip forces were essentially in phase with force contact, suggesting that fingertip contact forces are physically counteracting body sway. Time delays between body sway and fingertip forces were much larger with light touch contact, suggesting that the fingertip is providing information that allows anticipatory innervation of musculature to reduce body sway. The results are related to observations on precision grip as well as the somatosensory, proprioceptive, and motor mechanisms involved in the reduction of body sway.

  14. 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…

  15. 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

  16. Postural control at the human wrist

    PubMed Central

    Chew, John Z Z; Gandevia, Simon C; Fitzpatrick, Richard C

    2008-01-01

    In our movements and posture, we always act against a physical load. A key property of any load is its elastic stiffness (K), which describes how the force required to hold it must change with position. Here we examine how load stiffness affects the ability to maintain a stable posture at the wrist. Loads having positive (like a spring) and negative stiffness (like an inverted pendulum) were created by varying the position of weights on multiarm rigid pendulum. Subjects (n = 9) held 15 loads (K = ± 0.04, ± 0.01 and 0 N m deg−1 at mean torques of 0.2, 0.4 and 0.6 N m) still for 60 s. Residual wrist movement (sway) increased with mean torque and increased as stiffness became more negative. Large effects of load stiffness were seen at low frequencies (< 1.5 Hz) but not at higher frequencies that reflect load resonance and reflex activity. Subjects accurately perceived their postural sway while holding the loads but measured psychophysical thresholds showed that load stiffness was not perceived. We conclude that load stiffness, independent of force levels, affects the ability to control a load and that the postural control process relies on perception and volitional tracking rather than more automatic reflex pathways. Despite an awareness of their postural errors, we see no evidence for adaptation of postural control processes to compensate for changes in load properties. This is unlike the adaptation of feedforward control processes that produce targeted volitional movements when load properties are altered. We propose that postural control and movement control are fundamentally different neural processes. PMID:18187473

  17. Deficits in Lower Limb Muscle Reflex Contraction Latency and Peak Force Are Associated With Impairments in Postural Control and Gross Motor Skills of Children With Developmental Coordination Disorder

    PubMed Central

    Fong, Shirley S.M.; Ng, Shamay S.M.; Guo, X.; Wang, Yuling; Chung, Raymond C.K.; Stat, Grad; Ki, W.Y.; Macfarlane, Duncan J.

    2015-01-01

    Abstract This cross-sectional, exploratory study aimed to compare neuromuscular performance, balance and motor skills proficiencies of typically developing children and those with developmental coordination disorder (DCD) and to determine associations of these neuromuscular factors with balance and motor skills performances in children with DCD. One hundred thirty children with DCD and 117 typically developing children participated in the study. Medial hamstring and gastrocnemius muscle activation onset latencies in response to an unexpected posterior-to-anterior trunk perturbation were assessed by electromyography and accelerometer. Hamstring and gastrocnemius muscle peak force and time to peak force were quantified by dynamometer, and balance and motor skills performances were evaluated with the Movement Assessment Battery for Children (MABC). Independent t tests revealed that children with DCD had longer hamstring and gastrocnemius muscle activation onset latencies (P < 0.001) and lower isometric peak forces (P < 0.001), but not times to peak forces (P > 0.025), than the controls. Multiple regression analysis accounting for basic demographics showed that gastrocnemius peak force was independently associated with the MABC balance subscore and ball skills subscore, accounting for 5.7% (P = 0.003) and 8.5% (P = 0.001) of the variance, respectively. Gastrocnemius muscle activation onset latency also explained 11.4% (P < 0.001) of the variance in the MABC ball skills subscore. Children with DCD had delayed leg muscle activation onset times and lower isometric peak forces. Gastrocnemius peak force was associated with balance and ball skills performances, whereas timing of gastrocnemius muscle activation was a determinant of ball skill performance in the DCD population. PMID:26469921

  18. Force.

    ERIC Educational Resources Information Center

    Gamble, Reed

    1989-01-01

    Discusses pupil misconceptions concerning forces. Summarizes some of Assessment of Performance Unit's findings on meaning of (1) force, (2) force and motion in one dimension and two dimensions, and (3) Newton's second law. (YP)

  19. Postural sway following cryotherapy in healthy adults.

    PubMed

    Fukuchi, Claudiane A; Duarte, Marcos; Stefanyshyn, Darren J

    2014-01-01

    In light of the wide use of cryotherapy and its potential negative effects on postural stability, little is known about how postural sway is affected, particularly when the whole lower limb is immersed. The purpose of this study was to analyze the influence of cryotherapy on postural sway in healthy males. Twenty-six subjects were randomly assigned into two intervention groups: control (tepid water at ∼26°C) or ice (cold water at ∼11°C). Postural sway was measured through the center of pressure (COP) position while they stood on a force plate during bipedal (70 s) and unipedal (40 s) conditions before and after the subjects were immersed in a water tub up to the umbilical level for 20 min. COP standard deviation (SD) and COP velocity were analyzed in the anterior-posterior (AP) and medial-lateral (ML) directions. Statistical analysis showed that in the bipedal condition cryotherapy increased the COP SD and COP velocity in the ML direction. During the unipedal condition, a higher COP velocity in the AP and ML directions was also reported. Our findings indicate that cryotherapy by immersing the whole lower limb should be used with caution before engaging in challenging postural control activities. PMID:24631278

  20. Galvanic vestibular stimulation for analysis of postural adaptation and stability.

    PubMed

    Johansson, R; Magnusson, M; Fransson, P A

    1995-03-01

    Human postural dynamics was investigated in 12 normal subjects by means of a force platform recording body sway, induced by bipolar transmastoid galvanic stimulation of the vestibular nerve and labyrinth. The model adopted was that of an inverted segmented pendulum, the dynamics of postural control being assumed to be reflected in the stabilizing forces actuated by the feet as a result of complex muscular activity subject to state feedback of body sway and position. Time-series analysis demonstrates that a transfer function from stimulus to sway-force response with specific parameters can be identified. In addition, adaptation to the vestibular stimulus is demonstrated to exist, and we describe this phenomenon using quantification in terms of a postural adaptation time constant in the range of 40-50 s. The results suggest means to evaluate adaptive behavior and postural control in the erect human being which may be useful in the rehabilitation of individuals striving to regain upright stance. PMID:7698784

  1. Adaptation to transient postural perturbations

    NASA Technical Reports Server (NTRS)

    Andres, Robert O.

    1992-01-01

    This research was first proposed in May, 1986, to focus on some of the problems encountered in the analysis of postural responses gathered from crewmembers. The ultimate driving force behind this line of research was the desire to treat, predict, or explain 'Space Adaptation Syndrome' (SAS) and hence circumvent any adverse effects of space motion sickness on crewmember performance. The aim of this project was to develop an easily implemented analysis of the transient responses to platform translation that can be elicited with a protocol designed to force sensorimotor reorganization, utilizing statistically reliable criterion measures. This report will present: (1) a summary of the activity that took place in each of the three funded years of the project; (2) discussion of experimental results and their implications for future research; and (3) a list of presentations and publications resulting from this project.

  2. Vestibular humanoid postural control.

    PubMed

    Mergner, Thomas; Schweigart, Georg; Fennell, Luminous

    2009-01-01

    Many of our motor activities require stabilization against external disturbances. This especially applies to biped stance since it is inherently unstable. Disturbance compensation is mainly reactive, depending on sensory inputs and real-time sensor fusion. In humans, the vestibular system plays a major role. When there is no visual space reference, vestibular-loss clearly impairs stance stability. Most humanoid robots do not use a vestibular system, but stabilize upright body posture by means of center of pressure (COP) control. We here suggest using in addition a vestibular sensor and present a biologically inspired vestibular sensor along with a human-inspired stance control mechanism. We proceed in two steps. First, in an introductory review part, we report on relevant human sensors and their role in stance control, focusing on own models of transmitter fusion in the vestibular sensor and sensor fusion in stance control. In a second, experimental part, the models are used to construct an artificial vestibular system and to embed it into the stance control of a humanoid. The robot's performance is investigated using tilts of the support surface. The results are compared to those of humans. Functional significance of the vestibular sensor is highlighted by comparing vestibular-able with vestibular-loss states in robot and humans. We show that a kinematic body-space sensory feedback (vestibular) is advantageous over a kinetic one (force cues) for dynamic body-space balancing. Our embodiment of human sensorimotor control principles into a robot is more than just bionics. It inspired our biological work (neurorobotics: 'learning by building', proof of principle, and more). We envisage a future clinical use in the form of hardware-in-the-loop simulations of neurological symptoms for improving diagnosis and therapy and designing medical assistive devices. PMID:19665555

  3. Autoimmune Basis for Postural Tachycardia Syndrome

    ClinicalTrials.gov

    2016-03-30

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

  4. Tips to Maintain Good Posture

    MedlinePlus

    ... Pain and Chiropractic Posture Spinal Health Winter Activities Backpack Safety Kids and Sports Exercising Outdoors with Baby ... Pain and Chiropractic Posture Spinal Health Winter Activities Backpack Safety Kids and Sports Exercising Outdoors with Baby ...

  5. 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

  6. Determination of characteristic parameters of human postural dynamics.

    PubMed

    Johansson, R; Magnusson, M

    1989-01-01

    Posture control performance was quantified in three variables (swiftness, stiffness, damping). Subjects were tested with a force platform recording body sway induced by vibrators attached to the calf muscles. Parameter estimation was made with identification of a transfer function representing the stabilized inverted pendulum. It is conjectured that the state feedback parameters identified are suitable for use in assessing ability to maintain posture. PMID:2635507

  7. Comparison of a laboratory grade force platform with a Nintendo Wii Balance Board on measurement of postural control in single-leg stance balance tasks.

    PubMed

    Huurnink, Arnold; Fransz, Duncan P; Kingma, Idsart; van Dieën, Jaap H

    2013-04-26

    Training and testing of balance have potential applications in sports and medicine. Laboratory grade force plates (FP) are considered the gold standard for the measurement of balance performance. Measurements in these systems are based on the parameterization of center of pressure (CoP) trajectories. Previous research validated the inexpensive, widely available and portable Nintendo Wii Balance Board (WBB). The novelty of the present study is that FP and WBB are compared on CoP data that was collected simultaneously, by placing the WBB on the FP. Fourteen healthy participants performed ten sequences of single-leg stance tasks with eyes open (EO), eyes closed (EC) and after a sideways hop (HOP). Within trial comparison of the two systems showed small root-mean-square differences for the CoP trajectories in the x and y direction during the three tasks (mean±SD; EO: 0.33±0.10 and 0.31±0.16 mm; EC: 0.58±0.17 and 0.63±0.19 mm; HOP: 0.74±0.34 and 0.74±0.27 mm, respectively). Additionally, during all 420 trials, comparison of FP and WBB revealed very high Pearson's correlation coefficients (r) of the CoP trajectories (x: 0.999±0.002; y: 0.998±0.003). A general overestimation was found on the WBB compared to the FP for 'CoP path velocity' (EO: 5.3±1.9%; EC: 4.0±1.4%; HOP: 4.6±1.6%) and 'mean absolute CoP sway' (EO: 3.5±0.7%; EC: 3.7±0.5%; HOP: 3.6±1.0%). This overestimation was highly consistent over the 140 trials per task (r>0.996). The present findings demonstrate that WBB is sufficiently accurate in quantifying CoP trajectory, and overall amplitude and velocity during single-leg stance balance tasks. PMID:23528845

  8. 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.

  9. Assessing Postural Stability in the Concussed Athlete

    PubMed Central

    Ruhe, Alexander; Fejer, René; Gänsslen, Axel; Klein, Wolfgang

    2014-01-01

    Context: Postural stability assessment is included as part of the diagnostic and monitoring process for sports-related concussions. Particularly, the relatively simple Balance Error Scoring System (BESS) and more sophisticated force plate measures like the Sensory Organization Test (SOT) are suggested. Evidence Acquisition: Relevant studies were identified via the following electronic databases: PubMed, MEDLINE, EMBASE, Web of Science, ScienceDirect, and CINAHL (1980 to July 2013). Inclusion was based on the evaluation of postural sway or balance in concussed athletes of any age or sex and investigating the reliability or validity of the included tests. Study Design: Clinical review. Level of Evidence: Level 4 Results: Both the SOT and the BESS show moderate reliability, but a learning effect due to repetitive testing needs to be considered. Both tests indicate that postural stability returns to baseline by day 3 to 5 in most concussed athletes. While the BESS is a simple and valid method, it is sensitive to subjectivity in scoring and the learning effect. The SOT is very sensitive to even subtle changes in postural sway, and thus, more accurate than the BESS; however, it is a rather expensive method of balance testing. Conclusion: Both tests serve the purpose of monitoring balance performance in the concussed athlete; however, neither may serve as a stand-alone diagnostic or monitoring tool. Strength of Recommendation Taxonomy: B PMID:25177420

  10. Cognitive load affects postural control in children.

    PubMed

    Schmid, Maurizio; Conforto, Silvia; Lopez, Luisa; D'Alessio, Tommaso

    2007-05-01

    Inferring relations between cognitive processes and postural control is a relatively topical challenge in developmental neurology. This study investigated the effect of a concurrent cognitive task on postural control in a sample of 50 nine-year-old children. Each subject completed two balance trials of 60 s, one with a concurrent cognitive task (cognitive load) and another with no cognitive load. The concurrent cognitive task consisted of mentally counting backwards in steps of 2. Twelve posturographic parameters (PPs) were extracted from the centre of pressure (CoP) trajectory obtained through a load cell force plate. Analysis of variance revealed significant differences in the majority of the extracted PPs. CoP was found to travel faster, farther, and with substantially different features demonstrating an overall broadening of the spectrum in the frequency domain. Nonlinear stability factors revealed significant differences when exposed to a concurrent cognitive task, showing an increase of instability in the intervention rate of the postural control system. By grouping children through selected items from Teachers Ratings and PANESS assessment, specific significant differences were also found both in time and frequency domain PPs, thus confirming the hypothesis of an interaction between cognitive processes (and their development), and postural control. PMID:17136524

  11. Cardiac catheterization in children with pulmonary hypertensive vascular disease: consensus statement from the Pulmonary Vascular Research Institute, Pediatric and Congenital Heart Disease Task Forces.

    PubMed

    Del Cerro, Maria Jesus; Moledina, Shahin; Haworth, Sheila G; Ivy, Dunbar; Al Dabbagh, Maha; Banjar, Hanaa; Diaz, Gabriel; Heath-Freudenthal, Alexandria; Galal, Ahmed Nasser; Humpl, Tilman; Kulkarni, Snehal; Lopes, Antonio; Mocumbi, Ana Olga; Puri, G D; Rossouw, Beyra; Harikrishnan, S; Saxena, Anita; Udo, Patience; Caicedo, Lina; Tamimi, Omar; Adatia, Ian

    2016-03-01

    Cardiac catheterization is important in the diagnosis and risk stratification of pulmonary hypertensive vascular disease (PHVD) in children. Acute vasoreactivity testing provides key information about management, prognosis, therapeutic strategies, and efficacy. Data obtained at cardiac catheterization continue to play an important role in determining the surgical options for children with congenital heart disease and clinical evidence of increased pulmonary vascular resistance. The Pediatric and Congenital Heart Disease Task Forces of the Pulmonary Vascular Research Institute met to develop a consensus statement regarding indications for, conduct of, acute vasoreactivity testing with, and pitfalls and risks of cardiac catheterization in children with PHVD. This document contains the essentials of those discussions to provide a rationale for the hemodynamic assessment by cardiac catheterization of children with PHVD. PMID:27076908

  12. Cardiac catheterization in children with pulmonary hypertensive vascular disease: consensus statement from the Pulmonary Vascular Research Institute, Pediatric and Congenital Heart Disease Task Forces

    PubMed Central

    del Cerro, Maria Jesus; Moledina, Shahin; Haworth, Sheila G.; Ivy, Dunbar; Al Dabbagh, Maha; Banjar, Hanaa; Diaz, Gabriel; Heath-Freudenthal, Alexandria; Galal, Ahmed Nasser; Humpl, Tilman; Kulkarni, Snehal; Lopes, Antonio; Mocumbi, Ana Olga; Puri, G. D.; Rossouw, Beyra; Harikrishnan, S.; Saxena, Anita; Udo, Patience; Caicedo, Lina; Tamimi, Omar

    2016-01-01

    Abstract Cardiac catheterization is important in the diagnosis and risk stratification of pulmonary hypertensive vascular disease (PHVD) in children. Acute vasoreactivity testing provides key information about management, prognosis, therapeutic strategies, and efficacy. Data obtained at cardiac catheterization continue to play an important role in determining the surgical options for children with congenital heart disease and clinical evidence of increased pulmonary vascular resistance. The Pediatric and Congenital Heart Disease Task Forces of the Pulmonary Vascular Research Institute met to develop a consensus statement regarding indications for, conduct of, acute vasoreactivity testing with, and pitfalls and risks of cardiac catheterization in children with PHVD. This document contains the essentials of those discussions to provide a rationale for the hemodynamic assessment by cardiac catheterization of children with PHVD. PMID:27076908

  13. Disposal and reuse of Myrtle Beach Air Force Base, South Carolina final environmental impact statement. Final report

    SciTech Connect

    1993-02-01

    Pursuant to the Defense Base Closure and Realignment Act of 1990, Myrtle Beach AFB closed in March 1993. This EIS was prepared in accordance with the National Environmental Policy Act to analyze the potential environmental consequences of the disposal of the base. Although disposal will create few direct impacts, reuse by others will create indirect impacts. The EIS analyzes the effects a range of reasonable foreseeable alternative reuses may have on the local community; including land use and aesthetics, transportation, utilities, hazardous materials/wastes, geology and soils, water resources, air quality, noise, biological resources, and cultural resources. Preservation covenants within the disposal document could eliminate or reduce any negative environmental effects to a non-adverse level. Because the Air Force is disposing of the property, some of the mitigation measures are beyond Air Force control. Remediation of Installation Restoration Program sites will continue to be the responsibility of the Air Force.

  14. Gravitational Effects upon Locomotion Posture

    NASA Technical Reports Server (NTRS)

    DeWitt, John K.; Bentley, Jason R.; Edwards, W. Brent; Perusek, Gail P.; Samorezov, Sergey

    2008-01-01

    Researchers use actual microgravity (AM) during parabolic flight and simulated microgravity (SM) obtained with horizontal suspension analogs to better understand the effect of gravity upon gait. In both environments, the gravitational force is replaced by an external load (EL) that returns the subject to the treadmill. However, when compared to normal gravity (N), researchers consistently find reduced ground reaction forces (GRF) and subtle kinematic differences (Schaffner et al., 2005). On the International Space Station, the EL is applied by elastic bungees attached to a waist and shoulder harness. While bungees can provide EL approaching body weight (BW), their force-length characteristics coupled with vertical oscillations of the body during gait result in a variable load. However, during locomotion in N, the EL is consistently equal to 100% body weight. Comparisons between AM and N have shown that during running, GRF are decreased in AM (Schaffner et al, 2005). Kinematic evaluations in the past have focussed on joint range of motion rather than joint posture at specific instances of the gait cycle. The reduced GRF in microgravity may be a result of differing hip, knee, and ankle positions during contact. The purpose of this investigation was to compare joint angles of the lower extremities during walking and running in AM, SM, and N. We hypothesized that in AM and SM, joints would be more flexed at heel strike (HS), mid-stance (MS) and toe-off (TO) than in N.

  15. Postural perturbations: new insights for treatment of balance disorders

    NASA Technical Reports Server (NTRS)

    Horak, F. B.; Henry, S. M.; Shumway-Cook, A.; Peterson, B. W. (Principal Investigator)

    1997-01-01

    This article reviews the neural control of posture as understood through studies of automatic responses to mechanical perturbations. Recent studies of responses to postural perturbations have provided a new view of how postural stability is controlled, and this view has profound implications for physical therapy practice. We discuss the implications for rehabilitation of balance disorders and demonstrate how an understanding of the specific systems underlying postural control can help to focus and enrich our therapeutic approaches. By understanding the basic systems underlying control of balance, such as strategy selection, rapid latencies, coordinated temporal spatial patterns, force control, and context-specific adaptations, therapists can focus their treatment on each patient's specific impairments. Research on postural responses to surface translations has shown that balance is not based on a fixed set of equilibrium reflexes but on a flexible, functional motor skill that can adapt with training and experience. More research is needed to determine the extent to which quantification of automatic postural responses has practical implications for predicting falls in patients with constraints in their postural control system.

  16. Postural dependence of human locomotion during gait initiation.

    PubMed

    Mille, Marie-Laure; Simoneau, Martin; Rogers, Mark W

    2014-12-15

    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

  17. 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). PMID:16814770

  18. Stand Up Straight: Posture for Singers.

    ERIC Educational Resources Information Center

    Gauthier, Delores R.

    2002-01-01

    Focuses on the importance of posture in music-making. Provides information on the importance of posture and the different types of posture stances to help students work toward better posture. Includes information on using kinesthetic experiences to help students improve their posture. (CMK)

  19. 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. PMID:26117153

  20. Postural stress analysis in industry.

    PubMed

    Genaidy, A M; Al-Shedi, A A; Karwowski, W

    1994-04-01

    Both observational and instrumentation-based techniques have been used to conduct postural stress analysis in industry. As observational methods are more widespread than instrumentation-based techniques and can be used as a practical tool in the workplace, this study reviews and assesses the scientific literature on observational techniques. Techniques are classified into macropostural, micropostural and postural-work activity. The basis for each classification is outlined and evaluated. Postural recording is performed either continuously or intermittently. Intermittent postural recording procedures lack the criteria for determining the optimum number of observations for low and high repetitive jobs. Research is warranted to examine the sources and magnitudes of errors associated with postural classification. Such information is required to train job analysts in the ergonomics of working postures. PMID:15676953

  1. Exercise and Posture

    MedlinePlus

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  2. Assessment of postural balance function.

    PubMed

    Kostiukow, Anna; Rostkowska, Elzbieta; Samborski, Włodzimierz

    2009-01-01

    Postural balance is defined as the ability to stand unassisted without falling. Examination of the patient's postural balance function is a difficult diagnostic task. Most of the balance tests used in medicine provide incomplete information on this coordination ability of the human body. The aim of this study was to review methods of assessment of the patient's postural balance function, including various tests used in medical diagnostics centers. PMID:20698188

  3. 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…

  4. 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…

  5. Management of Postural Tachycardia Syndrome, Inappropriate Sinus Tachycardia and Vasovagal Syncope

    PubMed Central

    Raj, Satish

    2016-01-01

    Postural tachycardia syndrome (POTS), inappropriate sinus tachycardia (IST) and vasovagal syncope (VVS) are relatively common clinical syndromes that are seen by physicians in several disciplines. They are often not well recognised and are poorly understood by physicians, are associated with significant morbidity and cause significant frustration for both patients and their physicians. The 2015 Heart Rhythm Society Expert Consensus Statement on the Diagnosis and Treatment of Postural Tachycardia Syndrome, Inappropriate Sinus Tachycardia and Vasovagal Syncope provides physicians with an introduction to these disorders and initial recommendations on their investigation and treatment. Here we summarise the consensus statement to help physicians in the management of patients with these frequently distressing problems.

  6. Fitts’ Law in Early Postural Adjustments

    PubMed Central

    Bertucco, M.; Cesari, P.; Latash, M.L

    2012-01-01

    We tested a hypothesis that the classical relation between movement time and index of difficulty (ID) in quick pointing action (Fitts’ Law) reflects processes at the level of motor planning. Healthy subjects stood on a force platform and performed quick and accurate hand movements into targets of different size located at two distances. The movements were associated with early postural adjustments that are assumed to reflect motor planning processes. The short distance did not require trunk rotation, while the long distance did. As a result, movements over the long distance were associated with substantiual Coriolis forces. Movement kinematics and contact forces and moments recorded by the platform were studied. Movement time scaled with ID for both movements. However, the data could not be fitted with a single regression: Movements over the long distance had a larger intercept corresponding to movement times about 140 ms longer than movements over the shorter distance. The magnitude of postural adjustments prior to movement initiation scaled with ID for both short and long distances. Our results provide strong support for the hypothesis that Fitts’ Law emerges at the level of motor planning, not at the level of corrections of ongoing movements. They show that, during natural movements, changes in movement distance may lead to changes in the relation between movement time and ID, for example when the contribution of different body segments to the movement varies and when the action of Coriolis force may require an additional correction of the movement trajectory. PMID:23211560

  7. Postconcussion Postural Sway Variability Changes in Youth: The Benefit of Structural Variability Analyses

    PubMed Central

    Quatman-Yates, Catherine C.; Bonnette, Scott; Hugentobler, Jason A.; Médé, Butovens; Kiefer, Adam W.; Kurowski, Brad G.; Riley, Michael A.

    2016-01-01

    Purpose The purpose of this study was to evaluate the utility of postural sway variability as a potential assessment to detect altered postural sway in youth with symptoms related to a concussion. Methods Forty participants (20 who were healthy and 20 who were injured) aged 10 to 16 years were assessed using the Balance Error Scoring System (BESS) and postural sway variability analyses applied to center-of-pressure data captured using a force plate. Results Significant differences were observed between the 2 groups for postural sway variability metrics but not for the BESS. Specifically, path length was shorter and Sample and Renyi Entropies were more regular for the participants who were injured compared with the participants who were healthy (P < .05). Conclusion The results of this study indicate that postural sway variability may be a more valid measure than the BESS to detect postconcussion alterations in postural control in young athletes. PMID:26397071

  8. Single-leg postural stability deficits following anterior cruciate ligament reconstruction in pediatric and adolescent athletes.

    PubMed

    Sugimoto, Dai; Howell, David R; Micheli, Lyle J; Meehan, William P

    2016-07-01

    The objective of this study was to compare the postural stability of pediatric and adolescent athletes without anterior cruciate ligament injury with those who underwent anterior cruciate reconstruction (ACLR). Postural stability ratings derived from a video-force plate system during the three stances of the modified Balance Error Scoring System were collected from pediatric and adolescent athletes who underwent ACLR (N=24; mean 1.2 years after surgery) and from uninjured controls (N=479). The postural control rating was calculated as the mean of the displacement and variance of the torso and center of pressure data, normalized on a scale from 0 to 100. A higher rating indicates greater postural stability. Participants who underwent ACLR showed lower postural stability ratings during single-leg stance compared with uninjured controls (40.0 vs. 48.7; P=0.037). ACLR is associated with deficits in postural stability. PMID:26863483

  9. Otolith and Vertical Canal Contributions to Dynamic Postural Control

    NASA Technical Reports Server (NTRS)

    Black, F. Owen

    1999-01-01

    The objective of this project is to determine: 1) how do normal subjects adjust postural movements in response to changing or altered otolith input, for example, due to aging? and 2) how do patients adapt postural control after altered unilateral or bilateral vestibular sensory inputs such as ablative inner ear surgery or ototoxicity, respectively? The following hypotheses are under investigation: 1) selective alteration of otolith input or abnormalities of otolith receptor function will result in distinctive spatial, frequency, and temporal patterns of head movements and body postural sway dynamics. 2) subjects with reduced, altered, or absent vertical semicircular canal receptor sensitivity but normal otolith receptor function or vice versa, should show predictable alterations of body and head movement strategies essential for the control of postural sway and movement. The effect of altered postural movement control upon compensation and/or adaptation will be determined. These experiments provide data for the development of computational models of postural control in normals, vestibular deficient subjects and normal humans exposed to unusual force environments, including orbital space flight.

  10. Postural strategy changes with fatigue of the lumbar extensor muscles.

    PubMed

    Wilson, Erin L; Madigan, Michael L; Davidson, Bradley S; Nussbaum, Maury A

    2006-04-01

    The purpose of this study was to investigate the effect of lumbar extensor fatigue on postural strategy in response to a balance perturbation. Anteriorly-directed force perturbations were applied to the upper back with a padded pendulum and attempted to challenge the postural control system without eliciting a stepping response. In three separate sessions, subjects were perturbed both before and after a fatiguing protocol that induced lumbar extensor fatigue to one of three different fatigue levels. Postural strategy was quantified using center of pressure position along with joint angles and joint torques for the ankle, knee, hip, and "low back" joints. Results showed both proactive and reactive changes in postural strategy. Proactive changes involved a slight anterior lean prior to the perturbation, and reactive changes were consistent with a shift toward more of a hip strategy with fatigue. In addition, results suggested that subjects classified as moving mostly at the hip prior to fatigue were more affected by fatigue compared to subjects classified as moving roughly equal amounts at the ankle and hip prior to fatigue. Increasing fatigue level exaggerated some, but not all, of the changes in postural strategy with fatigue. These findings illustrate that neuromuscular fatigue can influence postural strategy in response to a balance perturbation. PMID:16023345

  11. 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

  12. Lead effects on postural balance of children.

    PubMed Central

    Bhattacharya, A; Shukla, R; Bornschein, R L; Dietrich, K N; Keith, R

    1990-01-01

    The postural sway responses of 63 children with a mean age of 5.74 years were quantified with a Force Platform technique. The average maximum (max) blood lead (PbB) of these children during the first 5 years of life was 20.7 micrograms/dL (range 9.2 to 32.5). The backward stepwise regression analysis for sway area response during the eyes-closed, no-foam test with all the covariates and confounders and the PbB parameters showed a significant relationship with peak or max PbB during the second year of life. These results are consistent with our previous study with a smaller group of children. The data have been analyzed to provide some insight into the role of various afferent for the maintenance of postural balance. The results suggests a hypothesis that if the max PbB had caused some level of impairment in the functional capacities or interconnectivity of the vestibular and/or proprioception systems at 2 years of age, then it is reasonable to assume that the redundancy in the postural afferent systems would naturally adapt to rely more on the remaining intact afferent system (in this case, vision). PMID:2088753

  13. 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. PMID:26741255

  14. Postural performance of vestibular loss patients under increased postural threat.

    PubMed

    Young, Laurence R; Bernard-Demanze, Laurence; Dumitrescu, Michel; Magnan, Jacques; Borel, Liliane; Lacour, Michel

    2012-01-01

    The effects of increasing postural task difficulty on balance control was investigated in 9 compensated vestibular loss patients whose results were compared to 11 healthy adults. Subjects were tested in static (stable support) and dynamic (sinusoidal translation of the support) conditions, both at floor level and at height (62 cm above the floor), and with and without vision, to create an additional postural threat. Wavelet analysis of the center of foot pressure displacement and motion analysis of the body segments were used to evaluate the postural performance. Evaluation questionnaires were used to examine the compensation level of the patients (DHI test), their general anxiety level (SAST), fear of height (subjective scale), and workload (NASA TLX test). (Vestibular loss patients rely more on vision and spend more energy maintaining balance than controls, but they use the same postural strategy as normals in both static and dynamic conditions.) Questionnaire data all showed differences in behavior and perceptions between the controls and the patients. However, at height and without vision, a whole body strategy leading to rigid posture replaces the head stabilization strategy found for standing at floor level. The effects of height on postural control can be attributable to an increase in postural threat and attention changes resulting from modifications in perception. PMID:23000612

  15. Seated postural hypotension.

    PubMed

    Gorelik, Oleg; Cohen, Natan

    2015-12-01

    Most studies of postural hypotension (PH) have focused on standing PH. Less is known about PH after transition from a supine to sitting position. Moreover, seated PH has not been previously reviewed in the English literature. The aim of this review was to provide current information regarding seating-induced PH. Seventeen studies were reviewed regarding prevalence, methods of evaluation, manifestations, predisposing factors, prognosis, and management of seated PH. Prevalence ranged from 8% among community-dwelling persons to 56% in elderly hospitalized patients. Dizziness and palpitations were the most frequent symptoms. Of a variety of factors that have been identified as predisposing and contributing to seated PH, aging, bed rest, and hypertension were most important. Because seated PH is a common, easily diagnosable and frequently symptomatic condition, especially in elderly inpatients, this disorder warrants attention. Moreover, seating-induced falls in blood pressure and the associated symptoms, may be largely prevented by nonpharmacologic interventions. PMID:26515671

  16. Postural stabilization and balance assessment in Charcot–Marie–Tooth 1A subjects

    PubMed Central

    Lencioni, T.; Rabuffetti, M.; Piscosquito, G.; Pareyson, D.; Aiello, A.; Di Sipio, E.; Padua, L.; Stra, F.; Ferrarin, M.

    2014-01-01

    The aim of the present study was to assess postural stabilization skill in adult subjects affected by Charcot–Marie–Tooth disease (CMT) type 1A. For this purpose ground reaction force (GRF) was measured by means of a piezoelectric force platform during the sit-to-stand (STS) movement, until a steady state erect posture was achieved. Specific indexes to quantify Centre of Mass acceleration, both during postural stabilization and during quiet standing, were computed using a mathematical model. Forty-seven CMT1A subjects were recruited for the study, and the control group was formed by forty-one age- and sex-matched healthy subjects. The results show that CMT1A subjects are less stable than controls during the quiet stance. Greater difficulty (high values of Yinf, the final instability rate) to maintain erect posture appears to be mainly associated with plantar-flexor muscle weakness, rather than to damage of the proprioceptive system. The worst performances shown by CMT1A subjects in the stabilization phase (high values of I, the global index of postural stabilization performance) seem to be associated with reduced muscle strength and the loss of large sensory nerve fibres. Distal muscle weakness appears to affect both postural stabilization and quiet erect posture. The presented protocol and the analysis of postural stabilization parameters provide useful information on CMT1A balance disorders. PMID:25082324

  17. Postural stabilization and balance assessment in Charcot-Marie-Tooth 1A subjects.

    PubMed

    Lencioni, T; Rabuffetti, M; Piscosquito, G; Pareyson, D; Aiello, A; Di Sipio, E; Padua, L; Stra, F; Ferrarin, M

    2014-09-01

    The aim of the present study was to assess postural stabilization skill in adult subjects affected by Charcot-Marie-Tooth disease (CMT) type 1A. For this purpose ground reaction force (GRF) was measured by means of a piezoelectric force platform during the sit-to-stand (STS) movement, until a steady state erect posture was achieved. Specific indexes to quantify Centre of Mass acceleration, both during postural stabilization and during quiet standing, were computed using a mathematical model. Forty-seven CMT1A subjects were recruited for the study, and the control group was formed by forty-one age- and sex-matched healthy subjects. The results show that CMT1A subjects are less stable than controls during the quiet stance. Greater difficulty (high values of Yinf, the final instability rate) to maintain erect posture appears to be mainly associated with plantar-flexor muscle weakness, rather than to damage of the proprioceptive system. The worst performances shown by CMT1A subjects in the stabilization phase (high values of I, the global index of postural stabilization performance) seem to be associated with reduced muscle strength and the loss of large sensory nerve fibres. Distal muscle weakness appears to affect both postural stabilization and quiet erect posture. The presented protocol and the analysis of postural stabilization parameters provide useful information on CMT1A balance disorders. PMID:25082324

  18. 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

  19. Ankle and hip postural strategies defined by joint torques.

    PubMed

    Runge, C F; Shupert, C L; Horak, F B; Zajac, F E

    1999-10-01

    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

  20. The Effect of Body Posture on Brain Glymphatic Transport

    PubMed Central

    Lee, Hedok; Xie, Lulu; Yu, Mei; Kang, Hongyi; Feng, Tian; Deane, Rashid; Logan, Jean; Nedergaard, Maiken

    2015-01-01

    The glymphatic pathway expedites clearance of waste, including soluble amyloid β (Aβ) from the brain. Transport through this pathway is controlled by the brain's arousal level because, during sleep or anesthesia, the brain's interstitial space volume expands (compared with wakefulness), resulting in faster waste removal. Humans, as well as animals, exhibit different body postures during sleep, which may also affect waste removal. Therefore, not only the level of consciousness, but also body posture, might affect CSF–interstitial fluid (ISF) exchange efficiency. We used dynamic-contrast-enhanced MRI and kinetic modeling to quantify CSF-ISF exchange rates in anesthetized rodents' brains in supine, prone, or lateral positions. To validate the MRI data and to assess specifically the influence of body posture on clearance of Aβ, we used fluorescence microscopy and radioactive tracers, respectively. The analysis showed that glymphatic transport was most efficient in the lateral position compared with the supine or prone positions. In the prone position, in which the rat's head was in the most upright position (mimicking posture during the awake state), transport was characterized by “retention” of the tracer, slower clearance, and more CSF efflux along larger caliber cervical vessels. The optical imaging and radiotracer studies confirmed that glymphatic transport and Aβ clearance were superior in the lateral and supine positions. We propose that the most popular sleep posture (lateral) has evolved to optimize waste removal during sleep and that posture must be considered in diagnostic imaging procedures developed in the future to assess CSF-ISF transport in humans. SIGNIFICANCE STATEMENT The rodent brain removes waste better during sleep or anesthesia compared with the awake state. Animals exhibit different body posture during the awake and sleep states, which might affect the brain's waste removal efficiency. We investigated the influence of body posture on

  1. Dimension and Complexity in Human Movement and Posture.

    PubMed

    Morrison, Steven; Newell, Karl M

    2015-10-01

    There has been considerable effort over the last 25 years to understand the emergence of complexity in motor output and how this relates to properties of the individual (e.g., age, disease state, etc.), environment (e.g., information) and task (e.g., movement, posture, isometric force). This paper addresses the behavioral dimension of motor complexity in movement and posture from a degrees of freedom (DF) perspective together with the change of complexity through aging, disease and fatigue. The dimension of behavior for a given perceptual-motor output is shown to be relatively low, dependent on the interaction between the individual, environmental, and task constraints and varies within a limited adaptive range for a given motor task. The determination of dimension in movement and posture has taken us beyond the traditional motor performance scores of behavior but it is not a sufficient characterization of the adaptive and emergent processes of complexity. PMID:26375933

  2. 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. PMID:26979902

  3. Influence of gymnastics training on the development of postural control.

    PubMed

    Garcia, Claudia; Barela, José Angelo; Viana, André Rocha; Barela, Ana Maria Forti

    2011-03-29

    This study investigated the influence of gymnastics training on the postural control of children with and without the use of visual information. Two age groups, aged 5-7 and 9-11 years old, of gymnasts and nongymnasts were asked to maintain an upright and quiet stance on a force platform with eyes open (EO) and eyes closed (EC) for 30s. Area of the stabilogram (AOS) and mean velocity of the center of pressure (COP) in anterior-posterior (AP) and medial-lateral (ML) directions were calculated and used to investigate the effects of gymnastics training, age, and visual information. Younger gymnasts presented greater postural control compared to younger nongymnasts while visual information did not improve postural control in younger nongymnasts. Younger gymnasts displayed improved postural control with EO compared to EC. The mean velocity of the COP in the ML direction was: less for younger gymnasts than younger nongymnasts with EO. These results suggest that gymnastics training promotes improvements in postural control of younger children only, which results from their use of visual information when available. PMID:21276829

  4. A Simple Postflight Measure of Postural Atania in Astronauts

    NASA Technical Reports Server (NTRS)

    Reschke, M. F.; Harm, D. I.; Kofman, I. S.; Wood, S. J.; Bloomberg, J. J.

    2011-01-01

    Astronauts returning from space flight universally present with postural ataxia. Throughout the Space Shuttle Program, measurement of ataxia has concentrated on sway in the anterior-posterior (AP) plane. The current investigation, as a part of a larger functional study, concentrated on characterizing postural instability using dynamic stabilographic sway patterns in both the AP and medial-lateral (ML) planes. To accomplish this goal, six astronauts from short-duration (Shuttle) and three from long-duration (ISS) flights were required to recover from a simulated fall. Subjects with eyes open, wearing running shoes lay prone on the floor for 2 minutes and then quickly stood up, maintained a quiet stance for 3 minutes, arms relaxed along the side of the body, and feet comfortably placed on the force plate. Crewmembers were tested twice before flight, on landing day (Shuttle only), and 1, 6, and 30 days after flight. Anterior-posterior and ML center-of-pressure (COP) coordinates were calculated from the ground reaction forces collected at 500 Hz. The 3-minute quiet stance trial was broken into three 1-minute segments for stabilogram diffusion analysis. A mean sway speed (rate of change of COP displacement) was also calculated as an additional postural stability parameter. While there was considerable variation, most of crewmembers tested exhibited increased stochastic activity evidenced by larger short-term COP diffusion coefficients postflight in both the AP and ML planes, suggesting significant changes in postural control mechanisms, particularly control of lower limb muscle function. As expected, postural instability of ISS astronauts on the first day postflight was similar to that of Shuttle crewmembers on landing day. Recoveries of stochastic activity and mean sway speed to baseline levels were typically observed by the 30th day postflight for both long-duration and short-duration crewmembers. Dynamic postural stability characteristics obtained in this low

  5. Postural Tachycardia Syndrome (POTS)

    PubMed Central

    Low, Phillip A.; Sandroni, Paola; Joyner, Michael; Shen, Win-Kuang

    2014-01-01

    Introduction POTS is defined as the development of orthostatic symptoms associated with a heart rate (HR) increment ≥30, usually to ≥120 bpm without orthostatic hypotension. Symptoms of orthostatic intolerance are those due to brain hypoperfusion and those due to sympathetic overaction. Methods We provide a review of POTS based primarily on work from the Mayo Clinic. Results Females predominate over males by 5:1. Mean age of onset in adults is about 30 years and most patients are between the ages of 20–40 years. Pathophysiologic mechanisms (not mutually exclusive) include peripheral denervation, hypovolemia, venous pooling, β-receptor supersensitivity, psychologic mechanisms, and presumed impairment of brain stem regulation. Prolonged deconditioning may also interact with these mechanisms to exacerbate symptoms. The evaluation of POTS requires a focused history and examination, followed by tests that should include HUT, some estimation of volume status and preferably some evaluation of peripheral denervation and hyperadrenergic state. All patients with POTS require a high salt diet, copious fluids, and postural training. Many require β-receptor antagonists in small doses and low-dose vasoconstrictors. Somatic hypervigilance and psychologic factors are involved in a significant proportion of patients. Conclusions POTS is heterogeneous in presentation and mechanisms. Major mechanisms are denervation, hypovolemia, deconditioning, and hyperadrenergic state. Most patients can benefit from a pathophysiologically based regimen of management. PMID:19207771

  6. [What are the effects of the aging of the neuromuscular system on postural stability?].

    PubMed

    Cattagni, Thomas; Scaglioni, Gil; Cornu, Christophe; Berrut, Gilles; Martin, Alain

    2015-12-01

    Aging is frequently associated with a decreased postural stability, essentially after 60 years, leading to an increased risk of falling. In this article we propose to highlight the influence of the aging of the neuromuscular system on postural stability when standing upright. To maintain balance while standing upright, human needs to control the activity of ankle muscles and particularly the plantar flexors. During the aging process, the performance of these muscles are strongly altered. It is commonly observed large deficits in elderly people with history of falls. Some authors reported an inverse correlation between the amplitude of postural sway and the capacity of force production of ankle muscles suggesting that the assessment of neuromuscular function could be an index of postural stability or even of the falling risk. Finally, enhance the strength of ankle muscles in elderly through physical exercise could be an adequate intervention to improve postural stability and reduce the incidence of falls. PMID:26707554

  7. Postural threat influences conscious perception of postural sway.

    PubMed

    Cleworth, Taylor W; Carpenter, Mark G

    2016-05-01

    This study examined how changes in threat influenced conscious perceptions of postural sway. Young healthy adults stood on a forceplate mounted to a hydraulic lift placed at two heights (0.8m and 3.2m). At each height, subjects stood quietly with eyes open and eyes closed for 60s. Subjects were instructed to either stand normal, or stand normal and track their perceived sway in the antero-posterior plane by rotating a hand-held potentiometer. Participants reported an increased level of fear, anxiety, arousal and a decreased level of balance confidence when standing at height. In addition, postural sway amplitude decreased and frequency increased at height. However, there were no effects of height on perceived sway. When standing under conditions of increased postural threat, sway amplitude is reduced, while sway perception appears to remain unchanged. Therefore, when threat is increased, sensory gain may be increased to compensate for postural strategies that reduce sway (i.e. stiffening strategy), thereby ensuring sufficient afferent information is available to maintain, or even increase the conscious perception of postural sway. PMID:27016388

  8. Postural Stability When Leaning from Perceived Upright

    NASA Technical Reports Server (NTRS)

    Vanya, Robert D.; Grounds, John F.; Wood, Scott J.

    2011-01-01

    The transition between quiet stance and gait requires the volitional movement of one?s center of mass (COM) toward a limit of stability (LOS). The goal of this study was to measure the effect of leaning from perceived upright on postural stability when voluntarily maintaining fixed stance positions and during perturbations of the support surface. The COM was derived from force plate data in 12 healthy subjects while standing with feet positioned so that lateral base of support was equal to foot length. For all conditions, arms were folded and subjects were instructed to lean without bending at the hips or lifting their feet. The LOS was determined during maximal voluntary leans with eyes open and closed. The COM was then displayed on a monitor located in front of the subject. Subjects were visually guided to lean toward a target position, maintain this position for 10s, return to upright, and then repeat the same targeted lean maneuver with eyes closed. Targets were randomly presented at 2? in 8 directions and between 2-6? in these same directions according to the asymmetric LOS. Subjects were then verbally guided to lean between 2? back and 4? forward prior to a perturbation of the support surface in either a forward or backward direction. The average LOS was 5.8? forward, 2.9? back, and 4.8? in left/right directions, with no significant difference between eyes open and closed. Center of pressure (COP) velocity increased as subjects maintained fixed stance positions farther from upright, with increased variability during eyes closed conditions. The time to stability and COP path length increased as subjects leaned opposite to the direction of the support surface perturbations. We conclude that postural stability is compromised as subjects lean away from perceived upright, except for perturbations that induce sway in the direction opposite the lean. The asymmetric LOS relative to perceived upright favors postural stability for COM movements in the forward direction.

  9. Postural reorganization induced by torso cutaneous covibration.

    PubMed

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

    2013-05-01

    Cutaneous information from joints has been attributed proprioceptive properties similar to those of muscle spindles. This study aimed to assess whether vibration-induced changes in torso cutaneous information contribute to whole-body postural reorganization in humans. Ten healthy young adults stood in normal and Romberg stances with six vibrating actuators positioned on the torso in contact with the skin over the left and right external oblique, internal oblique, and erector spinae muscle locations at the L4/L5 vertebrae level. Vibrations around the torso were randomly applied at two locations simultaneously (covibration) or at all locations simultaneously. Kinematic analysis of the body segments indicated that covibration applied to the skin over the internal oblique muscles induced shifts of both the head and torso in the anterior direction (torso flexion) while the hips shifted in the posterior direction (ankle plantar flexion). Conversely, covibration applied to the skin over the erector spinae muscle locations produced opposite effects. However, covibration applied to the skin over the left internal oblique and left erector spinae, the right internal oblique and right erector spinae, or at all locations simultaneously did not induce any significant postural changes. In addition, the center of pressure position as measured by the force plate was unaffected by all covibration conditions tested. These results were independent of stance and suggest an integrated and coordinated reorganization of posture in response to vibration-induced changes in cutaneous information. In addition, combinations of vibrotactile stimuli over multiple locations exhibit directional summation properties in contrast to the individual responses we observed in our previous work. PMID:23637178

  10. An Increase in Postural Load Facilitates an Anterior Shift of Processing Resources to Frontal Executive Function in a Postural-Suprapostural Task

    PubMed Central

    Huang, Cheng-Ya; Chang, Gwo-Ching; Tsai, Yi-Ying; Hwang, Ing-Shiou

    2016-01-01

    Increase in postural-demand resources does not necessarily degrade a concurrent motor task, according to the adaptive resource-sharing hypothesis of postural-suprapostural dual-tasking. This study investigated how brain networks are organized to optimize a suprapostural motor task when the postural load increases and shifts postural control into a less automatic process. Fourteen volunteers executed a designated force-matching task from a level surface (a relative automatic process in posture) and from a stabilometer board while maintaining balance at a target angle (a relatively controlled process in posture). Task performance of the postural and suprapostural tasks, synchronization likelihood (SL) of scalp EEG, and graph-theoretical metrics were assessed. Behavioral results showed that the accuracy and reaction time of force-matching from a stabilometer board were not affected, despite a significant increase in postural sway. However, force-matching in the stabilometer condition showed greater local and global efficiencies of the brain networks than force-matching in the level-surface condition. Force-matching from a stabilometer board was also associated with greater frontal cluster coefficients, greater mean SL of the frontal and sensorimotor areas, and smaller mean SL of the parietal-occipital cortex than force-matching from a level surface. The contrast of supra-threshold links in the upper alpha and beta bands between the two stance conditions validated load-induced facilitation of inter-regional connections between the frontal and sensorimotor areas, but that contrast also indicated connection suppression between the right frontal-temporal and the parietal-occipital areas for the stabilometer stance condition. In conclusion, an increase in stance difficulty alters the neurocognitive processes in executing a postural-suprapostural task. Suprapostural performance is not degraded by increase in postural load, due to (1) increased effectiveness of information

  11. An Increase in Postural Load Facilitates an Anterior Shift of Processing Resources to Frontal Executive Function in a Postural-Suprapostural Task.

    PubMed

    Huang, Cheng-Ya; Chang, Gwo-Ching; Tsai, Yi-Ying; Hwang, Ing-Shiou

    2016-01-01

    Increase in postural-demand resources does not necessarily degrade a concurrent motor task, according to the adaptive resource-sharing hypothesis of postural-suprapostural dual-tasking. This study investigated how brain networks are organized to optimize a suprapostural motor task when the postural load increases and shifts postural control into a less automatic process. Fourteen volunteers executed a designated force-matching task from a level surface (a relative automatic process in posture) and from a stabilometer board while maintaining balance at a target angle (a relatively controlled process in posture). Task performance of the postural and suprapostural tasks, synchronization likelihood (SL) of scalp EEG, and graph-theoretical metrics were assessed. Behavioral results showed that the accuracy and reaction time of force-matching from a stabilometer board were not affected, despite a significant increase in postural sway. However, force-matching in the stabilometer condition showed greater local and global efficiencies of the brain networks than force-matching in the level-surface condition. Force-matching from a stabilometer board was also associated with greater frontal cluster coefficients, greater mean SL of the frontal and sensorimotor areas, and smaller mean SL of the parietal-occipital cortex than force-matching from a level surface. The contrast of supra-threshold links in the upper alpha and beta bands between the two stance conditions validated load-induced facilitation of inter-regional connections between the frontal and sensorimotor areas, but that contrast also indicated connection suppression between the right frontal-temporal and the parietal-occipital areas for the stabilometer stance condition. In conclusion, an increase in stance difficulty alters the neurocognitive processes in executing a postural-suprapostural task. Suprapostural performance is not degraded by increase in postural load, due to (1) increased effectiveness of information

  12. Objective Clinical Assessment of Posture Patterns after Implant Breast Augmentation

    PubMed Central

    Mandrini, Silvia; Finotti, Valentina; Dall’Angelo, Anna; Malovini, Alberto; Chierico, Simona; Faga, Angela; Dalla Toffola, Elena

    2015-01-01

    Background: An increased weight of the breasts causes several spinal postural alterations that reduce the ability to perform dynamic tasks requiring a stable balance. The effects of the increased weight of the breasts on static posture after implant breast augmentation have not been investigated yet. Methods: Forty volunteer healthy women were asked to wear different sized breast implants (800, 400, and 300 g) inside a dedicated sports bra for 6½ consecutive hours during their everyday life activities, 1 day for every implant size. Posture changes were assessed with the association of a physiatric clinical examination with a static force platform analysis. Results: A significant increase in cervical lordosis after the use of 400-g breast implants and upward was demonstrated. This alteration was stable between the 400-g and 800-g breast implants. The 400-g (per breast) implant might therefore be the load threshold that breaks the cervical postural physiologic balance. A significant increase in lumbar lordosis was demonstrated only after the use of the 800-g breast implants. The static force platform assessment demonstrated a worsening of the balance independent from the visual control with the use of 400-g and 800-g implants. Conclusions: Heavy breast implants proved to induce reversible alterations in the spinal curve, and 400 g is the cutoff for functional physiologic compensation in the short term. Such a weight might be considered the safety limit for the use of breast implants for cosmetic purposes. PMID:26218390

  13. The Relationship Between Postural Control and Self-Reported Engagement in Physical Activity in Young and Older Age.

    PubMed

    Wojciechowska-Maszkowska, Bozena; Borzucka, Dorota; Rogowska, Aleksandra Maria; Kuczynski, Michal

    2016-04-01

    Physical activity is known to have beneficial effects on a host of factors related to physical and mental health, and positively affects postural control. However, there is no agreement on which measures of postural control and to what extent they are dependent on the past and present physical activity in older adults. To answer this question we compared the postural performance in a 20-s quiet stance with eyes open on a Kistler force plate in 38 subjects, aged 60-92, who were formerly and are currently physically active (AA) with those who were always inactive (II) and those who were either formerly (AI) or are currently (IA) active. Results indicated that only current activity promoted better postural control while former activity was ineffective. Postural control in AA and IA was very similar and much better than in II and AI who, in contrast, displayed similarly deteriorated postural control. PMID:26252835

  14. Added cognitive load through rotary auditory stimulation can improve the quality of postural control in the elderly.

    PubMed

    Deviterne, Dominique; Gauchard, Gérome C; Jamet, Mallaury; Vançon, Guy; Perrin, Philippe P

    2005-01-30

    This study examined the effect of rotary auditory stimulation on postural control in the elderly. Thirty-two subjects aged over sixty were submitted to two rotary auditory stimulations, with a meaningful and a non-meaningful message, during a postural task. Although the non-meaningful task did not lead to postural control modification, the meaningful task allowed a reduction in the postural parameter values and therefore, a better stabilisation of posture. The attention, paid to the geography of the sound in understanding the story being told, forced the subject into taking into consideration the regularity and rotation of the stimulation, which meant relying on an auditory anchorage and so facilitated posture regulation. PMID:15639544

  15. The Impact of Posture on the Mechanical Properties of a Functional Spinal Unit During Cyclic Compressive Loading.

    PubMed

    Barrett, Jeff M; Gooyers, Chad E; Karakolis, Thomas; Callaghan, Jack P

    2016-08-01

    To assess how posture affects the transmission of mechanical energy up the spinal column during vibration, 18 porcine functional spinal units (FSUs) were exposed to a sinusoidal force (1500 ± 1200 N) at 5 Hz for 120 min in either a flexed, extended, or neutral posture. Force and FSU height were measured continuously throughout the collection. From these data, specimen height loss, dynamic stiffness, hysteresis, and parameters from a standard linear solid (SLS) model were determined and analyzed for differences between postures. Posture had an influence on all of these parameters. In extension, the FSU had higher dynamic stiffness values than when neutral or flexed (p < 0.0001). In flexion, the FSU had higher hysteresis than both an extended or neutral posture (p < 0.0001). Height loss was greatest in a flexed posture and smallest in an extended posture (p < 0.0001). In extension, the series spring element in the SLS model had a stiffness value higher than both flexed and neutral posture conditions, whereas the stiffness in the parallel spring was the same between extension and neutral (p < 0.01), both higher than in flexion. Viscosity coefficients were highest in extension compared to both flexed and neutral (p < 0.01). Based on these results, it was determined that posture had a significant influence in determining the mechanical properties of the spine when exposed to cyclic compressive loading. PMID:27322199

  16. 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

  17. 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. PMID

  18. Automatic and Interactive Key Posture Design by Combing the PIK with Parametric Posture Splicing

    NASA Astrophysics Data System (ADS)

    Li, Shilei; Wu, Bing; Liang, Jiahong; Su, Jiongming

    Key posture design is commonly needed in computer animation. This paper presents an automatic and interactive whole body posture designing technique by combining the PIK (prioritized inverse kinematics) with the proposed parametric human posture splicing technique. The key feature of PIK is that the user can design a posture by adding high level constraints with different priorities. However, the PIK is essentially a numerical IK algorithm which relies on the iterative optimization starting from a good enough initial posture to get the final result. To speed up the running efficiency and ensure the lifelikeness of the final posture, the parametric posture splicing technique is proposed to generate the initial guess of the PIK. According to the set of the high level constraints, the whole body is divided into some partial parts, whose postures are then generated by the parametric posture synthesis from a single posture database. Then an initial posture guess with some main characteristics of the finally acceptable posture can be generated approximately by splicing these partial body postures together. Starting from this initial guess and with all constraints considered at different priority levels, the PIK can be initialized with a bias defined by this particularly initial guess and iterated step by step to get a final posture. The total process of the whole body posture generation is automatic and interactive. The experimental results show that this combination method can not only improve the computation efficiency of the PIK but also can simultaneously ensure the naturalness of the final posture.

  19. Decreased variability in postural control strategies in young people with non-specific low back pain is associated with altered proprioceptive reweighting.

    PubMed

    Claeys, Kurt; Brumagne, Simon; Dankaerts, Wim; Kiers, Henri; Janssens, Lotte

    2011-01-01

    Optimal postural control is an essential capacity in daily life and can be highly variable. The purpose of this study was to investigate if young people have the ability to choose the optimal postural control strategy according to the postural condition and to investigate if non-specific low back pain (NSLBP) influences the variability in proprioceptive postural control strategies. Young individuals with NSLBP (n = 106) and healthy controls (n = 50) were tested on a force plate in different postural conditions (i.e., sitting, stable support standing and unstable support standing). The role of proprioception in postural control was directly examined by means of muscle vibration on triceps surae and lumbar multifidus muscles. Root mean square and mean displacements of the center of pressure were recorded during the different trials. To appraise the proprioceptive postural control strategy, the relative proprioceptive weighting (RPW, ratio of ankle muscles proprioceptive inputs vs. back muscles proprioceptive inputs) was calculated. Postural robustness was significantly less in individuals with NSLBP during the more complex postural conditions (p < 0.05). Significantly higher RPW values were observed in the NSLBP group in all postural conditions (p < 0.05), suggesting less ability to rely on back muscle proprioceptive inputs for postural control. Therefore, healthy controls seem to have the ability to choose a more optimal postural control strategy according to the postural condition. In contrast, young people with NSLBP showed a reduced capacity to switch to a more multi-segmental postural control strategy during complex postural conditions, which leads to decreased postural robustness. PMID:20824281

  20. 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…

  1. The interplay between speed, kinetics, and hand postures during primate terrestrial locomotion.

    PubMed

    Patel, Biren A

    2010-02-01

    Nonprimate terrestrial mammals may use digitigrade postures to help moderate distal limb joint moments and metapodial stresses that may arise during high-speed locomotion with high-ground reaction forces (GRF). This study evaluates the relationships between speed, GRFs, and distal forelimb kinematics in order to evaluate if primates also adopt digitigrade hand postures during terrestrial locomotion for these same reasons. Three cercopithecine monkey species (Papio anubis, Macaca mulatta, Erythrocebus patas) were videotaped moving unrestrained along a horizontal runway instrumented with a force platform. Three-dimensional forelimb kinematics and GRFs were measured when the vertical force component reached its peak. Hand posture was measured as the angle between the metacarpal segment and the ground (MGA). As predicted, digitigrade hand postures (larger MGA) are associated with shorter GRF moment arms and lower wrist joint moments. Contrary to expectations, individuals used more palmigrade-like (i.e. less digitigrade) hand postures (smaller MGA) when the forelimb was subjected to higher forces (at faster speeds) resulting in potentially larger wrist joint moments. Accordingly, these primates may not use their ability to alter their hand postures to reduce rising joint moments at faster speeds. Digitigrady at slow speeds may improve the mechanical advantage of antigravity muscles crossing the wrist joint. At faster speeds, greater palmigrady is likely caused by joint collapse, but this posture may be suited to distribute higher GRFs over a larger surface area to lower stresses throughout the hand. Thus, a digitigrade hand posture is not a cursorial (i.e. high speed) adaptation in primates and differs from that of other mammals. PMID:19639641

  2. Postural Performance and Strategy in the Unipedal Stance of Soccer Players at Different Levels of Competition

    PubMed Central

    Paillard, Thierry; Noé, Frédéric; Rivière, Terence; Marion, Vincent; Montoya, Richard; Dupui, Philippe

    2006-01-01

    Context: Sport training enhances the ability to use somatosensory and otolithic information, which improves postural capabilities. Postural changes are different according to the sport practiced, but few authors have analyzed subjects' postural performances to discriminate the expertise level among highly skilled athletes within a specific discipline. Objective: To compare the postural performance and the postural strategy between soccer players at different levels of competition (national and regional). Design: Repeated measures with 1 between-groups factor (level of competition: national or regional) and 1 within-groups factor (vision: eyes open or eyes closed). Dependent variables were center-of-pressure surface area and velocity; total spectral energy; and percentage of low-, medium-, and high-frequency band. Setting: Sports performance laboratory. Patients or Other Participants: Fifteen national male soccer players (age = 24 ± 3 years, height = 179 ± 5 cm, mass = 72 ± 3 kg) and 15 regional male soccer players (age = 23 ± 3 years, height = 174 ± 4 cm, mass = 68 ± 5 kg) participated in the study. Intervention(s): The subjects performed posturographic tests with eyes open and closed. Main Outcome Measure(s): While subjects performed static and dynamic posturographic tests, we measured the center of foot pressure on a force platform. Spatiotemporal center-of-pressure measurements were used to evaluate the postural performance, and a frequency analysis of the center-of-pressure excursions (fast Fourier transform) was conducted to estimate the postural strategy. Results: Within a laboratory task, national soccer players produced better postural performances than regional players and had a different postural strategy. The national players were more stable than the regional players and used proprioception and vision information differently. Conclusions: In the test conditions specific to playing soccer, level of playing experience influenced postural control

  3. 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. PMID:26967958

  4. The effect of smartphone usage time on posture and respiratory function

    PubMed Central

    Jung, Sang In; Lee, Na Kyung; Kang, Kyung Woo; Kim, Kyoung; Lee, Do Youn

    2016-01-01

    [Purpose] The aim of this study was to evaluate the changes in posture and respiratory functions depending on the duration of smartphone usage. [Subjects and Methods] Participants were randomly allocated to 2 groups: group 1 (subjects who used smartphones for <4 hours/day, n=25) and group 2 (subjects who used smartphones for >4 hours/day, n=25). The craniovertebral angles of all participants were measured and scapular indices were calculated to assess the change in posture and forced vital capacity, forced expiratory volume in 1 second, the ratio of forced expiratory volume in 1 second to forced vital capacity, and peak expiratory flow were measured to assess changes in respiratory function. [Results] There were significant differences in the craniovertebral angle, scapular index, and peak expiratory flow depending on the duration of smartphone usage. [Conclusion] The result of this study showed that prolonged use of smartphones could negatively affect both, posture and respiratory function. PMID:26957754

  5. INFLUENCE OF INJURY ON DYNAMIC POSTURAL CONTROL IN RUNNERS

    PubMed Central

    Klusendorf, Anna; Kernozek, Thomas

    2016-01-01

    ABSTRACT Background Injury has been linked with altered postural control in active populations. The association between running injury and dynamic postural control has not been examined. Hypothesis/Purpose The purpose of this study was to examine dynamic postural control in injured and uninjured runners using the Star Excursion Balance Test (SEBT), Time to Stabilization (TTS) of ground reaction forces following a single-leg landing, and postural stability indices reflecting the fluctuations in GRFs during single-leg landing and stabilization tasks (forward and lateral hop). It was hypothesized that dynamic postural control differences would exist between runners with a history of injury that interrupted training for ≥7 days (INJ) when compared to runners without injury (CON). Design Case-control study Methods Twenty-two INJ (14 F, 8 M; 23.7 ± 2.1 y; 22.3 ± 2.8 kg/m2; 29.5 ± 16.3 mi/wk) currently running > 50% pre-injury mileage without pain were compared with twenty-two matched CON (14F, 8M; 22.7 ± 1.2 y; 22.7 ± 2.7 kg/m2; 31.2 ± 19.6 mi/wk). INJ group was stratified by site of injury into two groups (Hip/Thigh/Knee and Lower Leg/Ankle/Foot) for secondary analysis. Leg length-normalized anterior, posterolateral, and posteromedial reach distances on the SEBT, medial/lateral and anterior/posterior ground reaction force TTS, directional postural stability indices, and a composite dynamic postural stability index (DPSI), were assessed using mixed model ANOVA (α=0.05) and effect sizes (d). Results No group X direction interaction or group differences were observed for the SEBT (p=0.51, 0.71) or TTS (p=0.83, 0.72) measures. A group X direction interaction was found for postural stability indices during the forward landing task (p<0.01). Both Hip/Thigh/Knee and Lower leg/Ankle/Foot INJ groups demonstrated a greater vertical postural stability index (VPSI) (p=0.01 for both, d=0.80, 0.95) and DPSI (p=0.01, 0.02, d=0.75, 0.93) when

  6. 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

  7. Closed loop kinesthetic feedback for postural control rehabilitation.

    PubMed

    Vérité, Fabien; Bachta, Wael; Morel, Guillaume

    2014-01-01

    Postural control rehabilitation may benefit from the use of smart devices providing biofeedback. This approach consists of increasing the patients perception of their postural state. Namely, postural state is monitored and fed back in real time to the patients through one or more sensory channels. This allows implementing rehabilitation exercises where the patients control their posture with the help of additional sensory inputs. In this paper, a closed loop control of the Center-Of-Pressure (CoP) based on kinesthetic feedback is proposed as a new form of biofeedback. The motion of a one Degree of Freedom (DoF) translational device, lightly touched by the patient's forefinger, is servoed to the patient's CoP position extracted from the measurements of a force plate on which he/she stands. As a result, the patient's CoP can be controllably displaced. A first set of experiments is used to prove the feasibility of this closed-loop control under ideal conditions favoring the perception of the kinesthetic feedback, while the subject is totally unaware of the context. A second set of experiments is then proposed to evaluate the robustness of this approach under experimental conditions that are more realistic with regards to the clinical context of a rehabilitation program involving biofeedback-based exercises. PMID:24968379

  8. Craniomandibular System and Postural Balance after 3-Day Dry Immersion

    PubMed Central

    Treffel, Loïc; Dmitrieva, Liubov; Gauquelin-Koch, Guillemette; Custaud, Marc-Antoine; Blanc, Stéphane; Gharib, Claude; Millet, Catherine

    2016-01-01

    The objective of the study was to determine the influence of simulated microgravity by exposure to dry immersion on the craniomandibular system. Twelve healthy male volunteers participated in a 3-day dry immersion study. Before and immediately after exposure we measured maximal bite force using piezoresistive sensors. The mechanical properties of the jaw and cervical muscles were evaluated before, during, and after dry immersion using MyotonPRO. Because recent studies reported the effects of jaw motor activity on the postural stability of humans, stabilometric measurements of center of pressure were performed before and after dry immersion in two mandibular positions: rest position without jaw clenching, and intercuspidal position during voluntary teeth clenching. Results revealed no significant changes of maximal bite force after dry immersion. All postural parameters were significantly altered by dry immersion. There were however no significant differences in stabilometric data according to mandibular position. Moreover the masseter tonicity increased immediately after the end of dry immersion period. Dry immersion could be used as a valid model for studying the effects of microgravity on human subjects. However, 3 days appear insufficient in duration to evaluate the effects of weightlessness on maximal bite force. Our research suggests a link between postural disturbance after dry immersion and masseter tonicity. PMID:26913867

  9. Craniomandibular System and Postural Balance after 3-Day Dry Immersion.

    PubMed

    Treffel, Loïc; Dmitrieva, Liubov; Gauquelin-Koch, Guillemette; Custaud, Marc-Antoine; Blanc, Stéphane; Gharib, Claude; Millet, Catherine

    2016-01-01

    The objective of the study was to determine the influence of simulated microgravity by exposure to dry immersion on the craniomandibular system. Twelve healthy male volunteers participated in a 3-day dry immersion study. Before and immediately after exposure we measured maximal bite force using piezoresistive sensors. The mechanical properties of the jaw and cervical muscles were evaluated before, during, and after dry immersion using MyotonPRO. Because recent studies reported the effects of jaw motor activity on the postural stability of humans, stabilometric measurements of center of pressure were performed before and after dry immersion in two mandibular positions: rest position without jaw clenching, and intercuspidal position during voluntary teeth clenching. Results revealed no significant changes of maximal bite force after dry immersion. All postural parameters were significantly altered by dry immersion. There were however no significant differences in stabilometric data according to mandibular position. Moreover the masseter tonicity increased immediately after the end of dry immersion period. Dry immersion could be used as a valid model for studying the effects of microgravity on human subjects. However, 3 days appear insufficient in duration to evaluate the effects of weightlessness on maximal bite force. Our research suggests a link between postural disturbance after dry immersion and masseter tonicity. PMID:26913867

  10. 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

  11. 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.

  12. Improvement of anticipatory postural adjustments for balance control: effect of a single training session

    PubMed Central

    Kanekar, Neeta; Aruin, Alexander S.

    2014-01-01

    Humans use anticipatory and compensatory postural strategies to maintain and restore balance when perturbed. Inefficient generation and utilization of anticipatory postural adjustments (APAs) is one of the reasons for postural instability. The aim of the study was to investigate the role of training in improvement of APAs and its effect on subsequent control of posture. Thirteen healthy young adults were exposed to predictable external perturbations before and after a single training session consisting of catches of a medicine ball thrown at the shoulder level. 3-D body kinematics, EMG activity of thirteen trunk and leg muscles, and ground reaction forces were recorded before and immediately after a single training session. Muscle onsets, EMG integrals, center of pressure (COP), and center of mass (COM) displacements were analyzed during the anticipatory and compensatory phases of postural control. The effect of a single training session was seen as significantly early muscle onsets and larger anticipatory COP displacements. As a result, significantly smaller peak COM displacements were observed after the perturbation indicating greater postural stability. The outcome of this study provides a background for examining the role of training in improvement of APAs and its effect on postural stability in individuals in need. PMID:25434280

  13. 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. PMID:26234473

  14. Does Observation of Postural Imbalance Induce a Postural Reaction?

    PubMed Central

    Tia, Banty; Saimpont, Arnaud; Paizis, Christos; Mourey, France; Fadiga, Luciano; Pozzo, Thierry

    2011-01-01

    Background Several studies bring evidence that action observation elicits contagious responses during social interactions. However automatic imitative tendencies are generally inhibited and it remains unclear in which conditions mere action observation triggers motor behaviours. In this study, we addressed the question of contagious postural responses when observing human imbalance. Methodology/Principal Findings We recorded participants' body sway while they observed a fixation cross (control condition), an upright point-light display of a gymnast balancing on a rope, and the same point-light display presented upside down. Our results showed that, when the upright stimulus was displayed prior to the inverted one, centre of pressure area and antero-posterior path length were significantly greater in the upright condition compared to the control and upside down conditions. Conclusions/Significance These results demonstrate a contagious postural reaction suggesting a partial inefficiency of inhibitory processes. Further, kinematic information was sufficient to trigger this reaction. The difference recorded between the upright and upside down conditions indicates that the contagion effect was dependent on the integration of gravity constraints by body kinematics. Interestingly, the postural response was sensitive to habituation, and seemed to disappear when the observer was previously shown an inverted display. The motor contagion recorded here is consistent with previous work showing vegetative output during observation of an effortful movement and could indicate that lower level control facilitates contagion effects. PMID:21423622

  15. Deficits in Lower Limb Muscle Reflex Contraction Latency and Peak Force Are Associated With Impairments in Postural Control and Gross Motor Skills of Children With Developmental Coordination Disorder: A Cross-Sectional Study.

    PubMed

    Fong, Shirley S M; Ng, Shamay S M; Guo, X; Wang, Yuling; Chung, Raymond C K; Stat, Grad; Ki, W Y; Macfarlane, Duncan J

    2015-10-01

    This cross-sectional, exploratory study aimed to compare neuromuscular performance, balance and motor skills proficiencies of typically developing children and those with developmental coordination disorder (DCD) and to determine associations of these neuromuscular factors with balance and motor skills performances in children with DCD.One hundred thirty children with DCD and 117 typically developing children participated in the study. Medial hamstring and gastrocnemius muscle activation onset latencies in response to an unexpected posterior-to-anterior trunk perturbation were assessed by electromyography and accelerometer. Hamstring and gastrocnemius muscle peak force and time to peak force were quantified by dynamometer, and balance and motor skills performances were evaluated with the Movement Assessment Battery for Children (MABC).Independent t tests revealed that children with DCD had longer hamstring and gastrocnemius muscle activation onset latencies (P < 0.001) and lower isometric peak forces (P < 0.001), but not times to peak forces (P > 0.025), than the controls. Multiple regression analysis accounting for basic demographics showed that gastrocnemius peak force was independently associated with the MABC balance subscore and ball skills subscore, accounting for 5.7% (P = 0.003) and 8.5% (P = 0.001) of the variance, respectively. Gastrocnemius muscle activation onset latency also explained 11.4% (P < 0.001) of the variance in the MABC ball skills subscore.Children with DCD had delayed leg muscle activation onset times and lower isometric peak forces. Gastrocnemius peak force was associated with balance and ball skills performances, whereas timing of gastrocnemius muscle activation was a determinant of ball skill performance in the DCD population. PMID:26469921

  16. The visual control of stability in children and adults: postural readjustments in a ground optical flow.

    PubMed

    Baumberger, Bernard; Isableu, Brice; Flückiger, Michelangelo

    2004-11-01

    The aim of this research was to analyse the development of postural reactions to approaching (AOF) and receding (ROF) ground rectilinear optical flows. Optical flows were shaped by a pattern of circular spots of light projected on the ground surface by a texture flow generator. The geometrical structure of the projected scenes corresponded to the spatial organisation of visual flows encountered in open outdoor settings. Postural readjustments of 56 children, ranging from 7 to 11 years old, and 12 adults were recorded by the changes of the centre of foot pressure (CoP) on a force platform during 44-s exposures to the moving texture. Before and after the optical flows exposure, a 24-s motionless texture served as a reference condition. Effect of ground rectilinear optical flows on postural control development was assessed by analysing sway latencies (SL), stability performances and postural orientation. The main results that emerge from this experiment show that postural responses are directionally specific to optical flow pattern and that they vary as a function of the motion onset and offset. Results showed that greater developmental changes in postural control occurred in an AOF (both at the onset and offset of the optical flow) than in an ROF. Onset of an approaching flow induced postural instability, canonical shifts in postural orientation and long latencies in children which were stronger than in the receding flow. This pattern of responses evolved with age towards an improvement in stability performances and shorter SL. The backward decreasing shift of the CoP in children evolved in adults towards forward postural tilt, i.show $132#e. in the opposite direction of the texture's motion. Offset of an AOF motion induced very short SL in children (which became longer in adult subjects), strong postural instability, but weaker shift of orientation compared to the receding one. Postural stability improved and orientation shift evolved to forward inclinations with

  17. Suboptimal Muscle Synergy Activation Patterns Generalize their Motor Function across Postures

    PubMed Central

    Sohn, M. Hongchul; Ting, Lena H.

    2016-01-01

    We used a musculoskeletal model to investigate the possible biomechanical and neural bases of using consistent muscle synergy patterns to produce functional motor outputs across different biomechanical conditions, which we define as generalizability. Experimental studies in cats demonstrate that the same muscle synergies are used during reactive postural responses at widely varying configurations, producing similarly-oriented endpoint force vectors with respect to the limb axis. However, whether generalizability across postures arises due to similar biomechanical properties or to neural selection of a particular muscle activation pattern has not been explicitly tested. Here, we used a detailed cat hindlimb model to explore the set of feasible muscle activation patterns that produce experimental synergy force vectors at a target posture, and tested their generalizability by applying them to different test postures. We used three methods to select candidate muscle activation patterns: (1) randomly-selected feasible muscle activation patterns, (2) optimal muscle activation patterns minimizing muscle effort at a given posture, and (3) generalizable muscle activation patterns that explicitly minimized deviations from experimentally-identified synergy force vectors across all postures. Generalizability was measured by the deviation between the simulated force direction of the candidate muscle activation pattern and the experimental synergy force vectors at the test postures. Force angle deviations were the greatest for the randomly selected feasible muscle activation patterns (e.g., >100°), intermediate for effort-wise optimal muscle activation patterns (e.g., ~20°), and smallest for generalizable muscle activation patterns (e.g., <5°). Generalizable muscle activation patterns were suboptimal in terms of effort, often exceeding 50% of the maximum possible effort (cf. ~5% in minimum-effort muscle activation patterns). The feasible muscle activation ranges of individual

  18. Predictive discomfort of non-neutral head-neck postures in fore-aft whole-body vibration.

    PubMed

    Rahmatalla, Salam; Deshaw, Jonathan

    2011-03-01

    It seems obvious that human head-neck posture in whole-body vibration (WBV) contributes to discomfort and injury risk. While current mechanical measures such as transmissibility have shown good correlation with the subjective-reported discomfort, they showed difficulties in predicting discomfort for non-neutral postures. A new biomechanically based methodology is introduced in this work to predict discomfort due to non-neutral head-neck postures. Altogether, 10 seated subjects with four head-neck postures--neutral, head-up, head-down and head-to-side--were subjected to WBV in the fore-aft direction using discrete sinusoidal frequencies of 2, 3, 4, 5, 6, 7 and 8 Hz and their subjective responses were recorded using the Borg CR-10 scale. All vibrations were run at constant acceleration of 0.8 m/s² and 1.15 m/s². The results have shown that the subjective-reported discomfort increases with head-down and decreases with head-up and head-to-side postures. The proposed predictive discomfort has closely followed the reported discomfort measures for all postures and rides under investigation. STATEMENT OF RELEVANCE: Many occupational studies have shown strong relevance between non-neutral postures, discomfort and injury risk in WBV. With advances in computer human modelling, the proposed predictive discomfort may provide efficient ways for developing reliable biodynamic models. It may also be used to assess discomfort and modify designs inside moving vehicles. PMID:21390956

  19. Anticipatory postural adjustments during standing in below-the-knee amputees.

    PubMed

    Aruin, A S; Nicholas, J J; Latash, M L

    1997-01-01

    OBJECTIVE: We studied the role of adaptive changes within the central nervous system in anticipatory postural adjustments seen in unilateral below-the-knee amputees. DESIGN: Changes in electromyographic and mechanical variables were compared during standardized tasks performed by standing subjects. BACKGROUND: Anticipatory postural adjustments represent an important mechanism of postural control which was expected to be changed in amputees because of both mechanical and secondary, neurological reasons. METHODS: Six patients after a below-the-knee amputation and six control subjects stood on a force platform and performed fast bilateral shoulder movements and also dropped or caught a load from (into) extended hands. Anticipatory changes in the background activity of postural muscles were analysed. RESULTS: In amputees, there were cases of marked asymmetry in anticipatory changes of the background muscle activity which were larger on the intact side of the body but were commonly small or absent on the side of the amputation. This asymmetry could lead to larger mediolateral forces and displacements of the centre of pressure. CONCLUSIONS: We suggest that asymmetrical patterns of anticipatory postural adjustments reflect central adaptive changes secondary to the amputation. Rehabilitation approaches would benefit from understanding and taking advantage of the adaptive changes within the central nervous system. RELEVANCE: We demonstrated asymmetries in patterns of anticipatory postural adjustments during voluntary arm movements and load manipulations by standing unilateral amputees. This finding is of potential importance for rehabilitation of amputees and their prosthetic training. PMID:11415672

  20. Haptic cues for orientation and postural control in sighted and blind individuals

    NASA Technical Reports Server (NTRS)

    Jeka, J. J.; Easton, R. D.; Bentzen, B. L.; Lackner, J. R.

    1996-01-01

    Haptic cues from fingertip contact with a stable surface attenuate body sway in subjects even when the contact forces are too small to provide physical support of the body. We investigated how haptic cues derived from contact of a cane with a stationary surface at low force levels aids postural control in sighted and congenitally blind individuals. Five sighted (eyes closed) and five congenitally blind subjects maintained a tandem Romberg stance in five conditions: (1) no cane; (2,3) touch contact (< 2 N of applied force) while holding the cane in a vertical or slanted orientation; and (4,5) force contact (as much force as desired) in the vertical and slanted orientations. Touch contact of a cane at force levels below those necessary to provide significant physical stabilization was as effective as force contact in reducing postural sway in all subjects, compared to the no-cane condition. A slanted cane was far more effective in reducing postural sway than was a perpendicular cane. Cane use also decreased head displacement of sighted subjects far more than that of blind subjects. These results suggest that head movement control is linked to postural control through gaze stabilization reflexes in sighted subjects; such reflexes are absent in congenitally blind individuals and may account for their higher levels of head displacement.

  1. Postural stability of older female Scottish country dancers in comparison with physically active controls.

    PubMed

    Dewhurst, Susan; Peacock, Leslie; Bampouras, Theodoros M

    2015-01-01

    Physical activity assists older individuals' functional ability and postural stability. Recently, Scottish country dance (SCD) was reported as being a beneficial form of physical activity for functional ability in older females. This study aims to examine the effect of SCD on postural stability. Scottish country dancers (n = 20) were compared with physically active controls (n = 33) for static postural sway measured on a force platform. The Romberg and Tandem stances were used under 'eyes open' and 'eyes closed' conditions. Ninety-five percent ellipse area and sway velocity were calculated from the center of pressure displacement. Ninety-five percent ellipse area was the same for both groups in all tests. The control group had greater sway velocity for all tests (P < .01) except Tandem eyes closed. SCD participation resulted in similar postural sway as participation in other physical activities, however nondancers may need a greater amount of regulatory activity to maintain balance. PMID:24515979

  2. 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…

  3. Effects of aging and tactile stochastic resonance on postural performance and postural control in a sensory conflict task.

    PubMed

    Dettmer, Marius; Pourmoghaddam, Amir; Lee, Beom-Chan; Layne, Charles S

    2015-01-01

    Postural control in certain situations depends on functioning of tactile or proprioceptive receptors and their respective dynamic integration. Loss of sensory functioning can lead to increased risk of falls in challenging postural tasks, especially in older adults. Stochastic resonance, a concept describing better function of systems with addition of optimal levels of noise, has shown to be beneficial for balance performance in certain populations and simple postural tasks. In this study, we tested the effects of aging and a tactile stochastic resonance stimulus (TSRS) on balance of adults in a sensory conflict task. Nineteen older (71-84 years of age) and younger participants (22-29 years of age) stood on a force plate for repeated trials of 20 s duration, while foot sole stimulation was either turned on or off, and the visual surrounding was sway-referenced. Balance performance was evaluated by computing an Equilibrium Score (ES) and anterior-posterior sway path length (APPlength). For postural control evaluation, strategy scores and approximate entropy (ApEn) were computed. Repeated-measures ANOVA, Wilcoxon signed-rank tests, and Mann-Whitney U-tests were conducted for statistical analysis. Our results showed that balance performance differed between older and younger adults as indicated by ES (p = 0.01) and APPlength (0.01), and addition of vibration only improved performance in the older group significantly (p = 0.012). Strategy scores differed between both age groups, whereas vibration only affected the older group (p = 0.025). Our results indicate that aging affects specific postural outcomes and that TSRS is beneficial for older adults in a visual sensory conflict task, but more research is needed to investigate the effectiveness in individuals with more severe balance problems, for example, due to neuropathy. PMID:25884289

  4. Does body posture influence hand preference in an ancestral primate model?

    PubMed Central

    2011-01-01

    Background The origin of human handedness and its evolution in primates is presently under debate. Current hypotheses suggest that body posture (postural origin hypothesis and bipedalism hypothesis) have an important impact on the evolution of handedness in primates. To gain insight into the origin of manual lateralization in primates, we studied gray mouse lemurs, suggested to represent the most ancestral primate condition. First, we investigated hand preference in a simple food grasping task to explore the importance of hand usage in a natural foraging situation. Second, we explored the influence of body posture by applying a forced food grasping task with varying postural demands (sit, biped, cling, triped). Results The tested mouse lemur population did not prefer to use their hands alone to grasp for food items. Instead, they preferred to pick them up using a mouth-hand combination or the mouth alone. If mouth usage was inhibited, they showed an individual but no population level handedness for all four postural forced food grasping tasks. Additionally, we found no influence of body posture on hand preference in gray mouse lemurs. Conclusion Our results do not support the current theories of primate handedness. Rather, they propose that ecological adaptation indicated by postural habit and body size of a given species has an important impact on hand preference in primates. Our findings suggest that small-bodied, quadrupedal primates, adapted to the fine branch niche of dense forests, prefer mouth retrieval of food and are less manually lateralized than large-bodied species which consume food in a more upright, and less stable body posture. PMID:21356048

  5. Is there an association between variables of postural control and strength in prepubertal children?

    PubMed

    Granacher, Urs; Gollhofer, Albert

    2012-01-01

    The risk of sustaining falls and sports-related injuries is particularly high in children. Deficits in balance and muscle strength represent 2 important intrinsic fall and 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 in prepubertal children. Thirty children participated in this study (age 6.7 ± 0.5 years; body mass index 16.0 ± 1.8 kg·m(-2)). Biomechanic tests included the measurements of maximal isometric torque and rate of force development (RFD) of the plantar flexors on an isokinetic device, jumping power and height (countermovement jump [CMJ]) on a force plate, and the assessment of static and dynamic posture during bipedal stance on a balance platform. The significance level was set at p < 0.05. No significant associations were observed between variables of static and dynamic postural control. Significant positive correlations were detected between the RFD of the plantar flexors and CMJ height (r = 0.425, p < 0.01). No statistically significant associations were found between measures of postural control and muscle strength. The nonsignificant correlations between static and dynamic postural control and muscle strength imply that primarily dynamic measures of postural control should be incorporated in fall and injury-risk assessment and that postural control and muscle strength appear to be independent of each other and may have to be trained in a complementary manner for fall and injury-preventive purposes. PMID:22201695

  6. Articulatory constraints on interpersonal postural coordination.

    PubMed

    Shockley, Kevin; Baker, Aimee A; Richardson, Michael J; Fowler, Carol A

    2007-02-01

    Cooperative conversation has been shown to foster interpersonal postural coordination. The authors investigated whether such coordination is mediated by the influence of articulation on postural sway. In Experiment 1, talkers produced words in synchrony or in alternation, as the authors varied speaking rate and word similarity. Greater shared postural activity was found for the faster speaking rate. In Experiment 2, the authors demonstrated that shared postural activity also increases when individuals speak the same words or speak words that have similar stress patterns. However, this increase in shared postural activity is present only when participants' data are compared with those of their partner, who was present during the task, but not when compared with the data of a member of a different pair speaking the same word sequences as those of the original partner. The authors' findings suggest that interpersonal postural coordination observed during conversation is mediated by convergent speaking patterns. PMID:17311488

  7. 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.

  8. 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. PMID:26118530

  9. The effects of deuterium on static posture control

    NASA Technical Reports Server (NTRS)

    Layne, Charles S.

    1990-01-01

    A significant operational problem impacting upon the Space Shuttle program involves the astronaut's ability to safely egress from the Orbiter during an emergency situation. Following space flight, astronauts display significant movement problems. One variable which may contribute to increased movement ataxia is deuterium (D2O). Deuterium is present in low levels within the Orbiter's water supply but may accumulate to significant physiological levels during lengthy missions. Deuterium was linked to a number of negative physiological responses, including motion sickness, decreased metabolism, and slowing of neural conduction velocity. The effects of D2O on static postural control in response to a range of dosage levels were investigated. Nine sugjects were divided into three groups of three subjects each. The groups were divided into a low, medium, and a high D2O dosage group. The subjects static posture was assessed with the use of the EquiTest systems, a commercially available postural control evaluation system featuring movable force plates and a visual surround that can be servoed to the subject's sway. In addition to the force plate information, data about the degree of subject sway about the hips and shoulders was obtained. Additionally, surface electromyographic (EMG) data from the selected lower limb muscles were collected along with saliva samples used to determine the amount of deuterium enrichment following D2O ingestion. Two baseline testing sessions were performed using the EquiTest testing protocol prior to ingestion of the D2O. Thirty minutes after dosing, subjects again performed the tests. Two more post-dosing tests were run with an interest interval of one hour. Preliminary data anlaysis indicates that only subjects in the igh dose group displayed any significant static postural problems. Future analyses of the sway and EMG is expected to reveal significant variations in the subject's postural control strategy following D2O dosing. While

  10. 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.

  11. Postural control in athletes participating in an ironman triathlon.

    PubMed

    Nagy, Edit; Toth, Kalman; Janositz, Gabor; Kovacs, Gyula; Feher-Kiss, Anna; Angyan, Lajos; Horvath, Gyöngyi

    2004-08-01

    We studied the degree of dependence on vision of static postural control among ten male adult ironmen and ten healthy subjects (firemen, control group) who took part in regular physical activity, and the perturbations of equilibrium after prolonged exercise in ironmen. Static postural stability was measured during standing on a single-force platform alternating between eyes open and eyes closed. First, body sway was analysed on a force plate in both groups, and the athletes then took part in an ironman triathlon. The measurement was repeated after the race. The sway in both directions was subjected to spectral analysis. The frequency spectrum of the platform oscillations was calculated by fast Fourier transformation in the intervals 0-0.3, 0.3-1 and 1-3 Hz. The sway path in both directions and the total path were significantly lower in the ironmen than in the control group without vision, and the absence of visual control caused a significant increase in sway in both directions in the control group, but not in the ironmen. The frequency analysis revealed a higher level of stability in the medio-lateral direction with closed eyes. The endurance race caused increases in both the total sway path only with closed eyes, and these changes were significant at higher frequency bands. These results indicate that ironmen are more stable and less dependent on vision for postural control than the control subjects, and the prolonged stimulation of the proprioceptive, vestibular and visual inputs in the endurance race causes a significant disturbance in postural control. PMID:15205962

  12. Dynamic Control of Posture Across Locomotor Tasks

    PubMed Central

    Earhart, Gammon M.

    2013-01-01

    Successful locomotion depends on postural control to establish and maintain appropriate postural orientation of body segments relative to one another and to the environment, and to ensure dynamic stability of the moving body. This paper provides a framework for considering dynamic postural control, highlighting the importance of coordination, consistency, and challenges to postural control posed by various locomotor tasks such as turning and backward walking. The impacts of aging and various movement disorders on postural control are discussed broadly in an effort to provide a general overview of the field and recommendations for assessment of dynamic postural control across different populations in both clinical and research settings. Suggestions for future research on dynamic postural control during locomotion are also provided and include discussion of opportunities afforded by new and developing technologies, the need for long-term monitoring of locomotor performance in everyday activities, gaps in our knowledge of how targeted intervention approaches modify dynamic postural control, and the relative paucity of literature regarding dynamic postural control in movement disorder populations other than Parkinson disease. PMID:24132838

  13. Effect of sitting posture on respiratory function while using a smartphone

    PubMed Central

    Kang, Kyung Woo; Jung, Sang In; Lee, Do Youn; Kim, Kyoung; Lee, Na Kyung

    2016-01-01

    [Purpose] The purpose of this study was to investigate respiratory function in different sitting postures while using a smartphone. [Subjects and Methods] Fifty healthy volunteers were recruited. Participants were divided into 2 groups, a control group of participants who spent time as they liked for 1 hour, and a smartphone group of participants who spent time using a smartphone in a sitting position for 1 hour. To investigate changes in respiratory function, we measured forced vital capacity, forced expiratory volume in 1 second, ratio of forced expiratory volume in 1 second to forced vital capacity, and peak expiratory flow. [Results] There was a statistically significant difference in forced vital capacity and forced expiratory volume in 1 second between the control group and smartphone group. [Conclusion] The clinical implication of our findings is that the posture assumed while using a smartphone leads to reduced respiratory function. PMID:27313358

  14. Effect of stance width on multidirectional postural responses

    NASA Technical Reports Server (NTRS)

    Henry, S. M.; Fung, J.; Horak, F. B.; Peterson, B. W. (Principal Investigator)

    2001-01-01

    The effect of stance width on postural responses to 12 different directions of surface translations was examined. Postural responses were characterized by recording 11 lower limb and trunk muscles, body kinematics, and forces exerted under each foot of 7 healthy subjects while they were subjected to horizontal surface translations in 12 different, randomly presented directions. A quasi-static approach of force analysis was done, examining force integrals in three different epochs (background, passive, and active periods). The latency and amplitude of muscle responses were quantified for each direction, and muscle tuning curves were used to determine the spatial activation patterns for each muscle. The results demonstrate that the horizontal force constraint exerted at the ground was lessened in the wide, compared with narrow, stance for humans, a similar finding to that reported by Macpherson for cats. Despite more trunk displacement in narrow stance, there were no significant changes in body center of mass (CoM) displacement due to large changes in center of pressure (CoP), especially in response to lateral translations. Electromyographic (EMG) magnitude decreased for all directions in wide stance, particularly for the more proximal muscles, whereas latencies remained the same from narrow to wide stance. Equilibrium control in narrow stance was more of an active postural strategy that included regulating the loading/unloading of the limbs and the direction of horizontal force vectors. In wide stance, equilibrium control relied more on an increase in passive stiffness resulting from changes in limb geometry. The selective latency modulation of the proximal muscles with translation direction suggests that the trunk was being actively controlled in all directions. The similar EMG latencies for both narrow and wide stance, with modulation of only the muscle activation magnitude as stance width changed, suggest that the same postural synergy was only slightly modified

  15. [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) PMID:2636023

  16. 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.

  17. Aging and balance control in response to external perturbations: role of anticipatory and compensatory postural mechanisms.

    PubMed

    Kanekar, Neeta; Aruin, Alexander S

    2014-06-01

    The ability to maintain balance deteriorates with increasing age. Anticipatory and compensatory postural adjustments (APAs and CPAs, respectively), both, are known to be affected in the elderly. We examined the effect of aging on the ability of older adults to utilize APAs and its effect on subsequent control of posture (CPAs). Ten elderly individuals were exposed to external predictable and unpredictable perturbations applied to the upper body in the sagittal plane. Body kinematics, electromyographic activity of 13 muscles, and ground reaction forces were analyzed during the anticipatory and compensatory phases of postural control. The elderly were capable of recognizing an upcoming predictable perturbation and activated muscles prior to it. However, the older adults used different muscle strategies and sequence of muscle recruitment than that reported in young adults. Additionally, when the perturbations were unpredictable, no APAs were seen which resulted in large CPAs and greater peak displacements of the center of pressure (COP) and center of mass (COM) following perturbations. As opposed to this, when the perturbations were predictable, APAs were seen in older adults resulting in significantly smaller CPAs. The presence and utilization of APAs in older adults also improved postural stability following the perturbation as seen by significantly smaller COP and COM peak displacements. Using APAs in older adults significantly reduces the need for large CPAs, resulting in greater postural stability following a perturbation. The results provide a foundation for investigating the role of training in improving the interplay between anticipatory and compensatory postural control in older adults. PMID:24532389

  18. 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.

  19. 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…

  20. 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)

  1. Articulatory Constraints on Interpersonal Postural Coordination

    ERIC Educational Resources Information Center

    Shockley, Kevin; Baker, Aimee A.; Richardson, Michael J.; Fowler, Carol A.

    2007-01-01

    Cooperative conversation has been shown to foster interpersonal postural coordination. The authors investigated whether such coordination is mediated by the influence of articulation on postural sway. In Experiment 1, talkers produced words in synchrony or in alternation, as the authors varied speaking rate and word similarity. Greater shared…

  2. 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…

  3. Postural balance in patients with social anxiety disorder

    PubMed Central

    Levitan, M.N.; Crippa, J.A.; Bruno, L.M.; Pastore, D.L.; Freire, R.C.; Arrais, K.C.; Hallak, J.E.; Nardi, A.E.

    2011-01-01

    Body stability is controlled by the postural system and can be affected by fear and anxiety. Few studies have addressed freezing posture in psychiatric disorders. The purpose of the present study was to assess posturographic behavior in 30 patients with social anxiety disorder (SAD) and 35 without SAD during presentation of blocks of pictures with different valences. Neutral images consisted of objects taken from a catalog of pictures, negative images were mutilation pictures and anxiogenic images were related to situations regarding SAD fears. While participants were standing on a force platform, similar to a balance, displacement of the center of pressure in the mediolateral and anteroposterior directions was measured. We found that the SAD group exhibited a lower sway area and a lower velocity of sway throughout the experiment independent of the visual stimuli, in which the phobic pictures, a stimulus associated with a defense response, were unable to evoke a significantly more rigid posture than the others. We hypothesize that patients with SAD when entering in a situation of exposure, from the moment the pictures are presented, tend to move less than controls, remaining this way until the experiment ends. This discrete body manifestation can provide additional data to the characterization of SAD and its differentiation from other anxiety disorders, especially in situations regarding facing fear. PMID:22086467

  4. Classification of posture maintenance data with fuzzy clustering algorithms

    NASA Technical Reports Server (NTRS)

    Bezdek, James C.

    1991-01-01

    Sensory inputs from the visual, vestibular, and proprioreceptive systems are integrated by the central nervous system to maintain postural equilibrium. Sustained exposure to microgravity causes neurosensory adaptation during spaceflight, which results in decreased postural stability until readaptation occurs upon return to the terrestrial environment. Data which simulate sensory inputs under various conditions were collected in conjunction with JSC postural control studies using a Tilt-Translation Device (TTD). The University of West Florida proposed applying the Fuzzy C-Means Clustering (FCM) Algorithms to this data with a view towards identifying various states and stages. Data supplied by NASA/JSC were submitted to the FCM algorithms in an attempt to identify and characterize cluster substructure in a mixed ensemble of pre- and post-adaptational TTD data. Following several unsuccessful trials with FCM using a full 11 dimensional data set, a set of two channels (features) were found to enable FCM to separate pre- from post-adaptational TTD data. The main conclusions are that: (1) FCM seems able to separate pre- from post-TTD subject no. 2 on the one trial that was used, but only in certain subintervals of time; and (2) Channels 2 (right rear transducer force) and 8 (hip sway bar) contain better discrimination information than other supersets and combinations of the data that were tried so far.

  5. 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

    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

  6. 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

  7. 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

  8. Postural Coordination during Socio-motor Improvisation.

    PubMed

    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

  9. Vestibular plasticity following orbital spaceflight: recovery from postflight postural instability

    NASA Technical Reports Server (NTRS)

    Black, F. O.; Paloski, W. H.; Doxey-Gasway, D. D.; Reschke, M. F.

    1995-01-01

    Results of previous studies suggested that the vestibular mediated postural instability observed in astronauts upon return to earth from orbital spaceflight may be exacerbated by an increased weighting of visual inputs for spatial orientation and control of movement. This study was performed to better understand the roles of visual and somatosensory contributions to recovery of normal sensori-motor postural control in returning astronauts. Preflight and postflight, 23 astronaut volunteers were presented randomly with three trials of six sensory organization test (SOT) conditions in the EquiTest system test battery. Sagittal plane center-of-gravity (COG) excursions computed from ground reaction forces were significantly higher on landing day than preflight for those test conditions presenting sway-referenced visual and/or somatosensory orientation cues. The ratio of summed peak-to-peak COG sway amplitudes on the two sway-referenced vision tests (SOTs 3 + 6) compared to the two eyes closed tests (SOTs 2 + 5) was increased on landing day, indicating an increased reliance on visual orientation cues for postural control. The ratio of peak-to-peak COG excursions on sway-referenced surfaces (SOTs 4, 5 & 6) to an earth fixed support surfaces (SOTs 1, 2 & 3) increased even more after landing suggesting primary reliance on somatosensory orientation cues for recovery of postflight postural stability. Readaptation to sway-referenced support surfaces took longer than readaptation to sway-referenced vision. The increased reliance on visual and somatosensory inputs disappeared in all astronauts 4-8 days following return to earth.

  10. 48 CFR 552.270-24 - Statement of Lease.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Statement of Lease. 552... Statement of Lease. As prescribed in 570.603, insert the following clause: Statement of Lease (SEP 1999) (a... this clause and, if such is the case, that (1) the lease is in full force and effect; and (2) the...

  11. Modeling the postural disturbances caused by upper extremity movements.

    PubMed

    Triolo, R J; Werner, K N; Kirsch, R F

    2001-06-01

    This paper describes the design, validation, and application of a dynamic, three-dimensional (3-D) model of the upper extremity for the purpose of estimating postural disturbances generated by movements of the arms. The model consists of two links representing the upper and lower arms, with the shoulder and elbow modeled as gimbal joints to allow three rotational degrees of freedom. With individualized segment inertial parameters based on anthropometric measurements, the model performs inverse dynamic analysis of recorded arm movements to calculate reaction forces and moments acting on the body at the shoulder in three dimensions. The method was validated by comparing the output of the model to estimates obtained from ground reaction loads during stereotypical and free form unilateral movements at various velocities and with different loads carried by human subjects while seated on biomechanical force platforms. The correlation between predicted and measured reaction forces and moments was very good under all conditions and across all subjects, with average rms errors less than 8% of measured peak-to-peak values. The model was then applied to bimanual activities representative of functional movements that would typically be performed while standing at a counter. The resulting estimates were consistent and adequate for the purpose of evaluating postural disturbances caused by upper extremity movements. PMID:11474966

  12. 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.

  13. Effects of cervical sustained natural apophyseal glide on forward head posture and respiratory function

    PubMed Central

    Kim, Se-Yoon; Kim, Nan-Soo; Kim, Laurentius Jongsoon

    2015-01-01

    [Purpose] To determine the effects of cervical sustained natural apophyseal glide on forward head posture and respiratory function. [Subjects and Methods] Thirty male and female adults in their 20s with forward head posture were included in the study. The subjects were divided randomly into experimental and control groups (n=15 each). Subjects in the experimental group performed cervical sustained natural apophyseal glide three times/week for four weeks while subjects in the control group did not perform the intervention. The craniovertebral angle, forced vital capacity and forced expiratory volume in the first second, as well as the % predicted value of each measurement were assessed to determine the changes in respiration functions before and after the exercise. [Results] The craniovertebral angle four weeks after the experiment was increased in the experimental group, whereas the control group showed no significant difference compared to baseline. The forced vital capacity, forced expiratory volume in the first second, and the % predicted values thereof were significantly increased in the experimental group four weeks after the experiment, but not in the control group. [Conclusion] Cervical sustained natural apophyseal glide was determined to be effective in improving neck posture and respiratory functions for patients with forward head posture. PMID:26180334

  14. The Effect of Vision on Postural Strategies in Prader-Willi Patients

    ERIC Educational Resources Information Center

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

    2011-01-01

    The aim of this study was to quantify the role of visual contribution in patients with Prader-Willi syndrome (PWS) on balance maintenance using a force platform. We enrolled 14 individuals with PWS free from conditions associated with impaired balance, 44 obese (OG) and 20 healthy controls (CG). Postural sway was measured for 60 s while standing…

  15. 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…

  16. Adaptation of Postural Stability following Stroke.

    PubMed

    Di Fabio, R P

    1997-01-01

    Activities of daily living require both anticipatory and reactive postural adjustments. The influence of stroke on anticipatory and reactive balance behaviors is addressed in this article. Two primary deficits appear to underlie postural instability following stroke. The first deficit type is characterized by a loss of postural muscle recruitment in both lower extremities (not hyperactive stretch reflexes). The second deficit type is related specifically to the lack of limb stabilization on the paretic side of the body. These two categories of deficit might result from the disruption of geocentric and egocentric references for postural stability with cerebrovascular disease. Context-dependent postural responses are either relearned or retained following stroke, but deficits in the sequencing and timing of stabilizing neuromuscular responses appear to be resistant to adaptation. Prior knowledge of an impending balance disturbance improves the initiation of reactive postural adjustments in subjects with stroke but has no effect on the initiation of stabilizing responses associated with voluntary motion. The results suggest that reactive and anticipatory postural adjustments are controlled by different neural mechanisms and may require separate attention in a rehabilitation program. PMID:27620375

  17. 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.

  18. Postural orthostatic tachycardia syndrome (POTS)

    PubMed Central

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

    2013-01-01

    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. PMID:24042210

  19. Reversible postural orthostatic tachycardia syndrome

    PubMed Central

    Abdulla, Aza; Rajeevan, Thirumagal

    2015-01-01

    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. PMID:26244158

  20. Postural correlates with painful situations

    PubMed Central

    Lelard, Thierry; Montalan, Benoît; Morel, Maria F.; Krystkowiak, Pierre; Ahmaidi, Said; Godefroy, Olivier; Mouras, Harold

    2013-01-01

    Background: Emotional context may play a crucial role in movement production. According to simulation theories, emotional states affect motor systems. The aim of this study was to compare postural responses assessed by posturography and electromyography when subjects were instructed to imagine themselves in a painful or a non-painful situation. Methods: Twenty-nine subjects (22.3 ± 3.7 years) participated in this study. While standing quietly on a posturographic platform, they were instructed to imagine themselves in a painful or non-painful situation. Displacement of the center of pressure (COP), leg muscle electromyographic activity, heart rate, and electrodermal activity were assessed in response to painful and non-painful situations. Results: The anteroposterior path was shorter (p < 0.05) when subjects imagined themselves in a painful situation (M = 148.0 ± 33.4 mm) compared to a non-painful situation (158.2 ± 38.7 mm). Higher tibialis anterior (TA) activity (RMS-TA = 3.38 ± 1.95% vs. 3.24 ± 1.85%; p < 0.001) and higher variability of soleus (SO) activity (variation coefficient of RMS-SO = 13.5 ± 16.2% vs. M = 9.0 ± 7.2%; p < 0.05) were also observed in painful compared to non-painful situations. No significant changes were observed for other physiological data. Conclusion: This study demonstrates that simulation of painful situations induces changes in postural control and leg muscle activation compared to non-painful situations, as increased stiffness was demonstrated in response to aversive pictures in accordance with previous results. PMID:23386816

  1. Trunk posture monitoring with inertial sensors

    PubMed Central

    Wong, Man Sang

    2008-01-01

    Measurement of human posture and movement is an important area of research in the bioengineering and rehabilitation fields. Various attempts have been initiated for different clinical application goals, such as diagnosis of pathological posture and movements, assessment of pre- and post-treatment efficacy and comparison of different treatment protocols. Image-based methods for measurements of human posture and movements have been developed, such as the radiography, photogrammetry, optoelectric technique and video analysis. However, it is found that these methods are complicated to set up, time-consuming to operate and could only be applied in laboratory environments. This study introduced a method of using a posture monitoring system in estimating the spinal curvature changes during trunk movements on the sagittal and coronal planes and providing trunk posture monitoring during daily activities. The system consisted of three sensor modules, each with one tri-axial accelerometer and three uni-axial gyroscopes orthogonally aligned, and a digital data acquisition and feedback system. The accuracy of this system was tested with a motion analysis system (Vicon 370) in calibration with experimental setup and in trunk posture measurement with nine human subjects, and the performance of the posture monitoring system during daily activities with two human subjects was reported. The averaged root mean squared differences between the measurements of the system and motion analysis system were found to be <1.5° in dynamic calibration, and <3.1° for the sagittal plane and ≤2.1° for the coronal plane in estimation of the trunk posture change during trunk movements. The measurements of the system and the motion analysis system was highly correlated (>0.999 for dynamic calibration and >0.829 for estimation of spinal curvature change in domain planes of movement during flexion and lateral bending). With the sensing modules located on the upper trunk, mid-trunk and the pelvic

  2. A novel approach to study human posture control: "Principal movements" obtained from a principal component analysis of kinematic marker data.

    PubMed

    Federolf, Peter A

    2016-02-01

    Human upright posture is maintained by postural movements, which can be quantified by "principal movements" (PMs) obtained through a principal component analysis (PCA) of kinematic marker data. The current study expands the concept of "principal movements" in analogy to Newton's mechanics by defining "principal position" (PP), "principal velocity" (PV), and "principal acceleration" (PA) and demonstrates that a linear combination of PPs and PAs determines the center of pressure (COP) variance in upright standing. Twenty-one subjects equipped with 27-markers distributed over all body segments stood on a force plate while their postural movements were recorded using a standard motion tracking system. A PCA calculated on normalized and weighted posture vectors yielded the PPs and their time derivatives, the PVs and PAs. COP variance explained by the PPs and PAs was obtained through a regression analysis. The first 15 PMs quantified 99.3% of the postural variance and explained 99.60% ± 0.22% (mean ± SD) of the anterior-posterior and 98.82 ± 0.74% of the lateral COP variance in the 21 subjects. Calculation of the PMs thus provides a data-driven definition of variables that simultaneously quantify the state of the postural system (PPs and PVs) and the activity of the neuro-muscular controller (PAs). Since the definition of PPs and PAs is consistent with Newton's mechanics, these variables facilitate studying how mechanical variables, such as the COP motion, are governed by the postural control system. PMID:26768228

  3. Human posture experiments under water: ways of applying the findings to microgravity

    NASA Astrophysics Data System (ADS)

    Dirlich, Thomas

    differences between underwater and real microgravity environment were analyzed in greater detail: external forces (buoyancy and grav-ity), required fixation, postural changes by breathing and subject orientation to gravitational vector. Goal of this analysis was to understand the respective effects of each environmental influence on subjects posture observed. Each of the different influences was then quantified and the postural change induced by it calculated. These were then combined using a specially programmed multi-body-simulation tool, making it possible to recompute 3D posture data dy-namically to the environmental influences. The simulation is based on the volumetric 3D model of each subject, specific anthropometric data, such as body-fat or muscle ratio, combined with external forces such as gravity and buoyancy. The recomputed data can then be compared independent from the environmental influences. The recomputed 3D posture data can then be re-evaluated focussing again on possible inter-personal neutral posture archetypes in the subject group. Some examples of recomputed data and inter-personal findings will be given.

  4. Using Accelerometer and Gyroscopic Measures to Quantify Postural Stability

    PubMed Central

    Alberts, Jay L.; Hirsch, Joshua R.; Koop, Mandy Miller; Schindler, David D.; Kana, Daniel E.; Linder, Susan M.; Campbell, Scott; Thota, Anil K.

    2015-01-01

    Context Force platforms and 3-dimensional motion-capture systems provide an accurate method of quantifying postural stability. Substantial cost, space, time to administer, and need for trained personnel limit widespread use of biomechanical techniques in the assessment of postural stability in clinical or field environments. Objective To determine whether accelerometer and gyroscope data sampled from a consumer electronics device (iPad2) provide sufficient resolution of center-of-gravity (COG) movements to accurately quantify postural stability in healthy young people. Design Controlled laboratory study. Setting Research laboratory in an academic medical center. Patients or Other Participants A total of 49 healthy individuals (age = 19.5 ± 3.1 years, height = 167.7 ± 13.2 cm, mass = 68.5 ± 17.5 kg). Intervention(s) Participants completed the NeuroCom Sensory Organization Test (SOT) with an iPad2 affixed at the sacral level. Main Outcome Measure(s) Primary outcomes were equilibrium scores from both systems and the time series of the angular displacement of the anteroposterior COG sway during each trial. A Bland-Altman assessment for agreement was used to compare equilibrium scores produced by the NeuroCom and iPad2 devices. Limits of agreement was defined as the mean bias (NeuroCom − iPad) ± 2 standard deviations. Mean absolute percentage error and median difference between the NeuroCom and iPad2 measurements were used to evaluate how closely the real-time COG sway measured by the 2 systems tracked each other. Results The limits between the 2 devices ranged from −0.5° to 0.5° in SOT condition 1 to −2.9° to 1.3° in SOT condition 5. The largest absolute value of the measurement error within the 95% confidence intervals for all conditions was 2.9°. The mean absolute percentage error analysis indicated that the iPad2 tracked NeuroCom COG with an average error ranging from 5.87% to 10.42% of the NeuroCom measurement across SOT conditions. Conclusions The i

  5. ISway: a sensitive, valid and reliable measure of postural control

    PubMed Central

    2012-01-01

    Background Clinicians need a practical, objective test of postural control that is sensitive to mild neurological disease, shows experimental and clinical validity, and has good test-retest reliability. We developed an instrumented test of postural sway (ISway) using a body-worn accelerometer to offer an objective and practical measure of postural control. Methods We conducted two separate studies with two groups of subjects. Study I: sensitivity and experimental concurrent validity. Thirteen subjects with early, untreated Parkinson’s disease (PD) and 12 age-matched control subjects (CTR) were tested in the laboratory, to compare sway from force-plate COP and inertial sensors. Study II: test-retest reliability and clinical concurrent validity. A different set of 17 early-to-moderate, treated PD (tested ON medication), and 17 age-matched CTR subjects were tested in the clinic to compare clinical balance tests with sway from inertial sensors. For reliability, the sensor was removed, subjects rested for 30 min, and the protocol was repeated. Thirteen sway measures (7 time-domain, 5 frequency-domain measures, and JERK) were computed from the 2D time series acceleration (ACC) data to determine the best metrics for a clinical balance test. Results Both center of pressure (COP) and ACC measures differentiated sway between CTR and untreated PD. JERK and time-domain measures showed the best test-retest reliability (JERK ICC was 0.86 in PD and 0.87 in CTR; time-domain measures ICC ranged from 0.55 to 0.84 in PD and from 0.60 to 0.89 in CTR). JERK, all but one time-domain measure, and one frequency measure were significantly correlated with the clinical postural stability score (r ranged from 0.50 to 0.63, 0.01 < p < 0.05). Conclusions Based on these results, we recommend a subset of the most sensitive, reliable, and valid ISway measures to characterize posture control in PD: 1) JERK, 2) RMS amplitude and mean velocity from the time-domain measures, and 3) centroidal

  6. Postural variability and sensorimotor development in infancy.

    PubMed

    Dusing, Stacey C

    2016-03-01

    Infants develop skills through a coupling between their sensory and motor systems. Newborn infants must interpret sensory information and use it to modify movements and organize the postural control system based on the task demands. This paper starts with a brief review of evidence on the use of sensory information in the first months of life, and describes the importance of movement variability and postural control in infancy. This introduction is followed by a review of the evidence for the interactions between the sensory, motor, and postural control systems in typically development infants. The paper highlights the ability of young infants to use sensory information to modify motor behaviors and learn from their experiences. Last, the paper highlights evidence of atypical use of sensory, motor, and postural control in the first months of life in infants who were born preterm, with neonatal brain injury or later diagnosed with cerebral palsy (CP). PMID:27027603

  7. Limit cycle oscillations in standing human posture.

    PubMed

    Chagdes, James R; Rietdyk, Shirley; Haddad, Jeffrey M; Zelaznik, Howard N; Cinelli, Michael E; Denomme, Luke T; Powers, Kaley C; Raman, Arvind

    2016-05-01

    Limit cycle oscillations (LCOs) are a hallmark of dynamic instability in time-delayed and nonlinear systems such as climate change models, biological oscillators, and robotics. Here we study the links between the human neuromuscular system and LCOs in standing posture. First, we demonstrate through a simple mathematical model that the observation of LCOs in posture is indicative of excessive neuromuscular time-delay. To test this hypothesis we study LCOs in the postural sway of individuals with multiple sclerosis and concussed athletes representing two different populations with chronically and acutely increased neuromuscular time-delays. Using a wavelet analysis method we demonstrate that 67% of individuals with multiple sclerosis and 44% of individuals with concussion exhibit intermittent LCOs; 8% of MS-controls, 0% of older adults, and 0% of concussion-controls displayed LCOs. Thus, LCOs are not only key to understanding postural instability but also may have important applications for the detection of neuromuscular deficiencies. PMID:27018157

  8. Confounders of Vasovagal Syncope: Postural Tachycardia Syndrome

    PubMed Central

    Nwazue, Victor C.; Raj, Satish R

    2012-01-01

    Most patients who present to a cardiologist with syncope will have vasovagal (reflex) syncope. A busy syncope practice will often also see patients with postural tachycardia syndrome, often presenting with severe recurrent presyncope. Recognition of this “syncope confounder” might be difficult without adequate knowledge of their presentation, and this can adversely affect optimal management. Patients with postural tachycardia syndrome exhibit an excessive increase in heart rate ≥ 30 bpm within 10 minutes of standing (in the absence of orthostatic hypotension), in addition to chronic symptoms of orthostatic intolerance. Postural tachycardia syndrome can often be differentiated from vasovagal syncope by its hemodynamic pattern during tilt table test and differing clinical characteristics. This article will briefly review the presentation of postural tachycardia syndrome, its putative pathophysiology and an approach to non-pharmacological and pharmacological management. PMID:23217691

  9. Impaired H-Reflex Gain during Postural Loaded Locomotion in Individuals Post-Stroke

    PubMed Central

    Liang, Jing Nong; Brown, David A.

    2015-01-01

    Objective Successful execution of upright locomotion requires coordinated interaction between controllers for locomotion and posture. Our earlier research supported this model in the non-impaired and found impaired interaction in the post-stroke nervous system during locomotion. In this study, we sought to examine the role of the Ia afferent spinal loop, via the H-reflex response, under postural influence during a locomotor task. We tested the hypothesis that the ability to increase stretch reflex gain in response to postural loads during locomotion would be reduced post-stroke. Methods Fifteen individuals with chronic post-stroke hemiparesis and 13 non-impaired controls pedaled on a motorized cycle ergometer with specialized backboard support system under (1) seated supported, and (2) non-seated postural-loaded conditions, generating matched pedal force outputs of two levels. H-reflexes were elicited at 90°crank angle. Results We observed increased H-reflex gain with postural influence in non-impaired individuals, but a lack of increase in individuals post-stroke. Furthermore, we observed decreased H-reflex gain at higher postural loads in the stroke-impaired group. Conclusion These findings suggest an impaired Ia afferent pathway potentially underlies the defects in the interaction between postural and locomotor control post-stroke and may explain reduced ability of paretic limb support during locomotor weight-bearing in individuals post-stroke. Significance These results support the judicious use of bodyweight support training when first helping individuals post-stroke to regain locomotor pattern generation and weight-bearing capability. PMID:26629996

  10. Postural Control in Dual-Task Situations: Does Whole-Body Fatigue Matter?

    PubMed Central

    Beurskens, Rainer; Haeger, Matthias; Kliegl, Reinhold; Roecker, Kai; Granacher, Urs

    2016-01-01

    Postural control is important to cope with demands of everyday life. It has been shown that both attentional demand (i.e., cognitive processing) and fatigue affect postural control in young adults. However, their combined effect is still unresolved. Therefore, we investigated the effects of fatigue on single- (ST) and dual-task (DT) postural control. Twenty young subjects (age: 23.7 ± 2.7) performed an all-out incremental treadmill protocol. After each completed stage, one-legged-stance performance on a force platform under ST (i.e., one-legged-stance only) and DT conditions (i.e., one-legged-stance while subtracting serial 3s) was registered. On a second test day, subjects conducted the same balance tasks for the control condition (i.e., non-fatigued). Results showed that heart rate, lactate, and ventilation increased following fatigue (all p < 0.001; d = 4.2–21). Postural sway and sway velocity increased during DT compared to ST (all p < 0.001; d = 1.9–2.0) and fatigued compared to non-fatigued condition (all p < 0.001; d = 3.3–4.2). In addition, postural control deteriorated with each completed stage during the treadmill protocol (all p < 0.01; d = 1.9–3.3). The addition of an attention-demanding interference task did not further impede one-legged-stance performance. Although both additional attentional demand and physical fatigue affected postural control in healthy young adults, there was no evidence for an overadditive effect (i.e., fatigue-related performance decrements in postural control were similar under ST and DT conditions). Thus, attentional resources were sufficient to cope with the DT situations in the fatigue condition of this experiment. PMID:26796320

  11. 14 CFR 21.130 - Statement of conformity.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... CERTIFICATION PROCEDURES FOR PRODUCTS AND PARTS Production Under Type Certificate Only § 21.130 Statement of... manufactured for an Armed Force of the United States, a statement of conformity is not required if the product has been accepted by that Armed Force. Effective Date Note: By Doc. No. FAA-2006-25877, 74 FR...

  12. Microgravity effects on 'postural' muscle activity patterns

    NASA Technical Reports Server (NTRS)

    Layne, Charles S.; Spooner, Brian S.

    1994-01-01

    Changes in neuromuscular activation patterns associated with movements made in microgravity can contribute to muscular atrophy. Using electromyography (EMG) to monitor 'postural' muscles, it was found that free floating arm flexions made in microgravity were not always preceded by neuromuscular activation patterns normally observed during movements made in unit gravity. Additionally, manipulation of foot sensory input during microgravity arm flexion impacted upon anticipatory postural muscle activation.

  13. 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

  14. Postural control in man: the phylogenetic perspective.

    PubMed

    Gramsbergen, Albert

    2005-01-01

    Erect posture in man is a recent affordance from an evolutionary perspective. About eight million years ago, the stock from which modern humans derived split off from the ape family, and from around sixty-thousand years ago, modern man developed. Upright gait and manipulations while standing pose intricate cybernetic problems for postural control. The trunk, having an older evolutionary history than the extremities, is innervated by medially descending motor systems and extremity muscles by the more recent, laterally descending systems. Movements obviously require concerted actions from both systems. Research in rats has demonstrated the interdependencies between postural control and the development of fluent walking. Only 15 days after birth, adult-like fluent locomotion emerges and is critically dependent upon postural development. Vesttibular deprivation induces a retardation in postural development and, consequently, a retarded development of adult-like locomotion. The cerebellum obviously has an important role in mutual adjustments in postural control and extremity movements, or, in coupling the phylogenetic older and newer structures. In the human, the cerebellum develops partly after birth and therefore is vulnerable to adverse perinatal influences. Such vulnerability seems to justify focusing our scientific research efforts onto the development of this structure. PMID:16097476

  15. Kinematid Parameters of Corrective Postural Responses Differ between Upper and Lower Body Perturbations

    NASA Technical Reports Server (NTRS)

    Sayenko, G.

    2004-01-01

    Balance control is disrupted following prolonged microgravity exposure, and to better understand this, both upper and lower body perturbations have been used to study postural control in space flight crewmembers. However, differences between several postural response indicators observed using the two techniques suggest that different sensory systems may be involved in organizing responses to these different perturbation approaches. The present study sought to compare differences in parameters of corrective postural responses between upper body perturbations (pushes to the chest) and forward translations of the support surface. Nine subjects participated in this study. Forward translations were performed using a NeuroCom EquiTest(TM) CDP system, which was synchronized with a Northern Digital OptoTrak motion tracking system (3 subjects). Chest pushes were applied using a hand-held force transducer device and were performed using a stabilometric system (6 subjects). Analysis of EMG has shown that: i) the earliest response of the leg muscles was registered significantly later during forward translation of the support surface than during chest pushes, and ii) there was a tendency for the different order of leg muscles activation during the translation tests. Analysis of the kinematic data showed a significant difference in the subject's body segments inclinations during corrective postural responses to upper and lower body perturbations. It appears that upper body perturbations likely engage the vestibular system more rapidly, while lower body perturbations likely engage somatosensory systems more rapidly. These differences must be taken into account when choosing the type of perturbation for testing postural function.

  16. Dynamic postural control but not mechanical stability differs among those with and without chronic ankle instability.

    PubMed

    Wikstrom, E A; Tillman, M D; Chmielewski, T L; Cauraugh, J H; Naugle, K E; Borsa, P A

    2010-02-01

    The purpose of this investigation was to compare dynamic postural control and mechanical ankle stability among patients with and without chronic ankle instability (CAI) and controls. Seventy-two subjects were divided equally into three groups: uninjured controls, people with previous ankle injury but without CAI, and people with CAI. Subjects completed a single-leg hop-stabilization task, and then had an anterior drawer test and lateral ankle radiograph performed bilaterally. The dynamic postural stability index was calculated from the ground reaction forces of the single-leg hop-stabilization task. Ankle joint stiffness (N/m) was measured with an instrumented arthrometer during the anterior drawer test, and fibula position was assessed from the radiographic image. Patients with previous ankle injuries but without CAI demonstrated higher frontal plane dynamic postural stability scores than both the uninjured control and CAI groups (P<0.01). Patients with and without CAI had significantly higher sagittal plane dynamic postural stability scores (P<0.01) and increased ankle joint stiffness (P=0.045) relative to the control group. The increased frontal plane dynamic postural control may represent a component of a coping mechanism that limits recurrent sprains and the development of CAI. Mechanical stability alterations are speculated to result from the initial ankle trauma. PMID:19422654

  17. Effects of Shift Work on the Postural and Psychomotor Performance of Night Workers.

    PubMed

    Narciso, Fernanda Veruska; Barela, José A; Aguiar, Stefane A; Carvalho, Adriana N S; Tufik, Sergio; de Mello, Marco Túlio

    2016-01-01

    The purpose of the study was to investigate the effects of shift work on the psychomotor and postural performance of night workers. The study included 20 polysomnography technicians working schedule of 12-h night shift by 36-h off. On the first day of protocol, the body mass and height were measured, and an actigraph was placed on the wrist of each participant. On the second day of protocol, sleepiness by Karolinska Sleepiness Scale, postural control by force platform (30 seconds) and psychomotor performance by Psychomotor Vigilance Task (10 minutes) were measured before and after 12-h night work. Results showed that after 12-h night work, sleepiness increased by 59% (p<0.001), postural control variables increased by 9% (p = 0.048), and 14% (p = 0.006). Mean reaction time, and the number of lapses of attention increased by 13% (p = 0.006) and 425% (p = 0.015), respectively, but the mean reciprocal reaction time decreased by 7%. In addition, there were correlations between sleepiness and postural control variables with opened eyes (r = 0.616, 95% confidence interval [CI] = 0.361-0.815; r = 0.538; 95% CI = 0.280-0.748) and closed eyes (r = 0.557; 95% CI = 0.304-0.764, r = 0497; 95% CI = 0.325-0.715) and a pronounced effect of sleepiness on postural sway (R2 = 0.393; 95% CI = 0.001-0.03). Therefore, 12-h night work system and sleepiness showed a negative impact in postural and psychomotor vigilance performance of night workers. As unexpected, the force platform was feasibility to detect sleepiness in this population, underscoring the possibility of using this method in the workplace to prevent occupational injuries and accidents. PMID:27115868

  18. Effects of Shift Work on the Postural and Psychomotor Performance of Night Workers

    PubMed Central

    Narciso, Fernanda Veruska; Barela, José A.; Aguiar, Stefane A.; Carvalho, Adriana N. S.; Tufik, Sergio; de Mello, Marco Túlio

    2016-01-01

    The purpose of the study was to investigate the effects of shift work on the psychomotor and postural performance of night workers. The study included 20 polysomnography technicians working schedule of 12-h night shift by 36-h off. On the first day of protocol, the body mass and height were measured, and an actigraph was placed on the wrist of each participant. On the second day of protocol, sleepiness by Karolinska Sleepiness Scale, postural control by force platform (30 seconds) and psychomotor performance by Psychomotor Vigilance Task (10 minutes) were measured before and after 12-h night work. Results showed that after 12-h night work, sleepiness increased by 59% (p<0.001), postural control variables increased by 9% (p = 0.048), and 14% (p = 0.006). Mean reaction time, and the number of lapses of attention increased by 13% (p = 0.006) and 425% (p = 0.015), respectively, but the mean reciprocal reaction time decreased by 7%. In addition, there were correlations between sleepiness and postural control variables with opened eyes (r = 0.616, 95% confidence interval [CI] = 0.361–0.815; r = 0.538; 95% CI = 0.280–0.748) and closed eyes (r = 0.557; 95% CI = 0.304–0.764, r = 0497; 95% CI = 0.325–0.715) and a pronounced effect of sleepiness on postural sway (R2 = 0.393; 95% CI = 0.001–0.03). Therefore, 12-h night work system and sleepiness showed a negative impact in postural and psychomotor vigilance performance of night workers. As unexpected, the force platform was feasibility to detect sleepiness in this population, underscoring the possibility of using this method in the workplace to prevent occupational injuries and accidents. PMID:27115868

  19. Stabilization of posture by precision contact of the index finger

    NASA Technical Reports Server (NTRS)

    Holden, M.; Ventura, J.; Lackner, J. R.

    1994-01-01

    Postural sway during quiet stance increases if sight of the surroundings is denied. We studied how sensory-motor information about body displacement provided by contact of the index finger with a stationary bar can be used to stabilize balance in the absence of vision. Stabilization equivalent to the contribution conferred by vision was achieved at contact force levels less than 1 N. This value is much below that necessary to provide significant physical stabilization of the body. We interpret our findings in relation to tactile thresholds for motion detection, "precision grip," and proprioceptive and sensory-motor information about the configuration of the arm to the torso. In conditions allowing higher force levels at the fingertip (5-8 N), subjects assumed a passively stable state to stabilize their stance.

  20. Influence of forward head posture on condylar position.

    PubMed

    Ohmure, H; Miyawaki, S; Nagata, J; Ikeda, K; Yamasaki, K; Al-Kalaly, A

    2008-11-01

    There are several reports suggesting that forward head posture is associated with temporomandibular disorders and restraint of mandibular growth, possibly due to mandibular displacement posteriorly. However, there have been few reports in which the condylar position was examined in forward head posture. The purpose of this study was to test the hypothesis that the condyle moves posteriorly in the forward head posture. The condylar position and electromyography from the masseter, temporal and digastric muscles were recorded on 15 healthy male adults at mandibular rest position in the natural head posture and deliberate forward head posture. The condylar position in the deliberate forward head posture was significantly more posterior than that in the natural head posture. The activity of the masseter and digastric muscles in the deliberate forward head posture was slightly increased. These results suggest that the condyle moves posteriorly in subjects with forward head posture. PMID:18808377

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

    PubMed

    McFarland, Joshua C; Meyers, Ron A

    2008-08-01

    Birds utilize one of two hindlimb postures during flight: an extended posture (with the hip and knee joints flexed, while the ankle joint is extended caudally) or a flexed posture (with the hip, knee, and ankle joints flexed beneath the body). American Avocets (Recurvirostra americana) and Black-necked Stilts (Himantopus mexicanus) extend their legs caudally during flight and support them for extended periods. Slow tonic and slow twitch muscle fibers are typically found in muscles functioning in postural support due to the fatigue resistance of these fibers. We hypothesized that a set of small muscles composed of high percentages of slow fibers and thus dedicated to postural support would function in securing the legs in the extended posture during flight. This study examined the anatomy and histochemical profile of eleven hindlimb muscles to gain insight into their functional roles during flight. Contrary to our hypothesis, all muscles possessed both fast twitch and slow twitch or slow tonic fibers. We believe this finding is due to the versatility of dynamic and postural functions the leg muscles must facilitate, including standing, walking, running, swimming, and hindlimb support during flight. Whether birds use an extended or flexed hindlimb flight posture may be related to the aerodynamic effect of leg position or may reflect evolutionary history. PMID:18506762

  2. Reliability of photographic posture analysis of adolescents

    PubMed Central

    Hazar, Zeynep; Karabicak, Gul Oznur; Tiftikci, Ugur

    2015-01-01

    [Purpose] Postural problems of adolescents needs to be evaluated accurately because they may lead to greater problems in the musculoskeletal system as they develop. Although photographic posture analysis has been frequently used, more simple and accessible methods are still needed. The purpose of this study was to investigate the inter- and intra-rater reliability of photographic posture analysis using MB-ruler software. [Subjects and Methods] Subjects were 30 adolescents (15 girls and 15 boys, mean age: 16.4±0.4 years, mean height 166.3±6.7 cm, mean weight 63.8±15.1 kg) and photographs of their habitual standing posture photographs were taken in the sagittal plane. For the evaluation of postural angles, reflective markers were placed on anatomical landmarks. For angular measurements, MB-ruler (Markus Bader- MB Software Solutions, triangular screen ruler) was used. Photographic evaluations were performed by two observers with a repetition after a week. Test-retest and inter-rater reliability evaluations were calculated using intra-class correlation coefficients (ICC). [Results] Inter-rater (ICC>0.972) and test-retest (ICC>0.774) reliability were found to be in the range of acceptable to excellent. [Conclusion] Reference angles for postural evaluation were found to be reliable and repeatable. The present method was found to be an easy and non-invasive method and it may be utilized by researchers who are in search of an alternative method for photographic postural assessments. PMID:26644658

  3. Scapular Bracing and Alteration of Posture and Muscle Activity in Overhead Athletes With Poor Posture

    PubMed Central

    Cole, Ashley K; McGrath, Melanie L; Harrington, Shana E; Padua, Darin A; Rucinski, Terri J; Prentice, William E

    2013-01-01

    Context Overhead athletes commonly have poor posture. Commercial braces are used to improve posture and function, but few researchers have examined the effects of shoulder or scapular bracing on posture and scapular muscle activity. Objective To examine whether a scapular stabilization brace acutely alters posture and scapular muscle activity in healthy overhead athletes with forward-head, rounded-shoulder posture (FHRSP). Design Randomized controlled clinical trial. Setting Applied biomechanics laboratory. Patients or Other Participants Thirty-eight healthy overhead athletes with FHRSP. Intervention(s) Participants were assigned randomly to 2 groups: compression shirt with no strap tension (S) and compression shirt with the straps fully tensioned (S + T). Posture was measured using lateral-view photography with retroreflective markers. Electromyography (EMG) of the upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and serratus anterior (SA) in the dominant upper extremity was measured during 4 exercises (scapular punches, W's, Y's, T's) and 2 glenohumeral motions (forward flexion, shoulder extension). Posture and exercise EMG measurements were taken with and without the brace applied. Main Outcome Measure(s) Head and shoulder angles were measured from lateral-view digital photographs. Normalized surface EMG was used to assess mean muscle activation of the UT, MT, LT, and SA. Results Application of the brace decreased forward shoulder angle in the S + T condition. Brace application also caused a small increase in LT EMG during forward flexion and Y's and a small decrease in UT and MT EMG during shoulder extension. Brace application in the S + T group decreased UT EMG during W's, whereas UT EMG increased during W's in the S group. Conclusions Application of the scapular brace improved shoulder posture and scapular muscle activity, but EMG changes were highly variable. Use of a scapular brace might improve shoulder posture and muscle activity in

  4. 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. PMID:25677032

  5. Postural adjustments associated with rapid voluntary arm movements. II. Biomechanical analysis.

    PubMed Central

    Friedli, W G; Cohen, L; Hallett, M; Stanhope, S; Simon, S R

    1988-01-01

    Normal subjects performed bilaterally symmetric rapid elbow flexions or extensions ("focal movements") while standing. Specific patterns of electromyographic activity in leg and trunk muscles ("associated postural adjustments") were seen for each type of movement. The biomechanical significance of these postural adjustments was analysed by means of the ground reaction forces and motion of the various body segments. Experimental data were compared with that from a theoretical model of the body consisting of a six segment kinetic chain with rigid links. Distinct patterns of the ground reaction forces with elbow flexion were opposite in direction to those seen with elbow extension. Movements of the various body segments were small and specific for a certain focal movement. Dynamic perturbations arising from the arm movement in an anteroposterior direction were found to be compensated by postural adjustments, whereas vertical perturbations were not compensated. The muscular activity acting about different joints in the different movements was found to correlate with the predictions of activity needed to compensate for net joint reaction moments arising from the focal movement. Motion of the various body segments could be understood as resulting from the interplay of the net reaction moments and the net muscular moments at the different joints. Dynamic postural requirements are accomplished by a precise active compensation initiated before the focal movement. PMID:3346688

  6. Investigation of the Differential Contributions of Superficial and Deep Muscles on Cervical Spinal Loads with Changing Head Postures

    PubMed Central

    Cheng, Chih-Hsiu; Chien, Andy; Hsu, Wei-Li; Chen, Carl Pai-Chu; Cheng, Hsin-Yi Kathy

    2016-01-01

    Cervical spinal loads are predominately influenced by activities of cervical muscles. However, the coordination between deep and superficial muscles and their influence on the spinal loads is not well understood. This study aims to document the changes of cervical spinal loads and the differential contributions of superficial and deep muscles with varying head postures. Electromyography (EMG) of cervical muscles from seventeen healthy adults were measured during maximal isometric exertions for lateral flexion (at 10°, 20° and terminal position) as well as flexion/extension (at 10°, 20°, 30°, and terminal position) neck postures. An EMG-assisted optimization approach was used to estimate the muscle forces and subsequent spinal loads. The results showed that compressive and anterior-posterior shear loads increased significantly with neck flexion. In particular, deep muscle forces increased significantly with increasing flexion. It was also determined that in all different static head postures, the deep muscle forces were greater than those of the superficial muscle forces, however, such pattern was reversed during peak efforts where greater superficial muscle forces were identified with increasing angle of inclination. In summary, the identification of significantly increased spinal loads associated with increased deep muscle activation during flexion postures, implies higher risks in predisposing the neck to occupationally related disorders. The results also explicitly supported that deep muscles play a greater role in maintaining stable head postures where superficial muscles are responsible for peak exertions and reinforcing the spinal stability at terminal head postures. This study provided quantitative data of normal cervical spinal loads and revealed motor control strategies in coordinating the superficial and deep muscles during physical tasks. PMID:26938773

  7. Investigation of the Differential Contributions of Superficial and Deep Muscles on Cervical Spinal Loads with Changing Head Postures.

    PubMed

    Cheng, Chih-Hsiu; Chien, Andy; Hsu, Wei-Li; Chen, Carl Pai-Chu; Cheng, Hsin-Yi Kathy

    2016-01-01

    Cervical spinal loads are predominately influenced by activities of cervical muscles. However, the coordination between deep and superficial muscles and their influence on the spinal loads is not well understood. This study aims to document the changes of cervical spinal loads and the differential contributions of superficial and deep muscles with varying head postures. Electromyography (EMG) of cervical muscles from seventeen healthy adults were measured during maximal isometric exertions for lateral flexion (at 10°, 20° and terminal position) as well as flexion/extension (at 10°, 20°, 30°, and terminal position) neck postures. An EMG-assisted optimization approach was used to estimate the muscle forces and subsequent spinal loads. The results showed that compressive and anterior-posterior shear loads increased significantly with neck flexion. In particular, deep muscle forces increased significantly with increasing flexion. It was also determined that in all different static head postures, the deep muscle forces were greater than those of the superficial muscle forces, however, such pattern was reversed during peak efforts where greater superficial muscle forces were identified with increasing angle of inclination. In summary, the identification of significantly increased spinal loads associated with increased deep muscle activation during flexion postures, implies higher risks in predisposing the neck to occupationally related disorders. The results also explicitly supported that deep muscles play a greater role in maintaining stable head postures where superficial muscles are responsible for peak exertions and reinforcing the spinal stability at terminal head postures. This study provided quantitative data of normal cervical spinal loads and revealed motor control strategies in coordinating the superficial and deep muscles during physical tasks. PMID:26938773

  8. Evaluation of Postural Control in Glaucoma Patients Using a Virtual 1 Reality Environment

    PubMed Central

    Diniz-Filho, Alberto; Boer, Erwin R.; Gracitelli, Carolina P. B.; Abe, Ricardo Y.; van Driel, Nienke; Yang, Zhiyong; Medeiros, Felipe A.

    2015-01-01

    Purpose To evaluate postural control using a dynamic virtual reality environment and the relationship between postural metrics and history of falls in glaucoma patients. Design Cross-sectional study. Participants The study involved 42 glaucoma patients with repeatable visual field defects on standard automated perimetry (SAP) and 38 control healthy subjects. Methods Patients underwent evaluation of postural stability by a force platform during presentation of static and dynamic visual stimuli on stereoscopic head-mounted goggles. The dynamic visual stimuli presented rotational and translational ecologically valid peripheral background perturbations. Postural stability was also tested in a completely dark field to assess somatosensory and vestibular contributions to postural control. History of falls was evaluated by a standard questionnaire. Main Outcome Measures Torque moments around the center of foot pressure on the force platform were measured and the standard deviations (STD) of these torque moments were calculated as a measurement of postural stability and reported in Newton meter (Nm). The association with history of falls was investigated using Poisson regression models. Age, gender, body mass index, severity of visual field defect, best-corrected visual acuity, and STD on dark field condition were included as confounding factors. Results Glaucoma patients had larger overall STD than controls during both translational (5.12 ± 2.39 Nm vs. 3.85 ± 1.82 Nm, respectively; P = 0.005) as well as rotational stimuli (5.60 ± 3.82 Nm vs. 3.93 ± 2.07 Nm, respectively; P = 0.022). Postural metrics obtained during dynamic visual stimuli performed better in explaining history of falls compared to those obtained in static and dark field condition. In the multivariable model, STD values in the mediolateral direction during translational stimulus were significantly associated with history of falls in glaucoma patients (incidence-rate ratio = 1.85; 95% CI: 1.30 – 2

  9. Effect of absence of vision on posture.

    PubMed

    Alotaibi, Abdullah Z; Alghadir, Ahmad; Iqbal, Zaheen A; Anwer, Shahnawaz

    2016-04-01

    [Purpose] The visual system is one of the sensory systems that enables the body to assess and process information about the external environment. In the absence of vision, a blind person loses contact with the outside world and develops faulty motor patterns, which results in postural deficiencies. However, literature regarding the development of such deficiencies is limited. The aim of this study was to discuss the effect of absence of vision on posture, the possible biomechanics behind the resulting postural deficiencies, and strategies to correct and prevent them. [Subjects and Methods] Various electronic databases including PubMed, Medline, and Google scholar were examined using the words "body", "posture", "blind" and "absence of vision". References in the retrieved articles were also examined for cross-references. The search was limited to articles in the English language. [Results] A total of 74 papers were shortlisted for this review, most of which dated back to the 1950s and 60s. [Conclusion] Blind people exhibit consistent musculoskeletal deformities. Absence of vision leads to numerous abnormal sensory and motor interactions that often limit blind people in isolation. Rehabilitation of the blind is a multidisciplinary task. Specialists from different fields need to diagnose and treat the deficiencies of the blind together as a team. Before restoring the normal mechanics of posture and gait, the missing link with the external world should be reestablished. PMID:27190486

  10. 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. PMID:26803676

  11. Correlation between Trunk Posture and Neck Reposition Sense among Subjects with Forward Head Neck Postures

    PubMed Central

    Lee, Han Suk; Chung, Hyung Kuk; Park, Sun Wook

    2015-01-01

    Objective. To assess the correlation of abnormal trunk postures and reposition sense of subjects with forward head neck posture (FHP). Methods. In all, postures of 41 subjects were evaluated and the FHP and trunk posture including shoulder, scapular level, pelvic side, and anterior tilting degrees were analyzed. We used the head repositioning accuracy (HRA) test to evaluate neck position senses of neck flexion, neck extension, neck right and left side flexion, and neck right and left rotation and calculated the root mean square error in trials for each subject. Spearman's rank correlation coefficients and regression analysis were used to assess the degree of correlation between the trunk posture and HRA value, and a significance level of α = 0.05 was considered. Results. There were significant correlations between the HRA value of right side neck flexion and pelvic side tilt angle (p < 0.05). If pelvic side tilting angle increases by 1 degree, right side neck flexion increased by 0.76 degrees (p = 0.026). However, there were no significant correlations between other neck motions and trunk postures. Conclusion. Verifying pelvic postures should be prioritized when movement is limited due to the vitiation of the proprioceptive sense of neck caused by FHP. PMID:26583125

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

    PubMed

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

    2013-06-01

    Postural steadiness while standing is impaired in individuals with spinal cord injury (SCI) and could be potentially associated with increased reliance on visual inputs. The purpose of this study was to compare individuals with SCI and able-bodied participants on their use of visual inputs to maintain standing postural steadiness. Another aim was to quantify the association between visual contribution to achieve postural steadiness and a clinical balance scale. Individuals with SCI (n = 15) and able-bodied controls (n = 14) performed quasi-static stance, with eyes open or closed, on force plates for two 45 s trials. Measurements of the centre of pressure (COP) included the mean value of the root mean square (RMS), mean COP velocity (MV) and COP sway area (SA). Individuals with SCI were also evaluated with the Mini-Balance Evaluation Systems Test (Mini BESTest), a clinical outcome measure of postural steadiness. Individuals with SCI were significantly less stable than able-bodied controls in both conditions. The Romberg ratios (eyes open/eyes closed) for COP MV and SA were significantly higher for individuals with SCI, indicating a higher contribution of visual inputs for postural steadiness in that population. Romberg ratios for RMS and SA were significantly associated with the Mini-BESTest. This study highlights the contribution of visual inputs in individuals with SCI when maintaining quasi-static standing posture. PMID:23332191

  13. Low back pain and postural sway during quiet standing with and without sensory manipulation: a systematic review.

    PubMed

    Mazaheri, Masood; Coenen, Pieter; Parnianpour, Mohamad; Kiers, Henri; van Dieën, Jaap H

    2013-01-01

    A previous review concluded that postural sway is increased in patients with low back pain (LBP). However, more detailed analysis of the literature shows that postural deficit may be dependent on experimental conditions in which patients with LBP have been assessed. The research question to be answered in this review was: "Is there any difference in postural sway between subjects with and without LBP across several sensory manipulation conditions?". A literature search in Pubmed, Scopus, Embase and PsychInfo was performed followed by hand search and contact with authors. Studies investigating postural sway during bipedal stance without applying external forces in patients with specific and non-specific LBP compared to healthy controls were included. Twenty three articles fulfilled the eligibility criteria. Most studies reported an increased postural sway in LBP, or no effect of LBP on postural sway. In a minority of studies, a decreased sway was found in LBP patients. There were no systematic differences between studies finding an effect and those reporting no effect of LBP. The proportion of studies finding between-group differences did not increase with increased complexity of sensory manipulations. Potential factors that may have caused inconsistencies in the literature are discussed in this systematic review. PMID:22796243

  14. Prompting correct lifting posture using signs.

    PubMed

    Burt, C D; Henningsen, N; Consedine, N

    1999-08-01

    The use of a symbol to prompt the adoption of correct lifting posture was examined in three studies. Study 1 used an Appropriateness Test to evaluate nine symbols designed to encourage the adoption of correct lifting posture. Four symbols met the appropriateness criteria and were tested for comprehension in Study 2. Study 3 examined the effect of the best performing symbol from Study 2 in a field setting which involved subjects lifting a small box. Results indicate significant increases in the adoption of the use of correct lifting posture when the symbol was present compared to a control condition. The study also identified the placement of a lifting criterion symbol onto packaging as a useful technique for communicating safety information. PMID:10416848

  15. Postural responses triggered by multidirectional leg lifts and surface tilts.

    PubMed

    Hughey, Lucinda K; Fung, Joyce

    2005-08-01

    The aim of the present study was to investigate the relationship between proactive and reactive components of postural control. We contrasted the kinematic and electromyographic (EMG) responses to multidirectional voluntary leg lifts with those elicited by unexpected surface tilts. In particular, we addressed the role of trunk stabilization following either a voluntary or forced weight shift from double to single limb support. Nine young female subjects stood with a standing posture of 45 degrees toe-out and their arms abducted to shoulder level. On the experimenter's signal, subjects either (1) lifted one leg as fast as possible in one of six directions (R/L side, R/L diagonal front, R/L diagonal back) to a height of 45 degrees or (2) maintained standing as the support surface tilted at a rate of 53 degrees /s to a height of 10 degrees in one of six directions (R/L-up, R/L diagonal toes-up, R/L diagonal toes-down). For both tasks, our results showed that the center of pressure (COP) displacement began before or in conjunction with displacement of the center of mass (COM), after which the COP oscillated about the horizontal projection of the COM. In addition, the muscles were recruited in a distal-to-proximal sequence, either in anticipation of the voluntary leg lift or in response to the sudden surface tilt. Thus, the COP was being used dynamically to control displacement of the COM. The axial postural strategy comprising head, trunk, and pelvis movements was quantified by means of principal component analysis. More than 95% of the variance in the data could be described by the first two eigenvectors, which revealed specific coordination patterns dominated by pelvis rotation in one direction and head/trunk rotation in the opposite direction. Unexpected surface tilting elicited an automatic response strategy that focused on controlling the orientation of the head and trunk with respect to the vertical gravity vector while trunk verticality was compromised for

  16. Postural Responses Following Space Flight and Ground Based Analogs

    NASA Technical Reports Server (NTRS)

    Kofman, Igor S.; Reschke, Millard F.; Cerisano, Jody M.; Fisher, Elizabeth A.; Tomilovskaya, Elena V.; Kozlovskaya, Inessa B.; Bloomberg, Jacob B.

    2013-01-01

    With the transition from the Shuttle program to the International Space Station (ISS), the opportunity to fly sensorimotor experiments in a weightless environment has become increasingly more difficult to obtain. As a result, more investigations have turned to ground-based analogs as a way of evaluating an experiment's viability. The two primary analogs available to most investigators are 6deg head down bed rest (HDBR) and dry immersion (DI). For the time being, HDBR investigations have been associated with studies conducted in the United States while the Russians and several other European Union states have concentrated their efforts on using DI as the space flight analog of choice. While either model may be viable for cardiovascular, bone and other system changes, vestibular and sensorimotor investigators have retained serious reservations of either analog's potential to serve as a replacement for a true weightless environment. These reservations have merit, but it is worthwhile to consider that not all changes associated with sensorimotor function during space flight are the result of top-down modifications, but may also be due to the lack, or change, of appropriate support surfaces applying force to the bottom of the feet. To this end we have compared quiet stance postural responses between short duration Space Shuttle flights, long duration ISS flights and HDBR of varying duration. Using these three platforms, representing different modifications of support we investigated postural ataxia using a quiet stance model. Quiet stance was obtained by asking the subjects to stand upright on a force plate, eyes open, arms at the side of the body for three min. From the force plate we obtained average sway velocity in two axes as well as length of line (stabilogram). These parameters were then related to EMG activity recorded from the medial gastrocnemius and lateral tibialis. It is significant to note that postural ataxia measured as quiet stance shows analogous

  17. Postural Control during the Stroop Test in Dyslexic and Non Dyslexic Teenagers

    PubMed Central

    Demule, Emilie; Fauvel, Caroline; Bucci, Maria-Pia

    2011-01-01

    Postural control in quiet stance although simple still requires some cognitive resources; dual cognitive tasks influence further postural control. The present study examines whether or not dyslexic teenagers experience postural instability when performing a Stroop dual task for which their performances are known to be poor. Fifteen dyslexics and twelve non-dyslexics (14 to 17 years old) were recruited from the same school. They were asked to perform three tasks: (1) fixate a target, (2) perform an interference Stroop test (naming the colour or the word rather than reading the word), (3) performing flexibility Stroop task: the subject performed the interference task as in (2) except when the word was in a box, in which case he had to read the word. Postural performances were measured with a force platform. The results showed a main task effect on the variance of speed of body sway only: such variance was higher in the flexibility task than for the other two tasks. No group effect was found for any of the parameters of posture (surface, mediolateral and anteroposterior sway, variance of speed). Further wavelet analysis in the time-frequency domain revealed an increase in the spectral power of the medium frequency range believed to be related to cerebellum control; an accompanying increase in the cancellation time of the high frequency band related to reflexive loops occurred for non-dyslexics only. These effects occurred for the flexibility task and could be due to its high cognitive difficulty. Dyslexics displayed shorter cancellation time for the medium frequency band for all tasks, suggesting less efficient cerebellar control, perhaps of eye fixation and attention influencing body sway. We conclude that there is no evidence for a primary posture deficit in 15 year old teenagers who come from the general population and who were recruited in schools. PMID:21556369

  18. Childhood Exposure to Manganese and Postural Instability in Children living near a Ferromanganese Refinery in Southeastern Ohio

    PubMed Central

    Rugless, Fedoria; Bhattacharya, Amit; Succop, Paul; Dietrich, Kim N.; Cox, Cyndy; Alden, Jody; Kuhnell, Pierce; Barnas, Mary; Wright, Robert; Parsons, Patrick J.; Praamsma, Meredith L.; Palmer, Christopher D.; Beidler, Caroline; Wittberg, Richard; Haynes, Erin N.

    2014-01-01

    Airborne manganese (Mn) exposure can result in neurotoxicity and postural instability in occupationally exposed workers, yet few studies have explored the association ambient exposure to Mn in children and postural stability. The goal of this study was to determine the association between Mn and lead (Pb) exposure, as measured by blood Pb, blood and hair Mn and time weighted distance (TWD) from a ferromanganese refinery, and postural stability in children. A subset of children ages 7–9 years enrolled in the Marietta Community Actively Researching Exposure Study (CARES) were invited to participate. Postural balance was conducted on 55 children residing in Marietta, Ohio and the surrounding area. Samples of blood were collected and analyzed for Mn and Pb, and samples of hair were analyzed for Mn. Neuromotor performance was assessed using postural balance testing with a computer force platform system. Pearson correlations were calculated to identify key covariates. Associations between postural balance testing conditions and Mn and Pb exposure were estimated with linear regression analyses adjusting for gender, age, parent IQ, parent age. Mean blood Mn was 10 μg/L (SEM=0.36), mean blood Pb was 0.85 μg/dL (SEM=0.05), and mean hair Mn was 0.76 μg/g (SEM=0.16). Mean residential distance from the refinery was 11.5 km (SEM=0.46). All three measures of Mn exposure were significantly associated with poor postural balance. In addition, low-level blood Pb was also negatively associated with balance outcomes. We conclude that Mn exposure and low-level blood Pb are significantly associated with poor postural balance. PMID:24370548

  19. Development of the Coordination between Posture and Manual Control

    ERIC Educational Resources Information Center

    Haddad, Jeffrey M.; Claxton, Laura J.; Keen, Rachel; Berthier, Neil E.; Riccio, Gary E.; Hamill, Joseph; Van Emmerik, Richard E. A.

    2012-01-01

    Studies have suggested that proper postural control is essential for the development of reaching. However, little research has examined the development of the coordination between posture and manual control throughout childhood. We investigated the coordination between posture and manual control in children (7- and 10-year-olds) and adults during…

  20. Pseudodystonic Posture Secondary to Klippel–Feil Syndrome and Diastematomyelia

    PubMed Central

    Lopez-Vicchi, Martin; Da Prat, Gustavo; Gatto, Emilia Mabel

    2015-01-01

    Background Dystonic postures possess a great number of differential diagnoses. Phenomenology Shown We describe a pseudodystonic posture in a 61-year-old woman with skeletal and extra-skeletal abnormalities. Educational Value Klippel–Feil syndrome represents an unusual cause of pseudodystonic posture to be considered in the differential diagnosis of dystonia. PMID:27352284

  1. Postural Control in Children: Implications for Pediatric Practice

    ERIC Educational Resources Information Center

    Westcott, Sarah L.; Burtner, Patricia

    2004-01-01

    Based on a systems theory of motor control, reactive postural control (RPA) and anticipatory postural control (APA) in children are reviewed from several perspectives in order to develop an evidence-based intervention strategy for improving postural control in children with limitations in motor function. Research on development of postural…

  2. Feet distance and static postural balance: implication on the role of natural stance.

    PubMed

    Kim, Ji-Won; Kwon, Yuri; Jeon, Hyung-Min; Bang, Min-Jung; Jun, Jae-Hoon; Eom, Gwang-Moon; Lim, Do-Hyung

    2014-01-01

    The purpose of this study was to investigate 1) the effect of feet distance on static postural balance and 2) the location of natural feet distance and its possible role in the relationship of feet distance and postural balance. Static balance tests were performed on a force platform for 100 s with six different feet distances (0, 5, 10, 15, 20, 25 cm). Measures of postural balance included mean amplitude of horizontal ground reaction force (GRF) as well as the mean distance and velocity of the center of pressure (COP). All measures were discomposed into anterioposterior and mediolateral directions. ANOVA and post-hoc comparison were performed for all measures with feet distance as an independent factor. Also measured was the feet distance at the natural stance preferred by each subject. All measures significantly varied with feet distance (p<0.001). Mean distance of COP showed monotonic decrease with feet distance. Mean amplitude of horizontal GRF as well as mean velocity of COP showed U-shaped pattern (decrease followed by increase) with the minimum at the feet distance of 15 cm or 20 cm, near which the natural feet distance of 16.5 (SD 3.8) cm was located. COP is regarded to be an approximation of the center of mass (hence the resultant performance of postural control) in an inverted pendulum model with the horizontal GRF ignored. On the other hand, horizontal GRF is the direct cause of horizontal acceleration of a center of mass. The present result on horizontal GRF shows that the effort of postural control is minimized around the feet distance of natural standing and implies why the natural stance is preferred. PMID:25226972

  3. A link-segment model of upright human posture for analysis of head-trunk coordination

    NASA Technical Reports Server (NTRS)

    Nicholas, S. C.; Doxey-Gasway, D. D.; Paloski, W. H.

    1998-01-01

    Sensory-motor control of upright human posture may be organized in a top-down fashion such that certain head-trunk coordination strategies are employed to optimize visual and/or vestibular sensory inputs. Previous quantitative models of the biomechanics of human posture control have examined the simple case of ankle sway strategy, in which an inverted pendulum model is used, and the somewhat more complicated case of hip sway strategy, in which multisegment, articulated models are used. While these models can be used to quantify the gross dynamics of posture control, they are not sufficiently detailed to analyze head-trunk coordination strategies that may be crucial to understanding its underlying mechanisms. In this paper, we present a biomechanical model of upright human posture that extends an existing four mass, sagittal plane, link-segment model to a five mass model including an independent head link. The new model was developed to analyze segmental body movements during dynamic posturography experiments in order to study head-trunk coordination strategies and their influence on sensory inputs to balance control. It was designed specifically to analyze data collected on the EquiTest (NeuroCom International, Clackamas, OR) computerized dynamic posturography system, where the task of maintaining postural equilibrium may be challenged under conditions in which the visual surround, support surface, or both are in motion. The performance of the model was tested by comparing its estimated ground reaction forces to those measured directly by support surface force transducers. We conclude that this model will be a valuable analytical tool in the search for mechanisms of balance control.

  4. Reducing postural sway by concurrently performing challenging cognitive tasks.

    PubMed

    Polskaia, Nadia; Lajoie, Yves

    2016-04-01

    The present experiment varied cognitive complexity and sensory modality on postural control in young adults. Seventeen participants (23.71±1.99years) were instructed to stand feet together on a force platform while concurrently performing cognitive tasks of varying degrees of difficulty (easy, moderate and difficult). The cognitive tasks were presented both, auditorily and visually. Auditory tasks consisted of counting the occurrence of one or two letters and repeating a string of words. Visual tasks consisted of counting the occurrence of one or two numbers. With increasing cognitive demand, area of 95% confidence ellipse and ML sway variability was significantly reduced. The visual tasks reduced ML sway variability, whereas the auditory tasks increased COP irregularity. We suggest that these findings are primarily due to an increase in sensorimotor integration as a result of a shift in attentional focus. PMID:26796418

  5. The effects of spaceflight on open-loop and closed-loop postural control mechanisms: human neurovestibular studies on SLS-2

    NASA Technical Reports Server (NTRS)

    Collins, J. J.; De Luca, C. J.; Pavlik, A. E.; Roy, S. H.; Emley, M. S.; Young, L. R. (Principal Investigator)

    1995-01-01

    Stabilogram-diffusion analysis was used to examine how prolonged periods in microgravity affect the open-loop and closed-loop postural control mechanisms. It was hypothesized that following spaceflight: (1) the effective stochastic activity of the open-loop postural control schemes in astronauts is increased; (2) the effective stochastic activity and uncorrelated behavior, respectively, of the closed-loop postural control mechanisms in astronauts are increased; and (3) astronauts utilized open-loop postural controls schemes for shorter time intervals and smaller displacements. Four crew members and two alternates from the 14-day Spacelab Life Sciences 2 Mission were included in the study. Each subject was tested under eyes-open, quiet-standing conditions on multiple preflight and postflight days. The subjects' center-of-pressure trajectories were measured with a force platform and analyzed according to stabilogram-diffusion analysis. It was found that the effective stochastic activity of the open-loop postural control schemes in three of the four crew members was increased following spaceflight. This result is interpreted as an indication that there may be in-flight adaptations to higher-level descending postural control pathways, e.g., a postflight increase in the tonic activation of postural muscles. This change may also be the consequence of a compensatory (e.g., "stiffening") postural control strategy that is adopted by astronauts to account for general feeling of postflight unsteadiness. The crew members, as a group, did not exhibit any consistent preflight/postflight differences in the steady-state behavior of their closed-loop postural control mechanisms or in the functional interaction of their open-loop and closed-loop postural control mechanisms. These results are interpreted as indications that although there may be in-flight adaptations to the vestibular system and/or proprioceptive system, input from the visual system can compensate for such changes

  6. Balance control in aging: improvements in anticipatory postural adjustments and updating of internal models.

    PubMed

    Kubicki, Alexandre; Mourey, France; Bonnetblanc, François

    2015-01-01

    Postural stability of older subjects can be estimated during orthostatic equilibrium. However, dynamic equilibrium is also important to investigate risks of fall. It implies different interpretations of measures given by force plates. Same dependant variables (e.g. center of pressure displacement) cannot be interpreted the same ways depending of the type of equilibrium that is investigated. In particular, sways increases during dynamic equilibrium and before movement execution may reflect an improvement of feedforward control. PMID:26643046

  7. Wearable monitoring of seated spinal posture.

    PubMed

    Dunne, L E; Walsh, P; Hermann, S; Smyth, B; Caulfield, B

    2008-06-01

    This work describes the evaluation of a wearable plastic optical fiber (POF) sensor for monitoring seated spinal posture, as compared to a conventional expert visual analysis, and the development of a field-deployable posture monitoring system. A garment-integrated POF sensor was developed and tested on nine healthy subjects. Data from the wearable sensor were compared to data taken simultaneously from a marker-based motion capture system, for accuracy and reliability. Peak analysis of the resulting data showed a mean time error of 0.53 plusmn 0.8 s, and a mean value error of 0.64 plusmn 3.1 deg, which represents 14.5% of the average range of motion. Expert determination of transitional (good to bad) posture showed a variation of 20.9% of range of motion. These results indicate that the wearable sensor approximates the accuracy of expert visual analysis, and provides sufficient accuracy of measurement to reliably monitor seated spinal posture. PMID:23852756

  8. 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

  9. 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

    2015-01-01

    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

  10. Influence of musical groove on postural sway.

    PubMed

    Ross, Jessica M; Warlaumont, Anne S; Abney, Drew H; Rigoli, Lillian M; Balasubramaniam, Ramesh

    2016-03-01

    Timescales of postural fluctuation reflect underlying neuromuscular processes in balance control that are influenced by sensory information and the performance of concurrent cognitive and motor tasks. An open question is how postural fluctuations entrain to complex environmental rhythms, such as in music, which also vary on multiple timescales. Musical groove describes the property of music that encourages auditory-motor synchronization and is used to study voluntary motor entrainment to rhythmic sounds. The influence of groove on balance control mechanisms remains unexplored. We recorded fluctuations in center of pressure (CoP) of standing participants (N = 40) listening to low and high groove music and during quiet stance. We found an effect of musical groove on radial sway variability, with the least amount of variability in the high groove condition. In addition, we observed that groove influenced postural sway entrainment at various temporal scales. For example, with increasing levels of groove, we observed more entrainment to shorter, local timescale rhythmic musical occurrences. In contrast, we observed more entrainment to longer, global timescale features of the music, such as periodicity, with decreasing levels of groove. Finally, musical experience influenced the amount of postural variability and entrainment at local and global timescales. We conclude that groove in music and musical experience can influence the neural mechanisms that govern balance control, and discuss implications of our findings in terms of multiscale sensorimotor coupling. (PsycINFO Database Record PMID:26727019

  11. Forearm Posture and Mobility in Quadrupedal Dinosaurs

    PubMed Central

    VanBuren, Collin S.; Bonnan, Matthew

    2013-01-01

    Quadrupedality evolved four independent times in dinosaurs; however, the constraints associated with these transitions in limb anatomy and function remain poorly understood, in particular the evolution of forearm posture and rotational ability (i.e., active pronation and supination). Results of previous qualitative studies are inconsistent, likely due to an inability to quantitatively assess the likelihood of their conclusions. We attempt to quantify antebrachial posture and mobility using the radius bone because its morphology is distinct between extant sprawled taxa with a limited active pronation ability and parasagittal taxa that have an enhanced ability to actively pronate the manus. We used a sliding semi-landmark, outline-based geometric morphometric approach of the proximal radial head and a measurement of the angle of curvature of the radius in a sample of 189 mammals, 49 dinosaurs, 35 squamates, 16 birds, and 5 crocodilians. Our results of radial head morphology showed that quadrupedal ceratopsians, bipedal non-hadrosaurid ornithopods, and theropods had limited pronation/supination ability, and sauropodomorphs have unique radial head morphology that likely allowed limited rotational ability. However, the curvature of the radius showed that no dinosaurian clade had the ability to cross the radius about the ulna, suggesting parallel antebrachial elements for all quadrupedal dinosaurs. We conclude that the bipedal origins of all quadrupedal dinosaur clades could have allowed for greater disparity in forelimb posture than previously appreciated, and future studies on dinosaur posture should not limit their classifications to the overly simplistic extant dichotomy. PMID:24058633

  12. Effect of absence of vision on posture

    PubMed Central

    Alotaibi, Abdullah Z.; Alghadir, Ahmad; Iqbal, Zaheen A.; Anwer, Shahnawaz

    2016-01-01

    [Purpose] The visual system is one of the sensory systems that enables the body to assess and process information about the external environment. In the absence of vision, a blind person loses contact with the outside world and develops faulty motor patterns, which results in postural deficiencies. However, literature regarding the development of such deficiencies is limited. The aim of this study was to discuss the effect of absence of vision on posture, the possible biomechanics behind the resulting postural deficiencies, and strategies to correct and prevent them. [Subjects and Methods] Various electronic databases including PubMed, Medline, and Google scholar were examined using the words “body”, “posture”, “blind” and “absence of vision”. References in the retrieved articles were also examined for cross-references. The search was limited to articles in the English language. [Results] A total of 74 papers were shortlisted for this review, most of which dated back to the 1950s and 60s. [Conclusion] Blind people exhibit consistent musculoskeletal deformities. Absence of vision leads to numerous abnormal sensory and motor interactions that often limit blind people in isolation. Rehabilitation of the blind is a multidisciplinary task. Specialists from different fields need to diagnose and treat the deficiencies of the blind together as a team. Before restoring the normal mechanics of posture and gait, the missing link with the external world should be reestablished. PMID:27190486

  13. Body Posture Facilitates Retrieval of Autobiographical Memories

    ERIC Educational Resources Information Center

    Dijkstra, Katinka; Kaschak, Michael P.; Zwaan, Rolf A.

    2007-01-01

    We assessed potential facilitation of congruent body posture on access to and retention of autobiographical memories in younger and older adults. Response times were shorter when body positions during prompted retrieval of autobiographical events were similar to the body positions in the original events than when body position was incongruent.…

  14. Classification of Posture in Poststroke Upper Limb Spasticity: A Potential Decision Tool for Botulinum Toxin A Treatment?

    ERIC Educational Resources Information Center

    Hefter, Harald; Jost, Wolfgang H.; Reissig, Andrea; Zakine, Benjamin; Bakheit, Abdel Magid; Wissel, Jorg

    2012-01-01

    A significant percentage of patients suffering from a stroke involving motor-relevant central nervous system regions will develop a spastic movement disorder. Hyperactivity of different muscle combinations forces the limbs affected into abnormal postures or movement patterns. As muscular hyperactivity can effectively and safely be treated with…

  15. Effect of Semi-Rigid and Soft Ankle Braces on Static and Dynamic Postural Stability in Young Male Adults.

    PubMed

    Maeda, Noriaki; Urabe, Yukio; Tsutsumi, Shogo; Numano, Shuhei; Morita, Miho; Takeuchi, Takuya; Iwata, Shou; Kobayashi, Toshiki

    2016-06-01

    Ankle braces have been suggested to protect ankle joints from a sprain by restricting inversion and improving proprioception. However, the difference in effects between a semi-rigid brace and a soft brace regarding dynamic postural control after landing is not known. The aim of the present study was to compare the effect of soft (SB) and semi-rigid (SRB) ankle braces on static and dynamic postural stability in healthy young men. Altogether, 21 male adults (mean age 24.0 ± 1.5 years) were assessed for one leg while wearing non-brace (NB), SB or SRB. Balance in single-limb stance on a single-force platform with open eyes and closed eyes were assessed for the non-dominant leg under SB, SRB, and NB conditions. Locus length/second (mm/s) and the enveloped area (mm·s(-2)) surrounded by the circumference of the wave pattern during postural sway were calculated. For assessing dynamic postural stability, the participant jumped and landed on one leg on a force platform, and the Dynamic Postural Stability Index (DPSI) and the maximum vertical ground reaction force (vGRFmax) were measured. The data were compared among the three conditions with repeated-measures analysis of variance. The correlations between locus length/second, enveloped area, DPSI values (DPSI, Anterior-Posterior Stability Index, Medial-Lateral Stability Index, and Vertical Stability Index), and vGRFmax were then calculated. The results indicated that locus length/second and enveloped area with open eyes and closed eyes were not significantly different for each condition. However, a significant lower in the DPSI and Vertical Stability Index were observed with the SRB in comparison to the SB and NB. A significant improvement in vGRFmax was also observed with the SRB in comparison to NB. SRB demonstrated a positive effect on dynamic postural stability after landing on a single leg and may improve balance by increasing dynamic postural stability. Key pointsThis study examined the effect of ankle braces on

  16. Effect of Semi-Rigid and Soft Ankle Braces on Static and Dynamic Postural Stability in Young Male Adults

    PubMed Central

    Maeda, Noriaki; Urabe, Yukio; Tsutsumi, Shogo; Numano, Shuhei; Morita, Miho; Takeuchi, Takuya; Iwata, Shou; Kobayashi, Toshiki

    2016-01-01

    Ankle braces have been suggested to protect ankle joints from a sprain by restricting inversion and improving proprioception. However, the difference in effects between a semi-rigid brace and a soft brace regarding dynamic postural control after landing is not known. The aim of the present study was to compare the effect of soft (SB) and semi-rigid (SRB) ankle braces on static and dynamic postural stability in healthy young men. Altogether, 21 male adults (mean age 24.0 ± 1.5 years) were assessed for one leg while wearing non-brace (NB), SB or SRB. Balance in single-limb stance on a single-force platform with open eyes and closed eyes were assessed for the non-dominant leg under SB, SRB, and NB conditions. Locus length/second (mm/s) and the enveloped area (mm·s-2) surrounded by the circumference of the wave pattern during postural sway were calculated. For assessing dynamic postural stability, the participant jumped and landed on one leg on a force platform, and the Dynamic Postural Stability Index (DPSI) and the maximum vertical ground reaction force (vGRFmax) were measured. The data were compared among the three conditions with repeated-measures analysis of variance. The correlations between locus length/second, enveloped area, DPSI values (DPSI, Anterior-Posterior Stability Index, Medial-Lateral Stability Index, and Vertical Stability Index), and vGRFmax were then calculated. The results indicated that locus length/second and enveloped area with open eyes and closed eyes were not significantly different for each condition. However, a significant lower in the DPSI and Vertical Stability Index were observed with the SRB in comparison to the SB and NB. A significant improvement in vGRFmax was also observed with the SRB in comparison to NB. SRB demonstrated a positive effect on dynamic postural stability after landing on a single leg and may improve balance by increasing dynamic postural stability. Key points This study examined the effect of ankle braces on

  17. Inertia sensor-based guidance system for upperlimb posture correction.

    PubMed

    Ding, Z Q; Luo, Z Q; Causo, A; Chen, I M; Yue, K X; Yeo, S H; Ling, K V

    2013-02-01

    Stroke rehabilitation is labor-intensive and time-consuming. To assist patients and therapists alike, we propose a wearable system that measures orientation and corrects arm posture using vibrotactile actuators. The system evaluates user posture with respect to a reference and gives feedback in the form of vibration patterns. Users correct their arm posture, one DOF at a time, by following a protocol starting from the shoulder up to the forearm. Five users evaluated the proposed system by replicating ten different postures. Experimental results demonstrated system robustness and showed that some postures were easier to mimic depending on their naturalness. PMID:21978912

  18. Methods of Postural Assessment Used for Sports Persons

    PubMed Central

    Singla, Deepika

    2014-01-01

    Occurrence of postural defects has become very common now-a-days not only in general population but also in sports persons. There are various methods which can be used to assess these postural defects. These methods have evolved over a period of many years. This paper is first of its kind to summarize the methods of postural assessment which have been used and which can be used for evaluation of postural abnormalities in sports persons such as the visual observation, plumbline, goniometry, photographic, radiographic, photogrammetric, flexiruler, electromagnetic tracking device etc. We recommend more and more postural evaluation studies to be done in future based on the photogrammetric method. PMID:24959470

  19. Posture and Texting: Effect on Balance in Young Adults.

    PubMed

    Nurwulan, Nurul Retno; Jiang, Bernard C; Iridiastadi, Hardianto

    2015-01-01

    Using a mobile phone while doing another activity is a common dual-task activity in our daily lives. This study examined the effect of texting on the postural stability of young adults. Twenty college students were asked to perform static and dynamic postural stability tasks. Traditional COP and multivariate multiscale entropy (MMSE) were used to assess the static postural stability and the Star Excursion Balance Test (SEBT) was used to assess the dynamic postural stability. Results showed that (1) texting impaired postural stability, (2) the complexity index did not change much although the task conditions changed, and (3) performing texting is perceived to be more difficult. PMID:26230323

  20. Posture and Texting: Effect on Balance in Young Adults

    PubMed Central

    Nurwulan, Nurul Retno; Jiang, Bernard C.; Iridiastadi, Hardianto

    2015-01-01

    Using a mobile phone while doing another activity is a common dual-task activity in our daily lives. This study examined the effect of texting on the postural stability of young adults. Twenty college students were asked to perform static and dynamic postural stability tasks. Traditional COP and multivariate multiscale entropy (MMSE) were used to assess the static postural stability and the Star Excursion Balance Test (SEBT) was used to assess the dynamic postural stability. Results showed that (1) texting impaired postural stability, (2) the complexity index did not change much although the task conditions changed, and (3) performing texting is perceived to be more difficult. PMID:26230323

  1. Physiological tremor reveals how thixotropy adapts skeletal muscle for posture and movement

    PubMed Central

    Vernooij, Carlijn A.; Reynolds, Raymond F.; Lakie, Martin

    2016-01-01

    People and animals can move freely, but they must also be able to stay still. How do skeletal muscles economically produce both movement and posture? Humans are well known to have motor units with relatively homogeneous mechanical properties. Thixotropic muscle properties can provide a solution by providing a temporary stiffening of all skeletal muscles in postural conditions. This stiffening is alleviated almost instantly when muscles start to move. In this paper, we probe this behaviour. We monitor both the neural input to a muscle, measured here as extensor muscle electromyography (EMG), and its output, measured as tremor (finger acceleration). Both signals were analysed continuously as the subject made smooth transitions between posture and movement. The results showed that there were marked changes in tremor which systematically increased in size and decreased in frequency as the subject moved faster. By contrast, the EMG changed little and reflected muscle force requirement rather than movement speed. The altered tremor reflects naturally occurring thixotropic changes in muscle behaviour. Our results suggest that physiological tremor provides useful and hitherto unrecognized insights into skeletal muscle's role in posture and movement. PMID:27293785

  2. The effects of hippotherapy on postural balance and functional ability in children with cerebral palsy

    PubMed Central

    Moraes, Andréa Gomes; Copetti, Fernando; Angelo, Vera Regina; Chiavoloni, Luana Leonardo; David, Ana Cristina

    2016-01-01

    [Purpose] This study evaluated the effects of hippotherapy on seated postural balance, dynamic balance, and functional performance in children with cerebral palsy and compared the effects of 12 and 24 sessions on seated postural balance. [Subjects and Methods] This study included 15 children with cerebral palsy aged between 5 and 10 years. Interventions: A hippotherapy protocol was performed for 30 minutes, twice a week, for 12 weeks. Postural balance in a sitting position was measured using an AMTI AccuSway Plus force platform 1 week before initiating the hippotherapy program and after 12 and 24 weeks. The Berg Balance Scale (BBS) and Pediatric Evaluation of Disability Inventory (PEDI) were used before and after 24 sessions. [Results] Significant differences were observed for center of pressure (COP) variables, including medio-lateral (COPml), anteroposterior displacement (COPap), and velocity of displacement (VelCOP), particularly after 24 sessions. There were also significant differences in BBS scores and PEDI score increases associated with functional skills (self-care, social function, and mobility), caregiver assistance (self-care), social function, and mobility. [Conclusion] Hippotherapy resulted in improvement in postural balance in the sitting position, dynamic balance, and functionality in children with cerebral palsy, an effect particularly significant after 24 hippotherapy sessions.

  3. Physiological tremor reveals how thixotropy adapts skeletal muscle for posture and movement.

    PubMed

    Vernooij, Carlijn A; Reynolds, Raymond F; Lakie, Martin

    2016-05-01

    People and animals can move freely, but they must also be able to stay still. How do skeletal muscles economically produce both movement and posture? Humans are well known to have motor units with relatively homogeneous mechanical properties. Thixotropic muscle properties can provide a solution by providing a temporary stiffening of all skeletal muscles in postural conditions. This stiffening is alleviated almost instantly when muscles start to move. In this paper, we probe this behaviour. We monitor both the neural input to a muscle, measured here as extensor muscle electromyography (EMG), and its output, measured as tremor (finger acceleration). Both signals were analysed continuously as the subject made smooth transitions between posture and movement. The results showed that there were marked changes in tremor which systematically increased in size and decreased in frequency as the subject moved faster. By contrast, the EMG changed little and reflected muscle force requirement rather than movement speed. The altered tremor reflects naturally occurring thixotropic changes in muscle behaviour. Our results suggest that physiological tremor provides useful and hitherto unrecognized insights into skeletal muscle's role in posture and movement. PMID:27293785

  4. Regular physical activity reduces the effects of Achilles tendon vibration on postural control for older women.

    PubMed

    Maitre, J; Serres, I; Lhuisset, L; Bois, J; Gasnier, Y; Paillard, T

    2015-02-01

    The aim was to determine in what extent physical activity influences postural control when visual, vestibular, and/or proprioceptive systems are disrupted. Two groups of healthy older women: an active group (74.0 ± 3.8 years) who practiced physical activities and a sedentary group (74.7 ± 6.3 years) who did not, underwent 12 postural conditions consisted in altering information emanating from sensory systems by means of sensory manipulations (i.e., eyes closed, cervical collar, tendon vibration, electromyostimulation, galvanic vestibular stimulation, foam surface). The center of foot pressure velocity was recorded on a force platform. Results indicate that the sensory manipulations altered postural control. The sedentary group was more disturbed than the active group by the use of tendon vibration. There was no clear difference between the two groups in the other conditions. This study suggests that the practice of physical activities is beneficial as a means of limiting the effects of tendon vibration on postural control through a better use of the not manipulated sensory systems and/or a more efficient reweighting to proprioceptive information from regions unaffected by the tendon vibration. PMID:24853711

  5. A passerine spreads its tail to facilitate a rapid recovery of its body posture during hovering

    PubMed Central

    Su, Jian-Yuan; Ting, Shang-Chieh; Chang, Yu-Hung; Yang, Jing-Tang

    2012-01-01

    We demonstrate experimentally that a passerine exploits tail spreading to intercept the downward flow induced by its wings to facilitate the recovery of its posture. The periodic spreading of its tail by the White-eye bird exhibits a phase correlation with both wingstroke motion and body oscillation during hovering flight. During a downstroke, a White-eye's body undergoes a remarkable pitch-down motion, with the tail undergoing an upward swing. This pitch-down motion becomes appropriately suppressed at the end of the downstroke; the bird's body posture then recovers gradually to its original status. Employing digital particle-image velocimetry, we show that the strong downward flow induced by downstroking the wings serves as an external jet flow impinging upon the tail, providing a depressing force on the tail to counteract the pitch-down motion of the bird's body. Spreading of the tail enhances a rapid recovery of the body posture because increased forces are experienced. The maximum force experienced by a spread tail is approximately 2.6 times that of a non-spread tail. PMID:22258552

  6. Substance Abuse. Policy Statement.

    ERIC Educational Resources Information Center

    National Collaboration for Youth, Washington, DC.

    This paper presents the policy statement on substance abuse from the National Collaboration for Youth (NCY). The policy statement section lists programs and activities supported by the NCY. A section on background includes a statement of the issue of substance abuse. Areas examined in this section include alcohol abuse and drunk driving among…

  7. 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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-09-01

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

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

    PubMed Central

    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. PMID:26447883

  11. Stability and Control of Constrained Three-Dimensional Robotic Systems with Application to Bipedal Postural Movements

    NASA Astrophysics Data System (ADS)

    Kallel, Hichem

    Three classes of postural adjustments are investigated with the view of a better understanding of the control mechanisms involved in human movement. The control mechanisms and responses of human or computer models to deliberately induced disturbances in postural adjustments are the focus of this dissertation. The classes of postural adjustments are automatic adjustments, (i.e. adjustments not involving voluntary deliberate movement), adjustments involving imposition of constraints for the purpose of maintaining support forces, and adjustments involving violation and imposition of constraints for the purpose of maintaining balance, (i.e. taking one or more steps). For each class, based on the physiological attributes of the control mechanisms in human movements, control strategies are developed to synthesize the desired postural response. The control strategies involve position and velocity feedback control, on line relegation control, and pre-stored trajectory control. Stability analysis for constrained and unconstrained maneuvers is carried out based on Lyapunov stability theorems. The analysis is based on multi-segment biped robots. Depending on the class of postural adjustments, different biped models are developed. An eight-segment three dimensional biped model is formulated for the study of automatic adjustments and adjustments for balance. For the study of adjustments for support, a four segment lateral biped model is considered. Muscle synergies in automatic adjustments are analyzed based on a three link six muscle system. The muscle synergies considered involve minimal muscle number and muscle co-activation. The role of active and passive feedback in these automatic adjustments is investigated based on the specified stiffness and damping of the segments. The effectiveness of the control strategies and the role of muscle synergies in automatic adjustments are demonstrated by a number of digital computer simulations.

  12. Thermal sensation during mild hyperthermia is modulated by acute postural change in humans

    NASA Astrophysics Data System (ADS)

    Takeda, Ryosuke; Imai, Daiki; Suzuki, Akina; Ota, Akemi; Naghavi, Nooshin; Yamashina, Yoshihiro; Hirasawa, Yoshikazu; Yokoyama, Hisayo; Miyagawa, Toshiaki; Okazaki, Kazunobu

    2016-05-01

    Thermal sensation represents the primary stimulus for behavioral and autonomic thermoregulation. We assessed whether the sensation of skin and core temperatures for the driving force of behavioral thermoregulation was modified by postural change from the supine (Sup) to sitting (Sit) during mild hyperthermia. Seventeen healthy young men underwent measurements of noticeable increase and decrease (±0.1 °C/s) of skin temperature (thresholds of warm and cold sensation on the skin, 6.25 cm2 of area) at the forearm and chest and of the whole-body warm sensation in the Sup and Sit during normothermia (NT; esophageal temperature (Tes), ˜36.6 °C) and mild hyperthermia (HT; Tes, ˜37.2 °C; lower legs immersion in 42 °C of water). The threshold for cold sensation on the skin at chest was lower during HT than NT in the Sit (P < 0.05) but not in Sup, and at the forearm was lower during HT than NT in the Sup and further in Sit (both, P < 0.05), with interactive effects of temperature (NT vs. HT) × posture (Sup vs. Sit) (chest, P = 0.08; forearm, P < 0.05). The threshold for warm sensation on the skin at both sites remained unchanged with changes in body posture or temperature. The whole-body warm sensation was higher during HT than NT in both postures and higher in the Sit than Sup during both NT and HT (all, P < 0.05). Thus, thermal sensation during mild hyperthermia is modulated by postural change from supine to sitting to sense lesser cold on the skin and more whole-body warmth.

  13. 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

  14. Evaluation of ergonomic factors and postures that cause muscle pains in dentistry students’ bodies

    PubMed Central

    Shirzaei, Masoumeh; Khaje-Alizade, Ali; Mohammadi, Mahdi

    2015-01-01

    Background Work-related musculoskeletal disorders commonly experienced by dental professionals are one of the main occupational health problem affecting their health and well-being.This study was conducted to evaluate ergonomic factors and profession-related postures and also investigate relationship between demographic factors and work condition with pain in dental students. Material and Methods 60 freshman and sophomore dentistry students were randomly chosen as the subjects of control group, and 60 of 5th and 6th-year students were selected as the members of exposure group. Data related to the subjects such as sex, doing exercise, severity of musculoskeletal pain were obtained through questionnaire. Students’ postures were directly observed while treating patients and they were scored by REBA method. Data were analyzed by SPSS software using Man-Whitney, Kruskal-Wallis, Spearman and Kendall correlation tests. Results 80.8% of the subjects were not aware of the correct ergonomic postures for dental procedures. Severity of musculoskeletal pain in the exposure group (15.9± 4.2) was significantly higher than the control group (10.5 ±3.2), (p <0.001). Risk of the most subjects (84%) was at the medium level. Students who were more involved in clinical activities experienced more muscular pains. Conclusions The musculoskeletal disorders are probable prolonged in working hours in static positions, incorrect work postures, implying more force and even tools and instruments. Therefore, students who are aware of ergonomic principals of their own profession would be able to maintain their health through activities and lifelong. Key words:Posture, dentistry, students, musculoskeletal pain. PMID:26330941

  15. The relationship between posture and equilibrium and the auriculotemporal nerve in patients with disturbed gait and balance.

    PubMed

    Stack, Brendan; Sims, Anthony

    2009-10-01

    Balance is defined as a state of equilibrium or parity characterized by cancellation of all forces by equal opposing factors. This is the act of maintaining an upright posture (static balance) or in locomotion (dynamic balance or gait). This system depends on vestibular function, vision, and proprioception to maintain posture, to navigate in one's surroundings, to coordinate motion of body parts, to modulate fine motor control, and to initiate the vestibuloculomotor reflexes. These parts of the vestibular system provide our brains with information about changes in head movement with respect to the pull of gravity. Besides the visual, vestibular, and skeletal systems, which contribute to balance disorders, the dental (stomatognathic) system may also contribute to balance disorders. It is when all four of these systems are in coordination with one another, that a person will maintain equilibrium and balance, proper gait, and posture. The current article demonstrates, through normal anatomical and neurological processes, how the stomatognathic system influences these activities. PMID:19891259

  16. Age-dependency of posture parameters in children and adolescents

    PubMed Central

    Ludwig, Oliver; Mazet, Carola; Mazet, Dirk; Hammes, Annette; Schmitt, Eduard

    2016-01-01

    [Purpose] Poor posture in children and adolescents is a well-known problem. Therefore, early detection of incorrect posture is important. Photometric posture analysis is a cost-efficient and easy method, but needs reliable reference values. As children’s posture changes as they grow, the assessment needs to be age-specific. This study aimed to investigate the development of both one-dimensional posture parameter (body inclination angle) and complex parameter (posture index) in different age groups (childhood to adolescence). [Subjects and Methods] The participants were 372 symptom-free children and adolescents (140 girls and 232 boys aged 6–17). Images of their habitual posture were obtained in the sagittal plane. High-contrast marker points and marker spheres were placed on anatomical landmarks. Based on the marker points, the body inclination angle (INC) and posture index (PI) were calculated using the Corpus concepts software. [Results] The INC angle significantly increased with age. The PI did not change significantly among the age groups. No significant differences between the corresponding age groups were found for PI and INC for both sexes. [Conclusion] When evaluating posture using the body inclination angle, the age of the subject needs to be considered. Posture assessment with an age-independent parameter may be more suitable. PMID:27313382

  17. Gnathological postural treatment in a professional basketball player: a case report and an overview of the role of dental occlusion on performance

    PubMed Central

    Baldini, Alberto; Beraldi, Alessandro; Nota, Alessandro; Danelon, Furio; Ballanti, Fabiana; Longoni, Salvatore

    2012-01-01

    Summary Aims During competitions and training many professional athletes use to wear occlusal splints to improve their sports performance. However, notwithstanding some studies concluded that achieving a balanced cranial-occlusal system could bring to an improvement of sports performances, the results are still contrasting. Probably the gnathological postural treatment of athletes has greater influence on performance when the individual suffers of Temporomandibular Joint Disfunction (TMJ) or physio-postural pathologies owing to the consequent alteration of the “tonic-postural system”. This clinical case details a gnathological postural approach to a professional basketball player suffering from muscular problems related to the stomatognathic apparatus and a low back pain unresolved with the only physiotherapy, which limited her performance. Methods Force platform and T-Scan III appliances were used in order to check the postural and occlusal condition of the athlete and as an aid to clinical parameters in achieving a correct splint balance. Results After the treatment involving inserting an occlusal splint and physiotherapy sessions, the patient no longer complained of low back pain problems and the symptoms associated with the stomatognathic apparatus improved considerably. In particular, after the tests carried out on an isokinetic machine, a force increase related to the quadriceps muscles was detected when the patient was wearing the occlusal splint. Conclusions All athletes must however be analysed individually and carefully with clinical and instrumental analyses in order to consider the possible real effectiveness of an occlusal splint for improving postural structure and sports performance. PMID:23087786

  18. Postural awareness among dental students in Jizan, Saudi Arabia

    PubMed Central

    Kanaparthy, Aruna; Kanaparthy, Rosaiah; Boreak, Nezar

    2015-01-01

    Objective: The study was conducted to assess the postural awareness of dental students in Jizan, Saudi Arabia. Materials and Methods: Close-ended, self-administered questionnaires were used for data collection in the survey. The questionnaire was prepared by observing the positions of students working in the clinics and the common mistakes they make with regard to their postures. The questionnaires were distributed among the dental students who were present and reported to work in the clinics. Levels of postural awareness and the relationship between postural awareness and the degree of musculoskeletal disorder (MSD) among the students was evaluated. This study was carried out in the College of Dental Sciences and Hospital, Jizan. Statistical Analysis: The level of knowledge of postural awareness was evaluated and correlated with the presence or absence of the MSDs. Categorical variables were compared using Chi-square test. P values of less than 0.05 were considered statistically significant. Results: A total of 162 dental students from the age group of 20–25 years were included in the survey, of which 134 dentists responded (83%). When their postural awareness was evaluated, results showed that 89% of the students had poor-to-medium levels of postural awareness. The relation between postural awareness and prevalence of MSDs indicated that 75% of the students with poor awareness, 49% of the students with average awareness, and 40% of the students with good awareness have MSDs. The results were statistically significant (0.002127, which is <0.005) stating that better awareness about proper postures while working helps to minimize the risk of MSDs. Conclusion: Evaluation of levels of postural awareness showed that 21% of the students had poor postural awareness, 67% had average awareness, and 11% had good postural awareness. The analysis of results showed that those students with low-to-average postural awareness had significantly greater prevalence of MSDs. PMID

  19. Smart Rehabilitation Garment for posture monitoring.

    PubMed

    Wang, Q; Chen, W; Timmermans, A A A; Karachristos, C; Martens, J B; Markopoulos, P

    2015-08-01

    Posture monitoring and correction technologies can support prevention and treatment of spinal pain or can help detect and avoid compensatory movements during the neurological rehabilitation of upper extremities, which can be very important to ensure their effectiveness. We describe the design and development of Smart Rehabilitation Garment (SRG) a wearable system designed to support posture correction. The SRG combines a number of inertial measurement units (IMUs), controlled by an Arduino processor. It provides feedback with vibration on the garment, audible alarm signals and visual instruction through a Bluetooth connected smartphone. We discuss the placement of sensing modules, the garment design, the feedback design and the integration of smart textiles and wearable electronics which aimed at achieving wearability and ease of use. We report on the system's accuracy as compared to optical tracker method. PMID:26737595

  20. Modulation of ankle stiffness during postural sway.

    PubMed

    Lang, Christopher B; Kearney, Robert E

    2014-01-01

    Ankle stiffness is a nonlinear, time-varying system which contributes to the control of human upright stance. This study sought to examine the nature of the contribution of stiffness to postural control by determining how intrinsic and reflex stiffnesses varied with sway. Subjects were instructed to stand quietly on a bilateral electro-hydraulic actuator while perturbations were applied about the ankle. Subjects performed three types of trials: normal stance, forward lean, and backward lean. Position, torque, and EMGs from the tibialis anterior and triceps surae were recorded. Background torque, intrinsic stiffness and reflex stiffness were calculated for each perturbation. Intrinsic and reflex stiffnesses were heavily modulated by postural sway. Moreover, they were modulated in a complimentary manner; intrinsic stiffness was lowest when reflex gain was highest, and vice versa. These findings suggest that intrinsic stiffness is modulated simultaneously with reflex stiffness to optimize the control of balance. PMID:25570884

  1. Time course analysis of influence of food hardness on head posture and pitching of head during masticatory movement.

    PubMed

    Shinya, Akimasa; Sato, Toru; Hisanaga, Ryuichi; Miho, Otoaki; Nomoto, Syuntaro

    2013-01-01

    The purpose of the present study was to investigate the relationship between mastication and head posture using foods with different degrees of hardness. A total of 12 healthy, dentulous volunteers participated in the study. Each participant was required to chew two types of gummy candy with two levels of hardness while sitting upright. Measurements were conducted using an optoelectric jaw-tracking system with 6 degrees of freedom (Gnatho-Hexagraph II JM-2000®). The horizontal plane perpendicular to the direction of gravitational force served as the reference plane. Analysis of the gradient of the Frankfurt plane (head posture) and pitching of the head during masticatory movement was conducted. The influence of the type of test food on these parameters was evaluated during mastication. During stable mastication, the gradient of the Frankfurt plane was 4.66 degrees on average, close to the horizontal plane. The time course of the Frankfurt plane gradient revealed a tendency toward dorsal flexion during the first to middle phases of mastication, and a tendency toward ventral flexion during the middle to last phases, regardless of the hardness of the test food. The participants were divided into two groups based on change in head posture during chewing. The results showed while there was no change in head posture in the group with marked pitching of the head, head posture did change in the group with little pitching. PMID:23903577

  2. Biomechanical and Electromyographic Comparisons of Isometric Trunk Flexor Endurance Test Postures: Prone Plank Versus V-Sit.

    PubMed

    Musalem, Lindsay L; Stankovic, Tatjana; Glisic, Drazen; Cook, Gillian E; Beach, Tyson A

    2015-12-01

    The objective of this study was to investigate why holding times on 2 different tests of isometric trunk flexor endurance capacity (prone plank and v-sit) are weakly correlated. Body position and ground reaction force data from 10 men and 10 women were used to conduct static biomechanical analyses of both test postures, and bilateral activations of the rectus abdominis, internal and external obliques, latissimus dorsi, and lumbar and thoracic erector spinae were measured in a second sample of 15 men and 15 women while holding the test postures. No between-posture differences in net low back flexor moments were found (P = .111), but the lumbar spine was 28° more flexed in the v-sit than in the plank (P < .001). No between-posture differences were detected in the rectus abdominis (P = .397), external obliques (P = .204), internal obliques (P = .226), or lumbar erector spinae (P = .116) activation levels, but those of the thoracic erector spinae (P = .0253) and latissimus dorsi (P < .001) were greater in the plank than in the v-sit. Altogether, the findings suggest that differences between plank and v-sit holding times are most likely related to between-test differences in lumbar spine postures and shoulder demands. PMID:26252077

  3. Ice skating promotes postural control in children.

    PubMed

    Keller, M; Röttger, K; Taube, W

    2014-12-01

    High fall rates causing injury and enormous financial costs are reported for children. However, only few studies investigated the effects of balance training in children and these studies did not find enhanced balance performance in postural (transfer) tests. Consequently, it was previously speculated that classical balance training might not be stimulating enough for children to adequately perform these exercises. Therefore, the aim of this study is to evaluate the influence of ice skating as an alternative form of balance training. Volunteers of an intervention (n = 17; INT: 13.1 ± 0.4 years) and a control group (n = 13; CON: 13.2 ± 0.3 years) were tested before and after training in static and dynamic postural transfer tests. INT participated in eight sessions of ice skating during education lessons, whereas CON participated in normal physical education. Enhanced balance performance was observed in INT but not in CON when tested on an unstable free-swinging platform (P < 0.05) or when performing a functional reach test (P < 0.001). This is the first study showing significantly enhanced balance performance after ice skating in children. More importantly, participating children improved static and dynamic balance control in postural tasks that were not part of the training. PMID:24739083

  4. Postural dynamics and habituation to seasickness.

    PubMed

    Tal, Dror; Bar, Ronen; Nachum, Zohar; Gil, Amnon; Shupak, Avi

    2010-07-26

    The computerized dynamic posturography (CDP) test examines the response pattern to simultaneous, multimodal sensory stimulation. The purpose of this prospective, controlled study was to investigate whether postural dynamics evaluated by CDP are related to seasickness severity and the process of habituation to sea conditions. Subjects included 74 naval personnel assigned to service aboard ship and 29 controls designated for shore-based positions. Study participants performed a baseline CDP test, and subsequent follow-up examinations 6 and 12 months after completion of their training. On those occasions they also completed a seasickness severity questionnaire. Longitudinal changes in postural parameters were examined, as well as a possible correlation between baseline CDP results and final seasickness severity scores. The results indicated longitudinal habituation to seasickness. Reduced scores were found for sensory organization sub-tests 3 and 5 in the first follow-up examination, reflecting increased weighting of visual and somatosensory input in the maintenance of balance. Scores in the second follow-up examination were above baseline values, indicating increased reliance on vestibular cues. These significant bimodal changes were found only in study subjects having the highest degree of habituation to seasickness. A significant decrease in motor response strength was found in parallel with increased habituation to seasickness. Baseline CDP results and postural control dynamics were not correlated with subjects' final seasickness severity score. These results suggest a potential role for CDP in monitoring the process of habituation to unusual motion conditions. PMID:20493235

  5. Minimalist, standard and no footwear on static and dynamic postural stability following jump landing.

    PubMed

    Zech, Astrid; Argubi-Wollesen, Andreas; Rahlf, Anna-Lina

    2015-01-01

    In recreational sports, uncushioned, light-weight and minimalist shoes are increasingly used to imitate barefoot situations. Uncertainty exists whether these shoes provide sufficient stability during challenging movements. In this randomised crossover study, 35 healthy distance runners performed jump landing stabilisation and single-leg stance tests on a force plate, using four conditions in random order: barefoot, uncushioned minimalist shoes, cushioned ultraflexible shoes and standard running shoes. Ground reaction force (GRF) and centre of pressure (COP) data were used to determine unilateral jump landing stabilisation time and COP sway velocity during single-leg stance. Repeated measures analysis of variance revealed significant footwear interactions for medial-lateral (p < 0.001) and anterior-posterior COP sway velocity during standing (p < 0.001). The barefoot condition produced significantly greater postural sway velocities (p < 0.001) compared to all footwear conditions. No significant effects were found for jump landing stabilisation time. In conclusion, the results of this study indicate that increased shoe flexibility and reduced sole support have no, or only minor influence on static and dynamic postural control, and therefore, may not increase the risk of traumatic events during sports activities. However, barefoot conditions should be considered carefully when adequate postural control is needed. PMID:25010996

  6. 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. PMID:26406054

  7. Postural Control of Healthy Elderly Individuals Compared to Elderly Individuals with Stroke Sequelae

    PubMed Central

    Alfieri, Fábio Marcon; Riberto, Marcelo; Lopes, José Augusto Fernandes; Filippo, Thais Raquel; Imamura, Marta; Battistella, Linamara Rizzo

    2016-01-01

    A stroke and aging process can modify the postural control. We aimed to compare the postural control of health elderly individuals to that of individuals with stroke sequelae. This cross-sectional transversal study was made with individuals capable of walking without any assistance and that were considered clinically stable. The study had 18 individuals in the group with stroke sequelae (SG) and 34 in the healthy elderly control group (CG). The participants were evaluated for the timed up and go test (TUG) and force platform. The SG showed the worst results in relation to the time of execution of the TUG and the force platform evaluation. The displacement of center of pressure was worse for both groups in the eyes-closed situation, especially in the anteroposterior direction for the CG. The GS showed worse results in the static and dynamic postural control. The healthy elderly showed more dependence on sight to maintain their static balance and there was no difference in the balance tests in relation to the side affected by the stroke. PMID:27053967

  8. 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. PMID:17273871

  9. Time-of-day effects on postural control and attentional capacities in children.

    PubMed

    Baccouch, Rym; Zarrouk, Nidhal; Chtourou, Hamdi; Rebai, Haithem; Sahli, Sonia

    2015-04-01

    The present study aimed to examine the effect of time-of-day on postural control, body temperature, and attentional capacities in 5-6 year old children. Twelve male children (5-6-year-old) were asked to maintain an upright bipedal stance on a force platform with eyes open (EO) and eyes closed (EC) at 07:00, 10:00, 14:00, and 18:00 h. Postural control was evaluated by center of pressure (CoP) surface area (CoPArea), CoP mean velocity (CoPVm), length of the CoP displacement as a function of the surface (LFS) ratio and Romberg's index (RI). Oral temperature and the simple reaction time were also recorded at the beginning of each test session. The one way ANOVA (4 time-of-day) showed significant time-of-day effects on CoPArea (p<0.001), CoPVm (p<0.01), LFS ratio (p<0.001) and RI (p<0.01). Children's postural control was lower at 07:00 h and at 14:00 h in comparison with 10:00 h and 18:00 h. Likewise, the reaction time was significantly (p<0.001) better at 10:00 h and 18:00 h in comparison with 07:00 h and 14:00 h. Oral temperature was higher at 14:00 h and 18:00 h than 08:00 h and 10:00 h (p<0.001). In conclusion, the children's postural control fluctuates during the daytime (i.e., better postural control at 10:00 h and at 18:00 h) with a diurnal rhythm close to that of body temperature and attentional capacities. Therefore, the evaluation of changes in postural control of 5-6-year-old children using force plate measures is recommended in the middle morning or the late afternoon to avoid the post-awakening and the post-prandial phases. PMID:25623540

  10. Postural control--a comparison between patients with chronic anterior cruciate ligament insufficiency and healthy individuals.

    PubMed

    Lysholm, M; Ledin, T; Odkvist, L M; Good, L

    1998-12-01

    Postural control in the sagittal plane was evaluated in 22 patients with chronic anterior cruciate ligament (ACL) deficiency and the result was compared to that of a control group of 20 uninjured subjects. Measurement of the body sway was done on a fixed and sway-referenced force plate in both single-limb and two-limb stance, with the eyes open and closed, respectively. Further, an analysis of the postural reactions to perturbations backwards and forwards, respectively, was made in single-limb stance. The results demonstrated statistically significant deficits of the postural control in the patient group compared to the control group, but also within the patient group. There was a significantly higher body sway within the patient group when standing on a stable support surface on the injured limb than standing on the uninjured limb with the eyes open, but no difference with the eyes closed. When standing on a stable support surface, there was a significantly higher body sway in the patient group standing on the injured leg than in the control group, both with eyes open and closed. The patient group also showed a significantly impaired postural control compared to the control group when standing on the uninjured leg with the eyes closed. There was no difference between the groups in the two-limb stance. When standing on the sway-referenced support surface, the patient group had a significantly larger body sway than the control group when the eyes were open, but there was no significant difference between the groups with the eyes closed. The measurement of the postural corrective responses to perturbations backwards and forwards showed that the reaction time measured from the initiation of the force plate translation, and the amplitude of the body sway was significantly greater in the patient group than in the control group. We conclude that patients with a continuing chronic ACL insufficiency several years after injury have an impaired postural control in the antero