scholarly journals Attentional demands associated with augmented visual feedback during quiet standing

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5101 ◽  
Author(s):  
Krzysztof Kręcisz ◽  
Michał Kuczyński
Keyword(s):  
Postural Control ◽  
Visual Feedback ◽  
Center Of Pressure ◽  
Quiet Standing ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Postural Control System ◽  
Power Frequency ◽  
Auditory Reaction Time ◽  
Anterior Posterior

To investigate how additional visual feedback (VFB) affects postural stability we compared 20-sec center-of-pressure (COP) recordings in two conditions: without and with the VFB. Seven healthy adult subjects performed 10 trials lasting 20 seconds in each condition. Simultaneously, during all trials the simple auditory reaction time (RT) was measured. Based on the COP data, the following sway parameters were computed: standard deviation (SD), mean speed (MV), sample entropy (SE), and mean power frequency (MPF). The RT was higher in the VFB condition (p < 0.001) indicating that this condition was attention demanding. The VFB resulted in decreased SD and increased SE in both the medial-lateral (ML) and anterior-posterior (AP) planes (p < .001). These results account for the efficacy of the VFB in stabilizing posture and in producing more irregular COP signals which may be interpreted as higher automaticity and/or larger level of noise in postural control. The MPF was higher during VFB in both planes as was the MV in the AP plane only (p < 0.001). The latter data demonstrate higher activity of postural control system that was caused by the availability of the set-point on the screen and the resulting control error which facilitated and sped up postural control.

Surface height effects on postural control: A hypothesis for a stiffness strategy for stance*

1999 ◽  
Vol 9 (4) ◽  
pp. 277-286 ◽  
Author(s):  
Mark G. Carpenter ◽  
James S. Frank ◽  
Cathy P. Silcher
Keyword(s):  
Postural Control ◽  
Center Of Pressure ◽  
High Surface ◽  
Quiet Standing ◽  
Vestibular Input ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Balance Confidence ◽  
Eyes Closed ◽  
Ankle Stiffness

One possible factor influencing the control of upright stance is the perceived threat to one's personal safety, i.e. balance confidence. We explored this factor by examining the control of stationary stance when standing on an elevated platform under various conditions of reduced visual and vestibular inputs. Twenty-eight adults (14 male and 14 female, mean age = 23.5 years) participated in the experiment. Postural control was examined by recording the amplitude variability (RMS) and mean power frequency (MPF) of center of pressure excursions (COP) over a 2-minute interval while participants stood in a normal stance on a low (0.19 m) and a high (0.81 m) platform with toes positioned either at or away from the edge of the platform. Vision was manipulated through eyes open and eyes closed trials. Vestibular input was reduced by tilting the head into extension [1]. Anterior-posterior RMS and MPF of COP were significantly influenced by an interaction between surface height and vision. When vision was available, a significant decrease in RMS was observed during quiet standing on a high surface compared to a low surface independent of step restriction. When vision was available MPF increased when subjects were raised from a low to a high surface. The mean position of the COP was significantly influenced by an interaction between height and step restriction. Differences in RMS and MPF responses to height manipulation were observed between genders in eyes closed conditions. Vestibular input influenced postural control at both low and high levels with significant increases in RMS when vestibular input was reduced. The reciprocal changes observed in RMS and MPF suggest modifications to postural control through changes in ankle stiffness. Vision appears to play a role in increasing ankle stiffness when balance confidence is compromised.

scholarly journals Characteristics of Functional Stability in Young Adolescent Female Artistic Gymnasts

2021 ◽  
Vol 77 (1) ◽  
pp. 51-59
Author(s):  
Agnieszka Opala-Berdzik ◽  
Magdalena Głowacka ◽  
Kajetan J. Słomka
Keyword(s):  
Postural Control ◽  
Center Of Pressure ◽  
National Level ◽  
Stability Limit ◽  
Young Adolescent ◽  
Quiet Standing ◽  
Adolescent Female ◽  
Functional Stability ◽  
Postural Control System ◽  
Stability Limits

Abstract The aim of this study was to determine whether young adolescent female artistic gymnasts demonstrate better functional stability than age- and sex-matched non-athletes. Different characteristics of the gymnasts’ postural control were expected to be observed. Twenty-two 10- to 13-year-old healthy females (ten national-level artistic gymnasts and twelve non-athletes) participated in the study. To assess their forward functional stability, the 30-s limit of stability test was performed on a force plate. The test consisted of three phases: quiet standing, transition to maximal forward leaning, and standing in the maximal forward leaning position. Between-group comparisons of the directional subcomponents of the root mean squares and mean velocities of the center of pressure and rambling-trembling displacements in two phases (quiet standing and standing in maximal leaning) were conducted. Moreover, anterior stability limits were compared. During standing in maximal forward leaning, there were no differences in the center of pressure and rambling measures between gymnasts and non-athletes (p > 0.05). The values of trembling measures in both anterior-posterior and medial-lateral directions were significantly lower in gymnasts (p < 0.05). Both groups presented similar values for anterior stability limits (p > 0.05). The comparisons of rambling components may suggest a similar supraspinal control of standing in the maximal leaning position between gymnasts and healthy non-athletes. However, decreased trembling in gymnasts may indicate reduced noise in their postural control system possibly due to superior control processes at the spinal level. The anterior stability limit was not influenced by gymnastics training in female adolescents.

scholarly journals Trends in the Analysis of Static Balance

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Vilma Juodžbalienė ◽  
Kazimieras Muckus
Keyword(s):  
Postural Control ◽  
Physiological Parameters ◽  
Quiet Standing ◽  
Static Balance ◽  
Foot Pressure ◽  
Postural Control System ◽  
Balance Disorders ◽  
Dependent Variables ◽  
Center Of Foot Pressure ◽  
Anterior Posterior

The aim of the paper was to discuss the trends in the analysis of static balance and relation between physiological parameters and characteristics of posturograms. Static balance is ability to keep steady posture in certain stance [2, 3]. Posturography is one of most popular research methods of static balance [10, 11]. During the last decade it was maintained that the most informative dependent variables defining postural stability were the amplitude of the center of foot pressure (COP) sway in anterior-posterior and mediolateral directions, the length of the COP pathway and the area of the COP sway [9, 15]. The output of the posturograms registered during quiet standing is irregular and erratic [14]. Therefore, methods analyzing the structure of the posturograms are very topical for physiology and Rehabilitation science. The scientists attempt to determine certain noise and oscillation patterns in the posturogram [20]. According to researchers [14], the structure and roughness or smoothness of the posturogram could reflect the changes in postural control system. It is still questionable which of the methods analyzing the posturogram outcomes could be the most informative and useful for the diagnostics of postural control disorders. It is important to be able to repeat the scientific study, but it is still complicated to solve tasks related to postural control disorders diagnostics and the evaluation of the treatment means effectiveness. It is important to define the relation between physiological parameters and characteristics of posturograms in order to apply the posturography for balance disorders diagnostics. We suppose that methods of posturogram structure analysis could improve the differential balance disorders diagnostics essentially.Keywords: static balance, static posturography, center of foot pressure.

Postural sway following inversion sprain of the ankle

1991 ◽  
Vol 81 (5) ◽  
pp. 243-247 ◽  
Author(s):  
MW Cornwall ◽  
P Murrell
Keyword(s):  
Ankle Sprain ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Control Group ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Linear Distance ◽  
History Of ◽  
Power Frequency ◽  
The Mean

The single-limb sway of 20 individuals with a history of unilateral inversion ankle sprain was compared to that of a control group of 30 individuals without a history of ankle sprain. Using a force platform to obtain center-of-pressure data, the linear distance traveled (mm) and the mean power frequency, (Hz) of postural sway were calculated for each subject. The results of this study showed that postural sway amplitude was significantly greater in the injured group than in the control group. Contrary to previous investigations, this study indicates that individuals with a history of inversion ankle sprain are less stable in single-limb stance compared to a noninjured control group. This decreased stability is evident as much as 2 years following the injury.

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

2010 ◽  
Vol 109 (6) ◽  
pp. 1786-1791 ◽  
Author(s):  
Brad Manor ◽  
Madalena D. Costa ◽  
Kun Hu ◽  
Elizabeth Newton ◽  
Olga Starobinets ◽  
...  
Keyword(s):  
Postural Control ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Quiet Standing ◽  
Multiscale Entropy ◽  
Postural Control System ◽  
Dual Tasking ◽  
Complexity Index ◽  
Pressure Dynamics ◽  
Boston Study

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

The influence of electrode placement over the innervation zone on electromyographic amplitude and mean power frequency versus isokinetic torque relationships

2007 ◽  
Vol 162 (1-2) ◽  
pp. 72-83 ◽  
Author(s):  
Travis W. Beck ◽  
Terry J. Housh ◽  
Michelle Mielke ◽  
Joel T. Cramer ◽  
Joseph P. Weir ◽  
...  
Keyword(s):  
Electrode Placement ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Innervation Zone ◽  
Power Frequency ◽  
Isokinetic Torque

Dependence of the mean power frequency of the electromyogram on muscle force and fibre type

1991 ◽  
Vol 142 (4) ◽  
pp. 457-465 ◽  
Author(s):  
B. GERDLE ◽  
K. HENRIKSSON-LARSÉN ◽  
R. LORENTZON ◽  
M.-L. WRETLING
Keyword(s):  
Fibre Type ◽  
Muscle Force ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Power Frequency ◽  
The Mean

Surface electromyogram power spectrum in human quadriceps muscle during incremental exercise

1993 ◽  
Vol 74 (6) ◽  
pp. 2704-2710 ◽  
Author(s):  
D. Gamet ◽  
J. Duchene ◽  
C. Garapon-Bar ◽  
F. Goubel
Keyword(s):  
Principal Component ◽  
Quadriceps Muscle ◽  
Bicycle Ergometer ◽  
Linear Increase ◽  
Total Power ◽  
Test Surface ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Incremental Test ◽  
Power Frequency

Spectral electromyographic (EMG) changes in human quadriceps muscles were studied to reinvestigate discrepant results concerning mean power frequency (MPF) changes during dynamic exercise. An incremental test consisting of a quasi-linear increase in mechanical power on a bicycle ergometer (for 20–100% of maximal aerobic power) was performed by forty subjects. During this test, surface EMGs from the quadriceps muscles showed that EMG total power (PEMG) increased with a curvilinear pattern for every subject, whereas MPF kinetics varied from one subject to another. PEMG changes had the same shape, which would lead to disappointing results in terms of discrimination between subjects. The ability of normalized MPF kinetics to define significant clusters of subjects was tested using a principal component analysis. This analysis led to the projection of all experiments onto a plane and revealed a relevant grouping of MPF profiles. Differences in MPF kinetics between clusters are interpreted in terms of various possibilities of balance between physiological events leading to an increase or a decrease in MPF.

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