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1

General muscle fatigue changed joint regulations in static and dynamic balance

Babayi Masumeh, Najafabadi Sayed Mohsen Mortazavi, Ashtiani Mohammed N., Grzelczyk Dariusz

Acta of Bioengineering and Biomechanics

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2023

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Vol. 25, no. 2

125--132

EN

This study was aimed at investigating the joint regulations and body sway after general muscle fatigue during tasks that involve both static and dynamic balance. This cross-sectional study used motion analysis to ascertain the kinematic changes in twelve healthy young individuals before and after running-induced fatigue. Six linear and nonlinear stability metrics were calculated to assess the whole body and joint-related variations. Significant instabilities were observed in the hip and specifically in the knee mechanisms and the whole body during the static condition. Velocity path length and approximate entropy for knee ( p = 0.019, p = 0.027) and hip ( p = 0.016, p = 0.042) were significantly greater after fatigue. These parameters for the whole body center of mass were also higher after fatigue ( p = 0.013, p = 0.013). General muscle fatigue did not significantly affect the ankle during static and dynamic standing ( p > 0.05). Dynamic standing did not reveal the effects of fatigue either on local joint regulations or on the whole body except for the nonlinear metrics of the proximal joints. The knee and hip were adversely affected by fatigue while the ankle strove to compensate for the fatigue-induced instability.

2

The effect of a light finger touch on the signal complexity during quiet standing

Brachman Anna, Sawicka Anna, Bednarz Bartłomiej, Akbas Anna, Słomka Kajetan J.

Acta of Bioengineering and Biomechanics

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2022

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Vol. 24, no. 3

91--97

EN

The purpose of the study was to investigate the influence of additional tactile information (light fingertip touch) on the postural sway and regularity of center-of-pressure (COP) fluctuations. Thirty-two young, healthy participants performed a quiet standing task (30 s) on a force platform with and without light fingertip touch. COP time-series were analyzed using standard postural sway measures (range, root mean square error, velocity), COP regularity was measured with Sample entropy. Participants demonstrated significantly smaller postural sway with a light touch, but only in the anteroposterior direction. The amount of sway with additional tactile information in the sagittal plane reached the level of sway in the frontal plane without this information. Similarly, COP fluctuations were more irregular during light touch condition only in the anteroposterior direction, as evidenced by significantly higher Sample entropy. Furthermore, COP regularity decreased in the sagittal plane and reached level in the frontal plane without light touch. These results suggest that postural sway is mostly controlled in the sagittal plane and that in the mediolateral direction the control is mostly automated. In conclusion, our results support the notion that the light touch provides additional information which enhances postural stabilization. Our results expand the relation between COP regularity and the attention invested in posture in the touch domain and prove that light touch, as an attentional demanding task, leads to increased COP irregularity. Nonlinear measures of signal regularity (i.e., SampEn) provide surplus insight into human postural control and can be used as an additional useful tool to traditional balance measures.

3

Effect of smooth eye tracking in different patterns on results of the modified Clinical Balance Sensory Integration Test in healthy young adults

Wójtowicz Sebastian, Łakoma Aleksandra, Ferenc Aneta, Daniluk Anna, Wiaderna Karolina, Hadamus Anna

Acta of Bioengineering and Biomechanics

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2022

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Vol. 24, no. 4

57--64

EN

The aim of the study was to determine whether eye tracking of a point moving in different directions influences balance test performance in young healthy subjects. Methods: The study enrolled 45 healthy young adults aged 19–26. Balance assessment was carried out according to the modified Clinical Balance Sensory Integration Test protocol using the Biodex Balance System with an additional 63” screen to present the eye-tracking task. Each participant repeated measurements in standing on a stable and foam surface in six test conditions: two without eye tracking with eyes open and eyes closed, and four with eye tracking: with vertical, horizontal, star, and circle moving point. Each trial lasted 30 sec. Results: Regression analysis for the Sway Index showed that there was no impact of eye tracking on test results ( p = 0.4326), although detailed analysis showed a significant impact of tracking a point moving in a circle in standing on a foam surface ( p < 0.001). Conclusions: The presented results show that eye-tracking does not influence the results of the balance test with exception of eye-tracking of the circle movement in standing on a foam surface. It suggests that eye movements may affect the test results when performing more difficult balance tests.

4

Characterization of the anteroposterior center of pressure in upright position in type 2 diabetics with peripheral diabetic neuropathy and paired healthy controls

Toloza-Cano Daissy Carola, Zequera Martha, González Gustavo Hernando Castro

Biocybernetics and Biomedical Engineering

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2021

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Vol. 41, no. 1

306--315

EN

Peripheral diabetic neuropathy (PDN) is a complication of type 2 diabetes (T2DM) that impairs posture control and increases the risk of falling. The aim of this study was to characterize the anteroposterior center of pressure (COP-AP) in the time and the frequency domains in the T2DM/PDN group in relation to the control group. To that end we: (1) evaluated the efficacy of using both linear and non-linear discrete wavelet transform (DWT) analyses to evaluate oscillation patterns in the anteroposterior center of pressure (COP-AP) in the bipedal position in terms of time and frequency and (2) established input parameters for a model for predicting the risk of falling. This study included an experimental sample of 30 people with T2DM/PDN matched by gender, age, weight and height with a control sample of 30 healthy individuals. Unreported techniques for analyzing the COP-AP literature were assessed for their capacity to model patient bodily stability in the proprioceptive, visual and vestibular systems. To measure COP-AP, five tests were performed under different conditions as outlined in the Romberg Test using the ‘‘PEDAR System’’ for measuring plantar pressure. DWTs were used to calculate excursion parameters, average speeds, range, RMS values, the average maximum and minimum amplitude, power spectral densities and energy percentages in 11 frequency bands (D1 to D10 and A10). There were significant differences between the two study groups in terms of the calculated linear parameters ( p < 0.05). Using linear and non-linear DWT analyses, a preliminary characterization of COP-AP patterns was achieved. DWT could be used alongside linear analysis to determine the effect changes in these systems have on postural oscillation in people with T2DM.

5

Nonlinear measures in posturography compared to linear measures based on yoga poses performance

Błażkiewicz MIchalina

Acta of Bioengineering and Biomechanics

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2020

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Vol. 22, no. 4

15--21

EN

Yoga is known as a type of exercise that combines physical, mental and spiritual aspects. There has not been much research on the postural control in various yoga poses. The aim of this study was to examine CoP regularity in both yoga instructors and novices during the performance of four yoga poses, and to verify the sensitivity of linear and nonlinear methods for assessing postural stability. Methods: The dynamic characteristics of CoP fluctuations were examined using linear and nonlinear methods on a group of 22 yoga instructors (Y) and 18 age-matched non-practitioners of yoga (NY). The study involved maintaining a balance for 20 seconds while performing four yoga poses. Results: Conventional analysis of CoP trajectories showed that NY and Y exhibited similar control of postural sway, as indicated by similar CoP path-length and area values observed in both groups. These results suggest that the special balance yoga training received by Y may not have an impact on less challenging balance conditions, such as the poses used in this experiment. Interestingly, nonlinear dynamical analysis of CoP showed that Y exhibited less CoP regularity and more complex signal than NY, as evidenced by higher values of sample entropy and fractal dimension. Conclusions: The results shed light on the surplus values of CoP trajectories in the nonlinear dynamical analysis to gain further insight into the mechanisms involved in posture control.

6

Stabilometric profile of handstand technique in male gymnasts

Sobera Małgorzata, Serafin Ryszard, Rutkowska-Kucharska Alicja

Acta of Bioengineering and Biomechanics

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2019

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Vol. 21, no. 1

63--71

EN

This study aimed to determine the characteristic features of handstand posture control associated with a high level of ability among male gymnasts. Methods: 8 acrobatic gymnasts (4 more and 4 less experienced) participated in the study. They performed a 10-second handstand five times with each hand positioned on one AccuSway (AMTI) force platform and the other hand on the second. Body sway changes were recorded in time series: centre of pressure (COP) and components of the ground reaction force (GRF) (vertical, medial-lateral and anterior-posterior). The COP amplitude and average of GRF components, the index of frequency (by Fast Fourier Transform) for the right and left hand were calculated. Results: More experienced gymnasts performing a handstand concentrate mainly on minimizing anterior-posterior body sway with minimum medial-lateral body sway. Less experienced gymnasts’ pressure exerted on a surface by the hands is irregular in a medial-lateral direction. More experienced gymnasts control body position in the handstand and show less variation of body sway compared to less experienced gymnasts. More experienced gymnasts revealed lower frequency of body sway in the handstand compared to less experienced gymnasts. Conclusion: The stabilometric profile of more experienced gymnasts means the better posture control in handstand. The minimizing of body sway is compensated by exerting more force on a floor surface and the less experienced athletes cannot do that even after several years of training. The gymnasts of both groups, during standing on their hands, put more load on the right hand.

7

Gender differences in postural stability in elderly people under institutional care

Wiśniowska-Szurlej Agnieszka, Ćwirlej-Sozańska Agnieszka, Wilmowska-Pietruszyńska Anna, Wołoszyn Natalia, Sozański Bernard

Acta of Bioengineering and Biomechanics

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2019

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Vol. 21, no. 2

45--53

EN

The aim of the research was to assess the postural stability indicators of older women and men receiving institutional care. Methods: The study involved 123 people aged 65–85, living in residential care homes in Rzeszów district. The main research tool was the CQ-Stab 2P 2-platform posturograph. Results: There were statistically significant differences between women and men in the total statokinesiogram path length, the statokinesiogram path length in the anteroposterior direction, the mean COP displacement in the anteroposterior direction as well as the mean velocity of the COP point in the anteroposterior direction under eye control ( p = 0.04). In the case of absence of visual control, men were characterized by significantly worse parameters in the area of mean COP displacement in the anteroposterior and lateral directions as well as the maximal COP displacement in the anteroposterior and lateral directions. It indicated that without visual control body balance parameters in men significantly worsened along with increasing age. A statistically significant difference was found between both genders in terms of the statokinesiogram path length, the mean COP displacement and the mean COP velocity ( p < 0.05). Conclusions: Gender differences in postural stability of older people under institutional care were noticed. Men were characterized by a lower level of postural stability compared to women. Elimination of visual control significantly worsened the balance of the body. The results obtained indicate the necessity of introducing therapeutic programs in nursing homes, taking proprioceptive exercises and exercises without visual input into account.

8

Quiet standing postural sway of 10- to 13-year-old, national-level, female acrobatic gymnasts

Opala-Berdzik A., Głowacka M., Wilusz K., Kołacz P., Szydło K., Juras G.

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 2

117--123

EN

Purpose: The aim of the study was to determine whether 10- to 13-year-old, national-level, female acrobatic gymnasts present a different quiet standing postural control (with and without visual cues) than untrained female peers. Methods: The mean velocity of the center of pressure (in anterior-posterior and medial-lateral directions) was computed from 60-s long quiet-standing trials on a stationary force plate in fifteen 10- to 13-year-old female acrobatic gymnasts and thirteen sex- and age-matched non-athletes. A two-way repeated measures ANOVA (acrobatic gymnasts vs. non-athletes and eyes open vs. eyes closed) was used for the anterior-posterior and mediallateral COP mean velocity. The relation between subjects’ body mass and COP mean velocity was tested with the used Spearman’s Rank Correlation Coefficient. Results: Postural sway (represented by COP mean velocity) was not significantly different between the acrobatic gymnasts and the non-athletes ( p > 0.05), except for the faster medial-lateral sway in eyes-open conditions in the acrobatic gymnasts ( p < 0.05). The gymnasts’ body mass negatively correlated with their anterior-posterior sway velocity in both visual conditions (eyes open: r = –0.7; eyes closed: r = –0.6) and with medial-lateral sway velocity during eyes-closed trials (r = –0.5; p < 0.05). Conclusions: Results of the study indicate that in quiet standing postural control 10- to 13-year-old acrobatic gymnasts did not make use of their trained abilities. Heavier gymnasts might have been more stable than lighter ones during quiet standing.

9

Effect of different balance training programs on postural control in chronic ankle instability: a randomized controlled trial

Youssef N. M., Abdelmohsen A. M., Ashour A. A., Elhafez N. M., Elhafez S. M.

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 2

159--169

EN

Chronic ankle instability (CAI) is a common sequence of ankle sprain. Conservative treatment of CAI is currently accepted as a primary mean of managing the condition and preventing of recurrence. Objectives: The purpose of the current study was to evaluate the effect of Weight-bearing Exercise for Better Balance (WEBB) program and unilateral balance training exercises on postural control in females with CAI. Methods: Thirty-five females with CAI participated in this study. The participants’ mean values of age, body mass, height, and body mass index were 21.76 ± 1.96 y, 64.82 ± 9.37 kg, 161.85 ± 7.24 cm, and 24.76 ± 3.76 kg/m², respectively. They were randomly assigned into three groups: experimental group A (n = 13) who received WEBB program, experimental group B (n = 12) who received unilateral balance training, and control group C (n = 10) using statistical random tables. Balance parameters were measured for all participants via Biodex Balance System (BBS) before and after four weeks of balance training. They included overall stability index (OASI), antero-posterior stability index (APSI), and medio-lateral stability index (MLSI). Results: There was a significant improvement in the post testing mean values of OASI and APSI, compared with the pre testing values in both experimental groups (A and B). There was no significant difference between the pre and post testing mean values of MLSI in the experimental group (A). Conclusions: Both WEBB program and unilateral balance training have positive effects on postural control in females with CAI.

10

The follow-up posturography in rehabilitation after total hip arthroplasty

Pethe-Kania K., Opara J. A., Kania D., Kidoń Z., Łukaszewicz T.

Acta of Bioengineering and Biomechanics

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2017

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Vol. 19, no. 1

97--104

EN

Purpose: Presentation of the results of clinical study on new supplementary method applied in the physical rehabilitation of patients who underwent total hip arthroplasty. The standard rehabilitation program was supplemented with the lower limb loading symmetry training based on the follow-up posturography with an adaptively modified visual biofeedback, performed on a double plate posturographic platform. Methods: The research involved 60 randomly selected patients included in prospective and comparative clinical study in the scheme of the parallel groups. The subjects were divided into two groups comprised of 30 patients each. In both groups a conventional 21-day rehabilitation was carried out. Additionally, in experimental group the limb loading symmetry restoration training based on the follow-up posturography with an adaptively modified biofeedback was implemented. The biofeedback coefficient reflected the distribution of loading exerted on a given patient’s legs and was evaluated during the static posturography examinations carried out before each symmetry training session. Results: The eyes-open static posturography examinations indicated significant improvement in the lower limb loading symmetry in 29 (97%) patients from the experimental group ( p = 0.000003). In the control group, such an improvement was observed in 20 (67%) patients ( p = 0.034796). In the eyes closed examinations correction in the limb loading symmetry was evident in 23 (77%) patients from the experimental group ( p = 0.000247) and 18 (60%) patients from the control group ( p = 0.043327). Conclusions: Significant improvement in the lower limb loading symmetry was observed in patients who underwent rehabilitation supplemented with the herein discussed training method.

11

Hip strategy alterations in patients with history of low disc herniation and non-specific low back pain measured by surface electromyography and balance platform

Ciesielska J., Lisiński P., Bandosz A., Huber J., Kulczyk A., Lipiec J.

Acta of Bioengineering and Biomechanics

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2015

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Vol. 17, no. 3

103--108

EN

Purpose: The appearance of pathology in the lumbar spine, such as a previous episode of low disc herniation or non-specific low back pain contributes to improper activation of the hip muscles. The aim of the study was to detect alterations in hip strategy manifested by differences in balance parameters and rectus femoris and gluteus maximus activity in people with previous episode of pain radiation to one lower limb caused by low disc herniation or non-specific low back pain. Methods: We studied 11 patients with history of low-disc herniation, 9 patients with history of non-specific low back pain and 10 healthy subjects. Hip strategy alterations were detected by measuring rectus femoris and gluteus maximus activity in bilateral surface polyelectromyographic recordings and by stability measurements on a balance platform. Results: In the surface polyelectromyography study, in both patients' group the value of the average amplitude was higher and the amount of the fluctuations was lower than in healthy subjects. There were no significant differences in stability parameters. Conclusions: A changed pattern of hip muscles activity was detected in the patients without changes in stability parameters. Greater disorder occurs in people in with previous episode of pain radiation to one lower limb caused by low disc herniation than in people with non-specific low back pain.

12

Disparity of a Seat Cushion and Its Influence on Postural Control

Nag P.K., Nag A., Vyas H., Shah P.

International Journal of Occupational Safety and Ergonomics

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2013

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Vol. 19, No. 4

573--581

EN

Properties of supporting surfaces of a seat have an influence on postural control. Centre of pressure (COP) displacement parameters reflect both the balance controlling process and movements of the centre of a mass of entire body. The subjects of the study were 9 healthy men. A seat cushion was examined with a 2-force platform setup. Force exertion at a seat pan and feet and COP displacement at a seat pan were measured to analyse postural control. Analysis of variance determined the differences in postural control depending on a cushion type among the subjects. Significant differences in COP displacement parameters were in COP trajectory length, medio-lateral COP displacement and COP velocity. The results of the study showed that foam cushion ensures better postural control.

13

Repeatability of frequency of corrective foot pressure during balance control in children aged between 2 and 7

Sobera M., Siedlecka B.

Acta of Bioengineering and Biomechanics

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2010

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Vol. 12, no. 2

73-77

EN

The frequency of corrective signal (the centre of corrective (COC) signal), which is the decomposition of COP (centre of pressure) and estimated COM (centre of mass) time series, is one of the indicators reflecting the quality of postural control during stance. Young children, in the period of intensive development, gradually improve the quality of postural control in a daily life. The purpose of this paper was to describe the time series of corrective centre of foot pressure repeatability in young children aged between 2 and 7 during body stability in natural stance position. 272 healthy children aged between 2 and 7 were divided into 6 age groups. Two AccuSway force platforms were used (one foot of the subject was on one platform, the second foot, on the other). The COP trajectories were the basis for the calculation of the frequency stability indices in frontal and sagittal planes for the left leg and right leg separately. The COC signals were collected by the method based on the Kuczyński viscoelastic model. In order to assess the repeatability, the concordance correlation coefficient (CCC) was used between the 1st and the 2nd trials, the 2nd and the 3rd trials, and the 1st and the 3rd trials. The maturation of postural control system goes rather slowly in two youngest groups which showed the poor repeatability in COC frequency between the 2nd and the 3rd years of life. From the 4th to the 7th year of life the inter-session repeatability rapidly increases in three consecutive trials. Poor difference of frequency concordance was found between the left and right lower limbs. It is concluded that the frequency of corrective foot pressure is the reliable indicator of postural control for children aged between 4 and 7, but not for younger ones.

14

Predictability of posturographic signals: influence of the window width and the embedding dimension

Michalak K. P., Jaśkowski P.

Biocybernetics and Biomedical Engineering

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2007

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Vol. 27, no. 4

71-83

EN

Predictability of 120s-long posturographic signals was investigated by the method of forecasting. We used signals from 32 young healthy participants registered with both open and closed eyes. Influence of the window width and the embedding dimension on predictability was studied. Our results indicate existence of a deterministic component in the posturographic signal. Predictability decreases with the increasing window width ranging from 0.24s to 3.84s. An increase of the embedding dimension, while keeping the window width constant and an adequate decrease of the lag is proposed as a method that could better estimate the saturation dimension of the medium- and high-dimensional signals. Moreover, we have found that the signals representing swaying in the anterio-posterior direction have a higher predictability than those representing lateral swinging and that closing the eyes deteriorates predictability of the posturographic signals.