Wyniki wyszukiwania - Biblioteka Nauki

1

A Comparative Analysis of the Kayak Forward Stroke

100%

Skopek M. , Bacakova R. , Bily M. , Tunkova K.

Physical Activity Review

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2019

|

nr 7

107-113

EN

This work follows previous research in the field which investigated the comparison of two types of paddling. These studies, however, focused on the similarity of kayaking and trainers, more precisely ergometers, that are used by racers during their training in the winter. However, the results of these studies indicate a significant difference in muscle involvement. Aim of Study: The aim of this study is to describe and to compare the muscle activation of the kayak forward stroke performed in a pool with an opposite/counter current and on flat/calm water. Material and Methods: The research was conducted via a selected sample of eight kayakers (subjects) who had attained a high level of performance in whitewater slalom. We observed the activity of twelve selected muscles used during the kayak forward stroke performed in a counterflow pool and on flat water by means of surface electromyography and kinematic analysis. Study results point to effects in relation to intraindividual and subsequently inter-individual muscle timing and the size of the muscle activation due to maximal voluntary contraction. We used comparative analysis and the data were measured by surface electromyography and 2D video-analysis. Results: The results proved equal timing of muscles in a counterflow pool and on flat water. The muscle activity in the counterflow pool was bigger than on flat water. Conclusion: From our results we can recommend a pool which makes use of a counter current as a replacement training tool. Compared with other training devices which might be used (such as, crank ergometers, paddling trainers, and paddling pools), this kind of training device gives the kayaker one great advantage. It is the fact that the kayaker has the same placement of the fixed point and the preservation of the feeling of grasping water.

2

Muscle Fatigue in the Three Heads of the Triceps Brachii During a Controlled Forceful Hand Grip Task with Full Elbow Extension Using Surface Electromyography

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Ali M. A. , Sundaraj K. , Ahmad R. B. , Ahamed N. U. , Islam M. A. , Sundaraj S.

Journal of Human Kinetics

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2015

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tom 46

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nr 1

69-76

EN

The objective of the present study was to investigate the time to fatigue and compare the fatiguing condition among the three heads of the triceps brachii muscle using surface electromyography during an isometric contraction of a controlled forceful hand grip task with full elbow extension. Eighteen healthy subjects concurrently performed a single 90 s isometric contraction of a controlled forceful hand grip task and full elbow extension. Surface electromyographic signals from the lateral, long and medial heads of the triceps brachii muscle were recorded during the task for each subject. The changes in muscle activity among the three heads of triceps brachii were measured by the root mean square values for every 5 s period throughout the total contraction period. The root mean square values were then analysed to determine the fatiguing condition for the heads of triceps brachii muscle. Muscle fatigue in the long, lateral, and medial heads of the triceps brachii started at 40 s, 50 s, and 65 s during the prolonged contraction, respectively. The highest fatiguing rate was observed in the long head (slope = −2.863), followed by the medial head (slope = −2.412) and the lateral head (slope = −1.877) of the triceps brachii muscle. The results of the present study concurs with previous findings that the three heads of the triceps brachii muscle do not work as a single unit, and the fiber type/composition is different among the three heads.

3

Effects of a Dynamic Warm-Up, Static Stretching or Static Stretching with Tendon Vibration on Vertical Jump Performance and EMG Responses

100%

Yapicioglu B. , Colakoglu M. , Colakoglu Z. , Gulluoglu H. , Bademkiran F. , Ozkaya O.

Journal of Human Kinetics

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2013

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tom 39

|

nr 1

49-57

EN

The purpose of this study was to investigate the short-term effects of static stretching, with vibration given directly over Achilles tendon, on electro-myographic (EMG) responses and vertical jump (VJ) performances. Fifteen male, college athletes voluntarily participated in this study (n=15; age: 22±4 years old; body height: 181±10 cm; body mass: 74±11 kg). All stages were completed within 90 minutes for each participant. Tendon vibration bouts lasted 30 seconds at 50 Hz for each volunteer. EMG analysis for peripheral silent period, H-reflex, H-reflex threshold, T-reflex and H/M ratio were completed for each experimental phases. EMG data were obtained from the soleus muscle in response to electro stimulation on the popliteal post tibial nerve. As expected, the dynamic warm-up (DW) increased VJ performances (p=0.004). Increased VJ performances after the DW were not statistically substantiated by the EMG findings. In addition, EMG results did not indicate that either static stretching (SS) or tendon vibration combined with static stretching (TVSS) had any detrimental or facilitation effect on vertical jump performances. In conclusion, using TVSS does not seem to facilitate warm-up effects before explosive performance.

4

A speech recognition system based on electromyography for the rehabilitation of dysarthric patients: A Thai syllable study

75%

Sae Jong N. , Phukpattaranont P.

Biocybernetics and Biomedical Engineering

|

2019

|

tom Vol. 39, no. 1

234--245

EN

The objective of this study is to develop a speech recognition system for classifying nine Thai syllables, which is used for the rehabilitation of dysarthric patients, based on five channels of surface electromyography (sEMG) signals from the human articulatory muscles. After the sEMG signal from each channel was collected, it was processed by a band-pass filter from 20–450 Hz for noise removal. Then, six features from three feature categories were determined and analyzed, namely, mean absolute value (MAV) and wavelength (WL) from amplitude based features (ABF), zero crossing (ZC) and mean frequency (MNF) from frequency based features (FBF), and L-kurtosis (L-KURT) and L-skewness (L-SKW) from statistics based features (SBF). Subsequently, a spectral regression extreme learning machine (SRELM) was used as the feature projection technique to reduce the dimension of feature vector from 30 to 8. Finally, the projected features were classified using a feed forward neural network (NN) classifier with 5-fold cross-validation. The proposed system was evaluated with the sEMG signals from seven healthy volunteers and five dysarthric volunteers. The results show that the proposed system can recognize the sEMG signals from both healthy and dysarthric volunteers. The average classification accuracies obtained from all six features in the healthy and dysarthric volunteers were 94.5% and 89.4%, respectively.

5

Komputerowo wspomagana klasyfikacja wybranych sygnałów elektromiografii powierzchniowej

75%

Rzyman G. , Redlarski G. , Krawczuk M.

Modelowanie Inżynierskie

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2017

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tom T. 31, nr 62

81--87

PL

Wykorzystywanie sygnałów elektromiografii powierzchniowej (ang. Surface Electromyography, SEMG) w procesach sterowania systemami rehabilitacyjnymi stanowi obecnie standardową procedurę. Popularność SEMG wynika z nieinwazyjności metody oraz możliwości szybkiej i precyzyjnej identyfikacji funkcji mięśniowej. W przypadku osób małoletnich proces klasyfikacji sygnałów jest utrudniony ze względu na mniejsze rozmiary i wyższą dynamikę aktywności włókien mięśniowych niż u osób dorosłych. W związku z powyższymi uwagami, w artykule przedstawiono wyniki badań zwiększających wskaźnik poprawnej klasyfikacji wybranych ruchów dłoni dzieci. Omówiono zastosowane do tego celu modele matematyczne: k-najbliższych sąsiadów, drzewo decyzyjne oraz metodę wektorów nośnych; a także zastosowane miary i metodykę „strojenia” parametrów modeli.

EN

Overarching objective of this paper is classification of basic hand gestures by surface electromyography for healthy children. Main difference between biosignals corresponding to adults and children muscle activity is disparate growth of muscles. For this reason youngsters need separate method of signals classification. In this paper we decide to create a mathematical model and compare three classification method: a support vector machine, k nearest neighbors and decision tree methods. Furthermore we used the best set of time domain (MAV, WAMP, WL and SSC) and selected several parameters to make each model as good as possible.

6

Shoulder girdle muscle activity and fatigue in traditional and improved design carpet weaving workstations

75%

Allahyari T. , Mortazavi N. , Khalkhali H. R. , Sanjari M. A.

International Journal of Occupational Medicine and Environmental Health

|

2015

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tom 29

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nr 2

345-354

EN

Objectives Work-related musculoskeletal disorders in the neck and shoulder regions are common among carpet weavers. Working for prolonged hours in a static and awkward posture could result in an increased muscle activity and may lead to musculoskeletal disorders. Ergonomic workstation improvements can reduce muscle fatigue and the risk of musculoskeletal disorders. Material and Methods The aim of this study is to assess and to compare upper trapezius and middle deltoid muscle activity in 2 traditional and improved design carpet weaving workstations. These 2 workstations were simulated in a laboratory and 12 women carpet weavers worked for 3 h. Electromyography (EMG) signals were recorded during work in bilateral upper trapezius and bilateral middle deltoid. The root mean square (RMS) and median frequency (MF) values were calculated and used to assess muscle load and fatigue. Repeated measure ANOVA was performed to assess the effect of independent variables on muscular activity and fatigue. The participants were asked to report shoulder region fatigue on the Borg’s Category-Ratio scale (Borg CR-10). Results Root mean square values in workstation A are significantly higher than in workstation B. Furthermore, EMG amplitude was higher in bilateral trapezius than in bilateral deltoid. However, muscle fatigue was not observed in any of the workstations. Conclusions The results of the study revealed that muscle load in a traditional workstation was high, but fatigue was not observed. Further studies investigating other muscles involved in carpet weaving tasks are recommended.

7

A method for designing the longitudinal position of a porthole in a manned submersible based on the back muscle fatigue characteristics

75%

Zhu M. , Chen D. , Fan Y. , Guo J.

International Journal of Occupational Medicine and Environmental Health

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2021

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tom 34

|

nr 6

701-721

EN

ObjectivesThe proper porthole angle contributes to relieving the operation fatigue and improving the efficiency of oceanauts. In this study, the authors explored the effect of 3 different porthole longitudinal positions on the oceanauts’ back muscles using surface electromyography (sEMG) analysis, and the characteristics of the perceived body comfort was obtained.Material and MethodsOverall, 40 healthy participants were recruited to perform tasks in a simulated cabin environment. Electromyographic (EMG) signals were recorded from the trapezius medius, lower trapezius, and erector spinal muscles for porthole angles of –5°, –15°, and +15°, relative to the horizontal line of sight during a 21-minute experiment. The subject comfort scores were collected at 7, 14 and 21 min. The integrated electromyogram (iEMG) and the root mean square (RMS) of EMG signals, as well as the mean power frequency (MPF), and the mean frequency (MF) were calculated.ResultsThe subjective scores of the +15° porthole at each stage of work are higher than those of the –15° and –5° portholes. The results of iEMG, RMS, MF and MPF all indicated that the +15° porthole design was more conducive to lowering the rate of muscle fatigue, while the –5° and –15° portholes increased the muscle fatigue rate and led to greater fatigue. It was found that the lower trapezius was more prone to fatigue than the trapezius medius and erector spinal muscles. The height, weight and body mass index of the participants were found to negatively correlate with muscles at the +15° porthole, which is highly consistent with the actual situation.ConclusionsThe findings suggested that the +15° position was optimal for delaying the muscle fatigue of the participants and for improving the work efficiency of oceanauts.

8

Shoulder girdle muscle activity and fatigue during automobile chassis repair

75%

Tian B. , Yu S. , Chu J. , Li W.

International Journal of Occupational Medicine and Environmental Health

|

2019

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tom 32

|

nr 4

537-552

EN

Objectives The objective of this study was to assess the postures that were commonly used in automobile chassis repair operations, and to evaluate shoulder girdle muscle fatigue for different combinations of the weight of hand-tools. Material and Methods Two right muscles, including upper trapezius (UT) and middle deltoid (MD), were selected. Surface electromyography (SEMG) and a perceived level of discomfort (PLD) were used to assess the degree of shoulder girdle fatigue. Fifteen healthy young male subjects from the Northwestern Polytechnical University participated in the test. The test consisted of assuming 4 different postures and maintaining each of them for 60 s. The 4 postures varied in terms of dumbbell weights, standing for the hand-tools weight: W1 was 0.48 kg and W2 was 0.75 kg; the 4 shoulder postures were shoulder flexions of 150°, 120°, 90°, and 60°, combined with an included elbow angle of 180°, 150°, 120° and 90°, respectively. The experimental sequences were randomly selected. The signals of SEMG and the values of PLD in the shoulder girdle were recorded in 60 s. All subjects completed the whole test. The repeated measure analysis of variance (ANOVA) was performed to ascertain differences between dumbbell weight (0.48 kg and 0.75 kg) and shoulder postures (150°/180°, 120°/150°, 90°/120° and 60°/90°). The Friedman test was utilized to determine the significant differences for UT(PLD) and MD(PLD) on shoulder postures. Spearman’s correlation was used to analyze the relationship between the subjective and objective measurements. Results Significant correlational relationships existed between the UT percentage of the maximal voluntary electrical activation (%MVE) and UT(PLD) (r = 0.459, p < 0.01), between MD(%MVE) and MD(PLD) (r = 0.821, p < 0.01). The results showed that SEMG and PLD of the 4 postures under analysis differed significantly (p < 0.05). Conclusions It was indicated that posture T4 (shoulder forward flexion 60° and included elbow angle 90°) resulted in the lowest fatigue, both in terms of the objective measure and the subjective perception, which meant that this posture was more ergonomic. Int J Occup Med Environ Health. 2019;32(4):537–52

9

Measurements comparison of finger joint angles in hand postures between an sEMG armband and a sensory glove

75%

Pallotti A. , Orengo G. , Saggio G.

Biocybernetics and Biomedical Engineering

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2021

|

tom Vol. 41, no. 2

605--616

EN

This study compares the simultaneous measurements of finger joint angles obtained with a myoelectric armband (Myo), composed of eight surface electromyography (sEMG) sensors mounted on an elastic support, and a data glove, equipped with ten flex sensor on metacarpal and proximal finger joints. The flexion angles of all finger joints in four hand postures, that is open hand, closed hand and grasping two 3D printed molds of different size, were measured with a manual goniometer, and used to create, for each finger joint, a linear model from the measurement of the corresponding flex sensor in an electronic glove, as well as a regression model from the simultaneous measurements of 8 sEMG sensors of the Myo armband. The regression models were extracted testing different algorithms from the Matlab Regression Learner Toolbox. The performance of the models of the two wearable devices were evaluated and compared, applying a standard test, taken from literature on sensory gloves to evaluate the repeatability, reproducibility and reliability of finger joint measurements. These results were also compared with those reported by published works that followed the same standard test, using data gloves based on different sensing technologies. This work aims to demonstrate that the sEMG armbands can be applied to register the static postures of each finger joint with almost the same accuracy of sensory gloves.

10

Zastosowanie EMG do analizy wybranych ruchów kończyny górnej

75%

Morawska N. , Wojnicz W. , Stawicki M.

Aktualne Problemy Biomechaniki

|

2016

|

tom z. 11

103--108

PL

Celem badań było przeprowadzenie pomiarów sygnału mioelektrycznego czterech mięśni powierzchniowych lewej kończyny górnej, biorących udział w ruchach zginania-prostowania w stawie łokciowym w płaszczyźnie strzałkowej. Rejestrację elektromiogramów (EMG) odprowadzono z: głowy długiej oraz bocznej mięśnia trójgłowego ramienia, głowy długiej mięśnia dwugłowego ramienia i mięśnia ramienno-promieniowego. Wykazano, iż metoda może zostać wykorzystana do oceny funkcjonowania wybranych mięśni.

EN

The aim of the study was to perform measurements of the sEMG signal for the analysis of the four surface muscles of the left upper limb participating in the flexion-extension movements at the elbow in the sagittal plane. Electromyography signal was measured and registered from the long head and lateral head of the triceps of the arm, the long head of the biceps and muscle brachioradialis. It has been shown that this method can be used to evaluate functioning of selected muscles.

11

The use of surface electromyography for diagnosis of muscle dysfunction with pain symptoms

75%

Huber J. , Kulczyk A. , Lisinski P. , Lipiec J.

Trends in Sport Sciences

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2013

|

tom 20

|

nr 3

EN

Surface electromyography (sEMG) is generally considered by neurologists as an unacceptable diagnostic tool for examination of changes in the activity of muscle motor units in patients with non-specifi c back pain. The aim of this review is to demonstrate the usefulness of neurophysiological findings for the application of sEMG in differentiation of root-conflict and non-root-conflict sources of muscle pathologies with pain as the main symptom. In the first experiment carried out on 30 patients with clinically recognized myofascial pain, an attempt was undertaken to find out whether surface electromyographic (sEMG) readings during relaxation and maximal contraction revealed differences in the activity of muscles with or without trigger points (TrPs) detected by palpation. In the second experiment carried out on 40 office workers similar methodologies of clinical and neurophysiological examination were used, however, with the aim to verify a hypothesis about the dysfunction of cervical and shoulder girdle muscle motor units as the cause of cervicogenic headache (CEH). The results of both experiments led to the following conclusions: 1. Surface EMG performed at rest and during maximal contraction is a precise diagnostic tool that can be used for detection of changes in the activity of motor units in patients with myofascial pain syndrome and cervocogenic headache; 2. Surface EMG readings at rest, with an amplitude exceeding 25μV, may be helpful for evaluation of increased muscle tension, which leads to a decrease of the activity of muscle motor units during maximal contraction.

12

Changes of bioelectrical activity in cervical paraspinal muscle during gait in low and high heel shoes

63%

Mika A. , Oleksy Ł. , Mikołajczyk E. , Marchewka A. , Mika P.

Acta of Bioengineering and Biomechanics

|

2011

|

tom Vol. 13, no. 1

27-33

EN

High heel footwear may be destructive for the spine because of an increased erector spinae muscle bioelectrical activity and increased ground reaction forces affecting lower limbs and the spine. The aim of this study was to evaluate the changes of bioelectrical activity in cervical paraspinal muscle during gait in low and in high heel shoes in different age groups. In 31 women aged 20-25 years and in 15 women aged 45-55 years without neck pain, the bioelectrical activity of the cervical paraspinal muscle was assessed during gait on flat surface with natural speed in three conditions: without shoes, in low (4 cm) and in high (10 cm) heel shoes. Higher bioelectrical activity cervical paraspinal muscle was noted during gait in high heel shoes in comparison to gait without shoes. The changes were more pronounced in the group of subjects aged 45-55 years. The prolonged wearing of shoes with stiletto type heels by individuals without neck pain is not safe for their spine and may lead to chronic paraspinal muscle fatigue.

13

Możliwości zastosowania sygnałów bioelektrycznych (EMG) w systemach sterowania

63%

Kegler M. , Jasińska-Choromańska D. , Fiok K.

Inżynier i Fizyk Medyczny

|

2016

|

tom Vol. 5, nr 6

329--334

PL

W dobie rozwoju inżynierii biomedycznej, technologie mające dotychczas zastosowanie jedynie w diagnostyce klinicznej zyskują coraz większą popularność w dziedzinach niebezpośrednio związanych z medycyną. W artykule przedstawiono przykłady możliwego zastosowania sygnałów elektromiograficznych (EMG) w systemach sterowania.

EN

In times of rapid development of biomedical engineering, technologies previously used exclusively in clinical diagnostics are becoming increasingly popular and applicable in other fields, less related to medicine. The examples of successful applications of control systems based on electromyographic (EMG) biosignals, are introduced in the article.

14

Opracowanie metod wykonywania badań biomechaniki ruchu człowieka przy wykorzystaniu elektromiografii kinezjologicznej

63%

Kukla M. , Wieczorek B. , Warguła Ł.

Autobusy : technika, eksploatacja, systemy transportowe

|

2019

|

tom R. 20, nr 1-2

295--298

PL

W artykule przedstawiono zagadnienia dotyczące opracowania metod wykonywania badań biomechaniki ruchu człowieka przy wykorzystaniu elektromiografii kinezjologicznej. Szczegółowo omówiono utworzone procedury dotyczące wyboru umiejscowienia elektrod, przygotowania pacjenta do badań, przeprowadzania eksperymentu oraz opracowania wyników pomiarów. Przedstawiono również wybrane wyniki badań wstępnych.

EN

The article presents the issues concerning the development of methods for performing human biomechanics research utilizing kinesiological electromyography. The procedures concerning the selection of the location of electrodes, patient preparation for testing, conducting the experiment and the development of measurement results are discussed in detail. Selected preliminary test results were also presented.

15

Use of the surface electromyography for a quantitative trend validation of estimated muscle forces

63%

Żuk M. , Syczewska M. , Pezowicz C.

Biocybernetics and Biomedical Engineering

|

2018

|

tom Vol. 38, no. 2

243--250

EN

Surface EMG is a non-invasive measurement of an individual muscle activity and it can be used as the indirect form of a simulated muscle forces validation. The quantitative curves comparison has some potential, which has not been fully exploited yet [13]. The purpose of current study was to quantitatively compare muscle forces predicted using musculoskeletal models to measured surface electromyography signals. A metrics based on correlation and an electromechanical delay correction for a quantitative trend validation has been proposed. Kinematics of a normal gait was collected for three healthy subjects together with ground reaction forces and EMG signals of eight different muscles of both legs. Dynamic simulations have been performed for two models of differing complexity from OpenSim library (Gait2392 and Gait2354) [2,5,6], static optimization method and computed muscle control algorithm [20] have been used. It has been shown, that the level of force-EMG trend compliance, obtained for applied models and simulation techniques, is related rather to the selected muscle than to applied optimization criteria or technique. The contribution of analyzed muscles during gait has been predicted better by complex model than by simplified model. Moreover relationship between the body proportion of subject and the degree of correlation has been observed. Proposed metrics and obtained results can be the basis for further identification of cost functions, which could most closely describe motor control strategy.

16

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

63%

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

Acta of Bioengineering and Biomechanics

|

2015

|

tom 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.

17

Adaptacyjny system sterowania protezą ręki wykorzystujący elektromiografię powierzchniową

63%

Gmerek A.

Prace Naukowe Politechniki Warszawskiej. Elektronika

|

2010

|

tom z. 175, t. 1

99-110

PL

Skuteczne sterowanie protezami kończyn o wielu stopniach swobody jest trudnym zadaniem, które wymaga innowacyjnego podejścia do zagadnienia sterowania. W nowoczesnych protezach do tego celu używa się sygnałów biologicznych natury elektrycznej. Autor eksperymentował z sygnałami EMG (elektromiograficznymi), rejestrowanymi za pomocą tzw. elektromiografii powierzchniowej. W artykule tym do sterowania skonstruowaną protezą ręki został zaproponowany algorytm bazujący na sztucznych sieciach neuronowych (SSN) i logice rozmytej. W celu wyodrębnienia unikalnych cech analizowanych sygnałów (potrzebnych na wejście sieci), były one poddawane wieloetapowemu procesowi przetwarzania i obróbki.

EN

An effective control of multi-DOF limb prosthesis is a difficult task, which require innovative approach to the problem. In high-tech limb prosthesis the electrical-nature biological signals are used for this task. Author experimented with EMG (electromyographic) signals, registered with a surface electromyography. In this paper for control a constructed artificial limb an algorithm based on Artificial Neural Networks (ANN) and Fuzzy Logic was proposed. In order to extract unique features of analyzed signals (needed for input of the net), they were expose to multi-level procedure of signal processing.

18

Intent based recognition of walking and ramp activities for amputee using sEMG based lower limb prostheses

63%

Hussain T. , Iqbal N. , Maqbool H. F. , Khan M. , Awad M. I. , Dehghani-Sanij A. A.

Biocybernetics and Biomedical Engineering

|

2020

|

tom Vol. 40, no. 3

1110--1123

EN

The use of surface electromyogram (sEMG) has grown in the field of gait analysis, prostheses and exoskeleton. Surface electromyogram can directly reflect the human intention for locomotion modes and can be used as a source of control for lower limb prosthesis. The variations factors such as non-Gaussian nature of sEMG signal and mobility of amputees have been observed to degrade the activity recognition performance. This study investigates the properties of the sEMG signal with the purpose of determining the discriminant features to classify the feature space into various activities especially in the context of amputees. To address the variations in activity recognition performance, this study proposed the magnitude of bispectrum as a novel feature extraction method that is invariant to the variations factors and an unsupervised feature reduction method was used to extract the discriminant features. Furthermore, sEMG signals from eleven wearable sensors located on the lower limb muscles were recorded from six subjects including four able-bodies, one unilateral transti-bial, and one unilateral transfemoral amputee during walking and ramp activities. Distinct muscles were selected using the L1-norm method. Effective classifier namely support vector machine and linear discriminant analysis were used to classify the multi-class sEMG signal patterns. The experimental results consistently showed an average accuracy of 99.7%. Further evaluation on three different types of prostheses revealed that the proposed method is more robust compared to the existing methods. The promising results of this study can be applied potentially in the control of lower limb wearable devices such as prostheses/ exoskeletons.

19

Określanie sił mięśniowych podczas chodu na podstawie sygnałów sEMG

63%

Świtoński E. , Głowacka A.

Modelowanie Inżynierskie

|

2013

|

tom T. 16, nr 47

185--189

PL

Praca zawiera opis metodyki wyznaczania sił mięśniowych na podstawie zarejestrowanych potencjałów czynnościowych mięśni kończyn dolnych podczas chodu dla zdrowej dorosłej osoby. Badania w ramach niniejszej pracy zostały przeprowadzone z wykorzystaniem zestawu do elektromiografii powierzchniowej BTS Pocket EMG.

EN

The paper contains a description of the methodology for determination of muscle forces on the basis of recorded action potentials of lower limb muscles during gait for a healthy adult. The research in this study were conducted using BTS Pocket EMG surface electromyography system.

20

Evaluation of the influence of low and high heel shoes on erector spine muscle bioelectrical activity assessed at baseline and during movement

63%

Mika A. , Oleksy Ł. , Mikołajczyk E. , Marchewka A.

Medical Rehabilitation

|

2009

|

tom 13(3)

9-18

EN

Introduction: Back pain due to the wearing of high heel shoes may result from increased erector spine activity and also from higher proximal ground reaction forces or center of body mass dislocation.Aim: The assessment of changes in the erector spine muscle due to the non-physiological foot position in low and high heel shoes.Material and Methods: In 31 women aged 20-25 years (height 167,6 ±5.8 cm; weight 60,35 ±6,49 kg) without back pain, the bioelectrical activity of the erector spine muscle was assessed. A lumbar spine sequence test was performed without shoes and in low (4 cm) and in high (10 cm) heel shoes. Muscle activity on the right and left sides was evaluated at baseline and during movement. The mean and peak signal value were compared between 3 measurements (without, in low and in high heel shoes).Results: A statistically significant increase in erector spine activity was observed in Trunk Flexion (p<0,05) and during Flexion-Relaxation Position (p<0,05) when wearing high hell shoes. Those variables correlated significantly in all 3 measurements (without, in low and in high heel shoes). A significant correlation was noted between the Flexion-Relaxation Position and Extension/Flexion Ratio (p<0,05). Bioelectrical erector spine activity differed significantly during Rotation Right and Rotation Left in all 3 measurements respectively (p<0,05).Conclusion: The prolonged wearing of shoes with stiletto type low and high heels by individuals without back pain is not safe for their spine and may lead to chronic paraspinal muscle fatigue