Wyniki wyszukiwania - Biblioteka Nauki

1

The Influence of Fatigue on Muscle Temperature

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Bartuzi P. , Roman-Liu D. , Wiśniewski T.

International Journal of Occupational Safety and Ergonomics

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2012

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tom Vol. 18, No. 2

233--243

EN

The aim of the study was to investigate the possibility of using infrared (IR) thermography for assessing muscle fatigue during low effort. Three tests at constant levels of load 5, 15 and 30% of maximum voluntary contraction (MVC) lasting 5 min each were performed on a group of 10 men. Temperature and electromyographic (EMG) signal were registered from biceps brachii (BB). Analysis focused on the influence of load on the values and changes in time of muscle temperature. Correlations between temperature and EMG parameters (RMS, MPF and MF) were also analysed. Constant load sustained during the tests resulted in an increase in the temperature of BB. There were statistically significant correlations between temperature and EMG parameters for most subjects. Results of the study suggest that IR thermography can be an alternative or supplementary method for assessing muscle fatigue at low levels of contraction.

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

Direct and indirect measurements relevant to the assessment of fatigue of the respiratory muscles - review

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Kuraszkiewicz B.

Polish Journal of Medical Physics And Engineering

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2011

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tom 17

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nr 1

35-43

EN

The purpose of this review is to present selected tests available with the potential to detect the development of respiratory muscle fatigue in normal subjects and patients. All reviewed techniques represent a part of a variety of measures and indices, which have been employed to assess this complex process at the present time.

4

Differences in bioelectrical activity of quadriceps muscle during various types of contraction

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Niespodzinski B. , Lukowicz M. , Mieszkowski J.

Baltic Journal of Health and Physical Activity

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2013

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tom 5

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nr 3

184-190

EN

Background: The aim of the study was to estimate differences in bioelectrical activity between rectus femoris (RF) and vastus medialis (VM) muscles of each lower limb. Material/Methods: 29 female and 18 male adult subjects participated in the study. Each subject performed the following quadriceps contractions with each lower limb: concentric, isometric, eccentric and 30-sec. long maximal voluntary isometric contraction. 3 parameters were obtained in surface electromyography (SEMG): mean RMS amplitude (RMS), mean percentage value of maximal voluntary contraction (%MVC) and mean frequency (MF). Results: RF occurred to have a lower percentage activity (-28.43%) and absolute amplitude (- 36.57%) value than VM during all three basic forms of contraction against gravity. Except the RMS values for concentric contraction, all the mentioned parameters were significantly different. In contrast, RF had a higher MF rate than VM. Differences were at the mean level of 22.57% for all activities. Conclusions: There are no differences in SEMG of quadriceps muscle between both lower limbs. VM and RF differ from each other in RMS, %MVC and MF during all types of studied contractions.

5

Development of Prolonged Standing Strain Index to Quantify Risk Levels of Standing Jobs

88%

Halim I. , Omar A. R.

International Journal of Occupational Safety and Ergonomics

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2012

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tom Vol. 18, No. 1

85--96

EN

Many occupations in industry such as metal stamping workers, electronics parts assembly operators, automotive industry welders, and lathe operators require working in a standing posture for a long time. Prolonged standing can contribute to discomfort and muscle fatigue particularly in the back and legs. This study developed the prolonged standing strain index (PSSI) to quantify the risk levels caused by standing jobs, and proposed recommendations to minimize the risk levels. Risk factors associated with standing jobs, such as working posture, muscles activity, standing duration, holding time, whole-body vibration, and indoor air quality, were the basis for developing the PSSI. All risk factors were assigned multipliers, and the PSSI was the product of those multipliers. Recommendations for improvement are based on the PSSI; however, extensive studies are required to validate their effectiveness.

6

Changes in contractile properties and action potentials of motor units in the rat medial gastrocnemius muscle during maturation

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Dobrzynska Z. , Celichowski J.

Journal of Physiology and Pharmacology

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2016

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tom 67

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nr 1

7

Astragalosides modulates contractile function of toad gastrocnemius muscle

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Wei S.-S. , Zou Y.-W. , Liu Z.-B. , Meng W. , Zhao K. , Wang S.-H. , Yao L.-H.

Journal of Physiology and Pharmacology

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2019

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tom 70

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nr 1

8

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

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

International Journal of Occupational Medicine and Environmental Health

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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.

9

Changes in blood morphology and chosen biochemical parameters in ultra-marathon runners during a 100-km run in relation to the age and speed of runners

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Jastrzębski Z. , Żychowska M. , Jastrzębska M. , Prusik K. , Prusik K. , Kortas J. , Ratkowski W. , Konieczna A. , Radzimiński Ł.

International Journal of Occupational Medicine and Environmental Health

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2016

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tom 29

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nr 5

801-814

EN

Objectives The objective of the study was to reveal morphology, electrolyte and chosen biochemical parameters in terms of health risk in runners in reference to their age and running speed in the case of running a distance of 100 km, which occur after 12 h or 24 h of recovery. Material and Methods Fourteen experienced, male, amateur, ultra-marathon runners, divided into two age and two speed groups took part in the 100-km run. Blood samples for analyses indexes were collected from the ulnar vein just before the run, after 25 km, 50 km, 75 km and 100 km, as well as 12 h and 24 h after termination of the run. Results The sustained ultramarathon run along with the distance covered (p < 0.05) caused an increase in myoglobin (max 90-fold), bilirubin (max 2.8-fold) and total antioxidant status (max 1.15-fold), which also continued during the recovery. Significant changes in the number of white blood cells were observed with each sequential course and could be associated with muscle damage. The electrolyte showed changes towards slight hyperkalemia, but no changes in natrium and calcium concentrations. There were no significant differences between the age and speed groups for all the parameters after completing the 100-km run as well as after 12 h and 24 h of recovery. Conclusions Considering changes in blood morphology and chosen biochemical parameters in ultra-marathon runners during a 100-km run it can be stated that such an exhausting effort may be dangerous for human health due to metabolic changes and large damage to the organs. Negative metabolic changes are independent of age of an ultramarathon runner and occur both in younger (32±5.33 years) and older participants (50.56±9.7 years). It can be concluded that organ damage and negative metabolic changes during a 100-km run occur similarly in participants less experienced as well as in well trained runners. Int J Occup Med Environ Health 2016;29(5):801–814

10

Assessment of shoulder and low back muscle activity of male kitchen workers using surface electromyography

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Subramaniam S. , Murugesan S. , Jayaraman S.

International Journal of Occupational Medicine and Environmental Health

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2017

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tom 31

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nr 1

81-90

EN

Objectives: This study aims to assess muscle fatigue for kitchen workers during various tasks in a kitchen. Material and Methods: This study consists of 2 phases: a) surface electromyography (EMG) to determine muscle fatigue of trapezius and erector spinae muscles bilaterally for 12 healthy male volunteers during 30 min of Indian flatbread (chapati) preparation, b) self-administered questionnaire study after 30 min preparation to determine the impact on performance. Results: Surface EMG results show that the right trapezius muscle had significantly higher fatigue during kneading, rolling and roasting tasks. Similarly, right erector spinae muscle showed significantly higher fatigue during rolling and roasting tasks. Conclusions: Both phases of the study conclude that, even though the dynamic postural adjustment may reduce fatigue during the work schedule; the combination of risk factors like the repetitive task, forceful exertion and prolonged standing during working results in a high risk of developing muscle fatigue. Int J Occup Med Environ Health 2018;31(1):81–90

11

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

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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.

12

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

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2019

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tom 32

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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

13

Measurement of abdominal retractor loading and its effects on the surgeons arm

75%

Hučko B. , Čekan M. , Horvát F. , Chlebo O. , Bachraty M. , Čambal M.

Interdisciplinary Journal of Engineering Sciences

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2018

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tom Vol. 6, no. 1

60--63

EN

A load measuring apparatus integrated into an abdominal retractors and its methodology are presented. The measured forces offer new knowledge in the fields of surgery and may be useful in the design of new retractors and fixing frames as well as the investigation of tissue loading during surgical intervention. Effort required to hold the retractor is quantified for the surgeons forearm and the approximation of muscle fatigue can be evaluated with respect to the duration of surgical intervention.

14

Lactate concentration and creatine kinase activity after 110-m and 400-m hurdles races

75%

Krysciak J. , Podgorski T. , Eichler A.

Trends in Sport Sciences

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2015

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tom 22

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nr 4

EN

Introduction. 110-m and 400-m hurdles races are based on anaerobic energy metabolism which can induce muscle fatigue and muscle fiber damage. The most common biochemical parameters used in controlling athletes’ training loads and post-exercise fatigue are blood lactate (La) concentration and creatine kinase (CK) activity. Aim of Study. The aim of the study was to determine and compare runners’ biochemical response after 110-m and 400-m hurdles races. The influence of warm-up before both races was taken into consideration. Material and Methods. Eight male hurdlers took part in this research. They were subjected to two test exercises: a 110-m and a 400-m hurdles race. During each test, pre-warm-up, post-warm-up, and post-exercise capillary blood from a fingertip was collected to determine the La concentration and CK activity. Furthermore, during both sprint runs the athletes’ time (to the nearest 0.01 s) and heart rate (HR) were measured. Results. Each kind of exercise test increased the La concentration and CK activity. More significant changes of both biochemical parameters occurred after the 400-m race. Furthermore, after each warm-up significant increases of La and CK levels were observed. After the 400-m hurdles race higher HR values were noted (184.50 ± 8.32 compared to 177.50 ± 11.14 after the 110-m sprint). Conclusions. Both specialist warm-up and 110 and 400 meters hurdles races lead to significant changes in athletes’ physiological and biochemical blood parameters. La concentration and CK activity demonstrate greater muscle fatigue and muscle fiber damage after a 400-m than a 110-m hurdles race.

15

The Effect of Upper Extremity Fatigue on Grip Strength and Passing Accuracy in Junior Basketball Players

75%

Ahmed T.

Journal of Human Kinetics

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2013

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tom 37

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nr 1

71-79

EN

Fatigue is an unavoidable part of a basketball game, which may affect an athlete’s performance. The aim of this study was to investigate the effect of upper extremity fatigue on grip strength and passing accuracy in basketball, and ascertain if the effects of different fatigue protocols on grip strength and passing accuracy are the same. Twenty-four juniors under 18 years old (age: 16.75 ± 0.62 years; body height: 184.5 ± 3.31 cm; body mass: 77.25 ± 3.22 kg) volunteered to participate in the study, and were divided into two groups. After a warm-up, both groups performed the basketball passing test and grip strength was recorded for each group under three different testing conditions: rest, 70% and 90% exercise intensity. The protocol used for the first group was the chest press, and for the second group the wrist curls. Results show that after the upper extremity fatigue protocol all parameters of the study (grip strength and passing accuracy) showed a significant decrease, and there was no significant difference between both groups regarding grip strength and passing accuracy. The study suggested that in order to avoid upper extremity fatigue, basketball trainers and coaches need to include upper extremity conditioning exercises into their training sessions.

16

Effects of two recovery methods on the leg muscle fatigue of oceanauts in a manned submersible

75%

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

Medycyna Pracy

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2022

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tom 73

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nr 2

95-107

EN

The cabin of the manned submersible is a narrow and sealed space. The long-time work of oceanauts is easy to cause muscle fatigue and stiffness, which reduces efficiency. This paper explored the relative more effective way to relieve leg muscle fatigue of the oceanauts in the manned submersible.Material and MethodsTwenty healthy young people with an average age of 24 years were selected as the participants, while the usual natural relaxation and the stretching method proposed by the surveys were selected as the relieve method for muscle fatigue. This study compared the effects of the 2 recovery ways using the electromyography data from the quadriceps femoris and biceps femoris, and the subjective scales.ResultsWith the support of data of integral electromyogram (iEMG), root-mean-square (RMS), subjective scales, authors finally found that the 2 muscles of the leg are fatigued significantly, and biceps femoris has more accumulation of fatigue. Although the 2 recovery ways have a significant relief effect on muscle fatigue, the stretching method can reduce more muscle fatigue in a short period of time, especially for biceps femoris. The stretching method is advocated for the oceanauts.ConclusionsThe findings suggested that the stretching method was optimal for relieving the muscle fatigue of the oceanauts during the operation. Med Pr. 2022;73(2):95–107

17

Physiological background of the change point in VO2 and the slow component of oxygen uptake kinetics

75%

Zoladz J. A. , Korzeniewski B.

Journal of Physiology and Pharmacology

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2001

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tom 52

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nr 2

18

Design and Development of a Pressure Sensing Device for Analysing the Pressure Comfort of Elastic Garments

63%

Senthilkumar M. , Kumar L. A. , Anbuman N.

Fibres & Textiles in Eastern Europe

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2012

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tom Vol. 20, no. 1 (90)

64-69

EN

In this paper, a pressure sensing device for analysing pressure comfort on elastic garments was designed and developed. The device was calibrated and tested on different compression garments for its reliability. This pressure comfort measurement device is used to measure the pressure between the human body and garments. The fabric resistance due to each and every body movement is noted to evaluate the effect of fabric compression on body muscles in order to assess the pressure comfort for sports persons. The new device proved that elastic garments certainly improve stamina and speed through its quick recovery and lower stress with higher elongation. There is a good correlation found between the pressure values given by the new sensing device and the Instron tester.

PL

Opracowano układ pomiarowy umożliwiający pomiar ciśnienia w układach ubiorów kompresyjnych mający istotny wpływ na komfort użytkowania takiej odzieży. Układ pozwala na pomiar ciśnienia pomiędzy ciałem człowieka a warstwa odzieży, również przy zróżnicowanych ruchach ciała, co jest niezbędne dla określenia komfortu odzieży np. w przypadku sportowców. Badania rożnych ubiorów kompresyjnych pozwoliły ocenić przyrząd jako dobrze nadający się do tego celu. Dzięki zastosowanemu przyrządowi udało się stwierdzić, że ubiory kompresyjne pozwalają na polepszenie zdolności wysiłkowej oraz szybkości regeneracji układów mięśniowych.

19

Predicting muscle fatigue during dynamic contractions using wavelet analysis of surface electromyography signal

63%

Shariatzadeh M. J. , Hadizadeh Hafshejani E. , Mitchell C. J. , Chiao M. , Grecov D.

Biocybernetics and Biomedical Engineering

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2023

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tom Vol. 43, no. 2

428--441

EN

Muscle fatigue is defined as a reduction in the capability of muscle to exert force or power. Although surface electromyography (sEMG) signals during exercise have been used to assess muscle fatigue, analyzing the sEMG signal during dynamic contractions is difficult because of the many signal distorting factors such as electrode movements, and variations in muscle tissue conductivity. Besides the non-deterministic and non-stationary nature of sEMG in dynamic contractions, no fatigue indicator is available to predict the ability of a muscle to apply force based on the sEMG signal properties. In this study, we designed and manufactured a novel wearable sensor system with both sEMG electrodes and motion tracking sensors to monitor the dynamic muscle movements of human subjects. We detected the state of muscle fatigue using a new wavelet analysis method to predict the maximum isometric force the subject can apply during dynamic contraction. Our method of signal processing consists of four main steps. 1- Segmenting sEMG signals using motion tracking signals. 2- Determine the most suitable mother wavelet for discrete wavelet transformation (DWT) based on cross-correlation between wavelets and signals. 3- Deoinsing the sEMG using the DWT method. 4- Calculation of normalized energy in different decomposition levels to predict maximal voluntary isometric contraction force as an indicator of muscle fatigue. The monitoring system was tested on healthy adults doing biceps curl exercises, and the results of the wavelet decomposition method were compared to well-known muscle fatigue indices in the literature.

20

Human muscle fatigue: the significance of muscle fibre type variability studied using a micro-dissection approach

63%

Sargeant A. J. , de Haan A.

Journal of Physiology and Pharmacology. Supplement

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2006

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tom 57

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nr 10

EN

During human locomotion the ability to generate and sustain mechanical power output is dependent on the organised variability in contractile and metabolic properties of the muscle fibres that comprise the active muscles. In studies of human exercise we have used a micro-dissection technique to obtain fragments of single muscle fibres from needle biopsies before and after exercise. Each fibre fragment is divided into two parts. One part is used to characterize the fibre type in respect of the heavy chain myosin isoform expressed. The other part of the fragment is analysed for high energy phosphate concentrations. Fibres are classified on the basis of expressing either type I, type IIA, or type IIX myosin heavy chain isoforms. It should be noted however that in the type II population many fibres co-express both IIA and the IIX isoforms and we therefore characterize these fibres on the basis of the degree of co-expression. We have used this technique to examine the time course of high energy phosphate concentration and fatigue in different fibre populations during exercise. The progressive reduction of power during maximal sprint efforts may be interpreted as the cumulative effect of metabolic depletion in successive fibre type populations from IIX to IIXa to IIAx to IIA to I. One important application of the micro-dissection technique is that PCr content may also be used as a very sensitive metabolic marker for fibre type recruitment during very short duration concentric, isometric and eccentric exercise.