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Wyświetlanie 1-3 z 3
Tytuł:
Shoulder girdle muscle activity and fatigue in traditional and improved design carpet weaving workstations
Autorzy:
Allahyari, Teimour
Mortazavi, Narges
Khalkhali, Hamid Reza
Sanjari, Mohammad Ali
Powiązania:
https://bibliotekanauki.pl/articles/2177075.pdf
Data publikacji:
2015-10-21
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
muscle activity
surface electromyography
muscle fatigue
carpet weaving
workstation
perceived fatigue
Opis:
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.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2016, 29, 2; 345-354
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method for designing the longitudinal position of a porthole in a manned submersible based on the back muscle fatigue characteristics
Autorzy:
Zhu, Mengya
Chen, Dengkai
Fan, Yu
Guo, Jiayan
Powiązania:
https://bibliotekanauki.pl/articles/2094205.pdf
Data publikacji:
2021-12-13
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
surface electromyography
muscle fatigue
work efficiency
manned submersible
porthole position design
oceanauts
Opis:
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.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2021, 34, 6; 701-721
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shoulder girdle muscle activity and fatigue during automobile chassis repair
Autorzy:
Tian, Baozhen
Yu, Suihuai
Chu, Jianjie
Li, Wenhua
Powiązania:
https://bibliotekanauki.pl/articles/2161964.pdf
Data publikacji:
2019-07-15
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
muscle activity
surface electromyography
muscle fatigue
perceived level of discomfort
automobile chassis repair
shoulder postures
Opis:
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
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2019, 32, 4; 537-552
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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