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    Tytuł:
    Electromyographic Analysis of a Repetitive Hand Gripping Task
    Autorzy:
    Cook, T.
    Rosecrance, J.
    Zimmermann, C.
    Gerleman, D.
    Ludewig, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/91061.pdf
    Data publikacji:
    1998
    Wydawca:
    Centralny Instytut Ochrony Pracy
    Tematy:
    electromyography
    cumulative trauma disorders
    work-rest cycle
    muscle force
    hand gripping
    elektromiografia
    siła mięśni
    cykl pracy
    kończyna górna
    Opis:
    Electromyography (EMG) has been proposed as a method for determining muscle effort in repetitive upper limb tasks, which are often related to cumulative trauma disorders. EMG activity of the finger flexor musculature was investigated during a repetitive hand gripping task having 5 different cycle durations (2 to 6 s), various percentage of work time (and rest) within the work cycle (20% to 80%), and 3 different grip force levels. Thirty healthy adult participants each performed 27 randomly ordered 30-s repetitive hand gripping trials as well as 3 isometric contractions, which were used to normalize data from the hand gripping trials. There was a significant decrease in mean EMG as the duration of the work-rest cycle time increased. At each force level, EMG increased as the percentage of work time within the work-rest cycle increased, but to a greater extent at the highest force level. The results of this study suggest that overall muscle effort, and perhaps muscle fatigue, can be reduced most effectively by modifying the force requirements of the repetitive task. Other variables, such as the percentage of work time within a cycle and overall work cycle time have less effect on the EMG activity level. The results of this study have implications for developing strategies to reduce muscle fatigue during repetitive hand gripping tasks in an effort to reduce the effects of cumulative trauma disorders.
    Źródło:
    International Journal of Occupational Safety and Ergonomics; 1998, 4, 2; 185-198
    1080-3548
    Pojawia się w:
    International Journal of Occupational Safety and Ergonomics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Force-Velocity Characteristics of Individual Human Skeletal Muscles: TBCIat and TBCIong. Outline of the Method
    Autorzy:
    Kornecki, S.
    Siemieński, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/90398.pdf
    Data publikacji:
    1998
    Wydawca:
    Centralny Instytut Ochrony Pracy
    Tematy:
    force-velocity characteristics
    modeling of the locomotor system
    muscle synergy problem
    iteration procedure
    układ ruchowy
    staw łokciowy
    synergia mięśniowa
    Opis:
    The aim of the work is to outline a procedure of finding force-velocity (F-V) characteristics (F = f(V)) of individual skeletal muscles of the human locomotor system. The presentation is based on an example concerning extensors of the elbow joint: the lateral and long heads of triceps brachii (TBCIat and TBCIong). The experimental part of the procedure involves a natural movement of using the upper extremity to push an external object of variable, adjustable load, engaging both the elbow and shoulder joint. Five men aged 23 took part in the experiment. Their task was to push the handle of a physical pendulum whose moment of inertia could be adjusted within the range of 58 kg ∙ m2-450 kg ∙ m2, so as to give it maximum angular velocity. During each trial the movement of the trunk, of the upper extremity and of the pendulum was video recorded and the force applied with the hand to the handle of the pendulum was measured. In order to find the F-V characteristics a simulation model SHOULDER was used, which is capable of solving the synergy problem for muscles of the arm and the shoulder girdle. It was found that despite considerable dispersion of experimental points the respective regression lines revealed a clear tendency of decreasing muscle force for increased shortening velocity of the monoarticular head (TBCIat) and of increasing muscle force for increased lengthening velocity of the Particular head (TBCIong) of the triceps brachii muscle.
    Źródło:
    International Journal of Occupational Safety and Ergonomics; 1998, 4, 1; 75-83
    1080-3548
    Pojawia się w:
    International Journal of Occupational Safety and Ergonomics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Zmiany mocy i skoczności u siatkarek w okresie przygotowawczym
    Changes of power and jumping skill in female volleyball players during preparatory period
    Autorzy:
    Lipińska, M.
    Michalski, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/99226.pdf
    Data publikacji:
    2011
    Wydawca:
    Politechnika Śląska. Katedra Biomechatroniki
    Tematy:
    kończyny dolne
    siła mięśni
    wyskok CMJ
    wyskok BCMJ
    siatkówka kobiet
    lower limbs
    muscle force
    CMJ jump
    BCMJ jump
    women's volleyball
    Opis:
    Celem pracy było określenie zmian mocy kończyn dolnych i wysokości uniesienia środka masy ciała mierzonych w wyskokach CMJ i BCMJ na platformie dynamometrycznej u siatkarek w okresie przygotowawczym. W badaniach uczestniczyło 14 siatkarek. Pomiar mocy kończyn dolnych i wysokości uniesienia środka masy ciała przeprowadzono na platformie dynamometrycznej. Moc maksymalna uległa nieistotnemu zwiększeniu o 6,3% w CMJ i zmniejszeniu o 4,1% w BCMJ podczas gdy wysokość uniesienia środka masy ciała nie uległa zmianie w CMJ i zwiększyła się istotnie o 4,7% w BCMJ.
    The aim of this study was to determine the changes of power of lower limbs and height of rise of the body mass center at CMJ and BCMJ jumps on the dynamometric platform of female volleyball players during preparatory period. Fourteen female volleyball players took part in this study. The measurement of lower limb power and height of rise of the body mass center was carried out on a dynamometric platform. Maximal power has nonsignificantly increased by 6.3% in CMJ, and decreased by 4.1% in BCMJ while height of rise of the body mass centre did not change in the CMJ and increased significantly by 4.7% in BCMJ.
    Źródło:
    Aktualne Problemy Biomechaniki; 2011, 5; 75-80
    1898-763X
    Pojawia się w:
    Aktualne Problemy Biomechaniki
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Muscle force distribution during forward and backward locomotion
    Autorzy:
    Błażkiewicz, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/307144.pdf
    Data publikacji:
    2013
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    muscle force contribution
    forward gait
    backward gait
    OpenSim
    mięśnie
    chód człowieka
    Opis:
    Backward walking (BW) is a common technique employed in the treatment of a variety of orthopedic and neurological diseases. BW training may offer some benefits especially in balance and motor control ability beyond those experienced through forward walking (FW). The purpose of this study was to determine whether BW represented a simple reversal of FW and, hence muscle force distribution is the same. The study involved one male healthy student of physical education (22 years, h = 185 cm, m = 80 kg). Measurements of spatial-temporal gait parameters were conducted using eight Vicon system cameras, and Kistler plates. Noraxon EMG was used to obtain muscles activity. OpenSim software was used to compute muscle force distribution during both types of gait. During FW and BW there is small difference for force curves produced by m. gluteus maximus (RMS = 0.04), m. biceps femoris short head (RMS = 0.19) and m. tibialis anterior (RMS = 0.16). Good validation by EMG signal was obtained for m. rectus femoris, m. biceps femoris short head, m. tibialis posterior during FW and BW. For m. iliacus, only during BW good validation was achived.
    Źródło:
    Acta of Bioengineering and Biomechanics; 2013, 15, 3; 3-9
    1509-409X
    2450-6303
    Pojawia się w:
    Acta of Bioengineering and Biomechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An artificial neural network approach and sensitivity analysis in predicting skeletal muscle forces
    Autorzy:
    Vilimek, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/306321.pdf
    Data publikacji:
    2014
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    staw łokciowy
    mięśnie
    sieć neuronowa
    elbow joint
    muscle force prediction
    neural network
    sensitivity analysis
    Opis:
    This paper presents the use of an artificial neural network (NN) approach for predicting the muscle forces around the elbow joint. The main goal was to create an artificial NN which could predict the musculotendon forces for any general muscle without significant errors. The input parameters for the network were morphological and anatomical musculotendon parameters, plus an activation level experimentally measured during a flexion/extension movement in the elbow. The muscle forces calculated by the ‘Virtual Muscle System’ provide the output. The cross-correlation coefficient expressing the ability of an artificial NN to predict the “true” force was in the range 0.97 - 0.98. A sensitivity analysis was used to eliminate the less sensitive inputs, and the final number of inputs for a sufficient prediction was nine. A variant of an artificial NN for a single specific muscle was also studied. The artificial NN for one specific muscle gives better results than a network for general muscles. This method is a good alternative to other approaches to calculating of muscle force.
    Źródło:
    Acta of Bioengineering and Biomechanics; 2014, 16, 3; 119-127
    1509-409X
    2450-6303
    Pojawia się w:
    Acta of Bioengineering and Biomechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Characterization of the mechanomyographic signal of three different muscles and at different levels of isometric contractions
    Autorzy:
    Jotta, B.
    Garcia, M. A. C.
    Pino, A. V.
    Souza, M. N. de
    Powiązania:
    https://bibliotekanauki.pl/articles/306272.pdf
    Data publikacji:
    2015
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    mechanomiografia
    sygnał MMG
    mięśnie
    siła mięśni
    mechanomyography
    MMG signal
    muscle twitch
    muscle activation pattern
    muscle force
    Opis:
    Purpose: Lateral (X) and longitudinal (Y) mechanical oscillations of muscle fibers that take place during muscular contraction seem to contain information additionally to the myoelectric activity, which can contribute to the interpretation of some muscle gradation force mechanisms. However, no previous study was found that had investigated the relationship between the muscle force and features associated to the mechanomyographic (MMG) signal obtained by means of a biaxial accelerometer in three different muscles. Therefore, the aim of this study was to evaluate the relationship between the force output at different load levels (20% to 100%) of the maximum voluntary isometric contraction (%MVIC) and the two signals supplied by a biaxial accelerometer and, in addition, the so-called resultant (R) acceleration signal derived from the two signals mentioned previously. Twenty seven male volunteers participated in this study. Methods: The force output related to the right biceps brachii, soleus and gastrocnemius medialis muscles was studied by means of linear regression models fit to log-transformed of the root mean square (RMS) values of the MMG signals in X, Y, and R axes versus each %MVIC. The phase angle of R acceleration (PhaseR) and anthropometric data were also considered. Results: The angular coefficient a and the antilog of y-intercept b from the log-transformed of MMG data values versus force output were able to distinguish partially motor unit strategies during isometric contractions in the three muscles studied. Conclusion: The findings suggest that biaxial accelerometer seems to be an interesting approach in the assessment of muscle contraction properties.
    Źródło:
    Acta of Bioengineering and Biomechanics; 2015, 17, 4; 73-84
    1509-409X
    2450-6303
    Pojawia się w:
    Acta of Bioengineering and Biomechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An application of a dynamic thermography for studying a relation between thermal and mechanical activities of a skeletal muscle during a static load
    Autorzy:
    Radomski, D.
    Kruszewski, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/114608.pdf
    Data publikacji:
    2017
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    dynamic thermography
    physical exercises
    muscle contraction
    muscle force
    impulse of a force moment
    Opis:
    A thermal distribution provides useful information of physiological and pathological processes. However, only a static thermography was applied in the most of medical studies. This paper shows an example of application of a dynamic thermography to study a physiological activity of a skeletal muscle. The goal of the presented work was to study a putative relationship between mechanical and thermal activity of the quadriceps during a static submaximal load. During a strain a dynamic temperature distribution on a thigh surface and a force moment of a knee erector were registered. The performed analysis used a time-dependent mean temperature, a time-dependent standard deviation and an impulse of a force moment. Moreover, we analyzed of autocorrelation functions to compare the dynamics of these parameters. Finally, we showed the nonlinear, statistically significant relationship between spatial-temporal variability of temperature and the force developing by a concentrative contracted quadriceps. A possible biological interpretation of the identified relation is also proposed taking the described mathematical model of muscle heat transfer into account.
    Źródło:
    Measurement Automation Monitoring; 2017, 63, 4; 139-142
    2450-2855
    Pojawia się w:
    Measurement Automation Monitoring
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Force analysis of shoulder joint muscles in the early phase of brain stroke
    Autorzy:
    Starosta, M.
    Kostka, J.
    Miller, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/306827.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    siła mięśni
    staw ramienny
    udar
    dynamometr
    muscle force
    upper limb
    shoulder joint
    stroke
    dynamometer
    Opis:
    Upper limb impairment in the early phase of brain stroke is one of the key problems in rehabilitation. An estimation of muscle force can be a helpful factor for functional improvement after a stroke. The primary goals of this study were to determine the muscles with the lowest force in the affected (A) and non-affected (non-A) upper limb. Moreover, the differences between men and women were compared and these values were correlated with age. Methods: One hundred (n = 35 female, n = 65 male) post-stroke patients met the inclusion criteria. The mean age of the study participants was 66.1 years. Muscle force for external and internal rotators of shoulder was measured with handheld dynamometer. Moreover, the correlation coefficients for differences in muscular force with the patient’s age were estimated. Results: Our study reports that the force of the (A) side in relation to the (non-A) was by 37% weaker. We observed about a 40% decrease in the force of the shoulder’s external rotation (female – 42%; male – 41%) and shoulder’s flexion (by 38% – female; 40% – male). Significant correlations between the muscle force and the age of post-stroke patients were also found. It was concluded that about 4 weeks after the first stroke in the patient’s life, the external rotators are the most affected group of shoulder muscles. Conclusions: Neither sex nor the side of the ischemic brain injury influence the muscle force, whereas age determines both muscle force and muscle force deficits. Older post-stroke patients demonstrate fewer deficits in muscle strength than younger ones.
    Źródło:
    Acta of Bioengineering and Biomechanics; 2018, 20, 3; 107-113
    1509-409X
    2450-6303
    Pojawia się w:
    Acta of Bioengineering and Biomechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effective utilization of man shift through sustainable workload testing for underground mining machine operators. An ergonomic based man-machine interface approach
    Autorzy:
    Dey, Netai Chandra
    Dey, Shibaji
    Powiązania:
    https://bibliotekanauki.pl/articles/2064404.pdf
    Data publikacji:
    2019
    Wydawca:
    STE GROUP
    Tematy:
    fatigue sustainability
    FS
    muscle force
    MF
    heart rate ratio
    HR ratio
    exposure time period
    ETP
    effective utilization of man shift
    EUMS
    workload simulation
    siła mięśni
    obciążenie pracą
    okres ekspozycji
    degradacja zmęczeniowa
    tętno
    środowiskowe warunki pracy
    Opis:
    Insight of man-machine interfaces during mining machine operations, better co-ordinance with human efficiencies and suitable workload selection in underground mining machine operation are the main viewpoints of the study. Total 12 side discharge loader (SDL) and load haul dumper (LHD) operators [N = 12] have been taken as participants of the study. The methodology is divided into two parts first part is devoted to measuring and analyzing workload response of machine operation with polar heart rate monitor. Machine operator’s heart rate ratio (HR ratio) for the whole shift is recorded and metabolic rate (MR) has been analyzed. Additionally, fatigue sustainability (FS) and degradation of muscle force (MF) are recorded for each work cycles up to exposure time period (ETP) of 360 minutes. In the second part of the methodology, based on the HR ratio recorded during the mining operation, a workload simulation study is undertaken on a treadmill at the surface following BRUCE protocol. At treadmill, based on HR ratio, workload achieved from mines along with three different workloads i.e. low, moderate and high has been tested. Differences in FS and degradation rate of MF after each workload experiment have been recorded. A result from the underground operational study shows that there is about 43.2% and 32.4% of decreasing MF for SDL and LHD operators after end of spells at mines. Additionally, a negative correlation (r = -0.99) is found between ETP and MF. The workload simulation study shows that there are significant differences between FS (p < 0.05) and MF (p < 0.05) data of mining and treadmill experiment with the same workload. In comparison to an underground operation, FS rate of low, moderate and high workload is recorded 60%, 35%, and 15% higher respectively than of mine workload. Higher FS rate may achieve due to availability of good environment. Among the tested workload only low kind of workload is found suitable for mining machinery job as degradation of MF is found significantly (p < 0.05) low and FS is found significantly (p < 0.01) high in this kind of workload. Therefore, it can be concluded that in mining machinery operation better to adopt low workload for effective utilization of man shift (EUMS) as it gives comparatively low MF degradation and better FS during continuous work.
    Źródło:
    New Trends in Production Engineering; 2019, 2, 1; 394--403
    2545-2843
    Pojawia się w:
    New Trends in Production Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Investigation of hand forces applied to a pruning tool - pilot study
    Autorzy:
    Romano, E.
    Caroso, L.
    Longo, D.
    Vitale, E.
    Schillaci, G.
    Rapisarda, V.
    Powiązania:
    https://bibliotekanauki.pl/articles/2085028.pdf
    Data publikacji:
    2019
    Wydawca:
    Instytut Medycyny Wsi
    Tematy:
    risk factors
    carpal tunnel syndrome
    pruning
    Borg scale
    grip force
    muscle skeletal disorders
    Opis:
    Introduction. Winter pruning is a cultivation practice necessary for maintaining the balance between the vegetative and the productive activity of plants and requires many working days using hand scissors. This operation involves the subjects carrying out a series of gestures that are repeated with considerable frequency, which are all musculo-skeletal disorders risk factors (MSDs) for the hand-wrist area. Objective. The aim of this study was to investigate the forces applied to pruning tools. Materials and method. Using a sensor matrix, peak and average forces were measured which are exerted while cutting branches of 3 different diameters, from 5 wine-grape cultivars. Samples were tested on 8 participants using sensored scissors to record, in 6 hand areas, the forces necessary to cut. Results. Results showed that while cutting, the factors which can impact the force employed (peak and average forces) by the subjects are branch diameter and percentage of branch humidity. Cut duration was inversely related to the size of the subject’s hand. The middle finger area of the hand recorded the highest force average and peak levels, while the hand region least affected during the cuts was the farthest from the thumb. Conclusions. The study enabled the highlighting of which factors influence the forces employed by the operator while cutting grape branches, and to identify the hand regions where muscle activation is at its most. These findings can be relevant in preventing MSDs. Further studies need to be conducted with a larger number of subjects.
    Źródło:
    Annals of Agricultural and Environmental Medicine; 2019, 26, 3; 472-478
    1232-1966
    Pojawia się w:
    Annals of Agricultural and Environmental Medicine
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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