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1

Use of selected methods of measurement in the assessment of milkers’ workload in the traditional milking

Kuta Ł., Cież J.

Journal of Research and Applications in Agricultural Engineering

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2014

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Vol. 59, nr 1

83--87

EN

The activities connected with the milker’s work are directly related to maintaining a special body posture due to the tension of specific muscles. Staying in one required position for a long time and work monotony in case have a negative effect on the person’s musculoskeletal system. Therefore a study was conducted to evaluate the level of muscle tension and perceptible load while performing individual steps of hand-milking procedure. A detailed timing of the milker’s work was also recorded. The workload was assessed according to the OWAS method and muscle tension was assessed according to the EMG method. On the basis of collected data it was assumed that the highest muscle tension for the evaluated group of 10 milkers was achieved with the forearm muscles. It is strictly connected with hands being raised forward and repeating the same movements. Based on the OWAS method it was observed that the milker’s overall workload level can be described as medium. Farmers conducting milking should have adequate work breaks and should reduce workload on the musculoskeletal system whenever possible.

PL

Czynności związane z pracą dojarzy wiąże się bezpośrednio z utrzymaniem pożądanej pozycji ciała dzięki napięciu odpowiednich mięśni. Długotrwałe utrzymywanie wymuszonej pozycji ciała oraz monotonia pracy dojarza negatywnie wpływają na jego układ mięśniowo-szkieletowy. W związku z tym przeprowadzono badania, których celem była ocena poziomu napięcia mięśniowego i odczuwalnego obciążenia podczas wykonywania poszczególnych czynności składowych dla doju ręcznego. Wykonano także chronometraż czynności pracy dojarza. Ocenę obciążenia pracą dojarzy wykonano metodą OWAS, zaś napięcia mięśniowego metodą EMG. Na podstawie uzyskanych wyników stwierdzono, że najwyższe napięcie mięśniowe dla badanej, 10-osobowej grupy dojarzy, uzyskano dla mięśni przedramienia. Związane jest to ściśle z wyciągniętymi ku przodowi rękoma, które wykonują powtarzalne ruchy. Na podstawie metody OWAS stwierdzono, że ogólny poziom obciążenia pracą dojarza określić można jako średni. Rolnicy wykonując dój powinni dokonywać odpowiednich przerw w pracy oraz redukować, na ile to możliwe, obciążenie układu mięśniowo-szkieletowego.

2

Can all muscular load sharing patterns be regarded as optimal in some sense?

Siemieński A.

Acta of Bioengineering and Biomechanics

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2006

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Vol. 8, nr 2

43-49

EN

Muscles crossing a joint usually outnumber its degrees of freedom, which renders the motor system underdetermined. Typically, optimization laws are postulated to cope with this redundancy. A natural question then arises whether all muscular load sharing patterns can be regarded as the results of optimization. To answer it we propose a method of constructing an objective function whose minimization yields a given load sharing pattern. We give necessary conditions for this construction to be feasible and investigate its uniqueness. For linear load sharing patterns the Crowninshield and Brand (1981) objective function is reproduced – nonlinear ones require a more general formula.

3

Sitting Posture, Postural Discomfort, and Visual Performance: A Critical View on the Interdependence of Cognitive and Anthropometric Factors in the VDU Workplace

Ziefle M.

International Journal of Occupational Safety and Ergonomics

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2003

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Vol. 9, No. 4

503--514

EN

The study focuses on individual and standard visual display unit (VDU) workplaces with respect to performance and muscular load. Three different work settings were realized: The workplace was either adjusted to individual preferences or to the European standard. The third condition mirrored exactly the individual setting, however participants were told that it was set according to another standard. Dependent variables were visual performance in a search task, the rated muscular load, and individual preferences. Results show that both individual work settings yielded a superior performance as compared to the standard. However, performance and muscular comfort improved when participants knew they had adjusted the workplace. Apparently, VDU users follow a intuitive rationale adjusting their work setting minimizing muscular load and optimizing performance.