Muscle work (work study)
Under muscle work is understood as work studying the energy content of work activities usually on the mobilization of skeletal muscle.
REFA distinguishes between four types of muscle work, which, however, belong together in pairs:
- static posture work
- static holding work
- heavy dynamic work
- one-sided dynamic work.
One speaks of static muscle work from a muscle tension of 4 to 6 seconds. Static work is not work in the physical sense. The balance is only kept against an external force. From a physiological point of view, this is measured as the product of force and time (instead of force times distance in physics). Posture work is the variant of static work in which only internal forces are present, i.e. a body position is maintained (dead weight of the limbs). During holding work, there are also outwardly directed forces, for example to hold a lifted load.
Dynamic work occurs when the muscle alternates between contraction and relaxation and physical work is performed. Examples are lifting a load or turning a crank. The distinction between difficult and one-sided results from the number of muscles involved. If the proportion of muscles involved in which fatigue occurs is less than a seventh of the body mass involved, one speaks of one-sided . Fatigue is assumed to occur if the contraction frequency is higher than 15 contractions per minute. The circulatory and respiratory systems are also involved in heavy dynamic muscle work.
swell
- ↑ Luczak, Holger: Ergonomics . 2nd completely revised edition Berlin: Springer, 1998. - ISBN 3-540-59138-9 . P. 28.
- ↑ REFA Association for Work Studies and Business Organization e. V. (Hrsg.): Methodology of the company organization: Lexicon of the company organization . Munich: Carl-Hanser, 1993. - ISBN 3-446-17523-7 . Page 124.
- ^ Spallek, Michael: muscle work, static . In: Landau, Kurt (Hrsg.): Lexicon of work design: Best practice in the work process . Stuttgart: Genter, 2007. - ISBN 978-3-87247-655-5 . P. 931 ff.