caa a22 4500 469054700 CHVBK 20180323132840.0 cr unu---uuuuu 170328e19921101xx s 000 0 eng 10.1007/BF00243516 doi (NATIONALLICENCE)springer-10.1007/BF00243516 Effects on efficiency in repetitive lifting of load and frequency combinations at a constant total power output [Elektronische Daten] [M. de Looze, H. Toussaint, R. Nibbelke, H. Eelderink] Sumary: Boxes were lifted and lowered repetitively at three different combinations of load and frequency. These combinations were chosen such that the total mechanical power generated was constant. Effects of the varying load or frequency conditions (but constant total mechanical power) on the rate of energy expenditure (M) and on the mechanical efficiency (ME) were measured. Mechanical power was determined from film analysis and separated into external power (generated to lift the load) and internal power (to raise the lifter's body mass). The M was determined from oxygen consumption measurements. The ME was calculated in two ways, depending on the definition of mechanical power, including either the external power only (MEext) or the total power output (MEtot). Despite a constant total mechanical power, M increased at higher loads and lower frequencies. This might be explained by the increasing isometric force required in postural and load control. The M increase resulted in a decrease of MEtot. However, at higher loads and lower frequencies MEext increased, indicating that more external work can be done at the same energy costs at higher loads or lower frequencies, which could be of interest from the point of view of occupational physiology. It would seem that at higher loads or lower frequencies the increased costs for isometric muscle action do not outweigh the benefit of raising the body less frequently. Furthermore, it was found that the ME,, in lifting was much lower than the values reported for other kinds of activity. This was due to the large proportion of total power output that was internal power in repetitive lifting [e.g. 83.1% (at a load of 6 kg) in the present study]. Springer-Verlag, 1992 Energy expenditure nationallicence Mechanical efficiency nationallicence Repetitive lifting nationallicence de Looze M. Department of Health Science, Faculty of Human Movement Sciences, Vrije Universiteit, van der Boechorststraat 9, NL-1081 BT, Amsterdam, The Netherlands aut Toussaint H. Department of Health Science, Faculty of Human Movement Sciences, Vrije Universiteit, van der Boechorststraat 9, NL-1081 BT, Amsterdam, The Netherlands aut Nibbelke R. Department of Health Science, Faculty of Human Movement Sciences, Vrije Universiteit, van der Boechorststraat 9, NL-1081 BT, Amsterdam, The Netherlands aut Eelderink H. Department of Health Science, Faculty of Human Movement Sciences, Vrije Universiteit, van der Boechorststraat 9, NL-1081 BT, Amsterdam, The Netherlands aut European Journal of Applied Physiology and Occupational Physiology Springer-Verlag 65/5(1992-11-01), 469-474 0301-5548 65:5<469 1992 65 421 https://doi.org/10.1007/BF00243516 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00243516 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- de Looze M. Department of Health Science, Faculty of Human Movement Sciences, Vrije Universiteit, van der Boechorststraat 9, NL-1081 BT, Amsterdam, The Netherlands aut NATIONALLICENCE 700 1- Toussaint H. Department of Health Science, Faculty of Human Movement Sciences, Vrije Universiteit, van der Boechorststraat 9, NL-1081 BT, Amsterdam, The Netherlands aut NATIONALLICENCE 700 1- Nibbelke R. Department of Health Science, Faculty of Human Movement Sciences, Vrije Universiteit, van der Boechorststraat 9, NL-1081 BT, Amsterdam, The Netherlands aut NATIONALLICENCE 700 1- Eelderink H. Department of Health Science, Faculty of Human Movement Sciences, Vrije Universiteit, van der Boechorststraat 9, NL-1081 BT, Amsterdam, The Netherlands aut NATIONALLICENCE 773 0- European Journal of Applied Physiology and Occupational Physiology Springer-Verlag 65/5(1992-11-01), 469-474 0301-5548 65:5<469 1992 65 421 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer