Experimental determination of muscular work capacity for repetitive static work in a predetermined work-rest rhythm
Pflugbeil, C.; Rehfeldt, H.; Kramer, H.
Zeitschrift für die Gesamte Hygiene und ihre Grenzgebiete 31(7): 436-439
1985
ISSN/ISBN: 0049-8610 PMID: 4049976 Document Number: 249709
For estimation of the local muscular work capacity of arm flexors for repetitve static work with a fixed work-test regime the following approach was tested. In the first series of 30 repeated isometric contractions the decrease of maximum available strength was determined in well motivated male volunteers. For contractions lasting 30 s with interspersed rest periods of 30 s the mean force level achieved by the 10 subjects was 34.7% MVC at the beginning and 26.4% MVC at the end of the last 10 contractions, i.e. about 30% MVC. During additional experiments performed 4 weeks later all the subjects were able to maintain that force level of 30% MVC for the whole investigated period of repeated contractions. Despite this, the heart rate and the mean bioelectrical muscle activity showed a continuous increase throughout these series of isometric contractions. From these results it can be concluded that the force level determined in the way described cannot be performed for unlimited work periods.