caa a22 4500 467941483 CHVBK 20180406153014.0 cr unu---uuuuu 170328e20060101xx s 000 0 eng 10.1007/s00421-004-1182-6 doi (NATIONALLICENCE)springer-10.1007/s00421-004-1182-6 Upper trapezius muscle conduction velocity during fatigue in subjects with and without work-related muscular disorders: a non-invasive high spatial resolution approach [Elektronische Daten] [E. Schulte, O. Miltner, E. Junker, G. Rau, C. Disselhorst-Klug] The development of fatigue at the muscle fibre level can be assessed in terms of a decrease in conduction velocity (CV). The present study aimed to investigate if work-related muscular disorders in occupations characterised by static loads of long duration affect fatigue resistance in the painful muscle. A group of eight secretaries suffering from bilateral chronic muscle pain in the shoulder/neck region was compared to a group of healthy subjects. The upper trapezius muscle was studied under isometric contractions, holding the arm in the horizontal plane up to the endurance point. Changes in CV estimated at the motor unit level were investigated using a non-invasive high spatial resolution electromyographic (EMG) approach. In addition, the number of motor unit potentials per second (PPS), and the root mean square (RMS) of bipolar signals were assessed, and the results reported as the mean and standard error for each value. Subjects with work-related disorders showed less pronounced changes in CV with respect to healthy subjects. No differences between subjects with and without work-related disorders were encountered for the PPS and RMS. The present findings on CV indicate an increased fatigue-related recruitment of MUs in the painful muscle with respect to a healthy muscle. The fact that this recruitment is not reflected in the PPS and RMS estimates might be due to a fatigue-induced decrease in the firing rate and/or the de-recruitment of fatigued MUs. Furthermore, methodological limitations of the adopted method in the estimation of ‘global' parameters such as the PPS and RMS have to be considered. Springer-Verlag, 2004 Conduction velocity nationallicence Fatigue nationallicence Motor unit nationallicence Myalgia nationallicence Surface electromyography nationallicence Schulte E. Helmholtz Institute, Chair for Applied Biomedical Technologies, Institute for Biomedical Technologies, RWTH Aachen, Pauwelsstrasse 20, 52074, Aachen, Germany aut Miltner O. Clinic for Orthopaedics, University Hospital RWTH Aachen, Aachen, Germany aut Junker E. Helmholtz Institute, Chair for Applied Biomedical Technologies, Institute for Biomedical Technologies, RWTH Aachen, Pauwelsstrasse 20, 52074, Aachen, Germany aut Rau G. Helmholtz Institute, Chair for Applied Biomedical Technologies, Institute for Biomedical Technologies, RWTH Aachen, Pauwelsstrasse 20, 52074, Aachen, Germany aut Disselhorst-Klug C. Helmholtz Institute, Chair for Applied Biomedical Technologies, Institute for Biomedical Technologies, RWTH Aachen, Pauwelsstrasse 20, 52074, Aachen, Germany aut European Journal of Applied Physiology Springer-Verlag 96/2(2006-01-01), 194-202 1439-6319 96:2<194 2006 96 421 https://doi.org/10.1007/s00421-004-1182-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00421-004-1182-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Schulte E. Helmholtz Institute, Chair for Applied Biomedical Technologies, Institute for Biomedical Technologies, RWTH Aachen, Pauwelsstrasse 20, 52074, Aachen, Germany aut NATIONALLICENCE 700 1- Miltner O. Clinic for Orthopaedics, University Hospital RWTH Aachen, Aachen, Germany aut NATIONALLICENCE 700 1- Junker E. Helmholtz Institute, Chair for Applied Biomedical Technologies, Institute for Biomedical Technologies, RWTH Aachen, Pauwelsstrasse 20, 52074, Aachen, Germany aut NATIONALLICENCE 700 1- Rau G. Helmholtz Institute, Chair for Applied Biomedical Technologies, Institute for Biomedical Technologies, RWTH Aachen, Pauwelsstrasse 20, 52074, Aachen, Germany aut NATIONALLICENCE 700 1- Disselhorst-Klug C. Helmholtz Institute, Chair for Applied Biomedical Technologies, Institute for Biomedical Technologies, RWTH Aachen, Pauwelsstrasse 20, 52074, Aachen, Germany aut NATIONALLICENCE 773 0- European Journal of Applied Physiology Springer-Verlag 96/2(2006-01-01), 194-202 1439-6319 96:2<194 2006 96 421 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer