Reliability of two SEMG normalization methods of the trapezius muscle

• Grant number: 13/23098-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2014
• End date: December 31, 2014
• Field of knowledge: Health Sciences - Physiotherapy and Occupational Therapy
• Principal Investigator: Ana Beatriz de Oliveira
• Grantee: Marina Machado Cid
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

The work related musculoskeletal disorders (WMSDs) are one of the main health problems among industrialized countries. The surface electromyography (sEMG) is the only non-invasive method that provides direct information about the muscle involvement during work related activities. Based on the muscle electrical signal, it is possible to evaluate the biomechanical exposure of workers, being the trapezius muscle investigated in this context. However, the sEMG amplitude is sensible to many factors, being necessary normalize the recorded signal. Although sEMG be usually used among different acknowledges areas, there isn't papers that evaluate the reliability of different normalization methods for the three portions of the trapezius muscle, considering the intra-session and inter-day variability. Therefore, the aim of the current study is to evaluate the intra-session and inter-day reliability of two sEMG normalization methods for the dominant trapezius muscle of healthy and myalgic subjects. Will be evaluated 20 women divided in two groups - healthy (HG) and with chronic trapezius myalgia (TMG). The subjects will be allocated according to the results from a physical evaluation and the Nordic Musculoskeletal Questionnaire. Besides that, the pressure pain threshold will be recorded to characterize the sample. After the local ethics committee approval and the subjects allocation, the electromyographic signal will be recorded on two distinct days, with an interval of 7 days between them. Will be evaluated three portions of the dominant trapezius muscle, during 3 maximal and submaximal contractions of 5 seconds each. The intra-session and inter-day reliability will be obtained based on the Intraclass Correlation Coefficients (ICCs). All tests will be run in SPSS software (Statistical Package for Social Science, v. 17, Chicago, IL).