earticle

영어

The purpose of this study was to compare the reliability of various methods of normalization electromyograms (EMGs) and categorize according to the magnitude and form of muscle contraction. We searched Scopus and Pubmed database for articles that published last 15 years, using following combinations of the key words: normalization method, EMGs and reliability. To compare the reliability, we chose the articles that analyzed the intra/inter class correlation coefficient (ICC) value such as test-retest, within-days and between-days each methods. Five normalization methods were identified and presented their reliability, benefit and limitation for providing the guidelines. Maximal voluntary isometric contraction (MVIC) can be a reliable method for within-days to healthy subjects but not to patients and the elderly. Submaximal voluntary isometric contraction (Sub-VIC) showed the good reliability both of within days and between days than MVIC. However, both of MVIC and Sub-VIC may be affected by internal effects such as muscle fatigue, the presence of synergist contribution, motivation, and pathologic conditions. Reference voluntary contraction (RVC) showed moderate reliable method for patients who are unable to produce the maximal voluntary contraction and repeated tests. Isokinetic MVC showed less reliability than other normalization methods. Mean and peak dynamic method (MDM and PMD) reduce the inter-subject variability than other normalization methods. However, it does not directly reflect the ability of maximal voluntary contraction of target muscle. When designing the clinical research by using EMGs, we must consider the characteristics of subjects, tasks and target muscles for improving the reliability and validity. In addition, it is necessary to develop the new normalization method which complements the limitation of traditional methods.