Abstract
The primary objective of the study was to explore the nonlinear characteristics of surface electrical activity of the biceps muscle during two (job safety critical) static postures observed on the assembly line. The results showed that for each trial in both postures (posture 1: the MVC condition, and posture 2: the no-loading test posture) the positive Lyapunov exponents exist. However, the statistical test of significance showed that surface EMG of the biceps brachii was more chaotic under the maximum loading in simulated posture 1 than under the no-loading condition in simulated posture 2. At the same time it was observed that the recorded two types of time series (EMG data) were almost equally complex, indicating the same source of the data. The existence of chaos in the EMG measure of muscle activity may indicate that conventional analysis could bear little meaning in explaining muscular fatigue.
Get full access to this article
View all access options for this article.