Could Thermal Imaging Supplement Surface Electromyography Measurements for Skeletal Muscles?

Abstract

(1) Background: The aim of this study is to present the results of experiments in which surface electromyography (sEMG) and thermal imaging were used to assess muscle activation during gait and to verify the hypothesis that there is a relationship in the case of low fatigue level between sEMGmeasured muscle activation, assessed in the frequency domain, and thermal factors calculated as minimum, maximum, kurtosis, mean, median and mode from the area of interest. (2) Methods: Comparison of activity calculated from the recorded sEMG data for rectus femoris, biceps femoris, tibialis anterior and gastrocnemius medialis with thermal data obtained from the infrared vision. (3) Results: Data of fourteen healthy volunteers obtained during 10 minutes of treadmill gait are presented and analyzed. The analysis revealed statistically significant: linear correlations for rectus femoris (five moderate relationships) and gastrocnemius medialis (one good relationship); moderate nonlinear correlations for all examined muscles. Also, a detailed protocol for precise, repeatable thermal examination is presented. (4) Conclusions: Estimated moderate linear and non-linear correlations between thermal and electromyographic parameters are found for low level of muscle fatigue, which suggests that the presented method is useful in the analysis of muscle activation with the use of a thermal imaging as a complement to sEMG.