ELECTROMYOGRAPHY OF TRUNK MUSCLES IN TIME-FREQUENCY DOMAIN DURING CORE STABILITY EXERCISES

Abstract

The aim of this work was to compare the electromyogram (EMG) of trunk muscles, in the time-frequency domain, among core exercises. The EMG of 17 men was recorded by electrodes placed on external oblique (EO), rectus abdominis (RA), lumbar erector spinae (LES) and multifidus (MT) muscles. Short-time Fourier transform was performed and instantaneous median frequency (MedFreq) was calculated and averaged. MedFreq of the EO and RA were significantly higher (p < 0.0001) during double leg back bridge exercise. Contrarily, LES and MT showed significant higher (p < 0.0001) MedFreq during frontal and left side bridge. Antagonist muscles showed greater MedFreq than agonist muscles. This may be explained by the low-pass filtering effect of the adipose tissue, which could attenuate the increase of high frequencies EMG energy of agonist muscles.