Effect of Electrical Muscle Stimulation Belt for Abdominal Muscles Activation

Objective: The purpose of this study is to observe the change in the thickness of abdominal muscles when electrical muscle stimulation (EMS) is applied to the abdomen during rest and abdominal muscle exercise to investigate the effect of EMS applied to the abdomen on the superficial and deep muscles thickness. Design: Cross sectional design. Methods: Twenty healthy subjects participated in this study. Subjects were performed resting position, resting position with EMS, curl-up and curl-up with EMS. The electrode of the EMS belt is attached to the abdominal wall between the 12th rib and iliac crest. The thickness of abdominal muscles including rectus abdominis (RA), external oblique (EO), internal oblique (IO), and transverse abdominis (TrA) were captured in each position by ultrasound image during expiration. All subjects were performed four positions randomly. Data were analyzed using repeated ANOVA with the level of significance set at α＝0.05. Results: The muscle thickness of RA, EO, IO and TrA were significantly different at each position (p<0.05). The thickness of all abdominal muscles increased significantly when curl-up than curl-up with EMS. Both RA and EO thickness were significantly increased at resting position than resting position and EMS were combined(p<0.05). But IO and TrA thickness were decreased at resting position when EMS were combined. Conclusions: The results suggest that EMS activates superficial abdominal muscles RA and EO. Therefore, abdominal strengthening exercise combined EMS can activate abdominal muscles and can be applied to various patients and rehabilitation in clinical practice.