Background: Whole body-electromyostimulation (WB-EMS) is widely used for the rehabilitation and recovery of patients with various neuromusculoskeletal disorders.
Objects: To objectively measure changes in lower extremity and abdominal muscles after sit-to-stand dynamic movement training using WB-EMS.
Methods: A total of 46 healthy adults (23 experimental and 23 control subjects) performed sit-to-stand exercise; the experimental group with WB-EMS, and the control group without WB-EMS. The muscle activity of the lower extremity, and the muscle thickness of the lower extremity and abdominal muscles were measured before and after the intervention.
Results: In terms of electromyographic activity, there was a significant interaction effect for the rectus femoris (RF) muscle (F=30.212, p=.000). With regards to ultrasonographic imaging, the muscle thickness of the RF muscle had a significant interaction effect at the muscle contraction ratio (F=8.071, p=.007). The deep abdominal muscles, such as the transverse abdominal (TrA) and internal oblique (IO) muscles, also showed significant interaction effects at the muscle contraction ratio (F=5.474, p=.024, F=24.151, p=.000, respectively)
Conclusion: These findings suggest that WB-EMS may help to improve the muscular activity of the RF muscle, and the muscle thickness of the RF muscle and deep muscles such as the TrA and IO muscles.

Abstract
Introduction
Methods
    Subjects
    Intervention
    Surface electromyographic recording and data processing
    Ultrasonographic imaging recording and data processing
    Statistical analysis
Results
Discussion
Conclusion
References

• Keun-hyo Lee(Dept. of Rehabilitation Medicine, Konyang University Hospital)
• Se-jin Park(Center for Medical Metrology, Korea Research Institute of Standards and Science)
• Seung-chul Chon(Dept. of Physical Therapy, College of Medical Science, Konyang University) Corresponding author