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.

The purpose of this study was to compare the effects of respiratory exercise on cardiopulmonary function and muscle activity of rectus abdominis in smokers and non-smokers with elderly people. All the participants were older than 65 years, and twenty non-smokers, and twenty smokers participated. Non-smokers and smokers were randomly divined into 10 feedback breathing exercises (FBE) and a balloonblowing exercise (BBE) group. The FBE and the BBE were performed three times a week for four weeks. Forced vital capacity (FVC), forced expiratory volume at one second (FEV1), forced expiratory volume at one second/forced vital capacity (FEV1/FVC), peak expiratory flow (PEF), and vital capacity (VC) were measured as pulmonary function. EMG was used to measure the activity of the rectus abdominis. In the FBE and BBE groups, FEV1 was significantly lower in non-smokers compared to smokers at two and four weeks (p<.05), FEV1/FVC, PEF and VC were significantly lower in non-smokers compared to smokers to pre-test, two weeks, four weeks and six weeks (p<.05). Muscle activity of rectus abdominis was significantly difference in the BBE group at pre-test, two weeks, four weeks, and six weeks (p<.05). These results suggest that respiratory exercise was effective in improving pulmonary function and rectus muscle activity.

This study examined the muscle recruitment order during extension of the hip joint in normal subjects, and evaluated whether the external support obtained from wearing a lumbosacral corset had an effect on muscle recruitment leading to increased lumbar stability. The subjects were 40 normal adults (32 male, 8 female) with no history of low back pain and no pathological findings in the nervous or musculoskeletal systems. All subjects extended their hip joints under 3 positions (prone, sidelying, standing). During extension, the onsets of contraction of the rectus abdominis, gluteus maximus, and semitendinosus muscles were measured. Electromyographic activity was measured using a surface electrode, and the muscle contraction onset time was designated as the point exceeding a threshold of 25 ms, using a mean plus twice of the standard deviation. To compare the average order of muscle contraction onset time, a Freedman two-way analysis of variance by ranks was used. The relative difference between muscle contraction onset time wearing and not wearing a lumbosacral corset was measured using a paired t-test. A difference in the average muscle contraction onset order for the rectus abdominis, gluteus maximus, and semitendinosus muscles was observed (p<.05) among three positions. However, wearing a lumbosacral corset did not. change the contraction order. In addition, wearing a lumbosacral corset produced a significant difference (p<.05) in the relative onset time between the rectus abdominis and gluteus maximus in the standing position, but no difference was observed for the other muscles or positions. In the future, patients suffering from low back pain should be compared with normal subjects to determine the effectiveness of a lumbosacral corset in changing muscle recruitment order.