Affiliations: [a] Department of Physical Medicine and Rehabilitation, College of Medicine, Catholic University, Daegu, Korea | [b] Medical Devices Clinical Trial Center, Yeungnam University, Daegu, Korea | [c] Department of Rehabilitation Science, Graduate School, Daegu University, Gyeongsan, Korea | [d] Department of Physical Medicine and Rehabilitation, Bogang Hospital, Daegu, Korea | [e] Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University, Daegu, Korea | [f] Department of Neurosurgery, College of Medicine, Yeungnam University, Daegu, Korea
Correspondence:
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Corresponding author: Sang Ho Ahn, Department of Physical Medicine & Rehabilitation and Spine Center, Yeungnam University College of Medicine, 317-1, Daemyung-dong, Nam-gu, Daegu, 705-717, Korea. Tel.: +82 53 620 3268; OPD: +82 53 620 3450; Fax: +82 53 624 8356; E-mail:spineahn@ynu.ac.kr
Abstract: BACKGROUD: Low back pain is associated with transversus abdominis (TrA)
dysfunction. Recently, it was proposed that Neuromuscular Electrical
Stimulation (NMES) could be used to stimulate deep abdominal muscle
contractions and improve lumbopelvic stability. OBJECTIVE: The purpose of this study was to determine the optimal
stimulation frequency required during NMES for the activation of deep
abdominal muscles. METHODS: Twenty healthy volunteers between the ages of 24 and 32 were
included. The portable research-stimulator was applied using a 10 second
contraction time, and a 10 second resting time at 20 Hz, 50 Hz, and 80 Hz.
Changes in muscle thicknesses were determined for the TrA, obliquus internus
(OI), and obliquus externus (OE) by real time ultrasound imaging. RESULTS: Significant thickness increases in the TrA, OI, and OE were
observed during NMES versus the resting state (p < 0.05). Of the frequencies
examined, 50 Hz NMES produced the greatest increase in TrA thickness (1.33
fold as compared with 1.22 fold at 20 Hz and 1.21 fold at 80 Hz) (p < 0.05). CONCLUSIONS: Our results indicate that NMES can preferentially stimulate
contractions in deep abdominal stabilizing muscles. Most importantly, 50 Hz
NMES produced greater muscle thickness increases than 20 or 80 Hz.
Keywords: Neuromuscular electrical stimulation, frequency, abdominal muscle thickness, transversus abdominis, low back pain, real time ultrasound imaging
