Research Report Abstracts - Gesundheit

eS538
Research Report Poster Display
Number: RR-PO-205-10-Tue Tuesday 21 June 12:00
RAI: Exhibit Halls 2&3
ULTRASONOGRAPHIC MEASUREMENT OF THE
THICKNESS OF THE RECTUS FEMORIS AND
VASTUS INTERMEDIUS DURING ELECTRICAL
STIMULATION
Ito T. 1 , Kobara K. 1 , Yoshimura Y. 1 , Tsubahara A. 2
1Kawasaki University of Medical Welfare, Department of
Rehabilitation, Kurashiki City, Japan, 2Kawasaki Medical
School, Department of Rehabilitation Medicine, Kurashiki
City, Japan
Purpose: Measurement of the muscle torque generated by
joint movement is a common method for evaluating muscle
contraction during electrical stimulation. However, there is
no method to measure the torque of individual muscles during
single joint movement. Further, no reports describe the
structural changes in muscles during electrical stimulation.
The purpose of this study was to investigate the effect of the
distance between 2 stimulation electrodes and the stimulation
intensity on the changes in the thickness of the rectus femoris
(RF) and vastus intermedius (VI).
Relevance: Our findings provide basic information on
instrument setup, such as the inter-electrode distance and
stimulation intensity, with which electrical stimulation can
be effectively used in clinical practice.
Participants: Ten healthy male volunteers (age, 20.2 (SD,
1.1) years) participated in this study. The study was conducted
with the approval of the Research Ethics Committee of the
Kawasaki University of Medical Welfare (#154), and written
informed consent was obtained from all participants.
Methods: The thickness of the right RF and VI was measured
using a B-mode ultrasonographic apparatus (UF-750XT;
Fukuda Denshi Co. Ltd., Japan) and a linear scanner (scanning
frequency: 7.5 Mz), with the participants in the sitting
posture. The scanning site was the midpoint between the
anterior superior iliac spine and the upper edge of the
patella (standard line: SL). Electrical stimulation was delivered
using a stimulator (ES-510; Ito Co. Ltd., Japan) via 2
self-adhesive electrodes (5 × 9 cm) placed over the SL. The
stimulus parameters were 30 Hz, 5 seconds on, 15 seconds
off. The electrodes were placed under the following 3 conditions:
at 20% of the SL symmetrically apart from the midpoint
(Ps1); at 30% (Ps2); and at 40% (Ps3). After the motor threshold
at Ps1 and Ps3 was confirmed by observation, 3 steps of
stimulation intensity—weak, intermediate and strong—were
selected for each individual on the basis of the lower motor
threshold. Under each condition, the muscle thickness was
measured 3 times, and the mean value was then calculated
with 2 of the 3 measurements in order to decrease the measurement
error.
Analysis: To investigate whether the inter-electrode distance
influenced the thickness of the RF and VI, a two-way analysis
of variance was used, and p values