Reliability and Validity of the Feedback Sensor for Activating the Transversus Abdominis Muscle

Duangruedee Dissanguan1, Patraporn Sitilertpisan1, Suchart Kiatwattanacharoen2, Leonard H. Joseph3, Pinyo Puangmali4, Aatit Paungmali1, *
1 Department of physical therapy, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
2 Department of Radiologic Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
3 School of Health Science, University of Brighton, East, Sussex, United Kingdom
4 Department of Mechanical Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai, Thailand



Core muscle activation is an effective intervention for the management of low back pain. This study developed new feedback for detecting activation of the transversus abdominis muscle in the lumbar spine. The purpose of this study was to examine the validity and reliability of the feedback device for transversus abdominis muscle contraction.


The participants in this study were 20 healthy males and females (aged 24.1 ± 6.8 years). The feedback sensor was attached to the lumbar support at the front of the trunk. The participants performed an abdominal drawing-in maneuver in order to activate the transversus abdominis muscle, and values from the feedback sensor were collected at the same time. Ultrasound imaging of the transversus abdominis muscle was also collected simultaneously. The feedback sensor collected values at different clinical levels of the pressure biofeedback unit at 64, 66, 68, and 70 mmHg. The protocol was repeated with a 24-hr interval. Intra-class correlation coefficient, coefficient of variation and standard error of measurements were used to examine reliability. The validity of the values obtained from the relationship between the feedback sensor and transversus abdominis muscle thickness was analyzed using Pearson’s correlation coefficients.


Test–retest reliability of the feedback sensor was excellent (ICC = 0.946, CV = 2.6%, SEMs = 0.54%). Values of the feedback sensor reported a significantly moderate correlation with the gold standard ultrasound measurement (r = - 0.514, p < 0.001).


The feedback device demonstrated potential reliability and validity for clinical use by indicating activation of the transversus abdominis muscle.

Keywords: Validity, Reliability, Transversus abdominis, Feedback, Sensor, Core muscles, Ultrasound.

Abstract Information

Identifiers and Pagination:

Year: 2019
Volume: 13
Publisher Item Identifier: EA-TOBEJ-2018-22

Article History:

Received Date: 16/12/2018
Revision Received Date: 15/03/2019
Acceptance Date: 18/03/2019
Electronic publication date: 10/04/2019
Collection year: 2019

© 2019 Dissanguan et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: ( This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Correspondence: Address correspondence to this author at the Department of physical therapy, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand; Tel: +66089422366; Fax: +66 053946042; E-mails:,