Continuous measurement of lumbar posture using flexible electrogoniometers

Abstract

Continuous measurement of changing limb segment angle is possible using a recently introduced flexible electrogoniometer but, unfortunately, the magnitude of linear displacements occurring during flexion and extension of the trunk has prevented its use as a measure of spinal mobility and posture. To overcome this limitation, a specially constructed, lightweight, aluminium carriage has been developed to allow free linear travel of the electrogoniometer, while maintaining the angle recorded between the thoracolumbar junction and the sacrum. The reliability and practicability of this new approach for recording changes in lumbar posture have been investigated. Following bench tests and operator training, measurements of maximal flexion and extension of the lumbar spine were repeated on 12 subjects. The extent of sagittal mobility was compared with measures from a fluid-filled inclinometer and a flexicurve. Analysis of the data showed that the use of the aluminium carriage did not markedly influence the accuracy of the electrogoniometer, and the technique as modified was found to be comparable with standard techniques for estimating the extent of lumbar sagittal flexibility. A field based study, involving four garage mechanics, was undertaken to examine the usability and acceptability of the electrogoniometer technique for continuous measurements. Lumbar curvature was monitored continuously for a two hour period during the course of the mechanics' working day. Dedicated software provided angle-time plots from which it was established that extreme flexed or extended postures were maintained only for relatively short periods; projection to an eight hour shift would indicate that a total of approximately 40 min is spent in extension beyond 10 degrees and flexion beyond 50 degrees. The technique has the potential to provide quantitative information on lumbar posture necessary for non-invasive, biomechanical investigations of spinal loading. It will be particularly useful for both sporting and occupational ergonomics field-studies.

The Effectiveness of a Lumbopelvic Monitor and Feedback Device to Change Postural Behavior: A Feasibility Randomized Controlled Trial

“…39,51,57 Previous studies have used a variety of devices for postural monitoring. 4,13,18,48,58 A common problem found in postural-monitoring devices used during daily activities is the trade-off between portability and accuracy of measurements. Instruments such as the moment T T STUDY DESIGN: Feasibility randomized controlled trial.…”

Clinical Applications of Sensors for Human Posture and Movement Analysis

“…Thoumie et al (1998) compared the results of radiography with the electrogoniometer in measuring lumbar curvature and motion change during flexion-extension of the spine. Although the measurements of electro-goniometer were not comparable with the value of radiographic data in lumbar curvature and range of motion, the device could provide quantitative information of lumbar sagittal motion in continuous measurement and was recommended for use in a variety of occupational and recreational environments (Boocock et al 1994). The inherent limitations of the flexible strain-gauged electro-goniometer should be considered in its application.…”

“…This portable design could be used in more clinical applications if the accuracy of this device is comparable to the commercial products. The use of commercial flexible electro-goniometer to provide continuous quantitative information on lumbar spinal motion has been reported by Boocock et al (1994) and Thoumie et al (1998). The electro-goniometer was directly attached onto the surface of the lower back.…”

“…The inherent limitations of the flexible strain-gauged electro-goniometer should be considered in its application. The flexible strain gauge of the commercial electrogoniometer may be susceptible to bending or buckling during studies of seated tasks with lumbar support (Boocock et al 1994). The measurement range of the spinal motion could be limited by exceeding the maximum preset distance between the two attachments with linear displacements occurring during flexion and extension of the lumbar spine.…”

Wearable Sensing for Solid Biomechanics

“…Mechanical instruments [4]- [14], marker-based optical systems [15]- [20], force sensing walkways [21]- [25], and electromyography (EMG) [25]- [28] allow detailed quantification of movement and the cause of motion. Fig.…”