Continuous measurement of lumbar posture using flexible electrogoniometers

Area of Science:

• Biomechanics
• Ergonomics
• Spinal Health

Background:

• Flexible electrogoniometers can measure limb segment angles.
• Linear displacements during trunk flexion/extension limit their use for spinal mobility.
• A novel approach is needed to accurately measure lumbar posture and mobility.

Purpose of the Study:

• To develop and validate a modified electrogoniometer system for measuring lumbar spinal mobility and posture.
• To assess the reliability and practicability of the new technique.
• To evaluate the usability and acceptability of the system in a field setting.

Main Methods:

• A lightweight aluminum carriage was designed to allow electrogoniometer linear travel while maintaining angular measurement.
• Bench tests and operator training were conducted.
• Lumbar spine sagittal mobility was measured in 12 subjects, comparing results with inclinometers and flexicurves.
• A field study monitored lumbar curvature in four garage mechanics over two hours.

Main Results:

• The modified electrogoniometer system showed accuracy comparable to standard techniques for lumbar sagittal flexibility.
• The aluminum carriage did not significantly impact electrogoniometer accuracy.
• Continuous monitoring in garage mechanics revealed limited time spent in extreme lumbar postures (approx. 40 min in 8-hour shift beyond 10° extension or 50° flexion).

Conclusions:

• The modified electrogoniometer system provides reliable and accurate quantitative data on lumbar posture and mobility.
• This technique is suitable for non-invasive biomechanical investigations of spinal loading.
• The system is particularly useful for occupational and sporting ergonomics field studies.