Straight-leg-raising test. Comparison of three instruments

Area of Science:

• Biomechanics
• Physical Therapy Measurement
• Musculoskeletal Assessment

Background:

• The passive straight-leg-raising (SLR) test is crucial for evaluating lumbar radiculopathy and hamstring flexibility.
• Accurate measurement of hip flexion during the SLR test is essential for reliable clinical assessment.
• Various instruments exist for measuring joint angles, but their comparative reliability in SLR testing is not well-established.

Purpose of the Study:

• To compare the intrasession and intersession reliability of three instruments—a standard plastic goniometer, a flexometer, and a tape measure—for assessing the passive straight-leg-raising test.
• To determine the most reliable and practical instrument for measuring hip flexion angles during the SLR test.

Main Methods:

• Ten healthy subjects participated in the study.
• Hip flexion angles were measured using a goniometer, flexometer, and tape measure at the point of initial pelvic tilt.
• Intrasession and intersession reliability were calculated for all three instruments.

Main Results:

• All three instruments demonstrated excellent intrasession reliability (alpha > .94).
• Goniometer and flexometer showed higher intersession reliability (.88) compared to the tape measure (.74).
• Using a distance-based trigonometric method with the tape measure improved its intersession reliability to .93 but yielded significantly lower hip flexion angles than the other instruments.

Conclusions:

• The flexometer is recommended for passive SLR assessment due to its high reliability and suitability for single-therapist use.
• While tape measures can be reliable with specific methods, they may produce different angle measurements compared to goniometers and flexometers.
• Standard goniometers and flexometers provide comparable and reliable measures for the passive SLR test.