Changes in Lumbar Lordosis During the Prone Knee-Flexion Test in Healthy Subjects

Background: Recently, researchers evaluate disorders of the lumbo-pelvic region such as low back pain through assessment of movement patterns with various clinical tests. Prone knee-flexion is one of the most common tests, which are used. Objectives: The purpose of this study was to investigate the changes in lumbar lordosis during the prone knee-flexion test in healthy subjects. Patients and Methods: This quasi-experimental study with repeated measurements was performed on 40 healthy subjects. Lumbar lordosis was measured with a standard flexible ruler first in prone position and then, after performing the prone knee-flexion test. The amount of change in lumber lordosis between the two measurements was recorded. Data were analyzed using paired t-test. Results: Results demonstrated that there was a statistically significant difference in lumbar lordosis in prone position and after performing the prone knee-flexion test among healthy subjects (P 0.0001). Conclusions: An increased lumbar lordosis during the prone knee-flexion test is due to instability in a lumbar spine region.