[Reproducibility of lumbar spine kinematics in clinical gait analysis]

The objective measurement of functional lumbopelvical movements enables the evaluation of the quantity and quality of movements referring to functional disorders in dynamic test-situations. The goal of the present study is the determination of the reproducibility of time-continuous movement analysis of the pelvic region during walking and the determination of possible errors. The movements of the thoracic (Th12), lumbar and sacrum-region (S1) of 17 healthy subjects (age: 32.1 +/- 2.3 years) during walking on a treadmill (4.5 km/h) were investigated twice in an interval of 24 hours by means of a 3D ultrasonic movement analysis system. The ensemble averages of the low-pass filtered and time-normalized angle-time sequences of all anatomical planes and regions showed high test-retest correlations (r > or = 0.92, p < 0.01) except fo the lumbar movement in the sagittal plane (r = 0.79, p < 0.01). A paired t-test showed no significant differences for the amplitudes of test and retest measurements except for the thoracolumbar movement in the sagittal plane (p < .05). The results show that the evaluation of lumbar movement patterns can be regarded as admissible and desirable for clinical movement analysis. The data can be used as a diagnostic tool for the planning and control of therapeutic interventions.