A computerized technique for analyzing lateral bending behavior of subjects with normal and impaired lumbar spine. A pilot study.

ABSTRACT

STUDY DESIGN: A computerized technique, employing a motion analysis system and a force platform, was developed to analyze lateral bending behavior of subjects with normal and painful spines. METHODS: Lateral bending was quantified using motion (angle and speed of rotation), force (ground reaction kinetics), and biomechanical behavior ("compliance" and "transfer mobility") characteristics of four discrete spinal segments measured during standing, range of bending, and bending at normal and maximum speeds. RESULTS: For subjects with pain, there were reductions in the range of lateral bend (43%) and speed of rotation (39%). Ground reaction moment about the medial-lateral axis was greater (58%), whereas that about the anterior-posterior axis was less (28%). "Compliance" was less (25%), whereas "transfer mobility" was greater (24%). CONCLUSIONS: The findings suggest that the characteristics of lateral bending, rather than range of motion, is most affected in subjects with pain.