The Importance of Pelvic Tilt in Reducing Compressive Stress in the Spine during Flexion-Extension Exercises
Gracovetsky S, Kary M, Pitchen I, Levy S, Ben Sa�d R.
Spine
14(4) : 412-416, 1989.
Abstract
An explanation for the importance of pelvic tilt exercises is proposed. This
explanation derives from a mathematical model that predicts the existence of a
relationship between lordosis (pelvic tilt) and the distribution of stresses within the
spine. The model predicts that, for every angle of forward flexion, there is a unique
degree of lordosis that will minimize and equalize the compressive stress within the
spine. This stress-minimizing posture also is associated with the minimum muscular
activity; the balance of the moment is supported by passive stretching of the connective
tissues. These predictions were tested by comparing them with empirical values of spinal
geometry and muscular activity, as measured simultaneously by an opto-electronic motion
analysis and electromyographic (EMG) data collection system.
