The purpose of this study was to examine the relationships between hip extension range of motion (ROM) and three determinants of postural alignment: standing pelvic tilt, standing lumbar lordosis, and abdominal muscle performance. The subjects were 25 healthy adults ranging in age from 21 to 49 years. The Pearson product-moment correlation of hip extension ROM with pelvic tilt was -0.04, with lumbar lordosis -0.09, and with abdominal muscle performance 0.09. These results indicate that these variables are not related. This study demonstrates that the hypothetical correlation among these clinical parameters needs to be reassessed. J Orthop Sports Phys Ther 1990;12(6):243-247.