Original Article: PDF OnlyQuantification of Lumbar Function Part 1: Isometric and Multispeed Isokinetic Trunk Strength Measures in Sagittal and Axial Planes in Normal SubjectsSMITH, SUSAN S. MS, PT*; MAYER, TOM G. MD*; GATCHEL, ROBERT J. PhD*; BECKER, THEODORE J. PhD, PT† Author Information *From the University of Texas Health Science Center at Dallas, Texas †From Fankhauser Physical Therapy, Everett, Washington Spine: October 1985 - Volume 10 - Issue 8 - p 757-764 Buy Abstract The goals of this study were to: (1) evaluate the repeatability of a method of measuring trunk strength; (2) measure isometric and isokinetic strength of trunk flexors, extensors and rotators; (3) explore relationships among these muscle groups; and (4) compare a torque to body weight adjustment measure versus lean body weight. One hundred twenty-five normal subjects (62 males, 63 females) were tested using a Cybex prototype trunk extension-flexion system. Sixty-seven subjects (25 males, 42 females) were tested using a prototype torso rotation unit. Fifty were tested on both devices. Results demonstrated that the strength data were reliable, with strength being greatest in extension. The following were also learned-torque output declined slightly with increased speed; extensor-flexor strength remained consistent from 18 to 44 years; extension-flexion ratios exceeded 1.1:1; left to right rotation ratios remained 1:1; there was no significant difference between torque adjusted to body weight or to lean body weight. © Lippincott-Raven Publishers.