Isokinetic trunk strength and lifting strength measures. Differences and similarities between low-back-injured and noninjured workers.

Fifty-eight back pain patients and 21 entry-level Postal Service workers without low-back pain were evaluated using a variety of lumbar function measures. Isolated trunk strength and full lifting strength were gauged with isokinetic and isometric methods. Lumbar range-of-motion was computed using toe-touch and goniometers. Conventional clinical techniques such as toe touch and straight leg raise were effective in distinguishing back-injured from normal subjects. Isometric and isokinetic peak force and torque tests failed to show significant differences between low-back pain and job applicant groups. When compared with published norms, our job applicant group was significantly deconditioned. Our data suggest that asymptomatic, deconditioned subjects could be mistaken for back-impaired patients or symptom magnifiers.