Date of Award

Winter 1987

Document Type


Degree Name

Doctor of Philosophy (PhD)


Urban Services - Urban Education

Committee Director

James R. K. Heinen

Committee Member

Maurice R. Berube

Committee Member

Larry Shall

Committee Member

Wolfgang Pindur

Committee Member

William G. Cunningham


The purpose of the present investigation was to study the effects of two lumbar/sacral back supports upon peak muscular force, total work, and average power. Subjects consisted of ten well conditioned male volunteers with an age range of 21-35 years. Each subject volunteered individually to participate and was required to read and sign an inform consent form prior to participating in the investigation.

The investigative design was quasi-experimental with a repeated measures (treatment-by-subjects) methodology. Each subject experienced three testing treatments to include each lumbar/sacral support and one without. The testing protocol consisted of three isokinetic back testing devices developed by Cybex, Incorporated. The performance tasks consisted of the Cybex Trunk/Extension (TEF), Trunk Rotation (TR) and Lifttask (LT) testing systems. A total of nine treatments were given for each of the ten subjects for a total of ninety treatments.

The resultant data were subjected to analyses of variance (ANOVA) with repeated measures. A post-hoc Scheffe test was incorporated in the event a significant Fratio was demonstrated. Omega Squared values followed to determine the effect level of the treatments upon the selected work performance variables. Results indicated that there were no statistically significant effects existing for peak force, total work, or average power with the two lumbar/sacral back supports recorded during the following measures: Lifttask sequences of 24, 30, 36 inches per second; trunk extension at 30, 60, 90, and 120 degrees per second; right trunk rotation at 60, 90, 120 and 150 degrees per second; peak torque for left trunk rotation at 90 and 120 degrees per second; total work and average power for left trunk rotation at 60, 90, 120, and 150 degrees per second; and trunk flexion of average power at 60, 90 and 120 degrees per second.

Significance did exist for trunk flexion of peak torque at 30 degrees per second (p

Changes in simulated lifting tasks relative to certain trunk flexion and left trunk rotation movements were determined to be significantly different. Scheffe's test for variable mean differences determined the experimental brace to be significantly different from the CompVest and/or controlled conditions in a majority of the various significant experimental observations. Omega Squared values were noted to be high for all significant and marginally significant performance tasks. It was concluded that the experimental brace employed in the present investigation was statistically different from the CompVest and controlled conditions during specific trunk flexion and left trunk rotation movements and may hold certain implications as an appropriate low back support.