Date of Award


Degree Name

Master of Science


Occupational Therapy

First Advisor

Dr. Barbara Hemphill

Second Advisor

Dr. Cindee Peterson

Third Advisor

Dr. David Smith

Access Setting

Masters Thesis-Open Access


The purpose of this study was to examine the amount of lower back muscle stress produced during lifting tasks, using variations in weight and postures. Electromyographic activity of the erector spinae muscles at the L4-5 vertebral level was measured.

Thirty healthy female subjects participated in the study. Each subject lifted loads of two given weights using both the stooped and squat lifting postures. Electromyographic activity was recorded and averaged throughout each lift.

Results indicated that increased weight resulted in increased stress on the erector spinae muscles, regardless of posture. The squat lifting posture was found to be more stressful on the erector spinae muscles than the stooped posture, however the squat lift is recommended because it may provide the best protection for the lumbar spine.