Master of Science in Industrial Engineering (MSIE)


Industrial Engineering

Document Type



Reports for adult population indicate that almost 80% of the adult population has reported some form of lower back aches. Each year American workers suffer more than 300,000 lost-time injuries involving musculoskeletal disorders of the back, with the costs that run into billions of dollars. Sedentary tasks are known to be major contributing factors of back pain. Prior studies have indicated that the myoelectric activity of the lumbar region decreases when the back rest inclination of a seat increased. An increase in seat pan inclination so that it increases pressure on the leg muscles is also a cause for back pain. Seating posture is also known to be a leading cause of back pain. This study focuses on the response of the latissimus dorsi muscle in the trunk, to the backrest and seat angle inclinations for different seating postures. Twenty one participants took part in the backrest experiment. The automobile seat backrest angle was varied for two angles of 90 and 100 degrees in a one hour driving session. Ten participants took part in the seat angle experiment; the seat was set at 0 and 10 degrees for a 30 minutes session at each angle. The muscle activity of the latissimus dorsi was recorded for seating postures at each angle. Based on the electromyography data, the results of analyses of variance for mean of root mean square values for the backrest experiment (P < 0.05) showed significant change. In seat angle experiment the analysis of variation of the mean values for root mean square values at (P < 0.05) was significant. It is concluded that increased backrest and inclined seat angle decreases muscle activity in the latissimus dorsi muscle.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Fred Aghazadeh