Trunk posture and load on the trapezius muscle whilst sitting at sloping desks

Abstract

Sitting posture in relation to three different desk slopes of 45,22 and 0° (horizontal) was examined by statometry on 10 subjects who were reading. With increasing desk slope the cervical as well as the lumbar spine were extended, and the head and trunk changed towards a more upright posture. Electromyography (EMG) from the descending part of the trapezius muscle was also recorded during both reading and writing. This muscular load was low and did not change with varying desk slopes for any of the two tasks. A rating for acceptability, performed for both tasks on each desk inclination, favoured a steep slope of the desk for reading, while the opposite was favoured for writing. The study suggests that the reading matter should be placed on a sloping desk, and the paper used for writing on the horizontal tabletop between the desk and the person.

Key words:

• Back
• Ergonomics
• Human engineering
• Occupational health
• Posture
• Shoulder