The effect of degree of upper arm flexion on shoulder-neck discomfort at the VDT

Two experiments investigated the effect of upper extremity posture on reported discomfort in the shoulder‐neck region. In Experiment 1, 12 participants worked in two postures that only differed in the position of the arms. The 7° posture” required 7° of upper arm flexion and a 90° upper arm‐forearm angle. The “30° posture” required 30° of upper arm flexion and a 90° upper arm‐forearm angle. Location and intensity of discomfort were reported every 5 min while participants performed a simple tracking task at the computer. Experiment 2 was identical to the first except participants worked in one of the postures for both work sessions. The 30° posture generally resulted in more frequent and intense reports of shoulder‐neck discomfort than the 7° posture. However, the 7° posture was not nearly as effective when it was assumed after the 30° posture. The implications of such carry over effects for VDT work in a seated posture are discussed.