THE EFFECT OF DEGREE OF UPPER ARM FLEXION ON SHOULDER-NECK DISCOMFORTAT THE VDT

Two experiments investigated the effect of upper extremity posture on reported discomfort in the shoulder-neck region. In Experiment 1, 12 p articipants worked in two postures that only differed in the position of the arms. The ''7 degrees posture'' required 7 degrees of upper arm flexion and a 90 degrees upper arm-forearm angle. The ''30 degrees po sture'' required 30 degrees of upper arm flexion and a 90 degrees uppe r arm-forearm angle. Location and intensity of discomfort were reporte d every 5 min while participants performed a simple tracking task at t he computer. Experiment 2 was identical to the first except participan ts worked in one of the postures for both work sessions. The 30 degree s posture generally resulted in more frequent and intense reports of s houlder-neck discomfort than the 7 degrees posture. However, the 7 deg rees posture was not nearly as effective when it was assumed after the 30 degrees posture. The implications of such carry over effects for V DT work in a seated posture are discussed.