[Study of scanner counter for POS terminal system from view point of posture when take-out goods]

Recently, an increasing number of supermarkets have been introducing the point of sales (POS) system. The scanner counter of this POS system makes repetitive operations including taking goods out of basket, letting them pass through the scanner for their bar codes and then putting them in the next basket. The basket is about 25.5 cm deep, and the counter must be high enough to satisfy two conditions that the base surface and the upper edge of the basket are not too low and not too high, respectively to take goods out of it. In the present study, repetitive operations of taking goods from 16 spots at their respective different heights 49.5, 57.5, 65.5 and 73.5 cm of four corners of the basket was made to measure the posture, heart rate (HR) and electromyograms (EMG) on four sites (right shoulder and loin , left loin and right femoris) of the operator and to examine the height of the counter. EMGs on the right loin , left loin and right femoris showed significant differences (P less than 0.05) in case of goods' position, operator side less than contralateral side and of counter's height, 73.5 less than 65.5 less than 57.5 less than 49.5 cm. EMG on the right shoulder showed significant differences (P less than 0.05) in case of the goods' position, operator side less than contralateral side and of the counter's height, 73.5 cm greater than another height on operator side.