Resultant compressions on the L5/S1 joint of 6 subjects were studied as they lifted light weights in sitting and standing work postures. The subjects' activities were photographed and analysed later by a static biomechanical computer model. Statistically significant differences were found between the results of the two postures analyses. Sitting showed significantly high compressions on that joint in doing several material handling tasks having the same loads from hip joint Therefore, it is recommended that working with light weight in standing is less hazardous than doing the same in sitting postures, although even the maximum compression in al exprements is under the NIOSH's AL (action limit).
