Effects of a Standing Aid on Loads on Low Back and Legs during Dishwashing.

Abstract

In order to prevent low back pain during dishwashing, we developed a standing aid for supporting the forward bending posture, and then evaluated the effects of the standing aid on decreasing load on the low back and legs. Eight female volunteers were asked to wash plates for 60 minutes in each of three working postures: (a) without the standing aid, (b) with the standing aid under the thighs, and (c) with the standing aid under the shins. The following were measured: electromyogram (EMG), electrocardiogram (ECG), the force applied to the standing aid, the ground reaction force, the bending angle of the trunk, the bending angle of the knee, and local discomfort in body regions. While using the standing aid under the shins, the muscle load decreased in the low back and legs. While using the standing aid under the thighs, the muscle loads decreased in the low back but increased in the legs. It was suggested that the standing aid under the shins was more effective in decreasing the load on the low back and legs than the standing aid under the thighs.

Shape and Thickness of Cushion in a Standing Aid to Support a Forward Bending Posture: Effects on Posture, Muscle Activities and Subjective Discomfort

“…Although heel and the calf discomfort with both the rectangular types of aid tended to be greater than that without the standing aid, no significant effect was observed in the various posture conditions. These findings were the same as those in our previous study 13) in which the working time was set at 60 min. Therefore, it was thought that the loads on the heels and the calves were not excessive when using the standing aid for up to 60 min.…”

“…The sponge of the cushion was made of flexible polyurethane foam and was covered with synthetic leather. The sponge was 30 mm thicker than that in our previous experiment 13) and the elasticity was same. The height of the cushion could be adjusted in multiples of 25 mm and the angle could be adjusted continuously.…”

“…The frame processing was the same as that in our previous study 13) . The bending angle of the trunk was formed by the acromion, iliocristale and trochanterion (Fig.…”

“…The subjects were instructed to support the shins with the standing aid and support the abdomen with the edge of the kitchen counter. The height of the standing aid was set at the shins since in the previous study 13) the muscle loads on the low back and legs were decreased by using the standing aid to support the shins. About the position of the standing aid at the shins, the subjects were instructed to use the round type of aid for the upper part of the shins, the small rectangular type of aid for the upper half of the shins, and the large rectangular type of aid for the whole shins.…”

“…We developed supplemental equipment, a standing aid, to support the forward bending posture during preliminary washing and evaluated the effects of the aid in decreasing Industrial Health 2004, 42, [15][16][17][18][19][20][21][22][23] the loads on the low back and the legs in our previous study 13) . Subjects leaned on the standing aid and the edge of a kitchen counter.…”