Body positions and motions are the key to effective body use. The feeling of comfort and discomfort are the results of the positioning of body weights, use of muscles and the use of skeletal system. Posture involves keeping the natural balance of the body stable, whether sitting, standing or moving.
According to Gross et.al (1973) “In correct posture, whether standing, sitting, or using a tool, muscles constructed to do certain things do them. In incorrect posture, muscles not so constructed must do the job”. When any part of the body gets out of line, muscular effort is required to maintain body in balance in addition to what ever work the body is doing.
To avoid strain and to develop a good body carriage while working, some attention should be given to posture habits in standing, sitting, stooping and bending while at work. Good posture in doing any task may define as the position which requires the expenditure of the smallest amount of energy.
A good standing posture is one in which the head, neck, chest and abdomen are balanced vertically one upon the other, so 'that the weight is carried mainly by the bony framework and a minimum of effort and strain is placed upon the muscles and ligaments. When the body is well balanced in the standing position, the head will be directly over the feet, and the center of gravity will pass through the middle of the face, nose, shoulder, hip, the outside of the knee, and the outside of the ankle.
A good sitting posture for work is well- balanced and poised position. The weight is carried by the bony support of the skeleton thus relieving the muscles and nerves of all strain. The poise is such that minimum adjustment is necessary for such action as the work may demand. The line of gravity falls through the middle of the shoulders, hips and seat bones. The body is straight from hips to neck, and there is no flex or bend at the waistline.
Poor standing and sitting postures may result in permanent changes in the spine in positions of the joints, ligaments and muscles and in the location of the organs of the body. Such changes produce strain and tensions which increase the fatigue costs of homemaking tasks.
Using the most comfortable body position while working eases the body and relieves strain. Alternating standing and sitting is more restful than either one continued for a long period.
In bending to do certain tasks, it is easier to put one foot slightly forward and bend through the knee and ankle joint. In lifting something heavy from the floor, such as a body or a bag of groceries, it is better to bend the knees and thigh joints and use the stronger leg muscles for the actual lifting. Pushing or pulling a large piece of furniture can be done with least strain by dropping into a partial crouch, knees limber, hips low, and pulling or pushing in that position. Carrying packages or other articles is easier when the load can rest against the hip. Balancing is done by bending toward the other side which shifts the weight to the large bones and leg muscles. That is why we find most of the labourers carrying their load at their backs and resting them on their hips.
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