It minimizes the compression of the abdominal organs which can cause a hernia. Tuck in the chin so the neck and head continue the straight back line. Tucking in the chin helps keep the spine straight and firm. Gripping with the palm is one of the most important elements of correct lifting. The fingers and the hand are extended around the object to be lifted - using the full palm.
Fingers alone have very little power - the strength of the entire hand is needed.
Arms and Elbows. Draw the load close, with arms and elbows tucked into the sides of the body. When the arms are held away from the body, they lose much of their strength, and because the weight is not fully supported on the spinal axis, back strain can result. The body should be positioned so that its weight is centered over the feet. This provides a more powerful line of thrust and ensures better balance.