Most of us know the hazard of picking up a heavy weight while bent over in a poor posture. The small muscles of the lower back were never intended to lift heavy things. The common result is a severely strained back. The most efficient way to lift is to bend the knees lowering the hips underneath the object. Then the weight is lifted and supported with the strong muscles of the legs.
Most would think that bending over to pick up a light object (like a pencil or paper) should not present a problem. Yet, the head alone can weighs more than 8 - 10 pounds. The upper torso of the body weighs considerably more. With this in mind you can easily see that lifting with the legs in a balance upright posture is profitable whether the object is large or small.
It is also helpful to maintain what we are lifting squarely in front of the body. This reduces strain that might occur due to the body twisting out of balance while lifting.
I use an image of a headlight in my abdomen. When I go to lift something, I first make sure that the headlight is shining on the object. Again it can be important to remember that even light objects such as telephones or activities such as writing or keyboarding on a computer are best support by utilizing this same imagery of clearly maintaining postural focus (the headlight).