Which statement correctly describes the effect of holding an object closer to the body on back strain?

Which statement correctly describes the effect of holding an object closer to the body on back strain?

• A. The closer an object is to your body, the greater the back strain.
• B. The distance between the object and your body has no effect on back strain.
• C. The closer an object is to your body, the less back strain.
• D. The weight of the object is the only factor determining back strain.

Answer: (C)

Holding a load closer to the body reduces the lever arm from the spine, so the turning force (torque) the back muscles must counteract is smaller. With a shorter lever arm, the weight exerts less rotational stress on the spine, meaning the muscles don’t have to work as hard and the overall back strain decreases. This is why keeping objects near your center of gravity at waist height is safer; the load is easier to control and requires less muscular effort. The idea that distance doesn’t matter or that weight alone determines strain ignores this lever-arm effect. The heavier the object, the more strain still occurs, but bringing it in closer consistently lowers the stress on the back.

Holding a load closer to the body reduces the lever arm from the spine, so the turning force (torque) the back muscles must counteract is smaller. With a shorter lever arm, the weight exerts less rotational stress on the spine, meaning the muscles don’t have to work as hard and the overall back strain decreases. This is why keeping objects near your center of gravity at waist height is safer; the load is easier to control and requires less muscular effort. The idea that distance doesn’t matter or that weight alone determines strain ignores this lever-arm effect. The heavier the object, the more strain still occurs, but bringing it in closer consistently lowers the stress on the back.