Which of the following is a proper technique for lifting heavy objects?

Bending at the knees and lifting with the legs is the correct technique for lifting heavy objects because it utilizes the strength of the larger muscles in the legs rather than straining the back. This method allows you to maintain a stable base of support and reduces the risk of injury by preventing excessive strain on the spine. When lifting, it is important to keep the load close to your body and to maintain a straight back to further minimize the risk of injury.

The emphasis on using leg muscles rather than back muscles is critical in preventing back injuries, which are common in lifting scenarios. Using proper lifting techniques is part of creating a safer work environment and enhances overall safety practices in the workplace.