What is the proper way to lift a heavy object?

Bending at the knees and keeping the back straight is the proper way to lift a heavy object because it utilizes the strength of the legs rather than the back. This technique minimizes the risk of back injury by allowing the larger, stronger muscle groups in the legs to do the work of lifting. When the knees are bent, the center of gravity is lowered, providing better balance and stability. Maintaining a straight back throughout the lift helps to keep the spine aligned and reduces the strain on the back muscles.

The other methods described, such as bending at the waist or lifting with your arms only, can lead to improper lifting techniques that increase the risk of injury. Twisting the body while lifting can also place undue stress on the spine and surrounding muscles, increasing the likelihood of strain or injury. Therefore, using proper lifting techniques, like bending at the knees and keeping the back straight, is essential for safety during lifting tasks.