The proper way to lift heavy objects involves several steps:
Stand close to the object with your feet shoulder-width apart. Squat down bending at the hips and knees, keeping your back straight. Secure a firm grip on the object, hugging it close to your body if possible. Use your leg and hip muscles, not your back, to lift the object by straightening your legs. Keep the object close to your body as you carry it. Avoid twisting your back, moving your whole body instead if you need to turn. To put the object down, reverse the process, bending at the hips and knees while keeping your back straight.