A、Because they bent over from the waist. B、Because they bent their knees and squat down. C、Because they keep their back and hips

Many people hurt their backs when they try to lift heavy things from the floor. It is easy to hurt your back muscles because if you bend over, the muscles in your lower back can be hurt easily. However, there is a correct way to lift things from the floor. First bend your knees and squat down. Keep your back straight. Don’t bend over from your waist; keep your back and hips and waist in a line. If you keep your back and hips straight the muscles are stronger, because they have much more support. The other muscles can then help the lower back muscles.
    As you get down, try to get as close to the object as possible. For example, if you are to pick up a heavy box, get down directly in front of it.
    Maybe you will have to spread your knees and legs. Put one knee on each side of the box. Remember at all times to keep your back straight. Put your hands under the object that is in front of you, between your knees. To lift the object, you should stand up slowly. Use your leg muscles in order to stand up. In other words, lift with your legs, not with your back.