Lifting an object from the floor (or from any height lower than your waist) is potentially dangerous. The heavier the object, the greater the risk of injury to your back.

The incorrect way to lift is shown below:

Lifting - incorrect

The knees are relatively straight: as a result, the subject has to bend over with his back in order to reach the object in the first place. From this position, the only way to lift the box is to use the spine (as opposed to the legs).

Note also, that the head is angled backwards, with the neck bent. This compresses the neck and leaves the back even more susceptible to injury.

The correct way to lift is shown below:

Lifting - correct

The knees are fully bent, allowing the object to be grasped without bending the spine. The whole back, including the neck, is kept fully straight at all stages of the lift.

You will note that the subject is not looking at the object: he is looking straight ahead. This locks the vertebrae in the spine, prevents them from moving, and hence lowers the risk of strain.

If you need to look at the object in order to pick it up, do so during the preparation phase (noted below) but reposition your neck before you lift.

The whole movement can be broken down into the following series of distinct phases.