Passive stretching

Passive stretching is a form of static stretching in which an external force exerts upon the limb to move it into the new position. This is in contrast to active stretching. Passive stretching resistance is normally achieved through the force of gravity on the limb or on the body weighing down on it. It can also be achieved with the help of a partner, stretch bands, or mechanical devices. The more force exerted on the limb, the less time it will take to drop lower into the stretch.

...
Wikipedia