The "Pull" part of the Pose Running mantra "Pose Fall Pull" is very confusing for many people, and also probably the hardest part to master. There are three aspects of the Pull that I want to discuss here, and they are the speed of the pull, the height of the Pull, and the position of the Pull.
The Speed of the Pull
If you accept that falling is primary way runners move forward, then it is important to understand that any weight behind the center line of your body is a counter balance to falling. So the longer you leave your trailing leg behind you when you run, the more of a counter balance there is, and your ability to fall forward is diminished. This is why it is important to pull you trailing leg up as fast as possible, it's to eliminate as much counter balance as possible.
The Height of the Pull
The faster you run the higher you pull your foot. When jogging, a runner should only pull his or her foot a few inches from the ground. When sprinting, a runner should pull his or her foot up as high as possible. The higher you pull your foot the higher your center of gravity is, and the higher your center of gravity, the easier it is to fall. So by varying the height of the pull, you can help to control your speed. You should never pull higher than necessary to accommodate the pace you wish to run, or you will be using more energy than necessary.
The Position of the Pull
In Pose Running you pull your foot up directly into the position of the Pose. The reason for this is that it places as much weight in front of you as possible, making it easier to fall. The Pose is a position that eliminates counter balance to falling. The faster you reach this position the more efficiently you can fall forward.
For Further Reading
Your Pose Running Coach's Blog: The Pull (and The Place)
Your Pose Running Coach's Blog: The Pose
Your Pose Running Coach's Blog: The Late Pull