A more advanced topic in this clip – how to apply the principles of the pole to emptyhand techniques.
The pole movement mentioned in the clip is on page 37 to 38, TaijiKinesis Official Handbook Vol 4 – Learning Pole.
The pole is a useful tool for training to generate power through an extended arm. When using the principle this way you have to imagine that your extended arm is the pole.
In this way you can expand the ability of your arm to carry on striking, giving your opponent lesser time to react and counter.