This clip is an example of the kinetic energy process described on page 101 TaijiKinesis Vol 2 : Learning the Taijiquan Form.
This model is commonly known. So why don’t we see it used more in Tai Chi fajing?
I suspect its due to the inability to put theory into practice. We can do so because we have an important training tool at our disposal as described on page 58 of TaijiKinesis Vol 2.
Now that you know the secret sauce make sure you pay lots of attention and love to it whenever you practice Tai Chi.