The way to control your breathing is to let your strength flow around your body. Gradually, you find that it picks up speed.
10 seconds sound clip from the Shaolin vs. Lama (1983) movie soundboard.
You can hear this line at 01:09:14 in the DVD version of the movie.
Quote context
[...]
- Abbot, please teach me Kung Fu.
- Once you have mastered how to breathe, you'll find your power increases.
- How can I learn? I don't know where to begin.
- Let's start with the basics.
- Do you really still want to learn?
- Yes.
- That's good. Now you have mastered breathing. You'll find your strength much increased.
- Now, you have to remember the principle of mercy.
[...]