We take breathing for granted in our everyday lives, it is pre-programmed in us in the womb. However in everyday life, we only use a small percentage of our lung capacity. Athletes use about 60% of their capacity, but as trumpet players, we use a far greater percentage, 85-90% of our total capacity.
There are plenty of opinions on respiration for brass players, and at the moment, the internet is a fantastic resource to access related material. But if we look outside the sometimes insular world of the brass player, there are thousands of hours of footage on YouTube of different disciplines of martial arts, yoga, pilates etc. Lots of these place emphasis on good breathing and an awareness of posture and the body.
The video clip below contains a set of Qi Gong (Chi Gong) exercises that stimulate the body's breathing aparatus and the body as a whole. Emphasis is placed on getting the Chi (energy) flowing, and the breathing centered around the Tan Tien (in Chinese philosphy, one of the body's Chakra points), which is just below the belly button. It also focuses on keeping the body relaxed but strong. These exercises are related to the various forms of Tai
It is important to look beyond one's own discipline for answers to our relatively basic playing problems, and undertaking a course of yoga or Tai Chi for instance can bring increased focus and energy to our playing.