I think breathing control is one of the most overlooked factors in training.
There is not much stuff you can find in the web but some interesting interview with Orlando Cani and a great breathing book from Vladimir Vasiliev.
I experimented a lot with breathing and still have thousands of questions about these things.
But what I epxerienced is that with relaxed breathing your skill is about 50-60% better because your body is reacting more natural more relaxed.
It sounds crazy but it isn?t. Just focus your attention on the times you hold your breath you will see that you hold your breath very often in day by day activities and in fighting this is happens even more.
Like I said I?am working on relaxed breathing and breathing, tension, muscle coordination.
I belive it can help you to skyrocket your game if you are able to apply it at will. Which I`am not able at the moment:-(
So what Rickson is doing maybe looks like simple Yoga but I think the reason behind it is different than in Yoga.