Iīve been adressing reverse abdominal breathing and itīs implications to Aikido briefly in my book "The Elements of Zen in Martial Arts".
Sorry if I do copy and post all this here, but instead point out to the pdf download on the authorīs homepage. There you can read about my experinece with reverse abdominal breathing in the chapters "Zuiho-in" and "Kokyu". Although it is a reading sample, these chapters are comlete. And - of course - itīs free.
Hereīs the link
(bottom of page)