Does anybody know of some good breathing exercises I can practice at home? I have a bad habit of breathing erratically when I am uke. It fatigues me badly.
I asked a few senior students and Sensei about what I can do at home and on the mat to help me breath right. So far I have received responses such as focusing on breathing during stretching, breathing out during every roll, and to practice breathing with my diaphragm to gain more breath.
Do any of you have any methods that you used at home to help you?
I don't know about dedicated home work, but as for practicing, when you find you are having trouble in practice see if you are exhaling or inhaling. With few exceptions, you should be inhaling when receiving either an attack or a technique, and exhaling when delivering an attack or technique.
Leaving aside all the structural and more esoteric explanations (which are very valuable, don't get me wrong) air itself (esp. oxygen) is potential power -- which brings your potential to maximum (inhaling) as his is being (literally) exhausted in exhaling. Try it and see if it helps. If you are exhaling to receive attacks as nage or exhaling to receive the technique application as uke, or not ordering your movement around your breathing at all, it will exhaust you, particularly in randori.
Apart from sitting kokyu practice there are also standing and moving breathing exercises that will help. Try funetori/funakogi undo (rowing exercise) with good kiai for slightly different rhythm of breathing. That you can easily do at home. The sounds are typically "eh" or "ee" going forward and "ho" or "sa" coming back. (The sounds really do matter as they shape the breath movment). You may find that you tend to breath in at the neutral (still points) of the movements. It makes you focus your attention on the structural aspects of what breath does to your movement. If you do not feel silly at first you probably are not doing it right. As my first teacher said, it doesn't matter if you understand why you should do it. Just do it and it will help.
Another and very different seeming rhythm is found in tekubi furi (wrist shaking) where the arms/wrists and the breath are variously coordinated in a shaking vibration over the head. You will find that if you are relaxed, the shaking naturally causes shallow involuntary panting breaths in time with the shaking cycle, as well as moving your whole body in tune with it and that vibrating cycle of breath. Then the wrists are are together flung at the ground with a natural and explosive exhalation (if you are relaxed and let the breath/motion coordinate with one another, it happens spontaneously).
Furitama (spirit shaking) is more subtle but the same basic thing with your hands cupped in front of your belt, and a slight vibration of the hands/arms coordinating the "liveness" of breath as you breathe in and out steadily. In both of these, you should focus on how your breath and your whole body movement relates to the shaking motion, when breathing in/out voluntarily and when at the still points of not voluntarily breathing at all.
Lastly are the standing ten no kokyu / chi no kokyu exercises, here you expand your arms and whole body up with the inhaled breath and then let your arms and whole body deflate steadily down with the exhaled breath.
And these are hardly exhaustive