Si Wilson wrote:
I know Eric has explained this (see below), but actually I see that when you are tired and are thrown hard "Osu" ("To push yourself through any hardship") is more than appropriate, it is damn essential (to those who understand it.
Hmm...I hate to disagree with you Si, but I do. Unless you are advocating talking to yourself
Osu is something said to someone else. It is not a kiai or a way of chanting or anything about digging deeper within yourself. It is a way of showing respect between people of similar minds and reminding *each other* to persevere.
"Also, in the field of Budo it is used as a greeting or reply with the connotation as a sign of your willingness to follow a particular teacher or way of training.
I read the link again...I was with Robert Sensei when he was working on that article...and I don't believe anywhere in there does it suggest that "Osu" be used by oneself. I think the above is probably the most indicitive of what he was trying to get across...(although I reserve the right to be wrong
) In this case it might mean "I will dig deeper to follow your teachings to the best of my ability", but again it is said to another person.
For drawing inner strength when exhausted and hurting I advocate stronger/louder kiai's, put everything you have into kamae and maybe a good "Isshou" now and then to your partner and when it gets really tough let out a primal roar that make your teachers grin to themselves, but gives you the energy to get you through the next technique.