Re: Backward Roll - Risks and benefits
As a background to the discussion between Kevin W and Ron T, I would suggest that the possibility of backward rolls during practice is closely related to the conventions of practice, which clearly varies in each organization/dojo.
Last night I practised in my university dojo with the students and the pace of training was not so fast and demanding. Sometimes backward rolls were executed by some students, but this was only because the waza was not applied to the end and so they were given the space and time to do so.
One waza in question was kokyu-nage from a morote-dori hold. This is a fundamental training tool and can be done with or without the ukemi. Last night some students were 'letting go' far too early (in my opinion), and so were given the space to do a backward roll. When we changed partners and these students practised with me, they could not do the backward roll because I did not give them the 'space' to do so.
If any of you have practised this waza with Masatake Fujita Shihan, you will know that a backward roll is completely impossible. He throws you straight down and does not 'let go' until the last minute: he continues the waza until you are lying flat on the mat, with his hand just above your head. The way he does this waza sometimes requires a back breakfall. And he expects feedback from his uke right until the end of the waza. I have seen one injury from this waza, as executed by Fujita Sensei: concussion caused by the head hitting the mat.
Compare this with the late Morihiro Saito Shihan. I once took part in a seminar taught by Saito Sensei and his uke was Bruce Klickstein. Bruce is now a non-person in the aikido world, but his ukemi was extraordinary. We did the same waza, morote-dori kokyu-nage with loads of variations, but Saito Sensei 'let go' somewhat earlier than Fujita Sensei and Bruce executed a superb ukemi. It was not really a roll, but Bruce was flexible enough to be able to land on his feet. It was more a 'side breakfall, but going backwards', which perhaps is what Kevin W has in mind. Except that you do not turn your body in the direction of the throw, and your feet should reach eye-level: it is the 'kick' that makes all the difference.
For the aikido history buffs who are around my age, the seminar was taught around 1981 or 1982 and was organized by the New England Aikikai. It was held in western Massachusetts (Springfield, perhaps) and was taught by Nobuyoshi Tamura and Morihiro Saito. It was the first joint seminar ever held by these two shihans. A youthful Bruce Bookman took part as did the late Paul Sylvain and other members of the Chiba-gumi.