I like many of you feel that I gain alot from the tradition which is evident in aikido however I still feel that I need to train outside of the dojo as well. Half of the club I attend feel that they need to train outside of the dojo as well. This isn't uncommon as sometimes due to the nature of a specific class it won't give you much of a physical work out and sometimes it will make you puke. Yet what we all share in common is that we train outside the dojo with the aim of improving or perfprmance inside the dojo.
Personally I go for the more endureance and anerobic stamina. Thirty miles a week road work and ten or twenty minutes, four times a week of anarobic work. For the anarobic I box as two minutes in the ring very similer to randori or jyu waza. Yes I moniter my heart beat during all of my training.
Aikido can be the most demanding thing on the planet if you let it be but training outside the dojo can really allow you to focus on more important matters.
As for wait training has nobody seen pictures of O'sensei in his fifties, Five foot and over seventy kilo's. Big boy. Gozo Shioda once said that you need to power/muscles through all your techniques until one day you don't need to.