My imagination only (not an offical logo) ;)
Below is some translated information on Osaka marathon 2011 from the Osaka Prefectural Government.
"The theme of the Osaka Marathon is “Hoist a rainbow high together”. Seven specific charity themes are to be decided, and participants are recruited per each theme, and each color. Participating runners are to pick a color to cheer for their teams such as red or blue. It is planned that the supporters will color the streets along the course in seven colors. The logo mark has been announced, full of vigor, portraying a runner at full speed in a motif of a character “run”. It is also designed in the seven colors of the rainbow.
Isn’t there a great fascination and significance to have a marathon in the big city of Osaka amid the running boom nowadays? It is a huge attraction for participating runners to experience the charm of the town by running along roads and through places usually inaccessible except by car. Moreover, in addition to the 30,000 runners taking part, the whole of Osaka including supporters and volunteers will become spirited, and the economic impact generated by them will be on a substantial scale. In addition, this is the best opportunity to convey the “hospitality of a town, Osaka” to runners from all over Japan and the world getting together in Japan.
The huge expectation for “Osaka Marathon” includes energizing the local community and spreading the word about urban attractions. It will be one of the largest sporting events in Japan supported by the unified cooperation of participants and local residents, contributing to the energizing of the whole Kansai area.
The governor Mr. Hashimoto said “I want it to become a good event, rivaling the Tokyo Marathon. I want the whole of Osaka town to be energized through the marathon, and I want to show it both inside and outside of Japan.”
Through this marathon, we will send out the word about the charm of the people and the town, and Osaka full of Energy!"