The way I see it, there's simply no space to write it in paragraph form. Write it however fits.
Here's what I did for Science Olympiad, for example:
position held, etc: Treasurer (10, 12)
details and accomplishments: Science Olympiad. Individual medals at regionals 2009, 2010; Team made states 2009, 2010
As long as it's clear and easy to understand, I think you're good. There was one activity that I couldn't explain in the given space, so I elaborated on it in additional information.