questions on the extra curricular and additional information secitons

Hey guys, I’m stuck in some questions regarding the common app extra curriculars section.
My question is that, if I didnt fill in all the activity lists, will writing about another activity not listed on the EC list on the additional information section be legit?
Because personally I have not devoted much time in it,─it’s local running race, we call it marathon in my country although some of them are not 42km long, and there’re not always much opportunities to go─ I don’t think putting little hours per week/weeks per year on the question look good. And instead if I go to the additional information section I can write about what I learned from participating in such events. So what are your thoughts and suggestions? Should I rather first list it on the EC and include little participating time or literally go to the additional info?

Personally I don’t really think that’s what the additional info section is for - I would have thought it’s for important things you feel need to be part of your application, but cannot be put elsewhere. That’s my opinion.

Do you spend time running every week to train for this race? Do you do other sports? You can list this EC as ‘sports’, and write down the total amount of time you work out each week. Grouping this activity together with other stuff can make it seem like a bigger commitment. Then in the description box mention how you participate in these races as an example of what your involvement looks like. Just an idea.