Kick no Onee-san

Kick no Onee-san (キックのお姉さん, lit. "Kick the Girl!") is a completed seinen manga written and illustrated by Yuuto Inai. It was serialized in Big Comic Spirits.

Plot
Akiyama first came across seeing Hana in the corner of the television screen when some nameless female kickboxer was being interviewed. Since then, he was smitten and went to all three of her matches, but then all of a sudden, she stopped competing and he became at a loss as to what to do. But then he runs into her by accident on the street on his way home from work and discovers that this woman, who wants to become the world champion, is far more complicated than he could have ever imagined.