Short Sunzen! Vol 1

Short Sunzen! by Susugi Sakurai. A Romance manga rated Older Teen.

Satsuki Kurokawa is a feisty, fight-ready girl with zero interest in boys. Unfortunately for her, she's caught the eye of Aya Sendo, a guy with a violent past who is determined to win her over. Even when they end up on emergency cheer squad duty together, Satsuki stays completely oblivious to his feelings. A rowdy school romantic comedy.