You are training your quirk. Izuku is doing arm exercises, Katsuki is shooting a long explosion in the sky, Shoto is in an ice bath, making ice around him and lighting it on fire, then making it into ice, Kirishima is practicing his hardening, Denki is practicing, with standing more electric power. Fumikage is in the cave, yelling at Dark Shadow. Yuga is shooting his lazer for more than a second. Tenya is doing long step runs to improve stamina and speed.