Hing kung is a discipline focused on balance and weightlessness, mentioned in the comic book Kung Fu Panda: Art of Balance. In the story "Art of Balance", Po was taught "hing kung" by Shifu, who had learned it in his youth from Oogway.
In Kung Fu Panda: Art of Balance, Shifu told Po that soon after being made a master, he'd found his many new responsibilities overwhelming, and was unable to focus, resolving to quit kung fu then and there. Oogway persuaded him otherwise, teaching him "hing kung", the concept of internal and external balance. Shifu was later able to walk on leaves after having learned this, and attained true balance by not allowing "the weight of the world control you, but by becoming weightless and taking control of the world."
In the story "Art of Balance", Po struggled in coping with his duties as the Dragon Warrior while working at the Noodle Shop, being exhausted and having trouble focusing. Shifu, noticing this, told Po about "hing kung", a concept that allowed one to be weightless and balanced both internally and externally.
Shifu had Po run on vases and sticks, the panda making several blunders and falls before he eventually improved. Later, when his father was threatened by the antelope chef Po had hired, Po showed his mastery of hing kung by jumping and treading on the thrown knives directed at him, and saved Mr. Ping. As a result, he found balance, fixing the problems he'd made as Po with the skills he'd learned as the Dragon Warrior.