From impossible to possible

On July 31st, Chinese swimming prodigy Pan Zhanle won gold and broke world record in men's 100-meter freestyle swimming, clocking a time of 46.40 seconds. While the world was still trying to make sense of this seemingly "impossible" feat, just four days later, Pan did it again, this time in men's 4*100 medley relay, clocking 45.92 seconds for the same distance. The splashes sent waves of public euphoria across China, but also prompted the big question: how did he do it? From an emerging swimmer who first caught the world's attention during Hangzhou Asian Games last year, to international stardom, what explains this phenomenally rapid rise?