http://sheltongstevens.blogspot.com/2014/04/a-look-behind-gold-of-chinese.html?spref=fb
Not exactly gymnastics, but there's a few gymnastics references. One of the videos even shows a kid doing spotted HSPU for double digit reps as accessory work. Also details how they are selected, how they train, their schedule, and even some very interesting recovery protocols that's unorthodox to the Western sports medicine (icing their testicles?
).