Some years ago, I saw a documentary on local TV. A team of doctors from US filmed an acrobatic academy in a rural area in China where they trained up little kids to do stunning acrobatic act including the extreme back-bend done by young boys and girls. The reason for the documentary was that these western doctors thought that such extreme back-bends will be detrimental to the growth of young kids and they wanted to check it up, partly for humanitarian reasons. After the trip, which include detail observations on the training method as well as detail medical checks on the training kids, the doctors concluded that the training method was sound, and would do no damage whatsoever to the kids. The doctors were satisfied with the health conditions of the kids, they were not interested in the training methods which they couldn't figure out the logic in the first place.
It is the legendary pre-puberty nei gung (童子功) that most practitioners of Chinese kung fu talked about, but few discussed about. Classical Taoist meditation also laid a strong emphasis on the milestone of puberty, saying that if a kid can be trained before 15, he can directly train on the level of macro-cosmic circulation instead of going through the stage of micro-cosmic circulation. In this post, I shall limit my discussion to the acrobatic training
The core foundation training of a pre-teen acrobatic is chi-rubbing by an experienced coach or trainer, at three areas: the abdomen, the diaphragm and the rib cage. An adult's hand is large enough to cover a major part of the kid's body and able to activate the fascia, muscles, bones and organs, with the objective of connecting them into whole. "Muscles as One" (肌肉如一) or "Body as molten metal" (身如铅灌). Different areas will necessitate different method of chi-rub, and will require a good pair of listening hands of the coach and the total trust towards the coach on the part of the student, otherwise he or she can't relax enough for the body to react accordingly to each rub. Only after this foundation has been built can actual back-bending exercises be started. And with this foundation, careful step-by-step bending can proceed fast and without damage to the student's spinal cord.
This kind of chi-rubbing can be done best for a pre-teen kid, after which the body will grow bigger, more rigid, and less trust and relaxation. I was told some traditional martial art schools still practice this kind of chi-rubbing, and on adults, by experienced sifus, behind closed door, as closely guarded secret, without knowing that the acrobatic school coaches openly allow the public (including the parents of course, nowadays no parent will allow their kids to do chi-rub behind closed doors) to visit, see and film.
Which school? which style? How do I know, it all happened behind closed doors...:):)