Little by little, every society is progressing in acknowledging its own abilities and so a special institute was open with the sole purpose to research the phenomenon of "contortionism".
The best performers from all over the world sign high budget contracts to work as "lab rats" for a year or two, until their bodies are thoroughly studied. After several decades the institute starts growing up their own "lab rats" by signing contracts with parents to be able to test various contortion training methods on their children since infancy.
The scientific approach gives amazing results and many methods are discovered that one can use to reach extreme flexibility painlessly, without any sort of medieval tortures, using the most modern devices and approaches. And since it's Japan we're talking about, all these devices look super cool and there are tons of anime and manga dedicated to the present and future of this equipment and contortion in general.
Contortion is now injected into all genres of manga, from dystopias and magic worlds to detective stories and social dramas, but... let's not get off topic here XD
The training devices become capable of monitoring all bodily functions, thus making the training very individual. Every trainee has a special internet account where all his parameters are stored, so he can just log in to any training device in the gym and it will automatically proceed with the most effective routine.
The scientific proof that extreme stretching can be painless and healthy for the body makes contortion so widely accepted in the world that it becomes one of the most popular forms of art, along with music or dance.
Here we can see a boy from the contortion studio "Origami". This is the studio that belongs to the aforementioned institude and its children have the access to all the latest inventions. The name Origami was chosen after the art of folding a simple sheet of paper in such a way that it forms various beautiful figures, all without the help of scissors or glue. Much like contortion is the art of making beautiful forms with nothing but the body itself!