Of course, I can recommend you a few books on flexibility training. 1. The protagonist had integrated the abilities of the willow seed, so he naturally had an advantage in the special forces fighting techniques. 2. "Lin Yu's Daily Traversal": Although it was a historical novel, the protagonist's life experience in the Lin Mansion was filled with all kinds of training, from martial arts to calligraphy, painting, and even flexibility training such as yoga. 3. "Ancient Immortal Track": Most Xianxia novels focused on martial arts, but some of them also included flexibility training. For example, the main character practiced the "Flying Snow in the Ninth Moon" cultivation technique. During the process of practicing the core skill "Snow Dance", the body needed to be flexible and agile. It was necessary to have a certain degree of flexibility. I hope the above novels can meet your needs! I hope you like my recommendation, Mwah ~😗