... i've read about Qigong, perhaps under a different name, years ago - when i've trained Karate Kyokushinkai at BKKK.
... at a certain point during my training activity i've been able to find energy for a very long trainig, perhaps this was an effect of a qigong exercise manifesting?
According to Buddhist, Daoist, and Confucian philosophy, respectively, qigong allows access to higher realms of awareness, awakens one's 'true nature', and helps develop human potential.
Over time, five distinct traditions or schools of qigong developed in China, each with its own theories and characteristics: Buddhist Qigong, Chinese Medical Qigong, Daoist Qigong, Confucian Qigong, and Martial Arts Qigong. All of these qigong traditions include practices intended to cultivate and balance qi.
Qigong is practiced for meditation and self-cultivation as part of various philosophical and spiritual traditions. As meditation, qigong is a means to still the mind and enter a state of consciousness that brings serenity, clarity, and bliss. Many practitioners find qigong, with its gentle focused movement, to be more accessible than seated meditation.
In Buddhism meditative practices now known as Buddhist Qigong are part of a spiritual path that leads to spiritual enlightenment or Buddhahood.
Martial arts applications.
The practice of qigong is an important component in both internal and external style Chinese martial arts. Focus on qi is considered to be a source of power as well as the foundation of the internal style of martial arts (Neijia). T'ai chi ch'uan, Xing yi, and Baguazhang are representative of the types of Chinese martial arts that rely on the concept of qi as the foundation. Extraordinary feats of martial arts prowess, such as the ability to withstand heavy strikes and the ability to break hard objects are abilities attributed to qigong training.
T'ai chi ch'uan and qigong.
T'ai chi ch'uan (Taijiquan) is a widely practiced Chinese internal martial style based on the theory of taiji ('grand ultimate'), closely associated with qigong, and typically involving more complex choreographed movement coordinated with breath, done slowly for health and training, or quickly for self-defense. In modern practice, qigong typically focuses more on health and meditation rather than martial applications, and plays an important role in training for t'ai chi ch'uan, in particular used to build strength, develop breath control, and increase vitality ('life energy').
Source: Qigong on Wikipedia.
See also: Limited Training.
Kyokushinkai Karate's Taikyoku Kata sono Ni,
... it's almost most-liked Kata by me,
... just after Tensho Kata, as well.