Wikipedia
Sotai or is a Japanese form of muscular or movement therapy invented by Keizo Hashimoto (1897–1993), a Japanese medical doctor from Sendai. The term So-tai (操体) is actually the opposite of the Japanese word for exercise: Tai-so (体操). Dr. Hashimoto conceived Sotai as an antidote to the forceful and regimented exercises of Japan, that anyone could practice easily to restore balance and health.
Sotai is different from regular exercise because it distinguishes between balanced movements that are natural and beneficial and those that are unnatural and cause strains and physical distortions. The aim of Sotai is to help the body restore and maintain its natural balance.
Dr. Hashimoto developed a model of treatment based on restoring structural balance that is claimed to work with the breath and movements toward comfort (or away from pain). He developed Sotai Therapy from traditional East Asian medicine ( acupuncture, moxibustion, bone setting ( Sekkotsu), Seitai Jutsu) in concert with his knowledge of modern medicine.
Sotai Therapy is intended to be a method of neuromuscular reeducation and unwinding muscular holding patterns. According practitioners, Sotai Therapy balances the nervous and muscular systems. Its central principle is backtracking movement or "reverse-motion" treatment. The idea is that structural distortions can be returned to a more normal condition by moving the body in the comfortable direction. Using the effects of an isometric contraction followed by a sudden relaxation ( post-isometric relaxation) can normalise the strained condition.