Suwariwaza —or what could be called sit-jutsu— essentially refers to the set of martial techniques performed from a seated position, such as agura, or kneeling, such as seiza.
It is a term from the Japanese martial arts.
It may seem a more comfortable application but, done correctly, it is even harder than standing techniques, since it requires a high degree of activation and management of balance and the center of gravity, in positions associated with rest.

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