It is a pose in which you stand with your hands spread wide.
It can be used for a variety of purposes, such as a boss-like laughter or a conductor who plays the climax of a song.
手を大きく広げて立つポーズです。
ラスボス的な笑いの立ち姿や、曲のクライマックスを奏でる指揮者など使用用途は様々です。