Different hand movements influence the mind differently. Rabbi Nachman of Bratzlav explained that lifting one's hands above the head has a special influence relating to prayer as "going beyond [above] the intellect."

Another beautiful and very meaningful gesture (especially when singing or listening to a song) is to wave with one hand held fully aloft, as if waving to someone leaving on a ship.

Yitzhak Buxbaum in Jewish Spiritual Practices