Is one who uses breathing techniques and focuses on a single point -inspired by yoga and relaxation exercises- to increase tranquility and focus during prayer in error?

It is permissible to contemplate in order to achieve focus and humility in prayer, based on the Prophet's (peace be upon him) saying: "Indeed, there is preoccupation in prayer," provided that the focus is on the place of prostration, and not on anything else, otherwise that would be a distraction from the prayer.