Many Ballroom dancers practice Yoga poses because it adds flexibility and calms the mind.
Every Ballroom Competition is a stressful day with dancers adrenals bouncing up and down. To be able to find a quiet corner in-between dances, and lose one's self in a peaceful meditation can calm the frantic stage fright and attract the judges eye for a higher score.
Judges score on a whole raft of personal traits beside the quality of the dance. They are good at spotting the nervous, frantic, worried dancers and they tend to score them accordingly. So, the trick is to fool the judges and keep that calm exterior vibrating "winner."
Below, a short vid on yoga