Why is John Bubbles called the Father of Rhythm Tap?

John Bubbles is recognized as the "Father of Rhythm Tap" because he was the most influential figure in developing the style, which emphasized the use of the heel tap to push rhythm from the 1920s jazz beat to the 1930s swing beat.1

While he may not have been the very first dancer to utilize the heel tap in this manner, his innovative approach became the standard for generations of dancers who followed and learned his style. Rhythm tap itself is characterized by its focus on complex, rapid, and rhythmic footwork using both heel and toe taps.1