Merce Cunningham began his training in tap dance. This biographical detail came up in all of the interviews I conducted, as well as the texts dealing with Cunningham on a personal-historical account. I believe it's relevant because it helps explain his commitment to rhythm in his choreography and the technique classes. 

In my own experience with Cunningham technique, and in learning choreography, the rhythm is what sticks with me, what compels me. For me the rhythm feels related to the idea of devotion. If devotion is the feeling I get about the work, a strong sense of rhythm brings that to me as well.