A short article I found in the New York Times, 25 January 1939 edition (page 18).

Advises Jitterbugs to Train
Jitterbugs should train in the same way that athletes do, or face the prospect of thick ankles, broken, maladjusted feet and exhausted nervous systems, according to Dr. John J. Lalli of the Philadelphia College of Osteopathy. He holds that no good can come from doing the Susie-Q, the Big Apple or other such modern dances, and describes them as “throwbacks to the war and religious dances of primitive tribes.”