Listen to the author narrate his story in this APTA podcast.
As a teachable 13-year-old softball player I paid close attention to a coach explaining how moving a light weight in certain directions could help with throwing. That day, I learned the basics of internal rotation, external rotation, and the ill-advised empty-can scaption, although not by those terms; I only knew these as ways to improve my throw. A few years later, a softball injury put me in physical therapy, and a career path was discovered.