What significant contribution did the Cramer family make to athletic training in the 1920s?

The Cramer family's significant contribution to athletic training in the 1920s was the publication of "First Aider" in 1932. This publication marked an important step in the development of athletic training by providing essential information on injury prevention, treatment, and management specifically catered to athletes. The "First Aider" helped to educate coaches, athletes, and trainers about basic first aid practices and the importance of immediate care for injuries, which laid the groundwork for more advanced athletic training principles. This initiative demonstrated the growing recognition of the need for specialized knowledge in sports medicine and athletic care, contributing to the evolution of the profession.

The other options highlight important aspects of athletic training history, but they do not reflect the specific contribution of the Cramer family during that time period. The establishment of the NATA occurred later, and the first athletic training manual was developed after the publication of "First Aider," making it a later contribution rather than a 1920s milestone.