In 1939, Elizabeth Kenny, or Sister Kenny, as nurses were called in Australia, came to the U.S. in 1940. Her methods of hot-pack applications, stretching, and muscle massage were unconventional and controversial, but eventually became part of standard care for polio.

Her techniques included the use of warm and cold compresses, saltwater immersion (although she later abandoned that treatment), and gentle progressive exercise of specific muscles, concentrating on allowing no muscle substitution or fatiguing of weakened muscles

She was appointed an army nurse in 1915, despite her lack of formal credentials. She was sent to France, where shortly thereafter she was wounded with shrapnel from a shell explosion, sustaining injuries to her left leg that would plague her throughout her life. She returned to the front, serving with distinction. Kenny was promoted to the nursing equivalent of first lieutenant, which in the Australian military gave her the formal title of Sister, a title that she proudly carried for the rest of her life.