Aerobics is a form of exercise based on cardiovascular activity that became a popular leisure-time activity for many Americans in the final quarter of the twentieth century. Dr. Kenneth H. Cooper, an Air Force surgeon, coined the term aerobics in a book of that title published in 1968. Cooper viewed aerobic activity as the cornerstone of physical fitness, and devised a cardiovascular fitness test based on one's ability to run a mile and a half in twelve minutes, a task that was used in military training. Cooper's work was endorsed by the medical community by the early 1970s, and contributed to the popularity of running during that period. By the end of the decade, aerobics had become synonymous with a particular form of cardiovascular exercise that combined traditional calisthenics with popular dance styles in a class-based format geared toward non-athletic people, primarily women. Jackie Sorenson, a former dancer turned...