Bonnie Prudden, 97, whose alarm over the flabbiness of American children propelled her to become one of the most visible postwar champions of physical fitness, died Dec. 11 in Tucson, Ariz.

Ms. Prudden appeared on the cover of Sports Illustrated in 1957. One of the first fitness instructors with a regular presence on national TV, she appeared on the Today show in the 1950s and on a syndicated show named for her in the 1960s.

She also wrote fitness books for babies, the elderly, and people eager to enliven their sex lives. She carried her message to schools, hospitals, and prisons, where she advocated sit-ups as a riot-prevention measure.

She entered the national spotlight as an author of a 1955 report to President Dwight D. Eisenhower that said 56 percent of U.S. children had failed at least one of a battery of fitness measures, including leg lifts and toe touches. The study resulted in creation of the President's Council on Youth Fitness, now the President's Council on Fitness, Sports, and Nutrition.

She also wrote fitness articles for Sports Illustrated, recorded six records, and wrote 15 books.

She never stopped exercising, however. Heart surgery at 92 did not hinder her daily routine, by then largely done in the swimming pool or in bed. Her marriage to Richard S. Hirschland ended in divorce in the 1950s. - N.Y. Times News Service