Why was fitness stressed in physical education programs in the early 1900's, 1930
's. 1950's, and 1960's?

From the late 1700s to the mid-1800s, three nations–Germany, Sweden, and England–influenced the early development of physical education in the United States. German immigrants introduced the Turner Societies, which advocated a system of gymnastics training that utilized heavy apparatus (e.g., side horse, parallel and horizontal bars) in the pursuit of fitness. In contrast, the Swedish system of exercise promoted health through the performance of a series of prescribed movement patterns with light apparatus (e.g., wands, climbing ropes). The English brought sports and games to America with a system that stressed moral development through participation in physical activities. The influence of these three nations laid the foundation for sport and physical education in America.

The 1800s were an important time for the inclusion of physical education in schools across America. The Round Hill School, a private school established in 1823 in Northampton, Massachusetts, was the first to include physical education as an integral part of the curriculum. In 1824 Catherine Beecher, founder of the Hartford Female Seminary, included calisthenics in her school's curriculum and "was the first American to design a program of exercise for American children" (Lumpkin, p. 202). She also advocated the inclusion of daily physical education in public schools. However, physical education was not offered in the public schools until 1855, when Cincinnati, Ohio, became the first city school system to offer this type of program to children.

Explanation:

sumerians were responsible.