The event that happened first among the options listed is "The YMCA opens a gym in America." The Young Men's Christian Association (YMCA) established its first gymnasium in Boston in 1851, making it a precursor to organized fitness activities in America.
The other events occurred later:
- Physical Education (PE) became part of American school curricula in the late 19th and early 20th centuries.
- Nautilus machines were introduced in the 1970s.
- Elliptical trainers gained popularity in the late 1990s to early 2000s.