A little infomation on outdoor fitness from Wikipedia.
Outdoor fitness consists of exercise undertaken outside a building for the purpose of improving physical fitness. It contrasts with exercise undertaken inside a gym or health club for the same purpose. The activity may be undertaken in a park, in the wilderness, or other outdoor location. The popularity of outdoor fitness grew rapidly in the second-half of the twentieth century and grew as a commercial consumer market in the twenty-first century
In nineteenth-century Germany, Turnplatz, an outdoor space for gymnastics, were promoted by German educator Friedrich Jahn and the Turners, a political and gymnastic movement. After the Second World War, as people did less exercise in their daily and work lives, individualistic, health-oriented physical and recreational activities such as jogging began to prevail. The Royal Canadian Air Force Exercise Plans, developed by Dr. Bill Orban and published in 1961, and Kenneth Cooper’s book “Aerobics” (1968) and mass-market version “The New Aerobics” (1979) helped to launch modern fitness culture. There was a running boom in the 1970s and outdoor fitness trails were developed in the USA and Europe. However, most of the growth in the fitness industry was through indoor gyms and health clubs.
Outdoor fitness boot camps developed in Australia, the United States and the United Kingdom in the 1990s and Canada in 2001. In the twenty-first century, outdoor fitness grew as a commercial consumer market. Outdoor group fitness classes led by a personal trainer or a fitness professional became a popular form of outdoor exercise. A variety of training courses for fitness professionals and certifications for companies specialising in outdoor fitness developed. Outdoor fitness can be studied as a specialism of exercise physiology. The trend towards outdoor fitness led to a proliferation of outdoor gyms.
Growing participation was seen in organized events that expanded internationally such as Parkruns, Tough Mudder and Be Military Fit and sports such as triathlon and cycling. Street workouts have also become a popular outdoor fitness activity is some countries, with a world championship taking place since 2011.
