Recently I hid a geocache named Parcourse, figuring that it would cause my fellow geocachers to learn something new by looking up the word. It turns out that what I also was sharing was a 40-plus-year-old concept has become popular once again.

First of all, let me give you a little history. A parcourse is a fitness trail that consists of a path or a course that has exercise stations distributed along the trail. The first parcourse was created in 1968 by Swiss architect Erwin Weckemann and was built in Zurich Switzerland. These fitness trails were built in Europe in the 1970s. For instance, the United Kingdom alone has more than 300 parcourses.

The equipment is designed to help you exercise specific parts of the body using either natural features (such as climbable rocks) or manufactured products (such as pull-up bars). Parcourses can vary in difficulty based on the terrain, surface and obstacle.

And now it seems that these exercise venues have spawned a new generation – the adult playground, also known as the outdoor gym. The credit for these adult playgrounds rests with the Chinese government, which started installing outdoor gym equipment in parks. That idea sparked a similar movement in the United Kingdom. And now it’s spread to the United States. The New York Times recently reported that the City of New York has created its first adult playground in the Bronx and plans to install up to 24 more in neighborhoods across the city during the next 18 months. Other outdoor gyms for adults have sprung up in Los Angeles (which has 30 outdoor gyms with 15 more planned), San Antonio (with 30 gyms), and Miami-Dade County (with four fitness zones available in neighborhoods that have high rates of cardiovascular disease). Another outdoor gym has opened in Auburn, Washington and another is being built in Redmond, Washington.

Much of the equipment is very similar to an indoor gym, according to a May 2012 story in the BBC News Magazine. The equipment includes assisted pull-up bars, 100 percent pull-up bars, a bench, a treadmill, a hand bike, a recumbent bike, a cross-trainer and a leg press. “Many of the new adult playgrounds will have comprehensive workout areas and equipment with moving pieces,” New York Times reporter Winnie Hu explained.

So do people use them? According to the BBC story, the London borough of Camden cited research that indicated that 26 percent of people who use outdoor gyms had not exercised before. Often these gyms are put next to children’s playgrounds, which enable parents to exercise while the children play. NBC reporter Ron Allen notes that one of the biggest lures of these gyms, which are popping up mostly in urban areas, is that they’re free to use.

Whereas people often find reasons to avoid going to the gym, they seem to be drawn to the opportunity to relive their childhood outdoors. "Play, by definition, is characterised by child-like activities, fun and spontaneity and therefore requires no planning or organization,” personal trainer Darren Putt told the BBC. "Adult playgrounds help to overcome the problem that exercise has become a chore for many - few people find plugging away on the treadmill a pleasure. But by positioning these playgrounds in convenient locations, people will be more likely to take the opportunity to exercise when it presents itself - without the need for marketing initiatives."