Playing is second nature for kids. Bring them to a park, let them loose, and watch the magic happen. Yet, for some strange reason, we often lose that unencumbered sense of play once we get older. “Parkour’’ reminds grown-ups of the intrinsic value of playing.

“I’ve told my kids that parkour class is my chance to play on the playground. Of course, in parkour, the entire city becomes the playground,’’ said Elizabeth Lowe, 41, a mother of two from Waltham. “When I’m talking with an adult who hasn’t heard of it, I usually compare parkour to obstacle-course training, but sometimes I also think of it as superhero training.’’

“Parkour motivates me to work out far more than anything else I’ve tried,’’ Lowe said. “It is infinitely challenging and never boring.’’

Developed during the 1980s in France as a military exercise, parkour is a variation of the word “parcours,’’ meaning “the way’’ or “the journey.’’ Essentially, parkour is a movement discipline in which practitioners train mind and body to overcome obstacles and physically interact with their environment, “often in strong, creative, playful, and fluid patterns,’’ said Blake Evitt, 30, director of Parkour Generations Boston in Somerville.

Evitt said parkour intrigued him because it combined his passions for running and exploring.

“Once I started,’’ he said, “the utility of the movements in my everyday life, and the fact that a workout could be both hard and fun, kept me coming back.’’

Perhaps the biggest difference between pure play and parkour, participants say, is the emphasis on understanding and mastering specific movements.

“The awareness of how we move is the key to improving our skills,’’ Lowe said. “As I learn a new vault, I’m aware of everything from hand and foot placement, the angle of my body, the order in which my feet hit the ground, and the overall direction of motion.’’

Lowe said some jumps are known as “precisions,’’ emphasizing the importance of a precise landing.

“That means paying attention to the amount of power in the jump, our foot placement, and where our center of gravity is going,’’ she said.

Though physically challenging, parkour has no age limits. Participants set their own learning curves.

“We’ve worked really hard to turn around the bogus belief that parkour is just for 20-something guys prancing topless between rooftops,’’ said Parkour Generations’ Natalia Boltukhova, 36, a native of Russia now living in Somerville. “It’s accessible to anyone.

“We have a pretty good diversity in our classes,’’ she said. “At our monthly free parkour jam, we had a 20-something Riley who was hopping down the steps in a handstand, and alongside him there was 62-year-old Bonnie, crawling in quadrupedal movement down the same steps and balancing on a rail.’’

Bonnie is Bonnie Black of Watertown. She said parkour is teaching her “to move mindfully and creatively through my everyday environment.’’

“We may look like a bunch of grown-up kids horsing around freely on the playground, but fundamentally we’re experiencing a training that is highly disciplined, focused, and mindful,’’ Black said. “The challenges are in every movement, small and large, with the goal of a fluid and controlled ‘catlike’ quality.

“That sounds easy, but it requires moment-to-moment problem-solving with strong mind-body connection at all times,’’ she said. “Every minute of a training session requires me to face certain challenges and fears I may have, and then to break down those barriers so I can move forward. This is a very empowering type of training.’’

Empowerment is a familiar refrain among participants, regardless of their ability levels, and its mental component is a key attraction.

“There’s a constant process of finding your own limits, breaking through them, and finding new challenges, and that happens at whatever speed you’re comfortable with,’’ said Emily Charles, 30, of Watertown. “No one ever forces you to do anything you’re uncomfortable with.’’

For 8-year-old Sky Fiuczynski of Watertown, parkour is play with a bonus, providing important life lessons often found in traditional sports.

“Parkour taught me that I have to be patient, because you have to wait for kids of all levels of experience to finish a move or a challenge,’’ Fiuczynski said. “Parkour is mental and physical because you have to use your mind to decide if it’s safe or not.

“I do the kids class and the monkey squad — an advanced kids class — so there’s girls and boys,’’ he said. “In the advanced class you have to jump off something high, and you feel like you’re gonna die doing cat leaps, dive kongs, and rolls, but the coaches are always under you, so if you fall they will catch you.’’

The idea of pushing boundaries is central to parkour.

“The discipline is focused on finding the edge of what scares you, and then discerning whether it’s a mental barrier that’s keeping you from doing it, or something that’s actually dangerous at your current skill level,’’ said Jonathan Eden, 43, of Cambridge. “The coaches with Parkour Generations are great at scaling things to different abilities.’’

For information, visit Parkour Generations Boston at pkgenboston.com. If you have an idea for the Globe’s “On the Move’’ column, contact Brion O’Connor at brionoc@verizon.net. Allow at least a month’s advance notice.