Players warm up during a Cardio Tennis class in Australia. (Tennis Industry Association)

A few months ago, my wife and I acquired a dog, and now she can’t stop comparing me to our canine companion in various respects. I will admit to at least one: If you tell me to go run five miles, I’ll probably just sit there, staring at you — and wondering when I’ll get a snack — but if you produce a ball, I’ll chase after that sucker until my tongue hangs out.

Which is why I enjoyed my recent introduction to Cardio Tennis, a branded fitness activity that more or less uses the basic elements of tennis as an excuse to run participants ragged.

At an open demonstration on some courts in Bethesda, I was one of about 10 people using rackets to hit balls over a net (or, all too often in my case, into the net). We took quick turns volleying with each other, usually with the instructor, David Robinson, feeding us balls to get things started in a certain way and to keep the tempo high.What we weren’t doing was keeping an overall score, or worrying about the relative abilities of other participants, or standing around very much.

Robinson told me that Cardio Tennis is meant to provide “a very consistent platform for a high caloric expenditure, regardless of skill level, and in a group format.” Created in 2005, it “was designed to attract fitness-seekers into the game of tennis,” Robinson said, and as such, it’s aimed more at folks who want to work up a sweat than those who want to work on technique.

Constant movement is the key. Conventional tennis can get slowed down by walking to collect balls, waiting for another player to do the same, or simply getting lazy after playing several points. In the demo class, Robinson made a point of having us keep running on, off and around the court, with agility ladders set up on each side to provide some extra exertion.

Players try out an agility ladder during a Cardio Tennis class in Sarasota, Fla. (Tennis Industry Association)

Robinson had our group start off by playing short bursts of doubles, with a lot of scampering either to the back of the court or over to the other side, depending on the outcomes of our best-of-three-points skirmishes. This was just one of many games devised to make Cardio Tennis a fun experience; music is often played at the same time (very much unlike a standard tennis lesson), to heighten the sense of fun, although it wasn’t during the session I attended.

One particularly taxing segment was the “poach” drill, in which we played an approach shot on the left side of the court, then immediately had to lunge to the right to play a cross-court return, then quickly backpedal and scuttle back over to the left to cover for doubles partners who were doing the same thing, with Robinson continually feeding balls. A few rounds of that, and I was less “Wimble” and more “done” — but I was darned if I wasn’t going to keep trying to track down those balls.

“Really a fun way to get fit with a tennis racket in your hand,” is how Scott Baxter described Cardio Tennis. Baxter is the chief executive of Play Your Court, a company that helps people who can’t afford club memberships, or who don’t want to travel far, get individual and group lessons from certified pros on public courts in or near their own neighborhoods.

“A very common reason why people are looking for tennis lessons” is simply for fitness, Baxter said. “A lot of people are sick of the gym, and they’re looking for a more fun way to stay in shape.”

Baxter also pointed out that Cardio Tennis classes, elements of which can be incorporated into individual sessions, are scalable to participants’ abilities. “Each class can accommodate a pretty broad range of skill level, and fitness level, so that’s one of the best parts about it.”

In Robinson’s class, there was actually a bit more down time than I would imagine a regular session involves. That was both because it took a little while to explain each drill to a bunch of newbies, and because he wanted the participants in the open demonstration to come away with a better understanding of the sport.

“Learn and burn” is Robinson’s preferred mode. “Basically, I have a high degree of instruction in my classes without slowing down the tempo of the class, with instructions provided during rest breaks, when people are picking up balls, or,” he added with a chuckle, “are so winded that we need a little ‘chalk talk’.”

Shelley Puterman, who was my doubles partner for most of the class, is a fitness buff who has been playing tennis for 13 years and appreciates how the Cardio version ramps up the physical benefits.

“Doubles is a lot of fun, and it’s strategic, but there’s not much exercise,” the 53-year-old District resident told me. “So that’s why I like to play singles, but not as many people play singles. So when you come to something like Cardio Tennis, you’re getting the exercise, you’re getting the cardio part, and you’re actually improving your strokes as you’re doing it.

“It keeps you moving, and in tennis, moving is important, because once your legs stay still, you’re stuck and you can’t get to anything.”

Puterman felt that participants “do need to have some sort of tennis skill,” or else risk slowing classes down. However, both Baxter and Robinson emphasized that a major goal of Cardio Tennis, at least as it was originally conceived, is to draw non-players into the sport, and I could see how it might be enticing for beginners, because it doesn’t require an ability to sustain long rallies.

Currently, there are about 1.7 million Cardio Tennis participants in the United States, according to Michele Krause, who manages the program for the Tennis Industry Association. She told me via e-mail that it is offered in about 3,000 facilities across the country, and in 30 other countries, particularly Britain and Australia.

“Growth has been tremendous, and it is the only tennis program which has shown consistent growth year after year,” Krause wrote.

My decidedly rusty game — especially a very loose cannon of a forehand — certainly has room to grow, but my interest in resuming some form of tennis also stems from the full-body workout it provides, one Cardio Tennis effectively accentuates.

“One of the inherent greatnesses of tennis is diversified movement,” Robinson said. “You’re running sideways, you’re backpedaling, you’re jumping, you’re at different speeds, you’re lunging. This is what our legs were designed to do. And the different intensities is what our hearts were designed to do.”

@desbieler on Twitter

Want to try a Cardio Tennis class or individual session? Go to www.cardiotennis.com, www.playyourcourt.com or www.playtennis.com to find a location.