CrossFit runs in the Cassidy family.

Mom Annemarie joined the popular fitness community four years ago because she wanted to boost her muscle mass and bone strength. She was soon addicted. "I love the sense of accomplishment ... and the social nature of CrossFit," says Cassidy, 44, a former Air Force pilot living in the District of Columbia.

About a year and a half ago, her preteen sons jumped on board.

"I like how it can be really competitive, but it's also really fun," says 11-year-old Ian Cassidy, a moppy-haired and boisterous rising fifth-grader who attends three classes each week in the District, like his 13-year-old brother, Connor. "And I absolutely love burpees – burpees are the best."

Ian may be among a growing number of children as young as 3 who not only know what burpees are, but also love them, thanks to CrossFit Kids, an offshoot of the strength and conditioning program known for its devoted following, bare-bones gyms called boxes and high-intensity, full-body movements like burpees, which involve a squat, a push-up and a jump.

"A lot of times in school these days they're not quite getting the same level of activity that maybe they used to get or they should, and I think CrossFit is a great way to introduce kids to simply moving," Annemarie Cassidy says. It's benefited her too: A recent scan revealed her bone density was "excellent" – even for a woman half her age, she says. Plus, she can climb ropes and hold handstands. "I can now do anything physically that my boys can do," she says.

Adults Versus Kids

The CrossFit company launched in the 1990s out of Santa Cruz, California. It has since expanded to more than 10,000 gyms nationwide where CrossFit-certified trainers are on staff. CrossFit Kids, meanwhile, has been offered to kids between ages 3 and 18 since 2004 at more than 1,800 gyms and 1,000 schools worldwide, according to the program's website.

The philosophy of the programs is the same: Build overall fitness – including endurance, strength, flexibility, speed, coordination and balance – by performing a variety of movements at a relatively high intensity. But in practice, CrossFit across the ages can look a lot​ different.

When adults ​go to a CrossFit "box," for instance, they might lift 150 pounds overhead and squat 10 times. They might sprint 800 meters and climb a 15-foot rope. Then, they do it as many times as they can in 20 minutes. "What can sell [CrossFit] to a certain group of individuals is the absolute intensity of it," says Jon Gary​,​ a CrossFitter in the San Diego area who teaches seminars on the CrossFit Kids ​methodology.

But when kids ​do CrossFit, that intensity is appropriately scaled-down – similar to how it should be for a first-time adult CrossFitter,​ Gary says. "You can have an adult be a CrossFitter and their relative high intensity is working with 3-pound dumbbells, and someone else’s might be with a 75-pound barbell," he says. "It’s very inclusive." Child CrossFitters, meanwhile, might run a few meters,​ squat without weights and push a wooden ​box across the room. They play tag, high-five and throw foam balls. In the kids' minds, it's all fun and games. In their coaches' minds, it's a basis for lifelong fitness.



The youth programs at the Balance Gym in Glover Park in the District​​, the Cassidy boys' gym, are designed to be safe, educational and fun, ​explains coach Andrew Shniderman​, who directs the gym's youth programs and is certified to teach CrossFit classes for kids and teens. ​"Who can say that's a bad thing for kids?"

More Than Exercise ​​

Ian Cassidy​ is just one of the dozens of kids who attends CrossFit Kids classes regularly at his gym, one of several CrossFit facilities in the District that offer classes to the 18-and-under crowd. "We have kids that are – by traditional standards – unathletic or uncoordinated, sometimes awkward," Shniderman says. "We have kids who are super athletic and just looking for an additional outlet. And then we have kids who are kind of in the middle."

All are welcome. One 8-year-old student, Shniderman says, used to refuse to play team sports. When his mom signed him up for CrossFit, he was reluctant, too. "He was the kid who would show up in jeans and not very proper shoes," Shniderman says. But just a couple weeks ago, the boy tried out for his school's football team because he was more comfortable with his body.

"The gratification that comes in from physical exercise where [kids] can actually conquer their own bodies is something that benefits them beyond most things," Shniderman says. "Kids open themselves up when they're in a gym or they're doing a physical activity in a way that they don't open up to in a classroom."

Gary says the program has also benefited kids with Down syndrome and attention deficit hyperactivity disorder,​ thanks in part to the class structure: First a lesson at a white board, then a warm-up, then a workout and finally a game. There are also programs that offer CrossFit to foster children and at-risk youth.

A Focus on Fun

At a recent CrossFit Kids class at Balance​ Gym​, Shniderman​ led Ian and another preteen in a call-and-repeat exercise: "Holster!" he yelled. "Holster!" the kids yelled back, placing their hands on their hips. "Diamond!" Shniderman called. "Diamond!" the kids called back, thrusting their thumbs and forefingers forward in the shape of a diamond. "Hips back! Sit down!" The game reminiscent of the childhood classic "head, shoulders, knees and toes" continued. "Knees out! Chest up!" They chanted. Once the group reached "Stand!" they had completed a squat – whether they knew it or not.

"We say that anything worth doing is worth doing right, whether it be school work or movements here," Shniderman says. "As long as it's a safe movement, the kids are going to be all right."

Andrew Gregory​, an associate professor of orthopaedics and pediatrics at Vanderbilt University's School of Medicine who treats injuries in young athletes, also sees benefits in weight-training programs for kids, though research is still needed on CrossFit Kids, he says.

"There's clear benefits to strength training in general, and I would include CrossFit in that," he says. For instance, kids who strength train and play sports might be less prone to injury during a game or match. In many ways, CrossFit is "just another physical activity that's a good thing in general for all aspects of health, including mental health and physical health," Gregory says.

However, it's still important to be cautious when introducing kids to new activities, and particularly weightlifting, Gregory says. While adults are prone to muscle tendon strains, for example, kids are more at risk for back,​ he says.

"What we worry about with kids is having too much weight too quickly," Gregory says. That's why it's crucial​ for coaches to monitor how much weight children are lifting and to increase the weight at smaller increments than adults. It's also important to be sure that kids don't get so caught up in the competitive spirit that they try to take on more than they can handle. Further, ​children shouldn't try to do "single repetition maximum exercise" – or lift as much as they possibly can just once, as adult weightlifters sometimes do.

Gregory recommends parents observe a class before enrolling their children. "As long as focus is on form and that they're being supervised and that it's fun, then in general I think it's a very safe activity to do," he says. It's also a good idea for kids to see a pediatrician or family physician before starting a formal strength-training program, since some conditions, such as uncontrolled hypertension and seizure disorders, might rule them out of participation, advises the American Academy of Pediatrics.