CrossFit for Kids? Experts Weigh the Benefits and Risks

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CrossFit is the high-intensity training method that often pushes adult bodies and minds to their limits. But is a kid-friendly version of this challenging strength and conditioning program a good idea? 

Like its grownup counterpart, CrossFit for children and teens is a workout that combines aspects from gymnastics; weight lifting; body-weight training, such as squats and pull-ups; and endurance training, such as running, jumping and climbing ropes. Class activities can be adapted for the ages and skills of smaller participants.

CrossFit Kids launched in 2004 and "pairs fitness with fun," according to the company's website. The program "emphasizes good movement throughout childhood and adolescence," the site says. Group classes can be taught to children ages 3 to 18, but the age limits for classes vary at each CrossFit location.

But not all CrossFit "boxes," or gyms, offer youth classes. CrossFit Kids is offered at more than 1,800 gyms and 1,000 schools, and instructors need to take a special course before becoming a certified trainer for the kids' programs, according to the company's website.

The benefits for children and teens of doing CrossFit is that it "gets their butts off the couch," said Greg Myer, director of research and director of the human performance lab at Cincinnati Children's Hospital Medical Center. [9 Weird Ways Kids Can Get Hurt]

"Childhood is an ideal window of opportunity to influence proper motor and movement skills," said Myer, who is not affiliated with CrossFit. However, age should not be a determinant of when kids try a program such as CrossFit, he said, because different kids mature at different rates.

Instead of going strictly by age, parents should base their decisions as to whether their kids could do CrossFit on whether their child can listen to instructions and pay proper attention to those instructions, Myer said.

Encouraging children to become involved in an exercise program, whether it's called CrossFit or something else, can be a way of getting kids active and encouraging them to master movement skills during their growing years, he said.

But if children don't receive good instructions, especially when it comes to strength or resistance training, they may develop muscle soreness or get hurt, said Myer, who has studied injuries caused by resistance training in children and adults. This may cause kids to shy away from doing future resistance training, which can be a valuable fitness tool across a person's lifetime, he said. 

Research done by Myer has found that the majority of weight-lifting injuries in children ages 8 to 13 result from accidents, such as dropping a weight or using equipment improperly. Many of these injuries can be prevented with better supervision and stricter safety guidelines, the research showed.

Fit kids

In 2015, the CrossFit Games — a yearly competition televised on ESPN to crown the "Fittest on Earth" — added a teenage division for the first time. Kids as young as 14 were allowed to compete in the event, with one boy and one girl named as champions in each of the 14-to-15 and the 16-to-17 age groups.

During the CrossFit Games, the teenage athletes performed the same workouts as the adult divisions, with slight changes, such as in the amount of weight they lifted or the number of repetitions they did, according to a statement from the company.

But Myer noted that teenagers who want to compete in weight lifting with overhead, Olympic-style lifting, should follow a long progression of training over time, to develop the skills and techniques needed to lift heavier weights.

The American Academy of Pediatrics (AAP) recommends that heavy, Olympic-style lifting and powerlifting should be delayed until kids' bones and bodies reach maturity. The AAP also said that children can begin other types of strength training around age 8, and the group said it considers this a safe and effective way for kids to prevent injuries and get stronger.

Little is known about the injury rates among children and teens participating in CrossFit, because there hasn't been any published research on the subject. But the fitness experts interviewed by Live Science for this article agreed that the safety of kids involved in CrossFit hinges to some degree on the knowledge and supervision of the program's instructors. Many other exercises can be used to help kids get stronger that don't involve lifting heavy weights, the experts noted. [7 Ways to Short-Circuit Kids' Mobile Addiction]

CrossFit can be a fun activity for kids and teens that offers them plenty of variety, said Linda Pescatello, a professor of kinesiology at the University of Connecticut, who has studied the health benefits of exercise across the human life span. For younger children, the workouts can be organized like an obstacle course or as games, making them more enjoyable and keeping kids active for an extended period of time, she said.

Safety & support

CrossFit can be a safe training program, but kids should not be doing an adult workout, said Yuri Feito, an assistant professor of exercise science at Kennesaw State University in Kennesaw, Georgia, who is currently doing research on the effects of CrossFit in adults. Children need to do kid-specific movements, he said, and this comes down to how well the instructor scales down the basic movements of the workout for the ages and skills of the children in the class, he explained.

But the group-lesson setting and community-support environment of CrossFit could help boys and girls to grow and mature, as well as socialize with other kids, Feito told Live Science. 

Physical inactivity is a huge problem in this country and throughout the world, Feito said. Kids are spending more time in front of computer and television screens. If CrossFit is an avenue that gets them moving, let's encourage children to do it, he suggested.

Ultimately, the goal is to get kids active, Feito said. The brand name that may help them move more is irrelevant, he said.

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Live Science Contributor

Cari Nierenberg has been writing about health and wellness topics for online news outlets and print publications for more than two decades. Her work has been published by Live Science, The Washington Post, WebMD, Scientific American, among others. She has a Bachelor of Science degree in nutrition from Cornell University and a Master of Science degree in Nutrition and Communication from Boston University.