When a 13-year-old football player suffered a severe lower leg injury during practice at Friarsgate Park a few weeks ago, he was lucky.

An athletic trainer graduate student from USC was at the practice field, participating in a research project on youth sports injuries.

Jessica Koller checked out the injured player and recommended he be rushed to a hospital. She also called somebody at USC Sports Medicine who made sure Palmetto Health knew the child was coming and got USC team physician Dr. Jeffrey Guy to hustle in for surgery.

Just a few hours later, the child had two metal plates holding together fractured bones in his lower leg and ankle.

“He got to the hospital very fast, and that’s critical,” said Guy, team physician at USC. “He was losing blood supply (in the area where the broken bone had pushed forward). If he had waited four or five hours, the skin would have died.”

And a skin graft to fix that would have been the last thing the youngster needed, considering his injury was so severe he will have to wear a cast for weeks and then go through weeks of rehabbing the ankle injury.

The child was lucky because it’s extremely rare for somebody with athletic trainer credentials to be at a youth sports practice. That’s unlikely to change because of the cost for leagues to provide such a service. Not even every high school in the state has staff athletic trainers. But Guy encourages leagues to have someone with a medical background at practice and game sites.

Based on her experience, Koller said it’s less of a problem during games. It’s rare that there’s not some friend or family member watching a game with a medical background. Practices, however, are not as well-attended, and kids spend more time in practice than playing games.

Youth sports injuries are a huge concern. A study 10 years ago found more than 3.5 million children ages 13 and younger receive medical treatment for sports injuries each year. Experts suspect that number has grown since then.

The number of young athletes treated for traumatic brain injury or concussion has increased by 60 percent in the past decade to nearly 175,000 per year, according to the Centers for Disease Control and Prevention. (Football is second among the causes to bicycle falls.)

As part of the grant project, Koller and co-researcher John Dickenson also are working to educate volunteer youth coaches on things to look out for. For instance, growth-plate injuries — to the fast-growing ends of long bones in youngsters — often are seen as nothing more than chronic pain from the pounding of long practices. But those injuries can impact the growth of bones if they aren’t treated correctly, mostly with rest.

The medical expertise of Koller and Dickenson at practices is one benefit of the local project, which is funded by a $32,000 grant from the youth sports organization USA Football. But the major goal of the project is for those two — along with fellow researchers from six other colleges throughout the country — to provide injury data that helps set league policies.

Koller and Dickenson are comparing injuries from two similar leagues that use different policies.

Players in the Pop Warner league at Friarsgate are divided by age and weight, while the teams in the Irmo-Chapin Recreation Commission league at Seven Oaks Park are divided only by age.

There’s been a long-standing debate about which is the safest way to divide players into teams. While weight might seem to be the most important factor, there are skill and development aspects that are determined more by age than size. The data collected by Koller, Dickenson and the other researchers might help settle the argument.

The data also might impact the trend toward more low-contact flag football leagues for youngsters instead of full-contact tackle leagues.

They have only preliminary data so far — Koller’s league has been practicing for six weeks, Dickenson’s for three weeks. Mostly, they’ve seen lots of bumps, bruises and strains, along with a few fractures.

While head injuries have been in the news lately, Koller and Dickenson have yet to diagnose any concussions. But they expect to see some, and the project’s findings will be another building block in the growing sports concussion library.

The damage seen in brain scans of former professional football players “may start as early as 8-9 year-olds, nobody knows yet,” Guy said.