Athletes who specialize in a single sport are more likely to suffer knee injuries, largely because of overuse and little time for recovery. (For Spectrum Health Beat)

Last Month, Franck Ribery—one of the greatest French soccer players in history—was sprinting down the left side of the pitch during a match in Germany when he collapsed to the ground in pain.

He tore the lateral collateral ligament in his left knee, better known as the LCL, and will likely miss nine months.

Several weeks before him, Nicolai Muller, another high-level European soccer player, jumped up to celebrate a goal and collapsed after landing. He tore the anterior cruciate ligament in his right knee, better known as the ACL, and will likely miss at least one year of competitive soccer.

Players last year in the Premier League—the top soccer league in England, and one of the top leagues in the world—suffered 17 ACL injuries, the highest number in the history of the sport, according to the BBC.

One broadcaster described the rising number of knee injuries in professional soccer as an “epidemic.”

But Kendall Hamilton, MD, who specializes in orthopedic sports medicine for Spectrum Health Medical Group, says this isn’t just a professional soccer problem. He says it’s a worldwide problem and the rise of knee injuries in professional soccer mirrors what he’s seeing at amateur levels in Michigan.

“I definitely see that trend,” said Dr. Hamilton, a former assistant team physician with the National Football League’s Houston Texans and Major League Baseball’s Houston Astros. “There’s been almost a 50 percent increase in ACL and MCL injuries. … From what I’ve seen and heard in West Michigan, it looks like there’s this same trend across the country.”

The causes

Dr. Hamilton attributes three causes to the ACL epidemic: First, the specialization of youth sports.

It used to be most children would play different sports as the seasons changed—baseball in the summer, soccer or football in the fall, basketball, skiing or ice hockey in the winter. Three-sport stars in high school weren’t unusual.

But with specialization over the past decade or so, many children pick one sport and focus on it, Dr. Hamilton said.

“When you’re not really delving into other sports, you subject one or a few particular muscle groups to fatigue, deconditioning, overuse,” Dr. Hamilton said. “Each sport works a different set of muscles and if you only specialize in one, you’re not getting the balance that comes from playing multiple sports and working multiple muscle groups.”

Not only are children mostly focusing on one sport, but they’re also playing that sport year-round, which is a second major contributing factor, he said. There’s no offseason, which is essential to giving muscles and ligaments time to heal.

“Now, kids are playing multiple leagues at one time year-round, maybe playing in their school soccer league or in AAU or a travel league,” he said. “Plus, there are showcases for recruiters, travel ball coaches and college scouts. So the season never ends, and it’s just really really wearing on the body.”

The numbers are stunning.

Premier League players in total suffered 28 knee-ligament injuries last year, the highest number in the last five seasons.

And one major Italian team, A.S. Roma, has lost 12 separate players to ACL tears since 2015.

The third reason for the spike in knee-ligament injuries, according to Dr. Hamilton, is playing surfaces. A lot of schools and professional teams have switched from grass fields to artificial turf, which is a much faster playing surface and has much more traction.

“There’s a lot of engineering going on, a lot of still tinkering with surfaces,” Dr. Hamilton said. “Early studies show that there is an association between artificial turf and increased ACL injuries in field sports. Traditionally, with natural grass, the field is softer and you tend to see a lot more ankle injuries like sprains. … But with turf there’s a lot more traction, the foot is more stable to the ground and energy is transferring up to the knee and bypassing the ankle.”

Artificial turf—which comes in many varieties—is easier and less costly to maintain. But the injuries to knees tend to be much more catastrophic than those to ankles on old playing surfaces, Dr. Hamilton said.

Dr. Hamilton recently treated Josh Sheldon, the owner of the Grand Rapids Football Club, a semi-professional team, for a torn ACL suffered during an indoor soccer game.

What’s the solution?

Dr. Hamilton believes with the right training regimen, the majority of these injuries can be avoided.

First, he suggests playing multiple sports instead of only focusing on one.

“In your younger years—your high school or formative years—you’re still trying to build body control, your body is still maturing skeletally and neuromuscularly and you’re building up core groups, which gives you the strength and balance and timing you need,” he said. “This all happens from doing a variety of physical activities.”

The second solution is even if an athlete is committed to only focusing on one sport, they should commit to having an offseason during which rest and cross-training are possible.

“Give the body the time it needs to rest,” Dr. Hamilton said. “Constant activity wears on the body, and we know the body is more prone to injury with fatigue. Six to eight weeks off in between seasons will allow the body to rehab appropriately and give you the ability to perform at a high level.”

Lastly, proper training programs are important.

“There are ACL-prevention programs backed by medicine,” he said, citing the Sportsmetrics program founded in Cincinnati and recommended by a lot of sports-medicine doctors.

“Work on balance, work on how to fire different muscle groups, particularly hamstrings and posterior muscle group and dynamic control,” he said. “A lot of times when you jump and land, people land in a more standing position—and that actually puts more force on the ACL. But people who land in a seated position, using the posterior muscles like hamstrings and glutes, that’s actually protective on muscle groups. Proper jumping and landing mechanics are key.”

Spectrum Health seasonally offers SHIPP, the Spectrum Health Injury Prevention Program, based on the Sportsmetrics philosophy.

Dr. Hamilton said the program, which focuses on proper jumping and landing mechanics, proper warmup and cool-down techniques, and proper neuromuscular control, can reduce ACL injuries in certain subsets of athletes by up to 90 percent.