Six decades ago, AstroTurf was promoted along with Houston's Astrodome as a space-age wonder. Today, artificial "turf fields" features even more prominently in sports. Half of NFL teams' stadiums use the plastic stuff and it's widespread in local communities across the U.S., including on many youth league fields. But in recent years, big-name athletes such as San Francisco 49er Nick Bosa and soccer great David Beckham, along with many others, have raised questions about whether turf fields lead to more injuries.
Brian Feeley , MD, UCSF orthopedic surgeon and professor and chief of the sports medicine and shoulder surgery service, talks about the evidence for injury and his recent study indicating that lower extremities bear the brunt.
Why is artificial turf so popular for playing fields?
The original AstroTurf from 1966 allowed sports to be played indoors. Outdoors, artificial turf remains usable in bad weather. Arguably, it's easier to care for in most situations. You don't need to water it. It can be used for a multi-purpose field. And if you put a concert crowd on a grass field, oftentimes you need to replace the grass afterward. Not so with turf.
The feel of artificial turf was once compared to asphalt, but today's turfs are much better and softer. Is it only older turfs that pose injury risk?
Field turfs today are much safer than what I was familiar with from childhood. Still, there has been controversy over recent studies on relative injury risks posed by newer field turfs compared to grass.
What did you study?
We focused on lower-extremity injuries: hamstrings, knees, calf strains, ACL (anterior cruciate ligament) and Achilles tendon tears. We figured that upper-body injuries such as finger fractures and elbow issues would not be much affected by turf. We identified game-day injuries and outcomes in the NFL for 2021 and 2022.
Were there injuries that occurred more frequently on artificial turf compared to grass?
The most common injuries in our study, both for artificial turf and natural grass, were ACL injuries. There were statistically higher rates of ACL injuries that needed surgery on artificial turf compared to grass. Achilles tendon injuries were the second most common to require surgery - and they, too, were more likely to occur on field turf.
Why are turf fields associated with more injuries compared to grass?
It's probably multi-factorial. But we know that artificial turf does not absorb as much force for the player's knee and ankle, which increases the risk of injury. Artificial turf also does not release cleats as easily and puts more strain on a player's extremities through greater force and increased torque.
Do the results from your NFL study apply to youth sports fields?
Yes, older, less tended-to turfs that many youth clubs play on are likely to pose even greater risks. Professional male athletes are most likely to play on the best-maintained, best-designed turf fields.
How are young athletes affected by the increased injury risk of artificial turf?
If you get an ACL injury as a young athlete, it's more likely you won't be able to play at the next level, and you're more likely to develop arthritis at a younger age.
How are cleats a factor?
While we know a lot about the right shoes to wear for grass, there is less refinement in understanding and designing the proper shoes for turf. Another wrinkle is that an athlete might choose to wear a less safe cleat on turf if it feels better.
Does that mean kids need different shoes to play on turf vs. grass?
Playing with long-cleated shoes designed for grass on artificial turf may put the player at a higher risk for injury. The tough part is not all high school athletes can purchase multiple pairs of cleats.
What should happen next to protect athletes from injury better?
It's important to acknowledge the increased risk for lower-extremity injuries on turf fields, especially for serious injuries that can cause a considerable loss of playing time. That's been borne out in our study, in other football studies, and in studies of other sports, including professional soccer. Sports teams should continue to look for ways to decrease injury risk.
