From AstroTurf to 'frankenturf': Inside the NFL's behind-the-scenes battle to fix its turf problem

Odell Beckham Jr. was on his way to a redemptive Super Bowl LVI last February until a wrong step derailed his crowning night.

The Los Angeles Rams receiver’s plant foot got stuck in the SoFi Stadium turf as he twisted his body to try to snag a pass thrown just behind him.

To NFL players who had campaigned in vain to rid the sport of artificial turf, the sight of Beckham crumpling to the ground and clutching his knee was not only tragic but avoidable. They unleashed a barrage of tweets slamming the NFL for failing to prioritize player safety and for allowing artificial turf to claim another victim.

“It’s 2022. Why do we still have turf fields?,” Green Bay Packers offensive tackle David Bakhtiari tweeted.

“Every player is one play away from altering their career forever when playing on turf,” San Francisco 49ers defensive end Nick Bosa wrote.

“I believe @obj injury doesn’t happen on grass,” Miami Dolphins return specialist River Cracraft added. “Turf needs to take a hike.”

While the safety of artificial turf might be a conversation killer at a family dinner or cocktail party, it has inspired intense debate in NFL circles since the heyday of AstroTurf. Players say that turf shortens their careers and adds to the injury risk already inherent in a contact sport. Team owners counter that synthetic surfaces cost less to maintain and offer the durability to host more money-making events. Then there are everyday fans who merely want to keep their favorite players healthy.

Rather than exert public pressure on teams to play on grass, the NFL has thrown considerable resources into trying to decrease the rate of lower-limb injuries on turf. For more than a decade, NFL-funded research teams have devoted endless hours to studying the mundane, from the safest cleat patterns, to the desired surface hardness, to the optimal infill depth. They’ve even designed a device known as the Beast to better understand the interaction between turf and cleats and how injuries occur.

The NFL’s ultimate goal is an ambitious one. Sooner than later, the league wants to unveil a “frankenturf” that meshes the best characteristics of natural and synthetic playing surfaces.

“There’s no reason to think we can’t build synthetic turf that is safer and better performing than natural grass,” biomechanical engineer and NFL consultant Richard Kent told Yahoo Sports. “With the right team and the necessary resources, it’s definitely possible to do it.”

Odell Beckham Jr. suffered a torn ACL in the Super Bowl, prompting players around the league to blame the injury on artificial turf. (AP Photo/Marcio Jose Sanchez)
Odell Beckham Jr. suffered a torn ACL in the Super Bowl, prompting players around the league to blame the injury on artificial turf. (AP Photo/Marcio Jose Sanchez)

Where did turf come from?

It's impossible to miss the irony of how artificial turf came into existence. A playing surface despised for its punishing qualities was originally conceived for health purposes.

In the 1950s, a U.S. military study revealed that urban young people generally were less physically fit than their suburban counterparts. Attributing this to a dearth of green space, the Ford Foundation funded research to create a synthetic surface to cover the asphalt of inner-city playgrounds and to mimic the grassy playing fields enjoyed by children in the suburbs.

Installing synthetic grass proved too expensive for most city budgets, but an unexpected buyer did show interest. The Houston Astros reached out to the Monsanto Company about installing the artificial surface in the newly built AstroDome.

When the Astrodome opened in 1965, players complained that the glare from the stadium's 4,000 skylights made it difficult to catch even the most routine pop-ups or fly balls. The Astros quickly addressed that by painting over the skylights, but solving one problem created another. The stadium's grass playing field withered and died due to insufficient sunlight, forcing the Astros to look into man-made surfaces.

Major League Baseball's first grassless game was a March 1966 matchup between the Dodgers and Astros. Within five years, more than a dozen other pro and college stadiums also went synthetic. They were seduced by promises from turf manufacturers that they would spend less on field maintenance, that the playing surface could withstand an unlimited number of events and that the smooth green carpet would cause fewer knee and ankle injuries than patchy, divot-laden natural grass.

On Jan. 27, 1969, Sports Illustrated published an article whose splashy headline proclaimed, "Dust will be history — mud too — in the brave new era of synthetic football fields." In that story, NFL commissioner Pete Rozelle predicted, "In five to 10 years any problems about playing championship games in cold-weather towns will be resolved — we'll have artificial turf on all of our fields by then."

And yet while some players marveled at the pace of football on turf, others raised concerns about playing a contact sport on a surface resembling a billiards table. Months before a series of knee and ankle injuries forced him into early retirement in 1972, Chicago Bears running back Gale Sayers ominously told Sports Illustrated that artificial turf "will shorten careers." A few years later, Dallas Cowboys receiver Drew Pearson told Texas Monthly that turf has "no benefits" and that "you know that if you're playing on artificial turf, the risk of injury is going to be greater."

In the 1970s, the NFL Players Association repeatedly urged the U.S. Consumer Product Safety Commission to reevaluate whether Astroturf and other artificial playing surfaces of that era posed an unnecessary safety risk. Each time, the USPSA rejected those petitions, dismissing direct testimony from NFL players and studies comparing injury rates on grass and turf as insufficient evidence.

The smoldering debate over the safety of artificial turf flared up anew on an October afternoon in Philadelphia 29 years ago. That was the day that an unlucky Chicago Bears receiver severed the patella tendon in both his knees without another player even touching him.

(Amber Matsumoto/Yahoo Sports illustration)
(Amber Matsumoto/Yahoo Sports illustration)

Wendell Davis goes down

Streaking downfield on a post pattern, Wendell Davis glanced over his shoulder and saw that the ball was underthrown. Davis realized his best chance was to slow down and attempt to out-jump 5-foot-7 cornerback Mark McMillian for the ball.

When Davis planted his feet to make his leap, his cleats clung to the notoriously treacherous Veterans Stadium astroturf as though they were nailed to the ground. Davis felt a pop in both his knees and he crumpled to the turf.

"My knees kind of moved up into my thighs," Davis told Yahoo Sports. "I remember the trainers coming out and asking which leg I hurt. I had to tell them it was both."

The rehab, Davis says candidly, “was a b—-.” For weeks, he wore casts on both legs from his ankle to just below his hips. It took 4 to 6 months before he was able to walk again. No longer able to sprint or cut the way he once did, Davis retired from football in 1995 after a failed tryout with the Indianapolis Colts.

The non-contact injury that ended Davis’ NFL career was no isolated incident in the era of old-school artificial turf. In the 1990s alone, the green monster claimed the knees of two heralded No. 1 overall picks, Steve Emtman and Ki-Jana Carter. It prematurely retired Michael Irvin and cost Rod Woodson a year of his prime.

That flurry of injuries proved to be a tipping point on attitudes toward artificial turf. When the St. Louis Rams replaced the field at the Edwards Jones Dome after the 2004 season, the NFL at last was cleansed of first-generation artificial turf. Some franchises embraced a return to natural grass. Others preferred a more grass-like form of artificial turf that had just hit the market.

FieldTurf billed itself as “the future of sports surfacing.” The company used longer plastic fibers, crumb rubber infill and other materials to create a softer, less abrasive artificial surface than the rug burn-inducing turf of the previous era.

Visitors to FieldTurf’s website in the 2000s might have come away with the impression that the company achieved what is still eluding engineering teams more than a decade later. FieldTurf boasted that its product had “all the benefits of real grass and artificial turf, with the drawbacks of neither.” Citing independent testing, the company claimed its turf had “proven to be consistently safer than any other turf system and equal to, if not better than, natural grass.”

And yet, while FieldTurf and other next-gen surfaces didn’t cause as many scrapes or rug burns, those safety claims didn’t fully hold up to further scrutiny. The NFL’s injury and safety panel compared injury rates in games played on grass and FieldTurf from 2002-2008. It found that the rate of ACL injuries was 88 percent higher on FieldTurf than grass, and the rate of ankle sprains was 32 percent higher.

Those results caused the NFL to act.

A mobile
A mobile "Beast," developed by engineers at the University of Virginia, is now being used to test artificial turf around the country. (Courtesy of Dr. Richard Kent)

Calling in the Beast

In 2008, two automobile safety experts received an unexpected plea for help.

The NFL asked them to take a fresh look at its decades-old artificial turf problem.

Jeff Crandall and Richard Kent are biomechanical engineers who have devoted most of their careers to the science of crash survival. They study how the human body reacts at impact, design and engineer tests for a range of auto safety features and make recommendations to the government and car manufacturers based on their findings.

The association with auto safety was a major selling point for the NFL because the league took inspiration from that industry’s success in lowering its rate of accident injuries and fatalities. NFL executives hoped that Crandall and Kent could take the principles involved in making cars safer and apply them to ascertaining why lower-limb injuries were happening and to developing better synthetic grass and cleats.

“An important aspect of injury mitigation strategy, whether it be head injuries or lower extremity injuries, is to understand the biomechanics involved in them,” Jeff Miller, the NFL’s executive vice president overseeing player health and safety, told Yahoo Sports. “If we can understand what causes the injuries, we can probably come up with some ways to intervene and maybe prevent some of those from happening.”

Inside two neighboring laboratories on the outskirts of Charlottesville, Va., Crandall and Kent began working on a machine that would model the traction behavior of cleats on artificial turf. The University of Virginia biomechanical engineers studied the force and torque that NFL players generate when they accelerate, stop or change directions and then designed their device to be able to mimic that.

The first version of the machine weighed 4,000 pounds, heavier than the average sedan. Kent named it the BioCore Elite Athlete Shoe-Turf Tester — or “the Beast” for short.

“It took me two days and a couple glasses of bourbon to come up with that,” Kent joked.

Previous research had shown that athletes are at risk of a non-contact lower-limb injury if their cleat sticks in the playing surface and doesn't release. Football players are especially susceptible to this sort of injury on artificial turf, which doesn’t tear away or divot like natural grass often does.

In 2015, Kent began using the Beast to annually test an array of football cleats at their performance limits to see which would break traction with various forms of artificial turf and which did not. Kent then shared his findings so that NFL players could make informed footwear choices and shoe companies could make their cleat patterns safer. Some manufacturers have pulled off the market cleats that were too aggressive or incorporated Kent’s research into their designs. Nike even built a Beast of its own, according to Kent.

“We try to find that sweet spot where the shoe still provides traction but also releases when you want it to,” Kent said. “It’s like an airbag or a seat belt. You want it to be strong but not too strong. The tighter you can define that threshold, the better you can make the design.”

Kent also used the Beast to evaluate every playing surface that each artificial turf manufacturer makes. Some of what he learned he’s not yet ready to share publicly, but he did say that the importance of maintenance is underappreciated. Turf can get too aggressive if crumb rubber pellets lost each season aren’t replaced. Or it can become too hard and slippery in spots that are repainted frequently.

Lately, there have been some heartening signs that endless hours of mundane research into infill depth and cleat patterns are starting to make a difference.

Four years ago, an NFL-commissioned study analyzed lower-extremity injuries reported during games from 2012-2016. Epidemiologist Christina Mack found that NFL players had a 16 percent higher rate of those injuries on artificial turf. The rate grew more pronounced when only non-contact injuries were considered.

Since that study, Miller told Yahoo Sports that the gap in non-contact lower-limb injury rate on turf and grass has “come down substantially.” In 2021, Miller said the difference was negligible.

“The synthetic surfaces in NFL stadiums are better than the ones that used to be there,” Miller said. “Some synthetic surfaces perform better than certain grass surfaces and certain grass surfaces perform better than certain synthetic surfaces as it relates to those non-contact lower-extremity injuries.”

State Farm Stadium, where the Arizona Cardinals play and where Super Bowl LVII will be played, uses a retractable natural grass field that can be rolled outside to gain sunlight. (Gene Lower/Getty Images)
State Farm Stadium, where the Arizona Cardinals play and where Super Bowl LVII will be played, uses a retractable natural grass field that can be rolled outside to gain sunlight. (Gene Lower/Getty Images)

Growing grass anywhere

Forgive the manager of a New Jersey turf farm if he doesn’t understand why the NFL invests so much time and money into trying to engineer the perfect artificial playing surface. Allen Carter can’t imagine any laboratory-produced product comparing favorably to the grass that Tuckahoe Farm supplies to college and professional teams.

“That's like taking a natural apple from a tree and comparing it to a plastic apple you see in a designer fruit basket,” Carter told Yahoo Sports. “Natural is always going to be better.”

While natural grass fields don’t withstand a string of events as well as artificial turf, today’s sod providers do offer a pricey solution. NFL teams can have a backup field prepped and ready at the farm for when they need to replace the existing one. Resodding can take as little as a day or two and the new field can be playable in as little as 48 hours.

There was a time when it was difficult for NFL teams to maintain healthy grass fields inside a domed stadium or in scorching or freezing weather conditions, but new technology has made those challenges more manageable.

The frozen tundra at Lambeau Field has been a myth for decades. The Packers are one of a handful of cold-weather teams that have installed an underground heating system to maintain a consistent soil temperature and keep the ground soft.

The Arizona Cardinals have a grass field that rolls in and out of State Farm Stadium, where Super Bowl LVII will be played next February. Whenever the stadium’s retractable roof is closed and the field isn’t getting enough sunshine, the team’s turf manager can wheel the field into the desert sun at the push of a button.

The systems that top European soccer teams have are even more state-of-the-art. For example, Real Madrid is constructing a retractable pitch that will be housed in six underground levels that reach a depth of over 75 feet. The 225-million-Euro underground greenhouse will feature an irrigation system as well as ultraviolet lighting to promote growth.

“Those types of options are now becoming available in the U.S.,” Carter said. “You can grow a lush, safe, healthy product anywhere now compared to 20 years ago.”

In September 2020, NFL players association president JC Tretter argued in a newsletter that the league’s 32 teams should “convert artificial practice and game fields to natural grass.” That’s still the NFLPA’s stance two years later, but the organization is supportive of efforts to make artificial turf safer and is encouraged by recent innovation.

“We are seeing synthetic surfaces catch up,” Sean Sansiveri, who leads the NFLPA’s health and safety efforts, told Yahoo Sports.

“Our position is that the NFL has an obligation to provide the safest surface possible in this inherently dangerous occupation. If that's natural grass, then that's fine. That said, the players union is committed to working with turf manufacturers to see what kind of product can be developed.”

The quest for a safer turf continues

If Sansiveri’s position differs from the rank-and-file NFL player, that’s only because he’s more up-to-date on the progress engineers are making.

When engineers at the University of Virginia lab first created the Beast, they soon discovered that the 4,000-pound turf-and-shoe-testing device was too unwieldy to move easily. Rather than transport the Beast to test actual playing surfaces at NFL stadiums, they had to bring aluminum trays containing replica turf and grass samples to Charlottesville.

To address that problem, engineers have recently designed and built a fleet of mobile Beasts. The eventual goal is to be able to deploy those at every NFL stadium and practice field and to be able to test how each surface is performing before players set foot on it. That way, turf managers can better address issues in advance and can more accurately suggest to players what cleats to wear.

What’s easy to forget is that no two playing fields perform exactly alike, not even ones that are the same type of grass or ones made by the same manufacturer. The age of the field plays a role, as does how it has been maintained and the weather conditions.

“To be actually on the field two days before a game is a game changer,” Sansiveri said. “It gives us a lot more confidence in the data.”

Another reason for optimism is that the University of Virginia lab is not the only one helping to make playing surfaces safer and better. John Sorochan, a professor of Turfgrass science at the University of Tennessee and an NFLPA consultant, has been working on a turf-and-shoe testing device that he says mimics the movements athletes make better than the Beast does.

For Sorochan, the goal is also to help design artificial turf that performs better than a perfect natural grass field, but he admits, “I don’t know if we’ll ever achieve that.”

“The serendipitous part about grass is that it divots,” Sorochan told Yahoo Sports. “That might compromise some performance, but there is a safety component to that.”

The NFL’s priority is to keep reducing the risk of lower-extremity injuries, but the league isn’t backing down from the ambitious goal of trying to create a synthetic surface that outperforms natural grass. To Miller, that could be a natural outcome of all the endless hours research teams have spent studying how cleats and turf interact.

“By better understanding turf and better understanding grass, you can eventually, with a fair amount of innovation, design something that’s better than either one,” Miller said. “We will maintain that as a goal and continue to try to research surfaces with the thought that one day we can design something better.”