Athletes cover themselves in all sorts of protective gear — shin guards, mouth guards, shoulder pads, helmets — in an effort to keep from getting hurt playing sports. One thing they probably don’t think about is the injuries that might be caused by the very field they’re playing on. Fortunately, that’s exactly what sports turf managers are most focused on.

“Over the 22 years that I’ve been in this industry, the one common thread that links every sports turf manager that I’ve ever met is the fact that safety is always their number one priority – upholding safety for the athletes is always job [number] one in everything they do,” says Jay Warnick, CSFM, director of sports maintenance for The Sports Force/FIELDS Inc., and chairman of the Sports Turf Managers Association charitable arm, SAFE (The Foundation for Safer Athletic Fields). While safety has always been a priority, Warnick says that today’s sports turf managers have access to more tools and research in their pursuit of safety than their predecessors did in past decades. He credits suppliers (for things like noninvasive aerification equipment and advanced seed and sod varieties) and researchers at academic institutions for their contributions to helping the industry better understand and achieve safe playing surfaces. And the whole endeavor is becoming more data-driven.

“What’s happening right now in real time is that we are getting to a point where we are able, as an industry, to put field testing data in direct correlation to injury data. It will never be a perfect science, where we can say, ‘This field that tests at this parameter is going to cause this injury,’ because sports is so unpredictable and there are so many variables,” says Warnick.

“But in a general scope, we are now able, through great research, to begin to be able to test surfaces in terms of hardness and stability and then also relate event-load, so that we can produce a predictive model to say, ‘If a given field has X amounts of events and is met by X amount of maintenance input, then we can reasonably predict how long that surface will remain in a safe condition given those parameters.’ So instead of a vague conversation about what safety is, we’re now starting to be able to define it with actual numbers…. We’re able to define what a safe field is in much more clear terms.”

Safety specifics

With research shedding more light on the connection between field conditions and athlete safety, the quest continues to manage fields with an eye toward reducing injuries. “A properly maintained field is the best defense for head impact criteria,” says Dr. John Sorochan, distinguished professor of plant sciences at the University of Tennessee and director of the UT Center for Athletic Field Safety. A field that’s well maintained can also reduce the chances of other injuries, notes Sorochan. “The key is to maintain a uniform cover with grass,” he states. “This ensures that a player won’t run from one type of surface to another, whether it’s a divot or an area that’s harder or softer or any other lack of uniformity where they could roll an ankle or catch their foot and blow a knee out.”

Making a natural grass field safe comes down to the basics of maintaining turfgrass, says Sorochan. “So, we’re talking about the five primary cultural practices: mowing, fertilization, irrigation, cultivation and then pest management – controlling weeds, diseases and insects. If you do each of those properly, you’re going to do what’s best for the grass to grow and maintain a consistent and uniform playing surface; and by doing that you’re going to reduce instances of athlete and player injury.”

That’s the good news for sports turf managers: the same cultural practices that should be followed to grow good turf are the very same practices that will keep a field playing safe. But while it makes sense that a perfectly maintained field will offer greater protection against injury, that contention also implies access to all the resources needed to achieve perfection.

This all may be the case at the professional and major college levels, but what about when it comes to K-12 and parks and rec settings? “My biggest concerns are native soil fields that get too hard and compacted,” says Sorochan, just the situation facing many sports turf managers who must maintain native soil fields that are over-used. Hard fields pose not only a greater danger in terms of concussions but could lead to greater injuries from falls, like broken collarbones and more, he points out.

“When you have a field that’s too compacted on native soil, you lose turf cover,” Sorochan explains. “Then there’s some areas that have grass and some that don’t, so a player could slip or slide, pulling a hamstring or groin muscle, or a low spot could cause them to hurt their ankle or knee.” In such cases, step one, says Sorochan, is to “go in and aerify to reduce compaction, so the grass can actually grow.”

Restoring uniform turf cover goes a long way toward reducing the likelihood of injury. “A field that’s properly mown and irrigated, so that a native soil field doesn’t get too hard, when an athlete’s head hits, it’s going to absorb the impact more,” Sorochan explains. Though he cautions that, “we don’t want to go overboard and try to make it too soft, because then the grass will just wear out and displace and blow out, and you get a lot more lower body injuries.”

Doug Rowe performs a solid-tine deep aeration on a field at Elon University in Elon, North Carolina. Scott Stevens, CSFM, the university’s sports turf manager, says that aerification helps to soften the playing surface to help reduce impact injuries, while also promoting root growth that makes the field more stable, helping to reduce the risk of injuries from slips.

Every field needs maintenance

When it comes to producing safe playing conditions, “consistency and uniformityare the two words that I try to emphasize,” says Sorochan. He recommends that sports turf managers convey this message to those who set the budgets for the fields they maintain, emphasizing that having the necessary resources will boost the performance and safety of the fields.

The bean-counters don’t always get the message, though. Instead, Sorochan says what often happens is a one-time capital expenditure to put in a synthetic field under the mistaken belief that synthetic fields are maintenance-free. “You need to maintain synthetic fields,” he emphasizes.

Sorochan says that, from a safety standpoint, one of the biggest problems with synthetic fields is the infill being displaced, especially in higher wear areas. This can lead to infill accumulating in areas that aren’t getting as much wear. “That can lead to areas that are too deep, and then ruts in the middle,” he explains.

“Then, over time, that infill gets tracked off the field. Our research has shown that, after 20 events or games, you need to brush in and redistribute and refill the infill. And if you think of a city park and rec field, between Friday, Saturday and Sunday they could have 20 events in one weekend. And I can guarantee you that most of them are not going out to brush and redistribute the infill every week,” Sorochan says. And if fields are being used extensively for practices during the week, that’s twice a week that the infill should be addressed. “It’s not necessarily the whole field, but they should be going down the middle or wherever the high-wear areas are,” he adds.

Sorochan says there currently aren’t any scientific studies comparing the safety of natural grass versus synthetic fields at the high school and parks and rec levels. This is in part because there are so many variables in the construction and maintenance practices of both types of fields.

It’s easier to compare the two at the professional level, where both types of fields are almost certain to be properly constructed and highly maintained for consistency and uniformity. “The data is that NFL players are 20 percent more likely to suffer a catastrophic lower extremity injury on artificial turf than they are on natural grass,” says Sorochan. Even so, it’s not just a case of the fields causing injuries. “It’s the surface, the athlete and the shoe,” he explains. Because synthetic turf doesn’t give the way that natural surfaces do, “foot lock” can occur, which essentially is too much traction not allowing the foot to give at all, leading to knee and ankle injuries.

Sorochan says more research is needed into specific factors, like the type and quantity of infill that provides the highest levels of safety, and similarly, how natural fields might be maintained for optimum safety. “We’re starting to introduce human test subjects and actually doing performance testing working with biomechanists and kinesiologists to look at their performance as they do a 40-yard dash, a shuttle run and three-cone drill.”

Looking at real athletes as they run, cut and make movements can provide real-world data on the impacts on the athletes on different surfaces, as well as when wearing different shoes and in different weather conditions.

“We’re looking at natural versus synthetic fields, with and without shock pads underneath, etc.,” Sorochan says. “The challenge is that this research takes a lot of time, and it’s expensive.” But the hope is that it will lead to more scientific data on how playing surfaces can play a role in reducing injuries.

How Can Sports Turf Managers Make Sure Fields Are Safe?

  • Jay Warnick, CSFM says it starts with “the low-hanging fruit; the things that we can control,” like ensuring that sprinkler heads are properly installed and covered for play, and that benches and fences, etc., are not so close to the field that they might pose a hazard.”
  • Safety also involves providing a level of consistency where the athlete is able to move with confidence over the field surface,” Warnick states. This involves making sure the field has complete and even turf cover, that it’s not too hard or too soft, and that the surface is stable so that when an athlete plants to make a cut, footing isn’t lost.
  • “It also means cooperation with our customers,” emphasizes Warnick. He says that, throughout his career, the single most important tool he’s found — beyond any cultural practice — to ensuring that fields are playable and safe, is communication. “If we can maintain that conduit of communication through education to our athletes, coaches and user groups, that is the absolute best preventative way to base a maintenance program,” says Warnick. “It’s never about, ‘Keep off my grass!’ It’s about, ‘Here’s how, if we work together, we can meet your needs while preserving the quality and safety of the field and our resources.’”
  • Ken Mrock, head groundskeeper for the Chicago Bears, works with the team’s coaches to help keep moving to different areas of the practice field in order not to wear out certain areas, damaging the turf and possibly leading to unsafe conditions. “I tell them that the turf needs rest and recovery, just like the players need rest and recovery. That’s something they understand and can relate to,” he explains.
  • Scott Stevens, CSFM, sports turf manager at Elon University and president of the North Carolina STMA chapter, says there are both preseason and in-season maintenance practices to keep fields playing safe. Months before the season, he begins an aerification program to alleviate and prevent compaction. “Compaction is one of the biggest concerns with athletic fields — that upper 2 inches,” says Stevens. “It can prevent water from draining through, and it can also lead to a hard surface that athletes are going to be falling on.” Aerification has benefits beyond preventing fields from becoming too hard, he adds: “We typically aerate about every three or four weeks, just to pull those cores out and get good grass rooting, because that will stabilize the surface.”
  • Aerification continues on a lessfrequent basis during the playing season, but once athletes are on the field, Stevens says he also focuses on things like making sure irrigation heads are seated properly and that grass coverage is maintained by repairing divots and wear areas.
  • Additionally, Stevens is also constantly monitoring weather conditions to see how they might impact the playability and safety of the fields, and responding accordingly. “Our number one concern is field safety— preventing injuries so that players can keep playing the entire season,” Stevens says.

Professional ranks

Ken Mrock, head groundskeeper for the Chicago Bears, says that he and other NFL groundskeepers work with the league and its various committees to better understand safety issues and their relationship to playing surfaces. “We want to make sure the fields are safe all of the time for the players,” he states. “And I see that same thing happening at the college and high school and rec levels; our counterparts are all striving for that safe surface.”

He says the link between field maintenance and safety has made people more aware of the professionalism of sports turf managers, and has made sports turf managers more aware of the important role they play; it’s not just about making the field look nice, but about keeping players healthy. “It makes everyone more aware of the job we’re trying to accomplish,” states Mrock.

What’s different at the NFL level is the amount of field testing that’s done. Field hardness is tested prior to each game using a Clegg Impact Tester, and Mrock takes digital moisture sensor readings and documents the visual appearance of the field. After each game, shear vane testing is completed on the field to assess the stability of the field (essentially the ability of the root systems to hold up to forces being applied by cleats.) “They collect all of this data and it goes into a database,” says Mrock.

But the role that the playing surface plays in athlete safety goes well beyond fulfilling league field testing requirements; it’s a core aspect of his job within the Bears organization, says Mrock. In that sense, the groundskeeping crew has the same mission as the team’s training staff: keeping players healthy so they can practice and play at the highest level possible. “I work very closely with our head trainer, general manager, head coach and the strength and conditioning coach – we all get together and talk about the field and how it’s performing.” If players, for example, are experiencing a little slipping in a certain area, they might look to see what could be done to address that.

Also, while moisture is obviously important to the turf, Mrock may sometimes have to keep the field a little on the drier side to promote better traction. “Or, sometimes we might go a little bit taller on the height of cut to get a little more canopy and cushion. And we try to promote a good thatch layer,” he says, noting the role that thatch plays in supporting the players on the field as they run and change directions.

“These days, a lot of teams would rather that a field play good than look absolutely perfect,” Mrock says.