Katerina Kerska, National Center for Health Research
Artificial turf is a synthetic surface that is made to look like real grass. The most common type of turf used today is referred to as third-generation turf, which isn’t exactly the same as the first and second generation turf fields installed in the 1960’s. Third generation turf has a few different layers.1 The bottom layer is either a gravel, asphalt, or concrete base. Sometimes a shock-absorbing pad is placed on top of the base. Next is the turf itself, which is made of pile fibers that look like grass. Finally, silica sand and/or tiny rubber pellets are used to fill in the space between the fibers. This is called the infill. The amount of infill can vary between fields.
Artificial turf has become a popular choice for sports fields across the country, but it has become increasingly controversial. The turf industry estimates that there are more than 11,000 artificial turf fields around the country.2
There are reasons for the controversy, and it is important to look at how these fields affect the health of those who use them. For example, the materials used in turf fields often contain lead and other chemicals that are harmful to human health. To learn more about these risks, read our article here.
The focus of this article is knee and ankle injuries, concussions, heat-related illness and injury, and abrasions, all of which may occur more frequently on turf than grass. These findings are present across different sports and from the high school through professional levels.
To investigate the effects of artificial turf on athletes, a large study was conducted to measure the rates of knee injuries in college football players over the course of 10 years.4 The study looked at the rates of 5 different knee injuries on grass vs. artificial turf across all 3 divisions of NCAA football. They found that posterior cruciate ligament (PCL) tears occurred almost 3 times as often on turf than on grass. Athletes playing at lower levels experienced anterior cruciate ligament (ACL) tears 1.6 times more often on turf than they did on the grass. There were 142 ACL tears on turf in Divisions 2 and 3 compared to 111 on natural grass despite athletes spending more time on grass. The difference was even greater for PCL tears: 3.3 tears per 10,000 competition exposures on turf compared to 1.1 per 10,000 on grass. An exposure was defined as 1 athlete participating in a game or practice, regardless of time played. The study indicates an increased risk of knee injuries for football players who play on turf.
This issue persists at the professional level as well. The debate about playing on turf versus grass came into the spotlight most recently when the National Football League’s Player Association cited the leagues official injury report regarding increases in injuries on artificial turf surfaces.3 Solomon Thomas, an NFL player, spoke out, saying “It should all be grass fields. We should take care of our players. Safety should be number one.” The report showed non-contact knee injuries happened 32% more often on turf.
A study that looked at 2,020 young, female soccer players from 109 teams over the course of a season found that ankle injuries were more common on turf than grass.5 Ankle sprain was the most common injury and occurred at a rate of 1.5 injuries per 1000 hours of play time on turf compared to 0.8 injuries per 1000 hours on natural grass. An even greater increase in injuries was found by researchers who studied professional male soccer players over the course of 4 Major League Soccer seasons.6 They found that the rate of Achilles injury was twice as high on turf as it was grass and rate ankle fracture was 6 times as high, on turf compared to natural grass. These studies point to an increased risk of ankle injury playing on turf instead of grass.
A nationwide study looked at rates of concussion in both collegiate and high school football players.7 The study looked at over 17,549 football players over the course of 3 years, 888 of whom reported having at least one concussion. There are 2 main causes for most concussions: 1) as a result of contact with another player or 2) as a result of contact with the ground. When looking at those that occurred from contact with the ground, the researchers found that head contact with turf was disproportionately associated with concussions. They also found that more serious concussions were associated with artificial turf than grass. To learn more about head injuries involving turf, you can read our article here.
Heat-Related Illness and Injury
Artificial turf can get extremely hot on sunny days. Researchers took temperatures of the surface of both grass and artificial turf fields and found the turf field got much hotter.8 For example, on a 90-degree day, the surface temperature of the grass field was about 98 degrees Fahrenheit, but the artificial turf got all the up to 166 degrees Fahrenheit. This can put athletes at higher risk of heat-related illness or injury such as dehydration, heatstroke, and thermal burns. It can obviously be dangerous to play on artificial turf fields when it gets this hot.
Another common injury that occurs on artificial turf is commonly known as “turf burn.” It is an abrasion injury that occurs from sliding contact with the turf. While turf burns are considered minor injuries and rarely result in lost playing time, there is a risk for infections, such as Staph or MRSA, as well as the risk of debris from the field getting stuck in the wound. To learn more about MRSA, read our article here. In a study looking at high school lacrosse games, it was found that abrasion injuries accounted for 19.3% of all injuries on turf while only accounting for 0.5% of injuries that occurred on grass.9 In a study conducted of elite players’ views on artificial turf, over 60% said they thought turf was too abrasive.10 While battling a lawsuit over the use of artificial turf in the World Cup, Sydney Leroux, a member of the Women’s National Soccer team tweeted out a photo of her bloodied turf burns with the caption “This is why soccer should be played on grass.” In an interview, she explained that she plays differently on turf specifically to avoid turf burns.11 If players are actively changing their style of play to avoid these abrasions, they could actually be putting themselves at greater risk for other injuries.10
Other Factors Affecting Injuries
There are other factors to consider when looking at rates of injury among athletes playing on turf. Turf maintenance can be a contributing factor in injury rates. One aspect of turf maintenance is infill weight. The amount of infill (the rubber pieces or sand that fills the space between the fibers) varies in turf fields. Lower weight infill systems are cheaper to maintain, so many artificial turf fields have little infill. Moreover, over time the amount of infill decreases as a result of getting kicked up during use or washed away in heavy rains. A study of 57 high school turf fields across 4 different states showed fields had varying infill levels. Despite turf manufacturers claiming that lower weight infill systems are just as safe as those with higher infill weight, researchers concluded that for football players, trauma to the head, knee or shoulder significantly increased when the infill weight decreased.12 Based on these findings, the researchers recommended that high school football fields need to have at least 6.0 pounds of infill per square foot for the safety of the athletes. Of the 1,837 games looked at in the study, 788 were played on less than 6.0 pounds per square foot, meaning the athletes were exposed to additional risks in 43% of the games studied.
The Bottom Line
Many studies have examined injury rates on artificial turf versus grass. In many cases, injury rates are greater on turf. Injuries are not the only risks associated with artificial turf. There are also concerns regarding the chemicals that can be found in artificial turf infill. These small rubber pieces are used not only for sports fields but playgrounds as well, putting young children at risk of harmful side effects. To learn more about the harms associated with turf, you can check out some of our related articles listed below.
- Jastifer, J. R., McNitt, A. S., Mack, C. D., Kent, R. W., McCullough, K. A., Coughlin, M. J., & Anderson, R. B. Synthetic Turf: History, Design, Maintenance, and Athlete Safety. Sports health. 2019; 11(1), 84–90. https://doi.org/10.1177/1941738118793378
- Synthetic Turf Council. About Synthetic Turf. Synthetic Turf Council.com. https://www.syntheticturfcouncil.org/page/About_Synthetic_Turf#:~:text=Currently%2C%20there%20are%20between%2012%2C000,1%2C500%20new%20installations%20each%20year.
- Dulik, Brian. NFLPA asking teams to change all fields to natural grass. AP News. September 20, 2020. https://apnews.com/article/nfl-football-archive-9b34d4402f2f82ae60708605f65aa560
- Loughran, G. J., Vulpis, C. T., Murphy, J. P., Weiner, D. A., Svoboda, S. J., Hinton, R. Y., & Milzman, D. P. Incidence of Knee Injuries on Artificial Turf Versus Natural Grass in National Collegiate Athletic Association American Football: 2004-2005 Through 2013-2014 Seasons. The American journal of sports medicine.2019;47(6), 1294–1301. https://doi.org/10.1177/0363546519833925
- Steffen, K., Andersen, T. E., & Bahr, R. Risk of injury on artificial turf and natural grass in young female football players. British journal of sports medicine. 2007; 41 Suppl 1(Suppl 1), i33–i37. https://doi.org/10.1136/bjsm.2007.036665
- Calloway, S. P., Hardin, D. M., Crawford, M. D., Hardin, J. M., Lemak, L. J., Giza, E., Forsythe, B., Lu, Y., Patel, B. H., Osbahr, D. C., Gerhardt, M. B., Mandelbaum, B. R., & Baldwin, W. W. Injury Surveillance in Major League Soccer: A 4-Year Comparison of Injury on Natural Grass Versus Artificial Turf Field. The American journal of sports medicine. 2019; 47(10), 2279–2286. https://doi.org/10.1177/0363546519860522
- Guskiewicz, K. M., Weaver, N. L., Padua, D. A., & Garrett, W. E., Jr. Epidemiology of concussion in collegiate and high school football players. The American journal of sports medicine. 2000; 28(5), 643–650. https://doi.org/10.1177/03635465000280050401
- Jim, C.Y. Solar–terrestrial radiant-energy regimes and temperature anomalies of natural and artificial turfs. Applied energy. 2016;173, 520–534. Elsevier Ltd.
- Hinton RY, Lincoln AE, Almquist JL, Douoguih WA, Sharma KM. Epidemiology of Lacrosse Injuries in High School-Aged Girls and Boys: A 3-Year Prospective Study. The American Journal of Sports Medicine. 2005;33(9):1305-1314. doi:10.1177/0363546504274148
- Twomey, Dara M, Petrass, Lauren A, Fleming, Paul, & Lenehan, Kurt. Abrasion injuries on artificial turf: A systematic review. Journal of science and medicine in sport. 2019; 22(5), 550–556. Journal Article, Australia: Elsevier Ltd.
- Foudy, Julie. Sydney Leroux: Why Turf Is Terrible For Soccer Players. ESPN W. November 13, 2014. https://www.espn.com/espnw/news-commentary/story/_/id/11868149/sydney-leroux-explains-why-turf-terrible-soccer-players
- Meyers, Michael C. Incidence, Mechanisms, and Severity of Game-Related High School Football Injuries Across Artificial Turf Systems of Various Infill Weights. Orthopaedic journal of sports medicine. 2019; 7(3), 2325967119832878. Journal Article, Los Angeles, CA: SAGE Publications.