Analyzing the Injury Data on Grass vs Turf (Does it Matter)
If you haven’t read any of my articles, I am a physical therapist who enjoys writing about pro sports injuries, specifically football and how they impact fantasy football.
This post is inspired by the outcry from NFL players saying how much they hate playing on turf and the NFLPA claiming that artificial turf causes unnecessary injuries.
First, let’s talk about Aaron Rodgers. Some of the risk factors for suffering an achilles rupture include being between 30-40 years old, having a history of calf strains, and “poor or altered environmental contact surfaces.” Sounds a lot like Aaron Rodgers, but the last one is the most interesting. All offseason, the Jets have practiced at their practice facility on grass. Is it possible that the change in surface to turf at Metlife contributed to the injury?
Based off of the mechanism Aaron Rodgers tore his achilles tendon, I don’t think that the turf had anything to do with his injury. Due to the fact that it was a contact injury with the defender pulling him down into an awkward position where Rodgers was trying to plant his foot, it does not appear that his foot gets “stuck” in the turf like you see in some injuries. But that’s just my opinion, what does the research say about it?
This first study looked at injuries across 8 different NFL seasons, in which 44 achilles ruptures were documented. They concluded that there was no difference in injury rates between surfaces among this sample. This same study also looked at ACL injuries over a 3 year sample which included 219 ACL injuries. They concluded that there was no significant difference in ACL injuries between different surfaces in NFL players, but a larger sample size study among NCAA football players showed an slightly increased risk of ACL injury.
Interestingly, this study also looked at achilles ruptures in professional soccer players, and concluded that they are more common in artificial turf as opposed to grass. My educated guess from this data is due to the high incidence of “contact” achilles injuries in football compared to soccer, and the forced “dorsiflexion” position is more due to your foot getting “stuck” in a sport with less contact. Where in football, it’s more common to see someone’s foot be in an awkward position due to a tackler.
The following tables are from the NFL/NFLPA’s data from 2018-2021 on playing surface. This data does not come with any statistical analysis, but the numbers being so close together leads me to think they are not statistically significant and the difference in injury rates is just due to random chance. Important to note that Metlife used to have Slit Film turf, but replaced it this offseason.
Contrary to the generally accepted narrative about this topic, the amount of non contact injuries are essentially the same between surfaces. However, this article shows that “contact” injuries increase on turf surfaces. Among the different articles I looked at when researching this topic, this article had the highest different when it comes to contact injuries, so I wanted to include it here just to have a better summary of what the data shows.
In researching this article I read a ton of different studies on all types of surfaces, sports, and contact vs non contact injuries. I am obviously not going to include them all here, and chose to include the studies I felt represented the overall data most accurately. The data shows that there may be some specific sports, where a specific type injury is marginally more common, but overall there is not much difference especially among high level football players. The data is very conflicting on this topic, however, and you can find a study that leans in either direction. In general when we have research with these conclusions, the general rule is to take all of them with a grain of salt and realize the truth is somewhere in the middle. When accounting for all variables, it’s possible that there is MAYBE a 1 or 2% higher injury risk on artificial turf, but that’s not a significant difference.
Conclusions:
So why did Aaron Rodgers tear his achilles? Well I believe it’s due to his age and history of calf strains during the offseason. In my opinion, artificial turf is not significantly different when compared to natural grass when it comes to injuries among NFL players. Therefore, I don’t think it’s necessary to consider this when building fantasy teams, as some in the industry have started to imply. Most injuries in the NFL are due to bad luck and injury history, as opposed to lack of preparation or playing surface. If you want to have a better chance at “predicting” injuries, learn about the players’ injury history to better understand their risk.