Injury Surveillance in Major League Soccer: A 4-Year Comparison of Injury on Natural Grass Versus Artificial Turf Field

Abstract

Background: Artificial playing surfaces are becoming more common due to decreased cost of maintenance and increased field usability across different environmental conditions. The Fédération Internationale de Football Association (FIFA) has approved newer generation artificial turf for soccer competition at the elite level, but many elite-level athletes prefer to play on natural grass surfaces due to a perceived increase in injury rate, discomfort, and fatigability on artificial turf. Hypothesis: Injury rates and rates of individually categorized types of injury experienced on artificial turf are noninferior to rates of injury on the standard comparator, natural grass, in elite-level Major League Soccer athletes. Study Design: Cohort study; Level of evidence, 2. Methods: Over the course of 4 Major League Soccer seasons (2013-2016), athlete injury data were recorded electronically. Injury data recorded in matches between 2 Major League Soccer teams were then analyzed. Playing surface was known for each venue, and all artificial turf surfaces were rated as 2-star according to FIFA criteria. Incidence rate ratios (Artificial Turf ÷ Natural Grass) were calculated with a 95% CI (α = .05) for both overall injury incidence and individual injury subgroups. A noninferiority margin (δ) of 0.15 was used to determine noninferiority of injury incidence rates. Results: A total of 2174 in-game injuries were recorded during the study period, with 1.54 injuries per game on artificial turf and 1.49 injuries per game on natural grass (incidence rate ratio, 1.033; 95% CI, 0.937-1.139). Within injury subgroups, overall ankle injury, Achilles injury, and ankle fracture were found to have a statistically higher incidence on artificial turf. Artificial turf was found to be noninferior to natural grass for overall foot injury and forefoot injury. No statistically significant differences were found in knee injuries between the 2 surfaces. Conclusion: The overall rate of injury on artificial turf was noninferior to that on natural grass. Within individual injury categories, a higher rate of ankle injury was found on artificial turf. No other injury subgroup demonstrated statistically significant differences between surfaces. Clinical Relevance: FIFA 2-star rated artificial turf is a viable alternative to natural grass in elite-level soccer competition. Innovative research methods for comparing artificial turf versus natural grass may elucidate relative advantages with respect to player safety.

Epidemiology of Anterior Cruciate Ligament Injury on Natural Grass Versus Artificial Turf in Soccer: 10-Year Data From the National Collegiate Athletic Association Injury Surveillance System

“…As mentioned above, Calloway et al 4 found no difference in the rate of total knee injuries and ACL injuries between elite soccer players competing on artificial turf versus natural grass during matches, which is in agreement with our results. In contrast, during practice, we found a higher incidence of ACL injuries on natural grass compared with artificial turf.…”

“…Regarding soccer, a systematic review showed that artificial grass did not increase the risk of injury compared with natural grass, but study heterogeneity limited the validity of the results. 23 Calloway et al 4 recently reported no difference in overall injury rate or knee injury rate of elite soccer players who played on artificial turf versus natural grass. Similarly, in a study of elite soccer players, Ekstrand et al 7 did not find any differences in the risk of acute knee injury during practice or games based on the type of surface played.…”

“…In an attempt to clarify risks related to field surfaces, recent studies have attempted to examine additional potential risk factors contributing to overall injury rates and/or ACL injuries among soccer athletes, including demographic variables, type of shoe, weather conditions, level of competition, and others. 4,9,11,15,16,23 None of the existing studies has focused on the risk of ACL injury in athletes of all NCAA divisions based on the surface played, nor have investigators examined whether the level of expertise (defined by the division) affects this risk.…”

The cumulative and residual fatigue response associated with soccer-specific activity performed on different playing surfaces

“…Equivocal information exists in relation to injury literature comparing the influence of different playing surfaces during intermittent team sports. For example, previous literature has identified increased ankle injury risk on AT when compared to NT (Calloway et al, 2019), increased overall injury rates on AT when compared to NT (Mack et al, 2019), increased incidence on NT when compared to AT (Meyers 2017), or no differences in overall injury rates across playing surfaces (Steffen, Andersen, and Bahr 2007). Due to differences in methods used between studies, and the potential of contextual factors which may influence between surface comparisons, it is often difficult to develop a cause and effect relationship between surface usage and types of injury.…”

Φυσιολογία Της Άσκησης

“…Αν και η παγκόσμια ομοσπονδία ποδοσφαίρου έχει εγκρίνει νέας γενιάς τεχνητούς χλοοτάπητες για παιχνίδια υψηλού επιπέδου, οι ποδοσφαιριστές υψηλού επιπέδου προτιμούν να παίζουν σε φυσικούς χλοοτάπητες πιστεύοντας ότι στον τεχνητό χλοοτάπητα υπάρχουν περισσότερες πιθανότητες για τραυματισμό ενώ αισθάνονται μεγαλύτερη δυσφορία και κόπωση από ότι στον φυσικό. Το είδος του χλοοτάπητα λοιπόν πιθανά να είναι ένας ακόμα παράγοντας κινδύνου για τραυματισμό με τον τεχνητό να έχει κατηγορηθεί από πολλούς ότι συμβάλει περισσότερο από τον φυσικό στην εμφάνιση τραυματισμών, ωστόσο αυτό δεν έχει αποδειχθεί επαρκώς (Calloway et al, 2019;Ekstrand, Hagglund, & Fuller, 2011;Meyers, 2013Meyers, , 2017. Τέλος το επίπεδο των ποδοσφαιριστών επηρεάζει σημαντικά τόσο τον αριθμό των περιστατικών όσο και την σοβαρότητά τους με τους αθλητές χαμηλού επιπέδου να εμφανίζουν υψηλότερες συχνότητες σε σχέση με τους υψηλού επιπέδου, παρόλο που η συνολική έκθεση των χαμηλού επιπέδου αθλητών σε ποδοσφαιρικές δραστηριότητες ήταν μικρότερη (Peterson et al, 2000).…”