Abstract
Objectives:
Artificial turf fields are increasingly being installed to duplicate the playing characteristics of natural grass. With the numerous proprietary sand/rubber infill systems available, the effect of infill weight on injuries when landing on an artificial surface has not been extensively addressed. Therefore, this study was conducted to quantify surface impact injuries during high school football games on light- and heavyweight artificial turf playing surfaces.
Methods:
Artificial turf infill systems were divided into two sand/rubber infill weight groups based on lbs per square foot: heavyweight (≥9.0 lb/ft2) and lightweight (3.0-6.0 lb/ft2). A total of 89 high schools participated across 6 states over the course of 12 competitive seasons. Outcomes of interest included injury severity; head, knee, and shoulder trauma; primary type of injury; anatomic location of injury; type of tissue injured; injury situation; player and skill position; environmental factors; elective imaging and surgical procedures; and turf age. Data underwent multivariate analyses of variance (MANOVA) and Wilks’ λ criteria using general linear model procedures and were expressed as injury incidence rates (IIR) per 10-game season.
Results:
Of 3,788 high school games documented, 1055 games (27.9%) were played on heavyweight (≥9.0 lb/ft2) infill and 2,733 games (72.1%) played on the lightweight (3.0-6.0 lb/ft2) infill surface. In sum, of 8,995 total injuries, 1,462 cases [heavyweight infill (n=269), lightweight infill (n=1,193)] were attributed to player-to-surface impacts. MANOVA indicated a significant main effect between infill weight by injury severity (F3,1458 = 6.210; P < .001), primary type of injury (F8,1453 = 2.865; P < .001), anatomic location of injury (F12,1449 = 1.354; P = .021), type of tissue injured (F4,1457 = 5.619; P < .001), injury situation (F10,1451 = 2.211; P < .001), player position (F2,1459 = 3.856; P < .001), skill position (F7,1454 = 6.526; P < .001), environmental factors (F6,1455 = 5.478; P < .001), elective imaging and surgical procedures (F4,1457 = 4.212; P = .015), and turf age (F3,1458 = 2.514; P = .010). No significant main effect between infill weight was observed by head injury (F3,1458 = 0.880; P = .451), knee injury (F7,1454 = 1.196; P = .246), or shoulder injury (F7,1454 = 1.447; P = .110). Post hoc analyses of surface impact trauma indicated significantly lower (P < .05) incidence of injury on the heavyweight (≥9.0 lb/ft2) infill when compared to the lightweight (3.0-6.0 lb/ft2) infill surface, in regard to total injuries [2.6 (95% CI, 2.3-2.8) vs 4.4 (4.2-4.6)], substantial injuries [7-21 days of injury time loss; 0.5 (95% CI, 0.4-0.6) vs 1.1 (1.0-1.2)], ligament sprain/tears [0.7 (95% CI, 0.6-0.9) vs 1.1 (1.0-1.2)], muscle-tendon strain/tears [0.1 (95% CI, 0.1-0.2) vs 0.5 (0.4-0.5)], joint [1.0 (95% CI, 0.9-1.2) vs 1.6 (1.4-1.7)] and muscle [0.6 (95% CI, 0.5-0.8) vs 1.8 (1.7-1.9)] trauma; injuries during rushing [1.0 (95% CI, 0.8-1.2) vs 1.8 (1.7-2.0)], passing [0.1 (95% CI, 0.1-0.2) vs 0.3 (0.2-0.4)], pass rush/defense [0.5 (95% CI, 0.4-0.6) vs 0.8 (0.8-1.0)], and kickoff/kickoff returns [0.1 (95% CI, 0.0-0.2) vs 0.3 (0.2-0.3)]; surface impact injuries to the shoulder girdle [0.7 (95% CI, 0.6-0.9) vs 1.1 (1.0-1.2)], arm [0.6 (95% CI, 0.5-0.8) vs 1.1 (1.0-1.2)], hand/wrist [0.3 (95% CI, 0.2-0.4) vs 0.5 (0.5-0.6)], foot/toe [0.1 (95% CI, 0.0-0.1) vs 0.2 (0.2-0.3)], and lower extremity injuries combined [0.5 (95% CI, 0.4-0.7) vs 1.0 (0.9-1.1)]; and during offensive [1.4 (95% CI, 1.2-1.6) vs 2.3 (2.2-2.5)], defensive [1.0 (95% CI, 0.9-1.2) vs 1.6 (1.5-1.8)], and special teams play [0.2 (95% CI, 0.1-0.2) vs 0.4 (0.3-0.5)], respectively. Post-injury medical procedures indicated significantly (P < .05) less radiographs [0.6 (95% CI, 0.5-0.7) vs 0.8 (0.7-0.9)], and total elective imaging and surgeries combined [1.0 (95% CI, 0.8-1.2) vs 1.5 (1.4-1.7)] following surface impacts while competing on a heavyweight (≥9.0 lb/ft2) versus a lightweight (3.0-6.0 lb/ft2) infill surface, respectively. A significantly lower incidence (P < . 05) of surface impact trauma was also observed among backfield, receiver, and secondary athletes, all ages of artificial turf, all temperature conditions, and during play on non-precipitation/dry fields while playing on heavyweight infill when compared to lightweight infill surfaces.
Conclusions:
The incidence of player-to-surface impact injury was significantly lower on the heavyweight playing surface during game-related high school football across numerous playing conditions. Based on the findings, a heavyweight artificial infill system is recommended for high school football fields to optimize player safety.