The second year of a two-year prospective survey of high school football participation on synthetic and natural turf was expanded to include participation on additional brands and generataions of synthetic turf as well as additional games played on grass. This permitted epidemiologic comparison of various brands and generations of synthetic turf with each other as well as with grass[1].

Torg et al. demonstrated in Philadelphia that altering the shoe portion of the shoe-surface interface decreased both frequency and severity of knee and ankle injuries on natural grass fields[4]. It would not be surprising to find that altering the turf portion of the interface alters the injury rate and the pattern as well.