During a baseball game, the ball will strike the playing surface at a variety of speeds and angles. The speed at which the ball travels after impact with the playing surface has been referred to as the pace of the surface. Wide variations in pace can reduce the safety and playability of baseball field surfaces. Pace can be quantified by measuring the coefficient of restitution. The coefficient of restitution is defined as the ratio of two velocities; the velocity of a baseball after impact with the surface divided by the velocity of the ball prior to impact. An apparatus was developed to measure the coefficient of restitution of a baseball striking various playing surfaces. The apparatus, termed Pennbounce, uses infrared screens to measure the coefficient of restitution of baseballs propelled at varying angles and velocities. Pennbounce was used to measure the pace of traditional synthetic turf (Astroturf), infilled synthetic turf (Fieldturf), natural turfgrass, and skinned infield surfaces. Baseballs were propelled at the surfaces using two velocities and impact angles. Surface pace was highest on traditional synthetic turf, skinned infield, infilled synthetic turf, and natural turfgrass areas, respectively.
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