TABLE 2.

Characteristics of balls that can produce targetoid erythema following high velocity contact impact of the ball to the skin [^a,^b]

Ball	Paintball	Ping pong ball	Racquetball	Squash ball
Composition	Gelatin [c]	Plastic [d]	Rubber	Rubber [e]
Weight (gm)	3.2–3.3	2.5–2.7	56.7–58.5	23–25
Diameter (mm)	17	38–40	57	39.5–40.5
Speed (kph) [f]	307–330	161	124–241	>241
References	6,7,17,18	6,8,19	14,20–22	14,23,24

^[a]Abbreviations: gm, grams; kph, kilometers per hour; mm, millimeters; mph, miles per hour

^[b]The paintball is smaller (more than half the diameter) and heavier (about 25%) than a ping pong ball [6–8,18,19]. In contrast, the squash ball is the essentially the same diameter as a ping pong ball, but ten times heavier [8,19,24]. And, the racquetball is nearly 1½ times larger in diameter and more than twenty times heavier than a ping pong ball [8,10,19,20]. All of these balls potentially travel 1½ to twice as fast as a ping pong ball [6–8,14,17–24].

^[c]Spherical gelatin capsules containing primarily polyethylene glycol, other non-toxic and water-soluble substances and dye.

^[d]Air filled, celluloid or similar plastics material.

^[e]The squash ball consists of two pieces of rubber compound, glued together to form a hollow sphere and buffed to a matte finish.

^[f]The speed of the ball can also be calculated in miles per hour: paintball = 191–205, ping pong ball = 100, racquetball = 77–150, and squash ball = >150. Racquetball speeds have ranged from: (1) 124 kph (77 mph) to 145 kph (90 mph) during matches with women and (2) 209 kph (130 mph) to 241 kph (150 mph) during matches with men; the fastest recorded speed is 307 kph (191 mph) [14,20–22]. The fastest recorded squash ball speed is 204 kph (127 mph) [14,23,24].