The first question squash aficionados get is how the game differs from racquetball. After they cringe, they might answer:

"An average pro (squash) rally is something like 11 seconds, which is the longest of any pro racquet sport; racquetball averages about 2 seconds," said University Club of Chicago squash pro John Flanigan. "Pro men's tennis is maybe 4 ½ seconds. I've seen one squash point go on for 6 minutes. That doesn't happen very often, but 2 minutes you will see."

• Balls: A squash ball, about the same size as a golf ball, is less bouncy than a racquetball ball and can travel 150 mph at top speed. It loses about half of its speed on the rebound, however, whereas a racquetball loses only about a quarter of its speed. "It's harder to kill the ball, and that's one of the reasons the rallies tend to go longer in squash than in racquetball," Flanigan said.

• Courts: A racquetball court is 20 feet wide and 40 feet long. An international (softball) squash court is 21 feet wide and 32 feet long. Some health clubs have courts that can convert between racquetball and squash.

• Racquets: A squash racquet is the same length as a tennis racquet, longer than a racquetball racquet. Head shape varies.

• Boundaries: Squash has more zone restrictions than racquetball. Among them: Shots must hit above the tin, which is a panel that extends about 17 inches up from the floor for pros and 19 for amateurs. The ceiling is out of bounds.

• Rules: If a player obstructs the opponent's shot, he or she loses the point. It doesn't matter if the block was unintentional. "Squash rules are much stricter than racquetball about getting out of the opponent's way," Flanigan said.

— Info: US-Squash.org

Chicago Tribune