The tennis courts at Washington Park were mostly vacant Saturday, but there was a lot of activity at the four adjacent platform tennis courts. That's not unusual since platform tennis is a cold-weather game. In fact, enthusiasts say the perfect time to play is an overcast day when the mercury is hovering around the 20-degree mark. On those days, players clean the snow off the outdoor court and turn on the built-in court heater to melt any new snow that might fall. "It's fun to play in the snow," said Dan Kepner, president of the Springfield Platform Tennis Association. "You turn on the heat, and it melts the snow as it hits the court. That creates steam. So if you have snow coming down and steam coming up, it adds a whole new dimension to being able to play and see the ball." Platform tennis is played on a court that is roughly a quarter the size of a traditional tennis court. One of the big differences is that the court is enclosed in screens and players can hit the ball after it bounces off the screen. Cron Mueller, a member of the platform tennis association, said allowing players to hit the ball off the screen enables them to compete against people who might be faster or stronger. "If the ball goes by too fast or the angle is too great, I can let it go by, bounce, rebound off the screen and play it back," Mueller said. "Once you figure out the footwork and the geometry, it's not as hard as it looks." The Springfield group started in the early 1990s and eventually got to the point where there were four courts and a small warming building at Washington Park. About 18 months ago, an electrical fire destroyed the warming building, and a tree fell on one of the courts. The American Platform Tennis Association gave the Springfield Park District a $15,000 grant to go toward repairing the damage. Club members and the park district also covered some of the cost. Kepner estimated that it cost about $50,000 to repair the warming building. While the warming building was damaged, the local popularity of the sport waned. There were about 100 members and 40 active players, but the numbers have dropped to about 40 members, with 30 active players. In an effort to boost local interest in the game, there were two pros from the American Platform Tennis Association in Springfield on Saturday conducting workshops to teach people about the sport. The workshop was sponsored by the national association and Vikings Athletics. Club members said the event went well. "We're hoping to get back to where we were when we were at top speed," Kepner said. "We hope this event will stimulate interests. We see some young kids and new faces out there."