Cause: Tennis was split between two parties - amateurs and professionals - and each had what the other wanted. The amateurs were playing in the best tournaments but for less money, while professionals were playing in exclusive tournaments for more money. Tennis fans were missing out on some great competitions and the gulf between the two parties was widening. Rule: In an emergency meeting called early in 1968, the International Lawn Tennis Federation gave in to pressure from tennis' governing bodies in Britain and America which had already voted to eliminate the amateur and professional distinction from tennis tournaments. It reluctantly agreed that tennis pros and amateurs alike were to be simply known as "players," and the two could compete openly for prize money against each other in the world's best tournaments. Effect: This new "open era" of tennis fueled the tennis boom of the 1970's and 80's. Professional stars like Rod Lever, Roy Emerson and Billie Jean King were no longer restricted to playing a limited crop of professionals and could establish their legacy against heavily-touted newcomers. Also, young stars (like those that dominate today) could now make an immediate mark on the sport, winning prestigious tournaments before leaving their teenage years. Out of the obscurity of the amateur ranks came names like Evonne Goolagong who won the French Open and Wimbledon at age 19 in 1971. The rule change also allowed players to benefit financially. Sponsors began lining up to offer prize money to these much-improved tennis tournaments and television wasn't far behind. The men benefited first. Annual prize money on the men's tour in 1964 was $150,000 worldwide. By 1979 it would be $12 million and the 2004 ATP Tour was worth over $80 million. A Big Hit for Baseball? — Baseball (1973)
Cause: A rule which would allow teams to use a substitute for pitchers in the batting was first proposed in 1890. The argument was that the pitcher was an easy out. Not to mention going up to hit every inning and running the bases would tire the pitcher out quicker. Rule: It wasn't until Jan. 11, 1973 that one of the two leagues in Major League Baseball would approve the designated hitter rule. The American League voted 8-4 in favor of using the designated hitter, or DH, on a three-year trial basis. The hitter was to be designated to bat for the starting pitcher and all subsequent pitchers in any game without otherwise affecting the status of the pitchers.
Effect: Ron Blomberg of the New York Yankees became the first DH onApril 4, 1973. And since that first at-bat fans have had plenty to say about the rule. Baseball's National League has still not been convinced of the DH's importance and still hasn't approved the rule. Since the rule change the American League's batting average has been higher than the National League's every year. But both leagues have seen a dramatic rise in batters' averages and pitchers' earned run averages over the last three decades. Does that mean the DH rule has been ineffective? Or is baseball's expansion in the last three decades from 20 teams in 1968 to 30 in 1998 responsible for all this? Or something else? It's a question that nobody seems tired of debating.