Mercer Beasley
Mercer Beasley (1882-196?) was the best-known American tennis coach of the first half of the 20th century. The grandson of an earlier Mercer Beasley (1815-1897), who served as Chief Justice of the New Jersey Supreme Court for a number of years, Beasley suffered from extremely poor eyesight, making it impossible for him to play tennis at more than a rudimentary level. In this he was probably unique: most other well-known tennis coaches such as Harry Hopman and Pancho Segura have generally been great or near-great tennis players in their own right.
After briefly attending Princeton in 1902, Beasley worked at a number of jobs before beginning to coach tennis at the age of 40. He spent the rest of a long and active life as the most influential and possibly most creative coach in the sport. The coach at numerous schools and colleges, including Tulane, Lawrenceville, and Princeton, he is best remembered today as the long-time coach and mentor of Frank Parker, one of the best American players of the 1930s and '40s. It is said[1] that Beasley also discovered the 14-year-old Ellsworth Vines working in a bakery in Pasadena and helped form him into one of the greatest players in the history of the game.
Beasley's 1933 "How to Play Tennis" was a highly influential book that emphasized accuracy and consistent play. He was also the first coach to see the value of so-called cross-training, in which he had his pupils develop different aspects of their game by emulating the movements from other sports such as gymnastics, basketball, track, boxing, and ballroom dancing. So well-known was Beasley that eventually Spalding Sporting Goods released its own Mercer Beasley racquet, which, for many years, was sold in stores next to those endorsed by Don Budge and Jack Kramer. Finally, Beasley was constantly seeking technological improvements. It is said[2] that he was a pioneer in promoting synthetic strings, composite racquets, and ultralight footwear as well as being one of the first coaches to design and use the now-ubiquitous tennis ball machine.