Martina Navratilova

Martina Navratilova revolutionized women's tennis with her fitness regime, becoming the first female player to train with weights year-round, which redefined physical standards in the sport. She won 18 Grand Slam singles titles and a record 31 Grand Slam doubles titles, totaling 59 majors—20 more than #4 Chris Evert. Navratilova held the world number one ranking for 332 weeks and competed in doubles until age 49, capturing the US Open mixed doubles title in 2006 at 49 years old. Her 1,442 career match wins are the most in tennis history. She was 30% quicker to the net than the typical rival, transforming serve-and-volley tactics.