21. Michael Jordan
Dream Team debates aside, few people dispute that Michael Jordan is—statistically speaking, anyway—the greatest basketball player of all-time. But he didn’t get there on raw talent alone.
In 1989, trainer Tim Grover read an article about Jordan wanting to begin strength training to better prepare for the physical style of play he would face against the Chicago Bulls’ chief conference rivals, the Detroit Pistons. Jordan was afraid to hit the weights for fear it would affect his game.
Grover contacted the Bulls to offer his services. “[Jordan] said he’d try it out for a month, and it ended up being 15 years,” Grover told ESPN in 2009. Fueled by the added muscle, Jordan led the Bulls to six NBA titles and a Hall of Fame career.