It seems almost ridiculous now, but early in his career LeBron James was worried that a bad back might derail his goal of becoming one of the best players in the history of the NBA.

Less than four years into his professional career, James found himself playing with chronic soreness in his lower back. He couldn't shake the pain.

"I hurt my back, and my back was really sore and I couldn't understand why it was bothering me," James said.

Convinced that his sore back would eventually become a significant problem, James adopted an elaborate routine of stretching exercises to increase his flexibility. His back stopped hurting but James' stretching routines — administered daily by a personal trainer — never stopped.

"I started stretching three times a day, started doing Pilates and stuff like that to maximize what I can do, because I love to play the game and I don't want to be sitting out because of my back hurting or something bothering me. It really helps," James said.

James credits flexibility, stretching and Pilates for his legendary durability. He calls it a proactive approach to avoiding injuries. James has only missed 33 games during his 10-year career.