Usain Bolt once opened up on the 2007 incident when his coach Glen Mills suggested that the former sprinter should train for the 400m to improve his strength and stamina for his main event, the 200m. Bolt initially responded positively, but Mills surprised him by proposing that he return to running the 400m, a distance Bolt ran in high school.
Although Bolt was interested in running the 100m, coach Mills made a deal with the sprinter, stating that if he broke the Jamaican record in the 200m, he would let him run the 100m. Bolt accepted the challenge and broke the record with a time of 19.75 seconds, and then reminded Mills of the promise to allow him to compete in 100m.
Reflecting on the incident in his autobiography Faster Than Lightning, Bolt wrote:
"'You should try running another distance.' Coach made it sound like I had a say in the matter, but we both knew it was an instruction. There was a feeling that my form in 200 could be improved by some extra training."
Bolt added:
"'Yo, nice idea coach,' I said, when it was first mentioned midway through '07. I like it.' Then he gave me stupid news. 'Usain I think you should take up the 400m again, just like you did in high school.'"
Bolt then competed in his first professional 100m race in the same year, clocking a stunning time of 10.03 seconds.
"He taught me the importance of learning" - Usain Bolt expressed his gratitude towards coach Glen Mills

Earlier this year, Usain Bolt expressed his gratitude towards his longtime coach Glen Mills, who has had a significant impact on his life and career. Mills coached Bolt from 2004 to 2017. Reflecting on his journey with the coach, Bolt conveyed that Mills changed the course of his journey.
Bolt further stated that he thought that success would come easily, but Mills taught him the value of learning from losses before achieving success.
"Shout out to my coach and mentor Glen Mills - 20 years ago I started working with this legend and it would change the course of my career and life. When I first came onto the professional scene as a sprinter I thought it would be easy… He taught me the importance of learning from losing before I could get to the top. Infinite respect to Coach Mills for everything you taught me - Living legend. 🙏🏿"
In his illustrious career, Usain Bolt has bagged eight Olympic gold medals.