What exactly is the 10,000-hour idea?

Author Malcolm Gladwell suggests that 10,000 hours of practice is the “magic number for true expertise.”

Of course, Gladwell says, talent is required for success. But it’s often overrated, he asserts: Practice is just as important. “The thing that limits us in our choices is not something we have no control over — our abilities. It is something we do have control over — our effort,” Gladwell told AARP magazine in 2008.

Ross Tucker, an exercise physiologist at South Africa’s University of Cape Town and the co-founder of a blog called “The Science of Sport,” argues otherwise.

Those who have run or worked out with a training group probably have noticed that different people respond differently to the exact-same training plan. A thousand hours of identical workouts will not produce an identical result. Athletic performance is largely determined by genetics, and training is simply the process for realizing one’s genetic potential,Tucker wrote in 2012 in the British Journal of Sports Medicine. Practice and training are necessary to reach an elite level in sports, but they are not sufficient, Tucker says.

Florida State University psychologist K. Anders Ericsson, whose research inspired Gladwell, has distanced himself from the writer’s idea. In a 2012 paper titled “The Danger of Delegating Education to Journalists,” Ericsson wrote that 10,000 hours of practice contained no magic: His research showed that was the average time put in by a group of high performers and most had actually accumulated fewer hours.