We spend a lot of our national attention examining how sports heroes move, but very little on how and what they think. With the accessible, engrossing documentary “In Search of Greatness,” filmmaker Gabe Polsky examines the startling way creativity has propelled some of the world’s most celebrated competitors to their groundbreaking achievements.

With extensive talking-head conversations and only minor visits onto the field, Polsky explores the surprising effects of inventiveness and individuality on athletic performance. He has pulled together an impressive roster of legendary sports champions to lead us deeper into the miracles of athletic genius.

His interview subjects include hockey icon Wayne Gretsky, the only NHL player to total more than 200 points in one season; soccer star Pelé, declared an official national treasure by Brazil’s government; and football great Jerry Rice, who played an unprecedented 20 NFL seasons and is widely considered the greatest pro football player of all time.

Each wraps his story of elite sports performance in personal stories that reveal the true complexity behind excellence.

Polsky’s film explores the paths that led each of them to their remarkable achievements and finds that each superstar followed a similar track. The consistent theme isn’t innate abilities such as natural talent, inborn intelligence or superior physical capabilities. What enabled them to thrive at the highest level is positive, confident mental health born from a youthful background of freedom, unstructured play and creativity.

While Polsky doesn’t deny that, for example, extraordinary height is a plus in basketball, he argues that, on the whole, genetic advantages don’t guarantee much.

Adding a tone of sports science to the discussion is David Epstein, bestselling author of “The Sports Gene,” who confronts the nature vs. nurture debate and clarifies how far science has come in unraveling it.

Ken Robinson, who was knighted by Queen Elizabeth for his projects on creativity, challenges us to rethink the very nature of athletic coaching in terms of young players finding and developing their own talents. It grants the confidence of success that often induces real success.

As he puts it, inventive people are “not hung up on fixed definitions of what any form of life or reality may be.” Instead, their own personalities shine through whether they’re athletes or artists.

That is guidance Polsky follows in his film. It balances a focus on Muhammad Ali’s balletic athleticism and John McEnroe's explosive, ­opponent-frightening temper with unexpected images of David Bowie’s invincible originality and mice whizzing their days away in exercise wheels.

At a brisk 80 minutes, this film should be important for coaches, athletes, artists and, above all, high-strung, fire-breathing sports parents.