Soccer is an intricate, high-speed game filled with split second, spontaneous decisions.  But that spontaneity is possible only when everyone first engages in hours of highly repetitive and structured practice.

Malcolm Gladwell

Sports specific practice has been shown to be a significant predictor of skills-based differences in sport.

K. Anders Ericsson et. al.

Deliberate practice is hard. But it works.  More of it equals better performance. Tons of it equals great performance.

Geoff Colvin

...the sheer amount of formal practice appears to be the best predictor of a player's level of accomplishment...

Michael J. A. Howe

Practice isn't the thing you do once you're good.  It's the thing you do that makes you good.

Malcolm Gladwell