Developing skill

I'm reading Angela Duckworth's book - "Grit: The Power of Passion and Perseverance." The excerpt below reinforced for me how important it is to have good teachers. Talents are only partially genetic. Even the most "genetically talented" person needs a good coach/teacher to draw out that his/her maximum potential. 

Excerpt:
Sociologist, Dan Chambliss, swam competitively in high school but stopped when it seemed clear he wasn't going to make it as a nationally ranked swimmer.

"I'm small," he explained, "and my ankles won't plantar flex... I can't point my toes. I can only flex them. It's an anatomical limitation. Which means, basically, at the elite level, I could only swim breaststroke." After our exchange, I did a little research on plantar flexion. Stretching exercises can improve your range of motion, but the length of certain bones does make a diference in how flexible your feet and ankles are. 

Still, the biggest impediment to improving wasn't anatomy, it was how he was coached: "In retrospect, I look back now and can see I had horribly bad coaches in a couple of crucial places. One of my high school coaches - I had him for four years - literally taught me zero. Nothing. He taught me how to do a breaststroke turn, and he taught me incorrectly."

What happened when Dan did, finally, experience good coaching, in part from hanging around the national and Olympic coaches he was studying? 

"Years later, I got back into the pool, got in shape again, and swam a two-hundred-yard individual medley as fast as I did in high school."