A short while ago I was upbraided for daring to suggest that individuals we commonly refer to as geniuses are not born with abilities beyond the scope of ordinary individuals. My thinking was heavily influenced by the publication in 2006 of The Cambridge Handbook of Expertise and Expert Performance, where two approaches to the expertise of exceptional individuals are examined: the first suggests that some people have greater minds or that their 'greatness or creativity arises from some chance and unique innate talent' (p.22); the second approach is more relative and assumes that 'expertise is a level of proficiency that novices can achieve' (p.22).
It is impossible to try and present or summarise even a tiny part of this book, so wide is the range of areas it covers, but since its publication it has spawned a huge amount of interest. The Cambridge Handbook has generated a host of popularised versions of the academic arguments it has put forward: The Talent Code by Daniel Coyle, Talent is Overrated by Geoff Colvin, Malcolm Gladwell's Outliers, and Matthew Syed’s Book Bounce. All pay homage to The Cambridge Handbook. [As an aside, Robert Morris provides a useful overview of Coyle's book on the Amazon site.]
What they all broadly agree on is that talent, in whatever area, be it chess, playing the violin, learning maths, or playing golf, depends less on innate talent and more on two fundamental factors: deliberate practice and expert tuition. But these two requisites need to be teased out a bit. In the case of deliberate practice, one needs to know what to practise: what does any particular skilled knowledge and ability entail and how can it be broken down into sub-components that can be taught and practised? In regard to expert tuition, a teacher may not need to be the most brilliant exponent of the learning target, but they do need to know how it should be taught, what the stages are and the order in which they should be introduced and mastered before moving on to the next level or stage.
If this is done well, there is no reason why just about anyone can't pretty much accomplish anything to a high level of skill, which is why teachers need proper training in whatever it is they teach.
However, to become a Rebecca Adlington, an Anamika Veeramani, or indeed a Stephen Hawking, you also need true grit, the willingness to practise every day for hour after hour, always in the knowledge that even that mightn't be enough to get you to the top.