1) The first example is identical twins Otto and Ewald, who pursued different sports and developed rather different physiques through their sports training.
http://thesameffect.com/check-out-identical-twins-otto-and-e...
(I learned about this case from a local professor who teaches courses in human behavior genetics. He uses this case as an example to correct misunderstandings about genetics.)
2) The second example is that Usain Bolt was once thought to be too tall to be a successful sprinter.
http://www.bbc.co.uk/programmes/p00v9bs4/profiles/usain-bolt
http://bleacherreport.com/articles/49040-usain-bolt-why-the-...
http://www.slate.com/articles/news_and_politics/recycled/200...
The simple fact is that athletic training reshapes bodies and makes what seems impossible possible after all.