Joe drove himself to become the best at multiple athletic events, unknowingly achieving a "mind/body link" that allowed him to surpass normal human ability.
When his trainers continued to push him towards an unseen goal, and contact with his parents became difficult, Joe began to suspect his benefactors and confronted them.
To a lesser degree, the link also provides him with a genius-level intellect & photographic memory, allowing him to quickly learn new languages and memorize facts or information.
His body is resistant to damage, almost to the point of being bulletproof, and his metabolism is such that he is practically immune to poisons while also healing somewhat faster than normal.
After meeting an ally who had also achieved the mind/body link (albeit in the opposite fashion), Joe learned that he could also harness limited psychic abilities such as telepathy and telekinesis.