Not always, but it certainly can be. Look at guys like Messier, Chelios, Jagr - or their football equivalents like Bruce Smith, Clay Mathews, Jerry Rice - They all had significant injuries at some point in their careers (I think), but mostly they played game after game of violent pro sports at the highest level for much longer than virtually all of their peers could. And many of those peers worked every bit as hard at conditioning.
They had the luck of good genetics, and probably a good measure of balance, skill, and smarts to avoid damage. That's TALENT.
That said, most guys probably have to rely on conditioning and luck.