The number one trait of athletes is something that I rarely hear mentioned. It's body control. Some people just seem more attuned to making their body do exactly what they want it to than others. I've known heavy guys that look like they will be clumsy, but who posses a high level of athleticism which only really becomes obvious in the heat of competition. I've also known guys who look like the epitome of athleticism... but some lack that element of fine motor control that makes all the difference.