The body of an an athlete is usually more slight. Then there is a grey area where some athletes look like bodybuilders. If you want an athletic build you need to train like an athlete does.To have good balance, excellent posture, and full-body strength you must train your core. This means doing a lot of different exercises that build the small muscles of the torso. The core is important for athletes because it is what helps you rapidly change direction, shift body weight, jump high, and control.