Running (and walking, for that matter) is on one level continuously falling forward while using your feet to stop you landing flat on your face.
Read up on chi or POSE running, which have exactly that as a fundamental part of the technique.
Bolt's torso may be vertical (well actually he IS leaning slightly forward, sorry), but his COG is well ahead of his driving foot - as is the same for one of the other runners.
You should not bend at the waist, but definitely have a slight forward lean, the degree dependent on how fast you are running.
wikipedia:
Elements of good running technique
Upright posture and a slight forward lean
Leaning forward places a runner's center of mass on the front part of the foot, which avoids landing on the heel and facilitates the use of the spring mechanism of the foot. It also makes it easier for the runner to avoid landing the foot in front of the center of mass and the resultant braking effect. While upright posture is essential, a runner should maintain a relaxed frame and use his/her core to keep posture upright and stable. This helps prevent injury as long as the body is neither rigid nor tense. The most common running mistakes are tilting the chin up and scrunching shoulders.[14]
Lean comes from the ankles, not the waist:
http://www.youtube.com/watch?v=Tx6x2cD6Y8Q
Can we get back to arguing about WC and MMA, rather than how to run? No one on the thread has any apparent expertise in the latter (and it is probable that the same is true of the former)