you know what i can't figure out if that camera is on his helmet how come his head never moves
1. Discipline - look where you want to go, don't 'sightsee'
2. Go Pro Hero2 camera I'd guess, with its wide angle lens. Movements are deceptively small due to the wide angle distortion.
3. His head is moving, just that the helmet doesn't move in relation to the camera (because it's fixed). Look at what is happening to his handlebars and front wheel on the odd occasion you see them.