I think his acceleration mechanics leave a little to be desired but I don’t have much problems with his top-end mechanics.
RE: Top End. I really don’t mind either his arm swing or his head position. I’m a big proponent of posterior pelvic position and as I mentioned I think any slight forward head position he has is a compensatory effect of the position of the pelvis. I don’t like how much Dix or Gatlin had but I don’t see anything that bothers me with that in AP. I think the arm swing is a by product of the tight leg cycle. I’d like to see a little more elbow-trunk separation in front of the body but it’s not a major deal as his posture is very good and this is one of the main thing this effects. As for the arms being ahead of the legs…they always are. Even in the most mechanically inefficient runners, the arms can easily lead the legs. In fact, they have to ‘wait’ at the terminal point of the swing for the legs to catch up.
What are some of the things he can improve on in his starts?