Well for all of the fast bowling experts, what is it, because I sure as hell don't know, other suggesting it is a confidence thing. You see the deliveries that got out Aaron Redmond and Brendon McCullum, where the sort of fast bowlers would dream about, just like a batsman playing a crisp cover drive VVS Laxman style. And now he has the all of the wickets New Zealand has lost (6), and yet in the last Test he bowled some absolute crap, boosted in the end by picking up the last few wickets to fall in the New Zealand innings to make it look like he had respectable bowling figures, and this has gone on long enough as well (Anderson bowling crap). You see how he bowled and it beggers belief why he can't do it more often because it would of got any top order batsman out being Aaron Redmond, to the likes of Jacques Kallis, Rahul Dravid or Ricky Ponting (if you had got bat on it you have likely have been caught behind or in the slips) for mine.
I don't know what is wrong with him, but I would wish he would do it more often as he clearly has ability.