But in Australia's second innings, he was notably less effective, only taking 1 for 113, and that wicket was more from Ricky Ponting playing a rather lazy shot to a wide delivery. It was not Ntini's best day at the office.

Being a Test bowler is a hard way to make a living. You need everything to go right, and sometimes, even that is not enough. But to make matters worse, someone in the South African team decided to change Ntini's run up, and it seemed to me that it unsettled him.

It might have been the coach, it might have been the captain, it might have even Ntini himself, but it was a blunder.

Makhaya Ntini has a rather odd action in that he usually delivers the ball from fairly wide from the popping crease. This is not an approach that meets with much approval from purists and bowling coaches, for the very good reason that it makes it hard to obtain LBW decisions. Against a left hander, it becomes well-nigh impossible, and with Australia fielding four left-handers in the top seven this can be a problem.

So Ntini changed his run up in Australia's second innings, to come in closer to the stumps when he releases the ball. Someone from Getty Images took a magnificent photo of Ntini which shows what has happened, although it is not perfect. However if you are familiar with watching him, you can see that he's letting the ball go from closer to the stumps then he usually does.

While there are plenty of good coaching reasons to tell a junior player to change his action to remove this flaw, the case for doing so for a proven Test player like Makhaya Ntini is rather less, especially given his first innings success. One of the first rules of cricket coaching is, don't change what works. Even Shane Warne has a technical flaw (yes, really*) but there are almost 650 good reasons to ignore it.

South Africa missed a few tricks in Australia's second innings, but the decision to change Ntini's action was one of the least obvious and most telling one.

(Warne's "stroll in" run up does not allow him to generate the bounce that leg-spinners like to get. This may explain why Warne generally struggled on the slower pitches in the sub-continent until he found a way around it. But with 650 wickets, you don't tell him how to suck eggs. It is just that a technically correct coach would tell off a Warne imitator who tried to replicate his action)

Scott, your point is fair enough, but I watched quite a bit of Australia's second innings, and I didn't discern that Ntini was regularly bowling from much closer to the stumps. I think we must also note that in the first innings Ntini got several batsmen, including three of the left-handers, on the pull shot, and in the second innings Australia had worked this out and didn't repeat their mistakes (or pulled better, as Matt Hayden's three pull shots to the boundary in Ntini's first over showed), thereby nullifying one of Ntini's main weapons. Ntini's overall record against Australia is very modest, and there is some justification in thinking that - regardless of how close or far he is to the stumps while bowling - he may not repeat that five-for in this series.

Having said that, I agree that his wide-of-the-crease approach has contributed greatly to his overall success in Test cricket - it presents a most unusual angle to both left- and right-handers. And, as Australia found out in the first innings, he's one of the most difficult bowlers in the world to pull because of how he skids on to you - he got a lot of cheap wickets against England at Lord's in 2003 after they decided to take on his short stuff.

The worst case to come across of a bowler suffering because of tinkering with his natural action has to be Jimmy Anderson. When I first saw him in the World Cup he was a lot more pacy then he is now, and even though he didn't look at the batsman at the point of release (he looked straight down on the pitch I think) it was something that had worked well for him (as it has for other bowlers too, Shaun Pollock for instance, who has 300 plus test wickets I may add, doesn’t look at his target at the point of release either). Anderson got so many wickets over the 2003 English summer with that same action, hideous though it was but it was affective for him. A season with Troy Coley later, and he's no way near as affective now. He doesn't get as much swing, and has lost a full yard of pace. The biggest victim through it all his been his confidence I think. Another young bowler who strikes me as having the potential for such a disaster is Shaun Tait. I know his action isn't easy on the eyes, and appears a bit crouched, but it’s legal, so I hope the coaches he works with don't tinker with it too much.

The problem with Anderson was that the ECB were terrified of him doing his back in. I agree with you it was a retrograde step for his action, but England have had big problems with young bowlers breaking down in the past. Dean Headley being a good example; Alex Tudor another. Both were excellent bowlers, and could have been top-class performers, but were dogged by unjuries. Injuries caused by wear and tear had a huge effect on the stability of the England team in the mid-90s and Fletcher is very keen to make sure it doesn't happen again.

The problem with Anderson's confidence, I think, also stems from the fact he was promoted so quickly and lauded everywhere as the golden boy. And wasn't ever really quite as good as the hype except in swinging conditions.

When tinkering with actions is spoken of, though, I remember what Shoaib said to his coach when he first came on the scene. "Coach, I'm going to have to remodel my action after injury sometime anyway. Why not let me bowl 100mph while I still can?"