A lot can change in a week. Just ask David Warner, Steven Smith, Cameron Bancroft and Darren Lehmann. In a less dramatic way, things have changed for Stuart Broad. Or actually, in a sense, they haven't.

In the build-up to the Auckland Test there was a strong indication that he would lose the new ball role he has held, largely without interruption, since 2013. Then England were bowled out for 58 and there was no time to try something new. Broad took the new ball alongside James Anderson.

His 400th Test wicket, when Tom Latham clipped to midwicket, was one of the more subdued landmark moments you could see but there were small signs that the work he had put in during the alone hours in the Trent Bridge indoor school were paying off. There was a little bit more zip and bounce than in Australia and he was better aligned to the right-handers.

But there was still the feeling he bowled a little too short, especially with the first new ball when Trent Boult and Tim Southee had pitched theirs up with devastating effect. The length of England's new-ball bowlers has often been a gripe and was never more evident than the first afternoon of the Adelaide Ashes Test when Joe Root had put Australia in and watched his senior duo waste conditions.

Two days before the second Test in Christchurch, Root had a long meeting with his bowlers which ran well past the end of an already lengthy training session. There have been a lot of meetings in the last few days. What was said will probably remain behind closed doors, but it would be a surprise if pitching the ball up had not been on the agenda.

If it wasn't, and the second morning in Christchurch was just Anderson and Broad thinking on their feet, then you would have to wonder why they couldn't have done it before.

The effect of pushing the ball full was almost instant and for Broad made for his most impressive spell since the start of the Ashes. He drew Latham onto the front foot, finding the outside edge as the opener looked to drive, then pushed one out a touch wider to Ross Taylor who couldn't resist a flat-footed flash which sent a catch to Alastair Cook at first slip. The scalp of Taylor will have been especially satisfying as it continued a hold Broad has had over him throughout their contests together. This was the 10th time he had dismissed Taylor in 14 Tests.

A full length also soon defeated Henry Nicholls, the ball nipping past the inside edge to take the back pad. CricViz analysis during Broad's first spell showed at one point he was pitching 37% of his deliveries in a full-length area compared to 30% normally - the difference in length was calculated at 30cm.

Bowlers have a natural length and it can be difficult to adjust at the drop of a hat, but when Broad gains the success he did pitching it up. it is a wonder why it hasn't been his default. When Broad went through a previous struggle in 2011 it came during a time when he was given the 'enforcer' tag which led him to bowling too short. After a lean series against Sri Lanka that summer, he then pitched the ball up against India and took 25 wickets in four Tests at 13.84.

"To go away and play for Notts and get a five-for pitching the ball up a week before the Test gave me a lot of confidence," he said at the time. "That was how I wanted to bowl in this series but then for it to happen straight away at Lord's, to pick up four wickets and could have potentially had more, that length showed me the way to go."

This time, the problems, Broad believed, had been caused by bowling so much round the wicket to the left handers. Leading into this series, having worked hard to make small corrections, Broad spoke about having plenty of legs in him at Test level. "I'm in a place now where I feel like I can do quite a bit of damage as a bowler again," he said. Whether the new-ball talk was a ploy to get the competitive juices flowing or not, it may now be a little while before the Anderson-Broad partnership is broken.

The new-ball burst didn't last long enough to be classed as a return to the streaks that made him such a devastating bowler up until early 2016, but there were signs that he still has some more in him. However, late in the day, with England having endured a 142-run partnership between BJ Watling and Colin de Grandhomme, Broad returned and struck with his second ball. How? Yes, it was a full delivery that got the batsman driving. Saturday's performance wasn't a case of teaching an old(ish, by fast bowling standards) dog new tricks, but reminding him of the ones that make him most effective.