Even as recently as last year, Ashish Nehra used to regularly clock 136 kmph on the speed gun. Try as he might, the Delhi paceman could barely graduate from being a medium fast bowler to a fast bowler.

In the World Cup, though, the transformation has been complete.

Against  Zimbabwe, he touched 149 kmph and regularly bowled over 140 kmph. And against England on Wednesday night, all the world saw what blistering pace accompanied by prodigious swing can do.

What has brought about the transformation? Just hard work and will power? Or is there something else behind probably the first genuine fast bowler in India's cricketing history?

Ever since he burst on the scene, there had always been talk about the imbalance in Nehra's bowling action and it was held up as the sole cause of all his problems.

A wonderful tour of Zimbabwe was followed by a period of broken promises as Nehra struggled to come to terms with international cricket. He was down with an ankle injury and few gave him the chance of recovering in quick time.

But everyone agreed that Nehra was a rhythm bowler -- if he found the conditions to his liking, then he could trouble the best in the world. If not, he could not. In South Africa, Nehra has been a revelation, stunning all with his pace, fitness and wicket-taking ability.

As the six pins tumbled in the India-England match at Durban, this reporter stumbled across the secert to Ashish Nehra's success: Dale Naylor.

Naylor is an Australian physiotherapist, based in London, who has extensively worked with cricketers all over the world. Ashish enlisted his help to get over the trauma of injury and get back to his best.

It was not easy but it was not impossible either.

"He wasn't stable around his pelvis muscles," Naylor told rediff.com. "As a result, when he tried to deliver the ball through his shoulders, his muscles were having to work to keep him stable as well as produce the energy to deliver the ball. Therefore, he was getting injured, losing direction and the strength to deliver the ball was missing.

"So the key thing he had to do was stabilize, because as you hit the delivery stride, between the time you land the front foot followed by the back foot, you got to have the control to put a lot of work on the ball and that is what was missing earlier. We analysed his bowling action, his muscle strength, how the muscles were working and basically changed the pattern.

 "It took a while because it was very, very weak at that time. It was little things like these that made the difference and once you get it going for a length of time, there are certain muscles that are real power muscles in the body and you need to work them in a very specific way for players and that's what we have been doing."

But does the fast bowling cricketer use any specific muscles or it just the overall fitness that needs to be worked on.

"The bum muscle, the gluteus maximus, that's where your power-house is. It's the upper hamstring and in Ashish, one-side was particularly weak and he was using muscles on the other side to compensate for that and it took a little while to re-educate him about that. But once we got it going, we just got better. Now, it looks like he is not bowling that hard but is delivering much more power."

There are a lot of people who believe that for a fast bowler it is very important to have great upper body strength. But the key issue is that the upper body is there mainly to put a lot of work on the ball but the real power comes from the back and the legs. A lot of people believe that the bowler is delivering the ball with shoulder power but it is actually the stomach muscles and the lower body.

"Having got the basics right, then doing all the development, you are allowed to get your rhythm. Rhythm doesn't just happen, once you get into game and get successes  like this (against England) and that's where the rhythm comes from," adds Naylor who, in conjunction with team physio Andrew Leipus and team fitness trainer Andrian Le Roux, has given Ashish a second lease of life.

The figures from Wednesday's game tell it all: 10-2-23-6.