Melbourne: India's bowling coach Bharat Arun on Saturday said Jasprit Bumrah's unconventional bowling action makes him one of the most difficult bowlers.
"What makes him (Bumrah) so special is because he is so unique (in his bowling action). Maybe the batsmen pick up his balls a little later than which they normally do from a clean action and that makes him so much more potent. Of course, for any fast bowler to be bowling 145 clicks and above consistently over a period of time, you need to generate a lot of speed from your arms," Arun said.
"We were extremely confident of Bumrah doing well even before he started playing Tests because he was unique and most batsmen who played against him said it was difficult to pick him," he added.
Bumrah has so far taken eight wickets in the third Test against Australia here.
Australia were left struggling at 258/8 in their second innings on the fourth day with India needing two more wickets to take a 2-1 lead in the four-match Test series.
"I had the opportunity to work with Bumrah when he was at U-19 level and when I was with NCA. I felt Bumrah was able to generate a lot of pace with his action, but puts a lot of strain on his body," Arun said.
"It was a challenge and we had discussions with the physios and trainers. We came to the conclusion that we need to work on him to become extremely strong to be able to sustain his bowling.
"He was someone who did exceptionally well in the domestic championships as well. So, we thought we would give him a go," the bowling coach added.
Arun termed 2018 as the breakthrough year for Indian pacers.
"Definitely yes (this is the year). Right from the period we started the tour of South Africa, England and right now, they (pacers) have done exceptionally well. Recently I was told that they have broken the record of the West Indian trio and that speaks volumes about these fast bowlers," he said.
"It is a combination of a lot of work, identifying what it requires to be bowling fast over a period of time, the strength-conditioning coach Shankar Basu and physio have played a major role in making these fast bowlers.
"I think load monitoring is extremely crucial if you want them to last over a period of time, and their inputs become extremely important. I think it is teamwork," he added.
Asked about Ravindra Jadeja only featuring in two overseas Tests this year, Arun said: "Jadeja has matured a lot over the years. He has gained a lot of confidence and the way he did in England at the Oval, we can be quite confident that Jadeja can lead the spin attack."
"I would say that a spinner maturing is about him understanding and discovering himself. And how he does it is trying various angles with which he can bowl and variations in position of wrists. In the last couple of years, Jadeja has learnt quite a lot and that has helped him evolve from what he was earlier," he added.