"Khan laboured with minor changes suggested to him in his bowling action. He put them into effect and bowled in match situations at the MRF Ground and felt he was able to bowl much faster and does not experience any pain," John said.
John, along with former Australian speedster Dennis Lillee, was in the city to assess the trainees besides Khan.
Video clippings of Khan's bowling action in Australia, Pakistan (the recent two tours) and at MRF were screened for the benefit of the bowler and compared with corrections made to his action.
John said Khan's high jump action before delivering the ball caused a lot of stress on his lower back and hamstring. "He was not making any good use of his front arm by jumping high in the air, which translates more power on his front leg," the Australian expert said, adding he was a bit confused about 'hitting the pitch high' which some time results in muscles being under significantly 'more stress'.
Khan said that he would speak to the media only at the camp starting in Chennai on July 3.
Confirming that the jumping action was the cause for Khan's hamstring injury, Lillee said it was a minor adjustment that made the star bowler get back to his natural abilities.
Lillee said John had offered to help MRF Pace Academy and had already held a meeting with Dr Gopal Ramanathan of the Academy in this regard.