The Cheltenham-born coach, who is currently undertaking an MSc in Strength & Conditioning with Edith Cowan University in Perth, Australia, has now committed to Warriors until 2010.
"It's an exciting time to be involved with Warriors with so much positive development happening both on and off the field," said Pickering.
"Despite recent results we know we are close to being where we want to be, we have a talented group of players at the club and it is a pleasure to come to work everyday.
"I've really enjoyed working with the dedicated backroom team at Sixways, in particular Keir Hansen who has revolutionised the conditioning at Warriors."
Director of Rugby Mike Ruddock is delighted that Pickering had agreed to extend his stay.
"Stuart has proven to be a very highly valued member of the backroom staff," he said. "His research methods and work towards to our fitness and conditioning programme is of the very highest standard.
"We are fortunate to have someone of his quality working under the tuition of Strength & Conditioning Co-ordinator Keir Hansen and his continued work can only be of real benefit to the club."