Lynn Snyder-Mackler (2 of 2) (image) University of Delaware Caption Lynn Snyder-Mackler, Ph.D promotes quadriceps exercise after knee replacement surgery. She's joined by patient T. Fraser Russell, who says after two months of rehab, he saw vast improvements. Credit Ambre Alexander, University of Delaware Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.