Lynn Snyder-Mackler (1 of 2) (image) University of Delaware Caption Lynn Snyder-Mackler, Ph.D encourages exercising your quadriceps after knee replacement surgery. Here she chats with patient, T. Fraser Russell. 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.