Proposed Investigation into Titin’s Elastic Behaviour during Active Stretch

INTRODUCTION Within skeletal and cardiac muscle exists a molecular spring responsible for maintaining muscle structure, preventing stretch related damage, and contributing to the development of muscle force. This spring, called titin, has almost exclusively been associated with passive (elastic) force, that develops when muscles are stretched. However, more recent work has suggested there may be a dynamic nature to titin that can be used to understand active stretches in muscle as well [1]. If this titin spring has the capability to reversibly bind to the filamentous protein actin, then the elastic region of the spring would be shortened which would generate more force.