Application of a force-clamp system to study auxotonic muscle contractions

The investigation of auxotonic muscle contractions is dependent on the understanding of both isometric (constant length) and isotonic (constant force) muscle contractions. An auxotonic contraction occurs when neither the force nor the length remain constant; essentially a combination of the variable isometric and isotonic states of contraction. In this study, previous research using a force-clamp system was improved upon to yield more accurate results. Circuitry along with instrumentation was redesigned and programmed to simulate a realistic muscular contraction waveform and later used in combination with the Aurora Dual Mode Lever System (ADMLS). The system uses feedback controls to regulate force and length in real-time according to user-defined specifications. The heart of a quahog (hard shell clam) was used for the experimental component of this study.