What is a property of muscle whereby steady or constant state partial contraction maintained in muscle?

The property of muscle whereby a steady or constant state partial contraction is maintained in muscle is called tonus or muscle tone. Muscle tone is a constant state of partial contraction that keeps muscles firm and ready for action. It is maintained by the continuous firing of motor units, even when the muscle is not actively contracting. Muscle tone helps to maintain posture, prevent muscle atrophy, and protect joints from injury.