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Muscle Tissue. Four Behavioral Properties Extensibility – The ability to be stretched Elasticity – Returns to length after being stretched Irritability – Responding to a stimulus Contractility - The ability to produce tension (Muscle generates force by contraction). Change In Muscle Length.
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Muscle Tissue Four Behavioral Properties Extensibility – The ability to be stretched Elasticity – Returns to length after being stretched Irritability – Responding to a stimulus Contractility - The ability to produce tension (Muscle generates force by contraction)
Change In Muscle Length Resting Length Stretched (extensibility) Passive Elastic Recoil (elasticity) Concentric Contraction (contractility)
The Elastic Behavior of Muscle Tissue • Parallel Elastic Component (PEC) • Parallel to the muscle fibers • Provided by muscle membranes • Supplies resistance when a muscle is passively stretched • Series Elastic Component (SEC) • In series (in line) with the muscle fibers • Resides in the tendons • Stores elastic energy when a tensed muscle is stretched
The Elastic Behavior of Muscle Tissue (continued) • Primarily due to the SEC • When a tensed muscle is stretched (eccentric contraction): • The SEC causes an elastic recoil effect • The stretch reflex initiates muscle contraction • Stretch-Shortening Cycle • The pattern of eccentric contraction followed by concentric contraction
The Stretch-Shortening Cycle • Important for many sporting actions • Stretch of shoulder extensors and horizontal adductors prior to throwing • Backswing in golf, softball, and baseball • Promotes storage and use of elastic energy for running, jumping, etc.
Viscoelastic Response of Muscle Tissue • Enables muscle to stretch and recoil in a time dependent fashion • A muscle or muscle group held in a stretched position tends to lengthen over time • After stretching, a muscle group shortens gradually rather than returning to its original length immediately
Irritability of Muscle Tissue • Muscles develop tension as a result of a stimulus • Electrochemical stimulus – An action potential from a motor neuron • Mechanical stimulus – Impact to the muscle may cause it to develop tension