Define and explain the difference between isotonic, isometric and eccentric contractions and give an example of a specific movement for each. What is the role of series elastic elements in muscle contraction?

Question

What will be an ideal response?

Answer 1

Isotonic means same tension, that is, a type of muscle contraction that involves movement with a constant tension
or force. An example is what the biceps brachii muscle does when flexing the elbow–once tension increases enough
to move the weight of the forearm, the forearm moves steadily without further increase in tension. Isometric means
same length, that is, a type of muscle contraction that involves development of force without the muscle actually
shortening and moving a load. An example is what the biceps brachii muscle does when trying to hold an object
without changing length. Tension is exactly equal to load, which is why length does not change. In an eccentric
muscle contraction, the load applied to the muscle is more than the tension that muscle can generate causing the
muscle to lengthen. For example, the biceps brachii muscle is flexed and you have in your hands a weight that is
greater than you can lift. Thus, you slowly allow the biceps muscle to lengthen resisting movement of that heavy
weight. The series elastic elements are composed of the connective tissue of the tendons and that, which is between
muscle cells. Before force would be detected at the tendon (latent period), some shortening of the contractile
elements occurs that pulls on the series elastic elements. Once stretched, the force can now be detected at the
tendon.