Answer to Question #58359 in Cell Biology for Sanjukta Ghosh

Question

What is isotonic and isometric contraction?

Answer 1

In case of isometric contraction muscle doesn't shorten but it's tension increases, and thus muscle may develop a higher effort. It is possible when two ends of the muscle are separately fixed on the certain distance, and stimulation causes the tension development in the muscle without changing it's length (for example, barbell retention). In case of isotonic contraction, muscle shortens but it's tension remains the same. It happens when one of the muscle ends is not fixed and is free to move, therefore muscle shortens without tension change (for example, barbell lifting).