Describe the process of isotonic contraction of the bicep muscle. Include these in explanation: FLEXION, EXTENSION, ORIGIN, INSERTION, and BELLY.

Explanation:

When we curl a weight like in the picture below the muscle changes its size. This is called an isotonic movement. When the bicep is flexed and the weight moves upwards towards our shoulder the muscle is pulling from the insertion and into the origin of the muscle. The belly of the bicep becomes small, round, and hard.