Muscles work by getting electrical impulses from the brain and the impulses signal them to contract by releasing calcium in sarcoplasmic reticulum of the muscle cells. When there’s fatigue, muscles are unable to generate force and it may caused by: nerve or muscle fibers limitations, which may be a result of tremendous workout or exercise. Nerves during neural fatigue are unable to generate signals to the muscles, while reduced activity in muscle fibers disable muscles to contract causing metabolic fatigue.
