Answer:
Well what I know about it is that muscles make up approximately 40 percent of total weight, and also an interesting fact about it is that the heart is the hardest-working muscle in the body, another fact is that YOUR body contains MORE THAN 600 muscles, The gluteus maximus is the body's largest muscle. Muscle actions are categorized as concentric, eccentric, or isometric depending on whether the muscle shortens, lengthens, or remains the same.
Hope it helps..