Which property of muscles is essential for locomotion?

The property of muscles that is essential for locomotion is contractility. Muscles have the ability to contract as they can shorten and generate force. This allows them to pull on bones and produce movement. This contraction is powered by the interaction between actin and myosin proteins in the muscle fibers. 

Without contractility, the body would not be able to perform the movements necessary for locomotion, such as walking, running, or jumping. Therefore, contractility is a crucial property of muscles for locomotion.