Sarcomeres are the basic contractile units of muscle fibers, responsible for muscle contraction and movement in vertebrates. These structures are made up of thick and thin filaments that slide past each other during muscle contraction. Sarcomeres are highly organized structures with distinct bands and zones, such as the A bands, I bands, and Z lines. They play a crucial role in muscle function and are often studied in the context of muscle physiology and biomechanics. Researchers study sarcomeres to understand muscle function, mechanics, and diseases that affect muscle contractility.