Contraction of a sarcomere, and thus contraction of the muscle as a whole, is accomplished by a cyclic sequence of interactions between actin (thin filaments) and myosin (thick filaments) in the sarcomere. Understanding this sequence of events is essential to understanding the mechanism of muscle contractio n at the cellular and molecular levels. Begin by considering a relaxed muscle. In this state, the myosin molecules of the thick filaments are not in contact with the actin of the thin filaments, and ADP and Pi are bound to the myosin heads. An action potential on the muscle cell plasma membrane initiates contraction of the sarcomeres from this relaxed state.

The locomotion or simple movement inside the animal body occurs in a given sequence, as there are different organs and structures which contributes in building up the whole structure of that organism, as there are different muscles and bones inside the basic frame work of the animal body. Some if the muscles are striated while others are not making it more simple to know that the Sacromere are the specialized structures contain the very unique proteins named as the myosin and actin.
As, due to the fact that the two proteins act in a more collaborative form of way to enhance the capabilities of the organism to move across a distance or perform any specific function in a given manner, as to avoid the complexity of the process the Sliding filament theory is here to guide us and tell more about the two proteins being interlinked and operate on the basis of the different level of chemical imbalances inside the muscle cells. And the different form of proteins structures or molecules go right past one another to cover the required form of position for the muscles.