What happens during the contraction of skeletal muscle?

During the contraction of skeletal muscle, the process known as the sliding filament theory explains that the actin myofilaments indeed move towards each other while the lengths of both actin and myosin myofilaments remain unchanged. The myosin heads attach to binding sites on the actin filaments, which results in the actin sliding over the myosin, bringing the Z-discs closer together and causing the overall muscle fiber to shorten.

This movement allows for the force generation necessary for muscle contractions, such as those needed for locomotion and posture. Throughout this contraction, while the muscle shortens and creates tension, the individual myofilaments do not actually shorten themselves; they remain at a constant length. This is a key aspect of how muscles operate, differentiating muscle contraction from potential misunderstandings that may suggest that the myofilaments get shorter.