kontraktionrelaxation
Kontraktionrelaxation refers to the fundamental physiological process by which muscles shorten and then lengthen. This cycle is essential for all forms of movement in living organisms, from the beating of the heart to the walking of a human. The process begins with a stimulus, typically an electrical signal from a nerve. This signal triggers a series of biochemical events within the muscle fibers. At a microscopic level, specialized proteins called actin and myosin interact. The myosin filaments slide over the actin filaments, causing the muscle fiber to shorten. This shortening is the contraction phase.
Following contraction, the muscle must return to its resting length. This is achieved through the relaxation