Video - Sliding filament model of muscle contraction

The sliding filament model of muscle contraction describes how muscles generate force and produce movement. Muscle contraction occurs as a result of the sliding of thin filaments (actin) over thick filaments (myosin) within muscle fibers.

The process of contraction starts when an action potential reaches the muscle fiber and triggers the release of calcium ions from the sarcoplasmic reticulum. The calcium ions bind to the protein troponin, which in turn causes a conformational change in tropomyosin, exposing the myosin binding sites on the actin filaments. Myosin heads then bind to the actin filaments and generate force. Attachment and detachment between actin and myosin occur several times during a single contraction.