Crossbridge cycling

Crossbridge cycling is the process that causes muscle contraction. When a muscle receives a signal, calcium ions are released inside the muscle cell, allowing the protein actin to bind to myosin, another protein with heads called crossbridges. The myosin heads then pivot, pulling the actin filaments closer together, generating a contraction. Afterward, the myosin heads release and reposition, ready to pull again if the signal persists. This cycle repeats rapidly, converting chemical energy from ATP into mechanical work, resulting in muscle shortening and movement.