Cross-bridge Cycle

The cross-bridge cycle is a critical process in muscle contraction. It occurs when muscle fibers shorten to produce movement. It starts when the protein myosin heads, which are like tiny paddles, attach to another protein called actin. This attachment pulls the actin filaments closer together, causing the muscle to contract. After the pull, the myosin heads release from actin and reset to grab again. This cycle repeats numerous times, making muscles work efficiently. The energy for this process comes from a molecule called ATP, which powers the movement of the myosin heads.