Inside the sarcomere, the myosin filament and actin filament slide over eachother making the sarcomere shorter- at rest there is no cross bridge, actin and myosin are apart, ADP + Pi are bound to myosin- Pi is released and a cross bridge happens - cross bridge bends, pulling actin filament past myosin and ADP is released- ATP binds the myosin head and the cross bridge breaks so actin and myosin separate - in the myosin head, ATPase hydrolyses ATP to ADP + Pi so the head bends back to the start positionThe cycle repeats