What is released from the myosin head just before the power stroke?

Just before the power stroke, the myosin head releases adenosine diphosphate (ADP) and inorganic phosphate (Pi). This release occurs after the myosin head has bound to actin, and it triggers the conformational change that results in the power stroke, pulling the actin filament toward the center of the sarcomere. This process is essential for muscle contraction.