This entire thin filament basically is pulled this way as our ADP and P basically detach from the myosin head and the myosin head is oriented once again at the 45 degree angle. So once it binds, once the myosin head binds onto the binding side, it must expel the ADP and the phosphate molecules in order to actually move the myosin head oriented at an angle of 45 degrees with respect to our thick filament. And that essentially pulls the thin filament as shown in this diagram. So this thin filament basically is pulled this way so that these two z lines are basically pulled inward. Now, this process of actually pulling on our thin filament by the movement of our mice and head is known as the power stroke. And the power stroke must take place when our phosphate is basically expelled from that myosin head.