The elastic forces of the reed push the blades to open again in order to return to the reed's rest position. The inertia of the movement exceeds the rest position by separating the sides of the reed blades.
With the reopening of the blades, airflow can pass through the reed and its speed creates a zone of low pressure between the two blades. These are sucked inward and begin to close. The elastic forces of the reed greatly slow the movement and the opening only narrows by a small amount.
The elastic forces are at their peak intensity and push the blades outward creating the maximum opening that can be adjusted during the whole cycle. This opening can be observed up to a third of the entire length of the blades. The deformation at the sides is evident and significant.