When moved from rest (35% VC), the lung-thorax unit exerts a force to return to rest.
The force used to return to rest generates recoil pressures
The recoil pressures are pressures within the lung and are a source of power for the speech system.
Recoil forces are proportional to the amount of distortion.
If we move far beyond the rest position, or say 55-60% VC (building up for yelling, perhaps) it would snap beyond rest (recoil to a smaller size) before it returns to rest.