Don't want to cause a bun fight. As I see the issue being discussed, the head can be unloaded (or at least partially unloaded) by two distinctly different stimuli:
control movements
external stimuli in the forms of turbulent air / down drafts / (up drafts?).
My question might warrant a two part answer, one for each way that the head got unloaded in the first place, though my initial question was about the turbulence kind.