The aortic valve leaflets can exhibit normal, excessive, restrictive, or a oscillating motion.  Normal leaflet motion occurs when leaflets coaptation occurs at the aortic valve annular plane during diastole and each leaflet extends to become parallel with the the LVOT/Aorta plane during systole.  Excessive leaflet motion is best recognized during diastole when a leaflet moves below the aortic valve annular plane during diastole.   Restricted leaflet motion occurs when the leaflets cannot extend to become parallel to the aorta during systole. 

Leaflets may oscillate or appear to be "flapping" during systole.  Oscillating leaflets indicate leaflets that are caught in a turbulent jet from subaortic stenosis or high velocity ejection of blood.  Excessive leaflet motion is an indication of aortic regurgitation.  Restrictive leaflet motion implies decreased cardiac output, aortic valve sclerosis or aortic valve stenosis.  Aortic valve sclerosis is calcification of the aortic valve leaflets which may cause turbulence (and a murmur) but does not decrease the aortic valve area to the threshold of stenosis. Aortic valve sclerosis has been associated with an increased morbidity and mortality in the elderly.