in test animation, there are several animations in the "held item" animation group that have nothing to do with held items 
said irrelevant animations:
air
head pitch
head yaw
health
hunger
light level
speaking

These do though, I believe air is when you are midair like jumping or something, head pitch is moving your head up and down, head yaw is left to right, hunger is player low on hunger, heath is the same, but health, light level is the player in a low light level I think, and speaking is actually for the simple voice chat mod or for Minecraft's builtin command only "voice" sound option.