Art Babbitt's camel from "Raggedy Ann" is held as a prime example of this device -although he did it (along with John Sibley) extensively on the Disney "Goofy" shorts, and other animators from Terrytoons' Jim Tyer to Ken Harris on Bugs Bunny employed it.
There's a notion that it gives that extra "something" to animation to make it snap.
In many instances, it actually mimics how film captures human motion.
This is a shot from a Cab Calloway documentary we're working on. Cab will be dancing with this dancer from Alvin Ailey.
We've picked just his arms moving, one at a time to focus on.
He begins to raise his right arm.
Look out. Not only is he moving faster than the lens/shutter can capture him -causing a blur, the angle of his arm in relation to the camera make his bend look impossible.
Arm lands at key position.
Now the right starts again.
And the hips follow once both arms go into motion.
Looseness in the right arm at the elbow and wrist. Not broken, just limber.