Staggering is a technique that can be used in animation to make characters and objects appear to shake (for example shivering or shaking in fear) it can also be used to create oscillating movements or add a feeling of strain.
“The Animators survival Kit” by Richard Williams has a great section on staggered timings if you want to know more about the different ways this technique can be used.
A simple way to create a stagger is to first animate the movement in the normal way and then rearrange the frames afterwards. This is what I did in the example below, which is a section from the short animation I’m currently working on, In this case I used staggering to add strain. The video shows the original animation and then the staggered version so that you can see the difference. In the staggered version I rearranged the frames so they were ordered 1,2,3,2,3,4,3,4,5,4,5,6…etc.