Jerky as in some segments snap out of their place or motion arc. It especially shows here when he's about to make the uppercut. It's wise to always pay attention to the motion arcs to prevent this from happening.
actually I really like the combo animation. Yes it's pretty hard to make out what's actually going on because it's so fast but overall it's a fluid motion that has really good weight.
It's kinda hard to make out all the movements with them all bunched together with the effects, but it's okay overall. I suggest focusing on making the movements more distinct and clear and less on the effects