Even a beginning animator will be asked to draw a person swinging a baseball bat, a tennis racket, a martial arts fighting stick, or a baton. So how might we go about this? And how do we get the next motion of the object from a still drawing? Well, let's take a look at what we need to do first.
The end of the action is where you want to start. Next, you'll want to back up the swing with sketches. The closer you get to the start of the action the more sketches or blurred sketches; always with greater distances (increasing) as the object gets closer to the first sketch or the end of the action. It makes sense to have lines between the points on the edges of the object from sketch to sketch.
In the case of drawing to people who are fencing with swords, there should be a sketch every time a person makes contact with the ground, even with their feet and every time the swords make contact with a person or each other. You can see how complicated this can get in a hurry.
If you are going to be an animator you are going to have to figure this out sooner or later, and even if you only specialize in the computer side of things, you have to be able to visualize this in your mind and therefore you need to be able to draw this, step-by-step. I hope you will please consider this, and I wish you well in your career as an animator.
“The Animator's Survival Kit; a Manual of Methods, Principles, and Formulas for Classical, Computer, Games, Stop Motion and Internet Animators” by Richard Williams (director of animation “Who Framed Roger Rabbit”), Published by Faber and Faber, New York; 2001. ISBN: 0-571-21268-9
“3D Graphics & Animation; from Starting Up to Standing Out,” by Mark Giambruno; New Riders Publishing; Indianapolis, IN; 1997. ISBN: 1-56205-698-0