The action back

Fitted bodices can really limit your range of movement. Of course, that can be down to a fitting issue but not necessarily. Some styles are just inherently restrictive (just ask anyone in a tailored jacket to hold out his/her arms out to the side at a right angle to the body). Perfect, individualized fitting can make the most of any style but that is a difficult job (one I should try and tackle once I'm fairly certain my shoulders will stay the same shape for a while).
Styles which allow for a great range of movement are traditionally wider and more casual in look. I say traditionally because a lot of that job is done nowadays by elastane. 

The pattern adjustment I used for my dress and jumpsuit is intended for fabrics without stretch. In fact, it is kind of like the "action back" on some casual jackets (for men as well as for women) from the 1940's. The adjustment adds room for movement but confines it in the general, fitted shape of the design.
It is easy to make using a sloper or a tried-and-tested pattern for a fitted bodice with sleeves (as ever, my drawings are not to scale) 

Your pattern will need a waist seam to make this adjustment possible. If your sloper doesn't have a waist seam, just cut it at the waistline.

Draw a line for the back yoke. My sloper has fairly long shoulder darts so my line crosses the shoulder dart. The line should be between a third and half the height of the arm scye when measured from the top.

Trace the yoke pieces fit them together. Here you can see that my drawing isn't very good. There shouldn't be a big dent in the shoulder line (there will probably be a small one. If there is, just keep it).

Clean up the shape of the yoke. It will end up with a slightly curved bottom edge. 

Draw lines from the tops of the waist darts (or dart, if the pattern you are using has only one) to the bottom of the shoulder dart. If you had a shorter shoulder dart, draw the lines to the point on the yoke line under were it ends.

Cut the lines and close the darts. This will transfer all the width from the darts to that one point on the yoke.

Mark the edges of the pleat.

Add seam allowance to the pattern pieces if you like. Both pieces should be cut with center back on the fold. 
Fold the pleats closed before sewing the lower bodice to the yoke.
I usually cut the yoke piece twice. I use one as a lining and sew the yoke seam and shoulder seams so that all seam allowances will be encased between outside and lining.