Thoracic Bridge and RC/PE1?

I was making good progress on RC/PE1 and I started the Thoracic Bridge Stretch Series a couple weeks ago.  About the same time I noticed my RC/PE1 was more difficult on the fourth and fifth sets.

 

Is this just a random coincidence or do the exercises in TB Stretch fatigue the RC muscles?  I realize one is pushing and the other is pulling, but I can't directly relate the perceived recent weakness in RC to anything else; hence the reason for my question.

Yes both tax the upper back muscles. Give your body a few weeks to adapt and you should be fine.

Cool, I suppose what is a break-in period will turn into a synergistic benefit that will help the RC/PE1.