For the pull ups I use slightly wider than shoulder and reverse/pronated (palms facing away) grip, I weigh 135 lbs. For shrugs I am standing holding dumbbells - 15 or 20 lbs. - at my side.
Are these opposing exercises? I mean, do they exercise opposing muscle groups?
My understanding is shrugs lift the should blades, while pull ups pull the arm down. So, not really opposite movements. However, I do pull my shoulder blades down and together as I perform the pull ups.
Maybe another way to state my question is what the ideal opposing exercises for pull ups and push ups? I do both of those, but they don't seem to have a perfectly match opposite like bicep/tricep. I have been doing push ups paired with reverse dumbbell flies and pull ups paired with shrugs.